Thèses sur le sujet « Environmetal remediation »

Photoactive semiconductors are a hot topic of research due to their applications in environmental remediation, photovoltaics, smart devices, light-activated synthesis and self-cleaning surfaces. Among them, oxide semiconductors play a main role thanks to their wide availability, stability, ease of preparation and tunable surface properties. In this context, my Ph.D. focused on the application of oxide semiconductors for three main purposes: pollutant remediation, photocatalytic synthesis of hybrid materials, and smart systems for the controlled release of active substances. Alongside this main research project, I developed two original hands-on activities based on oxide systems for public engagement. Oxide semiconductors for environmental remediation. Photocatalysis is an advanced oxidation process that can achieve the complete degradation of contaminants without the addition of reagents. However, its real-life application has been hindered by several limitations, such as the use of nanosized powder, costs of light irradiation, possible accumulation of toxic reaction intermediates and the sensitivity to complex water matrices. During my Ph.D., I investigated the deposition of photocatalyst powder on macroscopic devices based on aluminum plates for air purification. Aluminum is a cheap and technologically-relevant substrate, but its application as substrate for photocatalyst immobilization has been hampered by adhesion issues and metal ion diffusion within the photocatalytic layer that increases recombination of photogenerated carriers. Thus, I investigated the use of silica interlayers to promote adhesion, efficiency and reusability of TiO2 films on aluminum plates. Films were prepared from stable titania sols and deposited on aluminum substrates with different surface morphology and with silica interlayers of different thickness. The study of the coating structure, morphology, optical properties, adhesion and hardness showed that the nature of the substrate and its surface roughness determined the optimal number of silica interlayers. When the silica interlayer was too thin, moderate cracking was still observed, whereas a too thick silica interlayer led to peeling off of the film. The use of rougher surfaces, as in the case of sand-papered aluminum, required a higher number of silica layers to promote a more homogeneous surface where the titania coating could effectively adhere. However, the addition of a thicker silica layer did not erase the effect of the sand-paper pre-treatment on surface roughness. Films on sand-papered substrates showed promoted photocatalytic activity with respect to the smoother counterparts, possibly due to their larger exposed contact area. The prepared films exhibited excellent light-induced superhydrophilicity and self-cleaning properties towards fouling agents (alkylsilanes). Photocatalytic degradation tests were carried out using both a model volatile organic compound (ethanol) and NOx. The silica interlayer proved crucial to promote the film robustness, effectively increasing the mechanical stability and reusability when a thicker interlayer was adopted on sand-papered aluminum plates. In order to cut the costs associated with lamp irradiation, the visible-light promotion of large band gap photocatalysts is a widely investigated approach. In this regard, I studied the modification of TiO2 with Sn and N species aiming to improve the photocatalyst visible-light absorption for the solar-light photocatalityc degradation of emerging pollutants. Three different synthetic routes were investigated: a bulk synthesis, where Ti and Sn precursors were both added in the sol-gel synthesis, a seeded procedure, where pre-formed SnO2 crystals were added to TiO2 synthesis, and a mechanical mixture, where the oxides were mixed together then calcined. Marked differences were observed in the final composites’ structural, morphological and optical properties, leading to notable changes in the photocatalytic performance. Interestingly, bulk and seeded samples showed notable photochromic properties under UV light, which varied based on the doping level: this is the first time photochromic effects have been observed in Sn-promoted TiO2. These findings can be related to the different nature of the defects introduced in the oxide lattices depending on the synthetic route, which reflect in the photocatalytic performances of the modified semiconductors. The photocatalytic degradation of wastewater pollutants in complex matrices requires a close scrutiny of the generated byproducts to avoid possible accumulation of intermediates even more toxic than the parent compound. In this respect, I determined that the degradation of tetracycline, a widely used antibiotic, by a benchmark TiO2 sample, despite the fast pollutant disappearance, leads to poor mineralization and byproduct accumulation, especially in the presence of common electrolytes, such as HCO3-. Conversely, the use of commercial ZnO samples with the same surface area resulted in a faster tetracycline degradation kinetics and a much higher mineralization degree compared to TiO2 in all the investigated water matrices. These results can be attributed to different photo-degradation pathways followed by the two oxides, as shown by tests with radical scavengers and by-product analyses. While TiO2 degradation pathways are strongly dependent on both hydroxyl radicals and holes, ZnO mineralization activity is mostly related to holes, which limits the interference of •OH-scavenger species such as bicarbonates. Photo-induced synthesis of oxide-polyaniline composites for environmental remediation. To date, photocatalysis remains a comparatively slower and costlier wastewater treatment compared to adsorption. For this reason, during my Ph.D I also investigated new generation adsorbents characterized by easier regeneration and ability to perform a controlled release of the adsorbed species to be further treated or reused. To this aim, I investigated polyaniline (PANI) composites prepared via an innovative photocatalytically-induced synthesis. PANI materials have been recently adopted as sorbents for environmental remediation due to their stability, redox properties and acid-base characteristics. However, PANI traditional oxidative synthesis (here labeled as PANI-aniline) adopts noxious and toxic reagents (aniline and (NH4)2S2O8) and leads to carcinogenic by-products and large amounts of waste. The alternative photocatalytic approach I developed is a two-step synthesis starting from aniline dimer (N-(4-aminophenyl)aniline) and exploiting TiO2 photocatalyst to initiate the oligomerization, and a greener oxidant (H2O2) in the polymerization step. The resulting PANI-TiO2 nanocomposites showed very different structural, morphological and surface properties with respect to PANI-aniline, resulting in fast and efficient removal of water pollutants. To better understand the reaction pathway and tailor the material properties, the relative roles played by TiO2 and H2O2 in the synthetic procedure were investigated in depth. UV-irradiated TiO2 was found to promote PANI crystallinity and polymer-oxide interactions. The amount of added H2O2 has a crucial role on the composite properties by promoting either surface growth of PANI chains or polymerization in the liquid bulk. High H2O2 amounts seem to promote a homogenous polymer formation mechanism, leading to nanocomposites with high PANI content and thermal stability, but low crystallinity degree and surface area. Low H2O2 quantities give rise to highly porous, large surface area nanocomposites with good crystallinity but low PANI content. The latter samples exhibited the best performance in pollutant sorption tests, achieving a fast and complete removal of dyes and heavy metals also in the presence of electrolytes. These samples also showed reusability in consecutive stress tests and could be regenerated simply by treatment with alkaline aqueous solution at room temperature. The next step was to investigate the role of the nature and morphological features of the semiconductor: commercial TiO2 photocatalysts with either 50 m2g-1 (labeled TiO2-P25) and 12 m2g-1 (TiO2-Kronos) were compared with WO3 either lab-synthesized (3.5 m2g-1, named WO3-Synt) or commercial (6.1 m2g-1, WO3-Comm). The composites showed a nanorod / nano-wire morphology: the length of the polymeric rods and the embedding of the oxide particles within the polymer network strongly depended on the nature and morphology of the photocatalyst. Furthermore, while > 80% total dye removal capacity was observed for all samples (with the exception of PANI-WO3-Comm), notable differences were observed in terms of released tests. In particular, PANI-oxide composites consistently showed dye-release capacities far higher than PANI-aniline. The ease of desorption opened the door to the facile regeneration of the adsorbent and to the adsorbate recovery for its recycle in a circular economy perspective. Therefore, I investigated an adsorption-photocatalysis coupled system which exploited the reversibility of the pollutant removal process. In particular, after consecutive dye adsorption cycles, the contaminant was released by the PANI-oxide adsorbent and subsequently mineralized by a ZnO driven photocatalytic process. The nature of the adsorption process was deeply investigated and selectivity tests with cationic and anionic dye mixtures proved the preferential adsorption of PANI-oxide adsorbents towards anionic dyes. In the end, the promising and reversible adsorption capability of PANI composites prompted me to investigate their possible application in CO2 capture systems. Thus I have worked on reviewing the literature works on the topic, comparing the performances of different PANI materials towards CO2 removal. Smart systems based on light-responsive oxides. The intrinsic characteristics of semiconductor oxides, such as their photocatalytic and surface properties, can be exploited in the design of smart systems for the controlled release of unstable active substances, such as essential oils. Among them, cinnamaldehyde (CIN) is a low-cost natural compound endowed with antibacterial, anti-cancer, antifungal, and anti-inflammatory properties. However, CIN has poor water solubility, high volatility and very poor stability in environmental conditions, undergoing degradation when exposed to heat, light or even oxygen. These issues hinder CIN applicability, thus smart systems able to store this active substance and to safely release it at will, are of extreme interest for the scientific community. In this context, during my Ph.D. I developed oxide-based hybrid systems for the release of CIN catalyzed by acidic pH. The smart system was obtained by a grafting method based on amino-silane linkers and imine chemistry: (3-aminopropyl)triethoxysilane (APTES) was adopted for the functionalization of the oxide surface. The terminal amine group of the silane (-NH2) was used for a condensation reaction with the aldehydic group of CIN (-HC=O), yielding an imine bond (-HC=N-) between APTES and CIN and a loading of ca. 5 molecules/nm2, determined with CHN and TG analyses. The covalent grafting of cinnamaldehyde, showed by FTIR spectra, preserved the molecule stability, simplifying storage. Release tests were performed at pH values between 5.0 and 7.4: thanks to the pH-sensitivity of imine bonds, a fast CIN release was observed at pH 5.0. The grafting procedure was also performed on a porous semiconductor film, demonstrating the versatility of this method. Exploiting the oxide photoactivity, the fouled film was regenerated upon 1h UV irradiation, opening the door to reusable devices for CIN controlled release. Besides the conventional approach of loading bioactive compounds on solid drug carriers, smart systems based on particle-stabilized emulsions (i.e., Pickering emulsions) are receiving increasing attention from the scientific community. In this regard, during my last year of Ph.D. I investigated oil-in-water Pickering emulsions prepared with food-grade vegetable oils and stabilized with bare ZnO particles. FTIR studies highlighted that, during emulsification, ZnO particles undergo an in situ functionalization by fatty acids present in the vegetable oil. This procedure gives rise to very stable and homogeneous emulsions (mean droplet size ca. 1 μm). Confocal microscopy images demonstrated the high stability of the system towards long time storage (more than 9 months), temperature variations, mechanical stress and increased ionic strength. ZnO-Pickering emulsions were loaded with CIN in the oil phase, in order to store the active molecule and release it at will by the application of five different stimuli. In particular, thanks to the semiconductor and amphoteric properties of ZnO, the developed smart system was able to release CIN by switching to a water-in-oil Pickering emulsion when subjected to acidification, UV and solar light irradiation, CO2 bubbling and the addition of bi/trivalent cations. This is the first report of an emulsion system responsive to five different stimuli. Depending on the type of stimulus, either a burst release or a controlled release over the course of several hours could be achieved. The emulsion switching can be attributed to the oxide surface charge: when ZnO is negatively or slightly positively charged, the oil-in-water emulsion is stable, while, when the oxide surface has high positive charge, the oil droplets’ intrinsic negative charge is neutralized and coalescence phenomena occur. A more positive ZnO surface charge can be achieved through the addition of acidic species (such as H+ and H2CO3 via CO2 bubbling), multivalent cations, which give specific adsorption on ZnO surface, and through light irradiation, which activates the photocatalyst and generates acidic species. The starting oil-in-water emulsion could be reobtained by basification, N2 bubbling and storage in the dark. The ZnO Pickering emulsions were able to safely store and release CIN molecules, which did not undergo any degradation neither during storage, nor after release in water solution. In the end, I have contributed to a work on near infrared (NIR)-emitting GdVO4:Nd systems. This composite material proved promising for bioimaging applications, thus, I exploited my experience oxide synthesis to investigate the role of the synthetic procedure on the material properties and NIR-emitting activity. Moreover, test on GdVO4:Nd functionalization with silane molecules (octylsilane and APTES) were carried out. The modification of the material surface with organic compounds can led to a possible increase in the material biocompatibility, as well as to the possible grafting of active molecules, such as cinnamaldehyde, for application in theragnostic. Chemistry dissemination activities. During my PhD, I was involved in chemistry dissemination activities in the framework of the “Piano Lauree Scientifiche, PLS”. In this context, I helped to develop two laboratory activities for high school teachers and students. The first one, aimed at teaching the basic concepts of surface science, focused on the preparation of superhydrophobic coatings based on films of surface functionalized oxide particles. The film’s superhydrophobicity was tested for different applications (anti-stain, self-cleaning, liquid transportation) and compared with model hydrophobic, hydrophilic, and superhydrophilic surfaces. The second activity mimicked the chemistry of stained glass, introducing basic concepts of redox reactions, chemistry of color, and plasmonic nanoparticles. Stained glass colors were copied through the deposition, on glass slides, of silica coatings colored by metal ions and nanoparticles. A silica sol was used as matrix to embed metal ions, which were reduced in situ by thermal treatment on a hot plate. The formation of metal nanoparticles by this procedure induces plasmonic colors in the glass coating, thus “mimicking” the ancient procedure of stained-glass fabrication. These works led to two publications on the Journal of Chemical Education.

The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.

The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.

Esta tesis doctoral se ha centrado en la preparación de fotocatalizadores nanoestructurados basados en TiO2 modificados con metales de transición o carbón activado para su aplicación en reacciones de interés medioambiental, concretamente, en la eliminación de tres contaminantes: ácido acético y diurón, en fase acuosa, y propeno en fase gas. Se ha estudiado la influencia de las propiedades fisicoquímicas (porosidad, cristalinidad, composición química, propiedades electrónicas) de cada material en su actividad fotocatalítica.

Nella tesi l'inquinamento del suolo viene affrontato a diversi livelli, con l'obiettivo di prevenire, comprendere o risolvere specifici eventi di contaminazione. Lo studio si è concentrato su due classi principali di xenobiotici: elementi potenzialmente tossici e pesticidi. Sono stati discussi sette progetti di ricerca per indagare tre questioni principali: i) Applicazione di tecniche di biorisanamento contro la contaminazione da Ni in una cava in disuso (Capitoli 1 e 2), ii) Cinetica ed ecotossicità dei pesticidi in diversi substrati (Capitoli 3, 4 e 5), iii) Monitoraggio ed ecotossicità del rame in suoli di vigneti (Capitoli 6 e 7). Nel primo caso (i), la novità sta nell'applicare tecniche ecosostenibili per risolvere un reale caso di inquinamento; i principali risultati mostrano che minerali come bentonite e zeolite ed il fitorisanamento immobilizzano il metallo, contenendo così la deriva. Per quanto riguarda i pesticidi (ii), dopo una review riguardo l'impatto di dosi sub-letali di agrofarmaci sul biota del suolo agricolo, sono stati condotti due studi per valutare l'adsorbimento e la degradazione di tre pesticidi e gli effetti ecotossicologici di due insetticidi, uno naturale e uno sintetico, sui lombrichi e sui microorganismi del suolo. Lo studio suggerisce dinamiche diverse a seconda dei formulati e del substrato e può contribuire alla gestione sostenibile delle sostanze chimiche nell'ambiente: l'apporto al suolo di rifiuti organici economici riduce l'impatto dei pesticidi nell'ecosistema. I lombrichi aiutano la degradazione del bioinsetticida e la comunità microbica può adattarsi e cambiare in funzione del tempo e in base alla presenza di Eisenia fetida. Gli effetti del chlorpyrifos sui lombrichi si manifestano precocemente a livello genotossico e sulla loro crescita e a lungo termine, anche sull'attività riproduttiva. Infine, il tema del rame (iii) è stato affrontato inizialmente, monitorando due vigneti a conduzione biologica. Quindi sono stati condotti test ecotossicologici sui lombrichi. I danni precoci al loro DNA sono stati valutati con dosi sub-letali su suolo naturale. Il progetto sperimentale originale è stato ri-proposto per rilevare i cambiamenti della comunità batterica nel suolo e nell'intestino del lombrico. Inoltre, sono stati condotti test di riproduzione e di evitamento. I risultati hanno mostrato un'elevata capacità dei lombrichi di evitare il suolo contaminato dal rame già a basse concentrazioni e hanno mostrato effetti negativi dose-dipendenti sugli output riproduttivi. Nonostante ciò, questi anellidi sembrano recuperare il danno genotossico a concentrazioni intermedie di rame nel suolo, non bioaccumulano il metallo e riportano danni irreversibili oltre una certa soglia. Ad oggi sono in corso le analisi delle modifiche al microbioma intestinale del lombrico e del suolo.
In the thesis, soil pollution is addressed at different levels to prevent, understand, or resolve specific contamination events. The study focused on two main classes of xenobiotics: potentially toxic elements and pesticides. Seven research projects were discussed to investigate three main issues: i) Application of bioremediation techniques against Ni contamination in a disused quarry (Chapters 1 and 2), ii) Kinetics and ecotoxicity of pesticides in different substrates (Chapters 3, 4 and 5), iii) Monitoring and ecotoxicity of copper in vineyard soils (Chapters 6 and 7). In the first case (i), the novelty lies in applying eco-sustainable techniques to solve a real pollution case; the main results show that minerals such as bentonite and zeolite and phytoremediation immobilize the metal, thus containing the drift. Regarding pesticides (ii), after reviewing the impact of sub-lethal doses of pesticides on agricultural soil biota, two studies were conducted to evaluate the adsorption and degradation of three pesticides and the ecotoxicological effects of two insecticides, natural and one synthetic, on earthworms and soil microorganisms. The study suggests different dynamics depending on the formulations and the substrate and can contribute to the sustainable management of chemicals in the environment: the supply of cheap organic waste to the soil reduces the impact of pesticides on the ecosystem. Earthworms aid in the degradation of the bioinsecticide, and the microbial community can adapt and change over time and based on the presence of Eisenia fetida. The effects of chlorpyrifos on earthworms manifest early at the genotoxic level and on their growth. In the long term, it affects reproductive activity. Finally, the issue of copper (iii) was initially addressed by monitoring two organically run vineyards. Then ecotoxicological tests were conducted on earthworms. Early damage to their DNA was evaluated with sub-lethal doses on natural soil. The original experimental design was re-proposed to detect bacterial community changes in earthworm soil and gut. In addition, breeding and avoidance tests were conducted. The results showed a high ability of earthworms to avoid copper-contaminated soil already at low concentrations and showed dose-dependent adverse effects on reproductive outputs. Despite this, these annelids seem to recover the genotoxic damage at intermediate concentrations of copper in the soil, do not bioaccumulate the metal and report irreversible damage beyond a certain threshold. To date, analyses of changes in the intestinal microbiome of the earthworm and soil are underway.

Thesis (M.S. in Management)--Naval Postgraduate School, June 2000.
Thesis advisor(s), Lamm, David V. ; Smith, David A. "June 2000." Includes bibliographical references (p. 165-168). Also available online.

Membrane process including microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) have provided numerous successful applications ranging from drinking water purification, wastewater treatment, to material recovery. The addition of functional moiety in the membranes pores allows such membranes to be used in challenging areas including tunable separations, toxic metal capture, and catalysis. In this work, polyvinylidene fluoride (PVDF) MF membrane was functionalized with temperature responsive (poly(N-isopropylacrylamide), PNIPAAm) and pH responsive (polyacrylic acid, PAA) polymers. It’s revealed that the permeation of various molecules (water, salt and dextran) through the membrane can be thermally or pH controlled. The introduction of PAA as a polyelectrolyte offers an excellent platform for the immobilization of metal nanoparticles (NPs) applied for degradation of toxic chlorinated organics with significantly increased longevity and stability. The advantage of using temperature and pH responsive polymers/hydrogels also includes the high reactivity and effectiveness in dechlorination. Further advancement on the PVDF functionalization involved the alkaline treatment to create partially defluorinated membrane (Def-PVDF) with conjugated double bounds allowing for the covalent attachment of different polymers. The PAA-Def-PVDF membrane shows pH responsive behavior on both the hydraulic permeability and solute retention. The sponge-like PVDF (SPVDF) membranes by phase inversion were developed through casting PVDF solution on polyester backing. The SPVDF membrane was demonstrated to have 4 times more surface area than commercial PVDF MF membrane, allowing for enhanced nanoparticles loading for chloro-organics degradation. The advanced functionalization method and process were also validated to be able to be scaled-up through the evaluation of full-scale functionalized membrane provided by Ultura Inc. California, USA. Nanofiltration (NF) between UF and RO presents selectivity controlled by both steric and electrostatic repulsions, which are widely used to reject charged species, particularly multivalent ions. In this work, selective permeation of CaCl2 and high sucrose retention are obtained through the modification of nanofiltration membranes with lower charge compared to commercial nanofiltration membrane. The membrane module also shows high stability with constant water permeability in a long-term (two months) test. Extended Nernst-Planck equation were further used to evaluate the experimental results and it fits well.

Exide Technologies finally closed its secondary lead-battery recycling plant on March 12, 2015. The community of primarily Hispanics around the facility had to fight many years to have the polluting facility shut down. Because government agencies, whose job is to protect citizens from polluters, were not regulating the facility properly, residents are not sure if they can trust the agencies to carry out remediation effectively and efficiently either. In this paper I explore the environmental justice issues associated with environmental remediation and what community members can do to make sure that their neighborhood is cleaned up properly. Through interviews with government agencies and environmental activists heavily involved in this case, I discovered that the main environmental justice issue in remediation is increased exposure to toxins. I argue that strong community activism and involvement are necessary for remediation to happen properly, and explore some tools that can be used in this process.

The basis of prosperity of 20th centrury is oil. As oil is going to be used up, people need to find alternatives to meet the earth’s energy demand in 21st centrury. For each second, there are about 1.2×1017 J energy hitting the earth. The energy in 1 hour of sunlight is about 4.32×1020 J, which almost meets the energy consumed on earth in 2016. It determines solar energy may be a potential candidate to solve the energy crisis. As for techniques to utilize solar energy, the most popular one is using photovoltaic (PV) cells. PV cell is a device to convert solar energy into electricity. There are also some other techniques trying to utilize solar energy. Photocatalysis is one of them, which is to convert solar energy into chemical energy. Applications of photocatalysis have extended from hydrogen evolution via water splitting to environemtnal remediation, CO2/ N2 reduction and so on. Photocatalysis, as an advanced oxidation process, has been extensively studied and applied to the purification and remediation of contaminated water and wastewater, and exhibits advantages over conventional treatment technologies. When considering solar energy as an energy source for photocatalysis, it is key to prepare visible light-responsive materials. Bismuth-based semiconductors are promising materials as visible light-responsive photocatalysts primarily due to their suitable band gaps, well-dispersed valence bands, and commercial availabilities at reasonable costs, as well as the possibility of preparing them under mild conditions. Recent work focusing on the preparation, characterization and activity testing of bismuth-based photo-active materials as well as their associated photoreactor designs are introduced herein. In order to enhance the photocatalytic activities of the new materials, different precursors, additives, preparation procedures and process parameters, as well as surface treatments were explored to obtain binary and ternary heterostructures, with different doping, surface modification, nanoparticle sizes and morphologies. It was found that formation of heterojunction and loading metal nanoparticle on the surface are very effective to imrove the photocatalytic activity of the support. In this work, we found that palladium nanoparticles modified BiVO4 exhibited excellent activity in the decomposition of phenol, which was even higher than TiO2. To facilitate the separation process of catalysis particels from a slurry system, magnetically separable composites were also prepared, and it was found that it is very effective to remove the particles from the slurry system using external magnets. To further scale up this process, two different types of immbolized photoreactors (flat-plate and packed beads photoreactor) were also developed. Suggestions were made for further work in this research area.

A range of tools have been proposed to support decision making in contaminated land remediation (collectively referred to as Decision Support Tools or DSTs). From a European perspective it is clear, however, that there are considerable national differences in the decision support process, and more generally in the extent to which this process supports the se lection of less invasive, alternative and potentially more sustainable remediation options such as phytoremediation, in situ immobilisation etc. (referred to here as "gentle" remediation technologies or options). This thesis critically reviews available DSTs in terms of their fitness for purpose for the application of "gentle" remediation technologies, using published literature and data from two stakeholder surveys: the first from a European perspective (completed in the European Union ERANET SNOWMAN project SUMATECS (Sustainable Management of Trace Element Contaminated Sites)) (sample size of 130) and the second focused on contaminated land consultants and managers in the UK (sample size of 71). In general stakeholder feedback from both surveys indicates a lack of knowledge of currently available DSTs and the requirement for a simple OST using a tiered approach that can be integrated into an existing national framework. Based on this stakeholder feedback, a novel OST has been developed that will interface with an existing national framework and which will act as a guide to selection of "gentle" remediation approaches. This DST is a literature based tool that will direct users to collated information on successful practical pilot/field scale studies on " gentle remediation approaches and ensures that the elements or sustainability are considered during selection. The proposed approach is validated against data from three large-scale remediation projects, involving both gentle and more invasive remediation methods, in the UK, France and Belgium.

According to Environment Canada, across the country there are currently over 1400 abandoned gas station sites that are contaminated. Unbeknownst to local residents, many of these sites are undergoing remediation. Temporary interventions called remedial landscapes can be designed by landscape architects to communicate to the public the remediation activities, which are otherwise hidden from view. Environmental psychologists note that pro-environmental behaviour stems from increased awareness of environmental degradation. Furthermore, by presenting first hand information in the form of a landscape, people can make their own decisions concerning their role in unsustainable practices. This thesis posits that by experiencing remedial landscapes, people will change their environmental attitudes and or behaviours. Remedial landscapes also offer opportunities for public art and further exploration of alternative forms of remediation. It includes not only precedent studies of other remedial landscapes, but a public perception survey concerning a gas station undergoing remediation in Kerrisdale, Vancouver. The survey indicated that the remediation of contaminated sites is a community concern and that the remediation should be made more visible. Participants also agreed that the use of a designed landscape would be a viable tool for communicating the status of the site. This research informed a set of design guidelines for the Kerrisdale ‘test site.’ A remedial landscape has been designed using these guidelines and is included as part of the thesis.

The two objectives of this work were to develop a simplified method for the analysis of chlorinated organics in water samples and to improve an existing soil remediation technology. The contaminants considered for these studies were chlorinated hydrocarbons because of their relative frequency of appearance at contaminated sites. The first half of this study involved the analysis of chlorinated ethenes by gas chromatography with flame ionization detection (GC-FID). I tested the hypothesis that the FID response factor is the same for all chlorinated ethene compounds. The rationale for this investigation is that if the hypothesis is correct, a single calibration curve can be used for GC/FID analysis of all chlorinated ethene compounds, saving time and money during sample analysis. Based on my measurements, a single calibration curve fits PCE, TCE, and cis-DCE (R2=0.998). However, the apparent slope of the calibration curve for vinyl chloride is approximately 45% lower, indicating that a separate calibration curve must be used to quantify vinyl chloride. I believe this difference in vinyl chloride is due to loss of analyte mass due to volatilization. The second half of the study considered the effect of solvent composition for a soil remediation technology, entitled remedial extraction and catalytic hydrodehalogenation (REACH), developed by Dr. Hun Young Wee and Dr. Jeff Cunningham (Wee and Cunningham, 2008). The objective of this thesis is to convert 1,2,4,5-tetrachlorobenzene (TeCB) to cyclohexane, thus improving on the work of Wee (2007). Recent work by Osborn (2011) tested successfully the use of palladium and rhodium catalysts for this conversion, though it took twelve hours for full conversion. Osborn (2011) performed her experiments in a 50:50 water-ethanol solvent; previous work by Wee and Cunningham (2008) suggests that using a 67:33 water-ethanol composition may dramatically reduce the reaction time. Therefore, the goal of this research was to use palladium and rhodium catalysts with a 67:33 water-ethanol solvent composition, with an aim of reducing the reaction time required to fully convert benzene to cyclohexane. The data suggest that the time required for conversion of the analyte to its product was improved dramatically compared to previous experiments. However, powdered palladium catalyst was used in this study instead of pellet form as in previous studies. The powdered palladium allowed for full conversion of the target chemical, TeCB, to benzene in less than 5 minutes. Benzene was fully converted to cyclohexane within 45 minutes in the batch reactor when a rhodium catalyst was used jointly with palladium. This study suggests that the 67:33 water-ethanol solvent composition be utilized in continuous flow tests in the future to improve the efficiency of the REACH system. The results also suggest that powdered palladium catalyst be considered because of its ability to force the reaction to completion in significantly less time than previous experiments.

This dissertation presents an innovative methodology in the form of two papers for the feasibility assessment and optimization of Vacuum Enhanced Recovery (VER) to remediate non aqueous phase liquids (NAPLs) in the vadose zone. The first paper demonstrates the use of a pilot-scale two-dimensional laboratory soil cell and an automated dual-energy gamma ray attenuation system for the feasibility assessment of VER to remediate free-product NAPL spills. The investigations were conducted in a 1.5 x 1 x 0.08 meter cell filled with heterogeneous soils for the simultaneous and continuous measurement of NAPL and water saturations at 96 programmed locations. The dynamic laboratory method determines the spatial distributions of three-phase fluid saturations of an oil spill simulation from the surface as it migrates through the vadose zone during the sequential stages of infiltration, redistribution and VER. Contour plots of observed NAPL and water saturations identify the distribution of NAPL as entrapped liquid in heterogeneous soils unavailable for free-product recovery by VER. The accuracy of the methodology used for the measurement of NAPL retention in soil was illustrated by a NAPL retention measurement precision analysis. A mean difference of 0.97% was achieved by comparing gamma system measured NAPL retention volumes in the soil with that derived by the VER system. The second paper utilizes the pilot-scale laboratory results for a comparative analysis with model simulations to calibrate a three-phase model and optimize the design of VER systems for free-product NAPL remediation in heterogeneous soils.

This thesis aims to investigate the production of electrochemically activated solution via electrolysis of diluted NaCI solution using a commercial electrochemical system (STEL device), characterise the activated solution, and evaluate the potential application of this solution in the treatment of water containing organic compounds. The research shows that the electrolytic cell in the STEL device consists of a titanium based metal oxide (Ir02, Sn02, and Ti02) coated anode, a tubular titanium cathode, and a tubular ceramic diaphragm that separates the anode and cathode. A model electrolytic cell using STEL anode material was designed and constructed for investigating reaction mechanisms occurring at the electrode and identifying the oxidising species generated at the anode during the electrolysis of NaCI solution. Experimental results show that chlorine and oxygen were two main oxidants contained in the anolyte, indicating that the generation of chlorine and oxygen are involved in the electrode reactions. The evolutions of chlorine and oxygen were found to be achieved via the formation of a series of adsorbed intermediates such as OHad, Oad on the anode surface during electrolysis. Evidences for the occurrence of the intermediates were obtained by several electrochemical observations. It is suggested that the evolution reaction of chlorine involves a mechanism in which an intermediate of OClad is formed instead of Clad. The adsorbed intermediates may also be released from the anode surface to form chlorine free radicals and hydroxyl radicals when the electrolysis is carried out at higher potentials. This was investigated using the electro-oxidation of salicylic acid (SA). It was found that in a buffer solution containing chloride ions, the oxidation processes of SA were dependent on the potential applied on the anode. At + l.5V, the reaction product was 2,4,6-trichlorophenol, indicating that chlorine free radicals were generated. At +2.5V, the obtained products included 2,5-dichloro-l,4-benzoquinone, indicating that a hydroxyl group is introduced to the benzene ring of SA. These results suggest chlorine free radicals were generated at + l.5 V while hydroxyl radicals were generated at +2.5V. The operating conditions of the STEL device were optimised with respect to the redox potential, pH, and chlorine concentration of the generated ECAS. Anolyte produced from the STEL system, using a 100/0 NaCI solution under optimised electrolysis conditions, is an acidic solution (PH 2.2) containing a mixture of oxidants with a redox potential of 1190 m V and an available free chlorine concentration of 280 mgIL. The catholyte solution is a reductive basic solution with a pH of 12.6 and a redox potential of -950m V. The anolyte solution can maintain the oxidation ability up to 6 days when it is stored in an air tight container. However, it will lose its oxidation ability in 30 min if is purged by nitrogen or in 60 min if is stirred in the atmosphere. The anolyte solution can degrade trace amounts of aromatic compounds in aqueous solution. The degradation products are dependent on the concentration and chemical nature of the reagents. Usually, 10-4M SA can be converted to ring opened compounds, while 10·3M SA can only be converted to quinonic compounds. A subsequent dechlorination step is required when using anolyte for treating aqueous solution containing organic compounds as the by products include chlorinated compounds.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-110).
While often seen as utilitarian and technical, environmental remediation efforts have significant cultural, social and physical impacts. Accordingly, they demand responses that utilize a multi-disciplinary approach to the cleanup. The twelve case studies explored in this thesis represent examples of artists taking on leadership roles in environmental remediation projects as part of their artistic practice. The cases represent a unique type of public practice operating at the margins of aesthetics, science and public engagement. An examination of the details of these cases and their categorization along broad themes reveals lessons on where such an approach can be most effective and how, through interdisciplinary efforts, the practice of artists, planners, engineers and designers can be expanded to address the complex layers of environmental remediation. I conclude with seven factors that must be considered if such a model is to gain traction, including, but not limited to: the capacity for leveraging diverse funding sources, the need to acknowledge the professional uniqueness of artists, and the importance of public sector support. These factors point to a set of policy suggestions to help promote areas and approaches for successful interdisciplinary environmental remediation projects in the future. The case studies are organized under four categories. 'Artist-led remediation" cases include Spoils Pile Reclamation Park (Helen and Newton Harrison, 1976-1978), Twin Stupas (Angelo Ciotti, 1987-1996), Wheatfield- A Confrontation (Agnes Denes, 1982), Veden Taika (The Magic of Water) (Jackie Brookner, 2006-2009). "Post-facto artist engagement" cases include Byxbee Park (Peter Richards, Michael Oppenheimer, George Hargreaves, 1988-1992), North Waterfront Park Master Plan (Richard Haag, John Roberts, Agnes Denes, 1989-91), and Wingfield Pines (Allegheny Land Trust, Angelo Ciotti, 2001-2010). Cases where there is an "artist as activator" are New Haven Long Wharf Master Plan (Michael Singer, 1988-1990), Nine Mile Run Watershed Project (STUDIO for Creative Inquiry, 1997-2000), and Fundred/Operation Paydirt (Mel Chin, 2005-present). Lastly, the two "integrated models" explored are Vintondale AMD&ART Park (AMD&ART, 1994-2005) and West Palm Beach Waterfront (Michael Singer Studio, 2005- 2010).
by Jessica Fain.
M.C.P.

Thesis: S.M., Massachusetts Institute of Technology, Department of Biological Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 43-47).
Artificially photosynthetic systems aim to store solar energy and chemically reduce carbon dioxide. These systems have been developed in order to use light to drive processes for carbon fixation into biomass and/or liquid fuels. We have developed a hybrid-biological system that manages both genetically controlled generation of products along with the photoactivability of a semiconductor system. We show an increase in the production of ethanol, a common biofuel, through the electron transfer stimulated by biologically produced cadmium sulfide nanoparticles and light. This work provides a basis on which to improve the production of many metabolites and products through endogenously produced nanoparticles.
by Shalmalee Pandit.
S.M.
S.M. Massachusetts Institute of Technology, Department of Biological Engineering

A dense nonaqueous phase liquid, o-dichlorobenzene (o-DCB) was removed by surfactant-enhanced electrokinetic remediation from saturated bentonite clay. The surfactant was Antarox BL-236, a nonionic surfactant with a solubilization capacity of 0.052 g DCB/g surfactant. The 9 cm long bed, which initially contained 10 wt % bentonite and a dispersion of o-DCB (2910 or 5821 ppm) in water, was placed in a horizontal cylinder (5 cm ID) and held at each end by a supported filter paper. Carbon disk electrodes were located in compartments at each end of the bed. Surfactant solution or distilled water was fed to the anode compartment and effluent was withdrawn from the cathode compartment to maintain liquid levels. A constant direct current of 1.53 mA/cm2 of bed cross sectional area was applied. The current generated hydrogen ions at the anode, hydroxyl ions at the cathode, and an electroosmotic flow from the anode to the cathode. Stainless steel pin electrodes placed in the bed and pH electrodes inserted into the bed and the electrode compartments gave continuous measurements of voltage differences and pH changes. Experimental runs were 48 to 96 hours in duration.
To prevent cracking of the bed, which increased the energy requirements, the cathode compartment was flushed continuously with 0.01 M HNO3, a procedure called cathode rinse. An anode feed of 10 wt % surfactant solution removed six times more DCB in 4 days than distilled water. About 20% of the solubilization capacity of the surfactant was utilized at 2910 ppm initial DCB, increasing to 34% for 5820 ppm. DCB was detected in the effluent after about 1.5 pore volumes of liquid passed through the bed; thereafter the rate of DCB removal was approximately constant. The effects of surfactant concentration and NAPL concentration on DCB removal and the energy expenditure were determined.

Experiments were carried out to study the effects of jet velocity and the jet insertion depth on the characteristics of the fluidized region obtained when vertical and inclined water jets were submerged below the surface of saturated sand. Experiments were conducted using sand of mean particle size 507 mum. Water was injected into the sand through a tube of semicircular cross-section (internal diameter 0.55 cm) located at the wall of the tank, forming a half jet. At sufficiently high flowrate a U-shaped fluidized region formed around the jet tube. The fluidized zone was characterized by measuring scour depth, diameter of the fluidized region at the jet insertion depth and diameter of the fluidized region at half the jet insertion depth. For a fixed jet insertion depth, increasing the jet velocity increased the scour depth, the diameter of the fluidized region at the jet insertion depth, and the diameter at half the jet insertion depth. For a fixed jet velocity, the scour depth was independent of the insertion depth, however the two diameters of the fluidized region decreased with increasing jet insertion depth. The profiles obtained for inclined jets were more asymmetric than those for vertical jets.
The effectiveness of the 'up-flow washing' technique for the removal of a water-soluble contaminant (CuSO4) from a saturated bed of sand was investigated for a vertical jet at jet velocities of 213 cm/s and 320 cm/s and jet insertion depths of 5.5 cm and 7.5 cm. Up-flow washing removed the contaminant from the sand bed. The cleaned region extended well beyond the boundary of the fluidized region as jet liquid leaked from the fluidized region and percolated through the fixed bed region. An approximate model for the leakage suggested that 10--20% of the jet liquid leaked from the fluidized region to the fixed bed region.

This practice-based research study examines two questions in an effort to determine how the photographer can play a role in the promulgation of environmental activism. Firstly, I ask if certain aesthetic approaches to the documentation of industrial pollution can be regarded as antithetical to the values of environmentalism; in particular, I examine the use of the sublime and the role that beauty plays in documenting scenes of environmental despoliation. In response to this question, I describe the problems associated with establishing a counter-aesthetic position in my artistic practice, which is commensurate with environmental ethics. Secondly, I ask how photography can be used as a means of conducting environmental protest by working in solidarity with environmental scientists and activists, in the struggle for environmental remediation. In a bid to answer this question, I argue that the production and dissemination of the photobook is one method of realising the dissensual capacity of art to bring about the conditions necessary for remediation to occur. Importantly, my practice proceeds through an understanding of debates ongoing in contemporary theory. In particular, I argue that Jacques Rancière s conceptions of dissensus (Rancière, 2010: 173) and the politics of aesthetics (Rancière, 2004: 25) can be interpreted as a means of understanding how aesthetics can be used to enact a form of political praxis. Using Rancière and Murray Bookchin s concept of social ecology as a basis for my artistic practice, I claim that photography can not only make the existent reality of pollution visible, it can also initiate a form of participatory democratic subjectivity, allowing the demands of the artist to become visible too. Moreover, in the design and dissemination of the three photobooks I have created, I make a case for a collaborative model of artistic practice, which extends beyond the medium specificity of photograph, and embraces multimodality and trans-disciplinarity, as a means of situating the photograph into a broader discursive field.

Several mitigation procedures have been proposed to limit the transfer of Hg and MeHg to aquatic organisms but most cannot be applied to large reservoirs such as those of northern Quebec for practical, economical, and environmental reasons. A better understanding of the diagenetic behaviour of Hg and methylmercury in aquatic environments has lead us to consider methods of enhancing natural processes which would either limit the mobility of Hg in flooded soils or its methylation. Different concentrations of iron oxide, iron shavings and ferrous ammonium sulphate were added to soil slurries in the presence or absence of calcite and gypsum. Mercury released to the supenatent solutions and methylmercury adsorbed to the slurry solids were monitored with time to determine the trapping efficiency of the different chemical additives under both reducing and oxygenated conditions. Whereas all three reagents limited the release of Hg(2+) to the supernatent solution when reducing conditions were allowed to develop in the slurries, ferrous ammonium sulphate appeared to be the most effective at limiting Hg methylation. (Abstract shortened by UMI.)

This thesis reports the investigation of Bismuth oxybromide (BiOBr) semiconductor material as an efficient photocatalyst for the sunlight harvesting as well as environmental cleanup. I have utilised different synthetic methodologies to obtain BiOBr and its derivatives, such as co-precipitation, ultrasonification, and photo-deposition; and have studied their structural and optical properties by X-ray diffraction and surface analysis techniques. I report the synthesis and characterisation of two new p-n heterojunction systems, AgBr-BiOBr and BiOBr-ZnFe₂O₄, and have performed initial studies on photocatalytic reaction and their catalytic decomposition mechanisms. I have also reported the surface modification method including the deposition of noble metal on BiOBr to investigate the role played by the noble metal and the interactions between semiconductor and metal using various characterisation measurements. Furthermore, a continuous series of BiOBr-BiOI solid solutions were synthesised, characterised and the photocatalytic degradation was performed on the as-obtained semiconductors, to study the band structure properties of the solid solutions.

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
In the present time it has been growing a conscience about environmental problems. In this project it is intended to perform a Cost Benefit Analysis (CBA) of a specific environmental problem: Uranium mining exploration. The selected project was the Environmental Remediation of Cunha Baixa’s Mining Area. From this CBA it will be possible to understand the economic reliability of this sort of project using one criteria of efficiency. The CBA performed show a wide variety of interpretations given the assumptions made, becoming clear the great impact that Human decisions can have.

This chapter reports the outline of the results presented in the next chapters. CHAPTER 2 deals with the isolation and the characterization of new SAC-producing strains. From a site, chronically contaminated by diesel fuel, three bacterial strains (M22, BS25 and BS29) belonging to the Gordonia genus were isolated. Results showed that those Gordonia strains were able to grow using a wide range of straight and branched aliphatic hydrocarbons as carbon and energy source and to produce at least two classes of surface-active compounds. Emulsifying agent(s) was released in the culture medium when bacteria grew both on hydrocarbons and water-soluble substrates. Cell-bound biosurfactant(s), that reduce the surface tension, was produced on hydrocarbons; however, its production was significantly lower on water soluble substrates. Solvent extraction and Thin Layer Chromatography analyses allowed us to classify the cell-bound biosurfactants as glycolipids and to confirm that the chemical nature of the extracellular bioemulsans is different. The relation among growth phase, surface-active compound production and cell-surface properties was analysed in kinetic experiments on hydrocarbons. Gordonia sp. BS29 synthesised, and released extracellularly, bioemulsan(s) during the exponential phase with n-hexadecane as carbon and energy source. The production of biosurfactant(s) started in the exponential phase and its concentration increased during the following linear growth. Furthermore, the adhesion of bacterial cells to hydrocarbons decreased during growth. Our results let to hypothesize a change in the mode by which Gordonia cells access the substrate during growth on hydrocarbons. The results reported in CHAPTER 3 deals with the evaluation of the application potentialities of the isolates and the biosynthesised SACs in environmental restoration technologies. Microbial amphiphiles and their producing strains can be use both as enhancers of biodegradation rate in bioremediation technologies of hydrocarbon contaminated soil and chemico-physical technologies of soil washing. The applicability of our strains and SACs were evaluated for the following applications: bioremediation of (i) aliphatic and (ii) aromatic hydrocarbon contaminated soil and (iii) washing of soil contaminated by crude oil. Microcosm bioremediation experiments were carried out and the effect of BS29 and M22 bioaugmentation and the bioemulsans on biodegradation rate and extent were evaluated also in comparison to the effect of the rhamnolipids, biosurfactants known for their capacities of enhancing bioremediation. Over time, the humidity was kept constant (25%) and the analyses of residual hydrocarbons, total microorganisms and hydrocarbon-degrading microorganisms were carried out. Hydrocarbon biodegradation data were analysed by Analysis of Variance (ANOVA) to compare the tested conditions with the control without any addition. The dependent variables for the comparison were the biodegradation rate and the residual concentration of each contaminant at the end of the experiments. The bioremediation results showed that the bioemulsan is able to effectively reduce final concentration of recalcitrant branched hydrocarbons even not at the same extent of rhamnolipids. Batch soil washing experiments were carried and we compared the effect of the BS29 bioemulsans with the ones of the sole water and a mixture of rhamnolipids (biosurfactant already experimented and used in soil washing techniques) on the removal of the pollutants from soil. Experimental Design Techniques were utilised for an efficient experiment planning and to evaluate the effect of the operational parameters on pollutants removal. The investigated factors were (i) the time of washing and (ii) the ratio between the volume of washing solution and the weight of soil. The use of a crude solution of the BS29 bioemulsans in different conditions resulted in a mean of crude oil removal of 43.1%, while the mean removal in rhamnolipid experiments was 50.8%. ANOVA test showed that both of them are significantly different (α=0.05) from the mean of sole water removal (19.5%). Furthermore, in bioemulsan experiments, a significant effect of time of washing was observed with a positive correlation with the extent of the oil removal. On the contrary, in the tested experimental conditions, neither the solution:soil ratio nor the time of washing significantly affects the removal in rhamnolipids experiments. The results obtained from the optimisation procedure for the maximisation of biosurfactant concentration in cultural broth are reported in CHAPTER 4. The optimisation process involved three consecutive steps. In the first step a two level 2(8-2) Fractional Factorial Design (FFD) was used to identify cultural factors that have a significant influence on biosurfactant(s) biosynthesis. Concentrations of inorganic phosphorous and sodium chloride were found as most important factors affecting yield of biosurfactant biosynthesis Then, on the selected factors, a steepest ascent procedure and a Central Composite Design (CCD) were applied to obtain a second order polynomial function which fitted the experimental data in the vicinity of the optimum. The factors taken into account were inorganic nutrients, such as phosphorous, ammonium and micronutrients, the carbon sources and the time of growth. With the optimised broth composition we obtained a more than 16-fold increase in the biosurfactant concentration compared to the normal BH broth, reaching a Critical Micelle Diluton (CMD) value (129.43 (95% confidence interval: 119.47 – 139.40)) among the highest in literature. In CHAPTER 5 the whole conclusions of the project are drawn and the perspectives for the future are put forward. CHAPTER 6 presents the results of the studies dealing with the ecology and the survival of thermophilic bacteria in cold soil environments. Population analysis of thermophiles in rainwater and air samples has shown distinct differences supporting the view that long distance global transport and deposition in rainwater are a possible source of replenishment of the soil thermophile populations.

Tributyltin (TBT) is a pollutant, mainly introduced to the environment as a marine anti-fouling agent. The aim of this work was to assess and develop sustainable and cost-effective remediation technologies for TBT-contaminated dredged materials. For this purpose, analytical methods were developed for sediments and sediment leachates. For the sediments, a triple extraction followed by derivatisation and measurement by gas chromatography with pulsed flame photometric detection was employed, avoiding the lengthy concentration step of the organic layer. The TBT detection limit of ca 0.04 mg Sn/kg in sediment was below the suggested limit of 0.1 mg/kg for sea disposal of TBT-contaminated dredgings (OSPAR Commission). For the leachates, derivatisation and extraction into hexane was used. Also, a new procedure, with the potential for automation, was developed for the simultaneous analysis of multiple water samples, based on in situ extraction and derivatisation on C18 solid phase extraction cartridges. No legislative limits existed for TBT in leachates, therefore the detection limits of ca 6-10 ng Sn/L achieved were regarded satisfactory, as they were below or similar to the EQS for coastal and estuarine waters or freshwaters (2-20 ng/L TBT). A pilot investigation was carried out on a dockyard to evaluate the use of X-Ray fluorescence as a screening method for the presence of TBT in sediments. Due to tin contamination such a technique was not suitable for the site examined. Incineration was found to remove TBT but it would incur very high costs. Ultrasonic destruction was not effective enough, even on TBT-spiked water solutions. Carbon products, pure clays, organically modified clays, zero valent iron, fly ash and cements were screened for their abilities to prevent TBT leaching, using a leaching test. The best performer was a powdered activated carbon product which, even mixed with cement that increases the leaching of TBT, delivered a TBT-free (< 5 ng Sn/L) leaching test result 33 days after the mixing. The result showed that this technique could provide a solution for the immobilisation of TBT in contaminated dredgings by mixing this relatively low-cost, multi-purpose and inert additive, with or without cement according to the site specific requirements.

This work contains the results of studies of three fluid projects that investigated aspects of groundwater contaminant transport and remediation. The first project performed at Hill Air Force Base in Utah evaluated the performance of a vertical water flushing system for the remediation of a multi-component non-aqueous phase liquid. This project also encompassed determining contaminant distribution through soil core analysis and partitioning tracer studies. The work determined that the limited aqueous solubility of the primary contaminants led to the lack of efficient removal by the vertical water flushing system. The second remediation test evaluated the performance of the solubility enhancing agent cyclodextrin in restoring the contaminated aquifer at Air Force Plant 44 in Tucson, Arizona. The results concluded that this advanced remediation technique was efficient in removing trichloroethene. Further, the project demonstrated the ability to separate TCE from the extracted solution through treatment with an air-stripping system and re-inject it for another multiple flushing of the aquifer. Additional site assessment including determination of lithological and contaminant distribution through well-bore sampling and system optimization by conducting a series of vertical tracer studies. To evaluate the impact of groundwater chemistry and travel distances on the transport behavior of enteric virus, experiments were conducted in the unconfined aquifer at the USGS Cape Cod Research Site. Separate experiments examined the transport behavior of bromide (Br-) and the bacteriophage PRD-1 in the effluent plume and the shallower uncontaminated groundwater. Results indicated the vast majority of the bacteriophages were lost from solution upon injection. The results further showed that this initial loss occurred within the first meter for the uncontaminated zone, whereas it occurred over a 4-meter distance in the contaminated zone. The greater distance required for the contaminated zone to defect similar mass loss is attributed to anion-exchange competition by organic matter, phosphate, and other anions present in higher concentrations in the contaminated zone. The results of this study indicate that a small, but infectious fraction of viable virus particles can persist and travel significant distances in sedimentary aquifers, despite variability in water chemistry.

Metal pollutants such as copper released into the aqueous environment have been increasing as a result of anthropogenic activities, a topic causing global concern. Adsorption-based treatment technologies offer opportunities to remediate metal pollutants from municipal and industrial wastewater effluent. The aim of this work was to evaluate the capability of modified cellulose nanowhisker (CNW) adsorbents for the remediation of copper from water matrices under realistic conditions using response surface methodology (RSM) and artificial neural network (ANN) models. The first part of the study explored the preparation and characterisation of modified CNW adsorbents. It also focused on the stability of the modified CNW adsorbents at different time intervals under dry conditions (up to 28 days) and in the water matrix (up to 7 days). The results showed that the modified CNW adsorbents were stable at different time intervals under dry conditions and in the water matrix and proved that the functional groups were permanent and did not degrade under the tested conditions. The stability of these modified CNW adsorbents under these conditions, which is relevant from both the manufacturing and application perspectives, is reported for the first time in this study. The second part of the work focused on using copper as a case study for heavy metal pollution in a clean water matrix, to evaluate removal by modified CNWs under several conditions and ranges appropriate to wastewater treatment plants (WWTPs), using factorial experimental design. RSM and ANN models were employed in order to optimise the system and to create a predictive model to evaluate the Cu(II) removal performance by the modified CNW adsorbents. Moreover, unseen experiments not belonging to the training data set, located both inside and outside the test parameter system, were performed to test the model suitability. This is also novel, as generally only one or two parameter variations have been tested, without checking the chosen model suitability for parameters lying between the tested parameters, and certainly not for parameters lying outside the tested parameter space, as has been done in this study. The results obtained showed that the ANN model outperformed the RSM model when predicting copper removal from a clean water matrix. The Langmuir andFreundlich isotherm models were applied to the equilibrium data, and the results revealed that the Langmuir isotherm (R2 = 0.9998) had better correlation than the Freundlich isotherm (R2 = 0.9461). Experimental data was also tested in terms of kinetics studies using pseudo-first order and pseudo-second order kinetic models. The results showed that the pseudo-second-order model accurately described the kinetics of adsorption. The third part of the work was aimed at gaining a deeper understanding of the complexity and variability of the wastewater matrix, including evaluating the impact of the wastewater matrix temporally on adsorbent performance to remediate copper pollutant from a real-world wastewater matrix. This study has demonstrated that the wastewater matrix composition, which is both complex and variable, has an impact on adsorbent capability and performance. A benchmark study was adopted as a ‘new’ water quality parameter to inform on the effects of the wastewater matrix (wastewater composition and its variability) on the modified CNW adsorbent’s capability to remediate copper from this matrix. Since the process of adsorption from wastewater is often complicated due to the variation in wastewater composition, results obtained from the benchmark experiments were included as one of the independent variables in ANN modelling, unlike in other optimisation studies. The performance of the ANN and RSM models was statistically evaluated in terms of coefficient of determination (R2), absolute average deviation (AAD), and root mean squared error (RMSE) on predicted experimental outcomes. The ANN model including the variability of wastewater composition fitted the experimental data with excellent accuracy and better prediction (R2 = 0.9963) than both the ANN model that did not include this variability (R2 = 0.9945), and the RSM model (R2 = 0.9409). The outcome of this study showed that by supplying the ANN model with the data obtained from the benchmark experiments as the fourth independent variable, it was possible to improve the predictability of the ANN model. Continuous flow experiments for remediation of spiked Cu(II) from the wastewater matrix were conducted. However, the physical structure of modified CNW adsorbents renders them unsuitable for use in column operation. Therefore, a more detailed study of the mechanical properties of CNW adsorbents would be necessary in order to improve the strength and stability of the adsorbents. This work has demonstrated that modified CNW are promising adsorbents to remediate copper from water matrices under realistic conditions including wastewater complexity and variability. The use of models to predict the test parameter system and account for matrix variability when evaluating CNW adsorbents for remediating Cu from a real-world wastewater matrix may also provide the foundation for assessing other treatment technologies in the future.

Environmental pollution represents one of the most pressing problems in developed countries and in recent years has raised concern and doubts also from the scientific perspective. In fact, an ever-growing number of epidemiologic-observational studies, carried out on population at risk, correlated the exposure to environmental chemicals with the incidence of several pathological conditions, ranging from metabolic to cardiological and reproductive diseases, until the development of cancers. These evidences have made more urgent the need for further investigations on the biological mechanism at the basis of pollutants toxicity. In particular, significant attention has been paid to evaluating the impact of organochlorine pesticides (OCPs) on human health. OCPs belong to a large class of organic compounds that the Stockholm Convention catalogued as “POPs” (Persistent Organic Pollutants). The list of banned chemicals includes dioxins and their derivatives, hexachlorocyclohexane, polychlorinated biphenyls and aldrin, whereas many other similar substances are subjected to restrictions. OCPs are widely distributed in the biosphere and their hazardousness is mostly related to physicochemical properties such as lipophilia and energetic stability, that allow these molecules to be resistant to biodegradation and to bio-accumulate into the adipose tissue. Information about the molecular mechanisms of the most popular OCPs (i.e. dioxins, DDT) is already present in scientific literature and several studies indicated them as endocrine disrupting chemicals as well as oncogenes. On the other hand, not much is known about a dangerous and widely diffused compound: the hexachlorocyclohexane. Hexachlorocyclohexane (HCH) is a chlorinated cyclic saturated hydrocarbon that exists in four isomers: α, β, γ and δ hexachlorocyclohexane. The g-isomer of HCH, also known as lindane, is a broad-spectrum insecticide that has been extensively used for the control of agricultural pests and for health purposes. Among HCH isomers, which are by-products of lindane industrial synthesis, β-HCH is the most recalcitrant because of its higher energetic stability due to the equatorial position of all six chlorine atoms in the chair cyclohexane conformation; in addition, few reports are available about its metabolic breakdown. For this characteristic, it is usually the predominant isomer remaining in soils and in animal tissue and can still be detected at low background environmental levels. The improper disposal of huge amounts of β-HCH led to the generation of contaminated sites in several parts of the world (Italy, Turkey, Spain, Kazakhstan, Canada, India, China, Russia, Poland, Germany, Argentine): this classifies “lindane’s contamination” as one of the environmental catastrophe of global proportions on the planetary scale. A detailed epidemiological study, ongoing since 2006, has found correlation between high blood levels of β-HCH and the occurrence of a wide range of diseases in a sample of 660 exposed patients living close the Valle del Sacco, south of Rome. The Valle del Sacco, in fact, is characterized by the presence of a large industrial conglomerate in which lindane production has been stopped in 70’s. Although the biomonitoring study highlighted a link between β-HCH contamination and the incidence of several pathological conditions, few data are currently available in the scientific literature regarding the molecular mechanism of β-HCH. For this reason, our laboratory is investigating since 2015 the intracellular effects of β-HCH with a particular focus on its impact on cancer cells. In a first published study, experiments were carried out on a panel of cells representing different human tumor types (i.e. liver, lungs, prostate, breast) associated with the expression and activation of specific receptors or kinases that are related to STAT3 activity. The experimental concentration of 10 µM for β-HCH was chosen averaging across all the plasma concentration values detected in patients under the biomonitoring study carried out in the Valle del Sacco, in order to reproduce the real exposure conditions. After evaluating the effects of β-HCH on cellular viability, different types of analysis were performed to identify the transduction cascades involved in the molecular responses to β-HCH. Obtained results established that β-HCH can activate cell-line specific pathways that all converge in STAT3 activation. Then, a special focus was placed on investigating the putative role of β-HCH in prostate cancer progression; in fact, literature data, together with our previous findings, suggest that β-HCH could have an endocrine disrupting activity by interfering with Androgen Receptor (AR) signaling. To confirm this hypothesis, LNCaP cells (hormone-sensitive prostate cancer cell line) were treated with β-HCH or testosterone in the presence or absence of the chemotherapeutic agent bicalutamide. The outcomes show that AR nuclear translocation occurs upon both β-HCH and testosterone treatment, whereas is inhibited in the presence of bicalutamide, as evidenced by immunoblotting analysis on nuclear extracts and immunofluorescence experiments. Subsequently, was verified whether β-HCH could affect the activity of AhR (Aryl Hydrocarbon Receptor), the xenobiotic sensor par excellence, in both hormone-dependent and independent tumor types. Immunofluorescence analysis evidenced the capability of β-HCH to induce AhR nuclear translocation. In addition, immunoblotting analysis were performed on cells treated with β-HCH in the presence or not of MG-132 (proteasome inhibitor) and CH223191 (AhR inhibitor) and obtained results clearly highlighted the influence of β-HCH on AhR signaling. Then, experiments were performed to investigate whether β-HCH, on par with other organochlorine pesticides, can induce oxidative stress. For this purpose, ROS production and GSSG/GSH ratio were measured, evidencing the impact of β-HCH on cellular redox homeostasis. In parallel, variations in cellular bioenergetic profile were monitored, demonstrating that β-HCH promote a metabolic shift toward aerobic glycolysis. In this altered context, β-HCH can also induce DNA damage through H2AX phosphorylation. Subsequently, the potential role of β-HCH as a contributor in tumor initiation was inspected. Experiments were carried out on a continuous normal bronchial epithelium cell line to investigate whether β-HCH could trigger cellular malignant transformation toward cancer development. For this reason, β-HCH impact was evaluated on cells viability and morphology and some markers for tumorigenesis, as Ki67 positive-cells and EGF secretion, were studied along with β-HCH activation pathways. Experimental outcomes strongly support the oncogenic potential of this molecule. Considering the capability of β-HCH to promote cell growth and tumor progression, the next question to answer is whether the exposure to β-HCH may lead to a loss of response to chemotherapeutic agents such as tyrosine kinases inhibitors. Experiments carried out on a HER2-positive lung cancer cell line revealed that β-HCH can counteract the inhibitory activity of lapatinib, leading to a higher cell proliferation rate via STAT3 activation. Further investigations were conducted using other chemotherapeutic agents (cisplatin, camptothecin and paclitaxel) and preliminar results seem to confirm the loss of sensitivity to drugs in the presence of β-HCH. From an environmental point of view, the persistence of β-HCH still represents an open question for the presence of massive illegal repositories all around the world. For this reason, β-HCH degradation through a copper-based Fenton-like method was explored by setting up a HPLC protocol under different experimental conditions. The process focused on the quantitative degradation of the parental β-HCH, since the detection of its breakdown products or transformed molecules would need a mass-spectrometry for their qualitative characterization. In parallel with the β-HCH research topic, the role of the protein STAT3 in prostate cancer was further deepened. STAT3 (Signal Transducer and Activator of Transcription 3) is a converging point for many signaling cascades and has been reported constitutively activated in a wide range of solid tumors and hematological malignancies. STAT3 is a latent cytosolic transcription factor and upregulates the expression of genes involved in cell survival and proliferation upon a wide variety of stimuli, including cytokines, oncogenes, growth factors or cytosolic kinases. The dynamic biological behavior of STAT3 can explain the higher proliferation rate triggered by β-HCH through the activation of STAT3-mediated pathways. STAT3 fulfils its multifaceted molecular functions through two different intracellular mechanisms, generally referred as canonical and non-canonical pathways. The canonical activation of STAT3 is strictly dependent on its phosphorylation at the tyrosine residue 705; upon phosphorylation at Y705, induced by the binding of a ligand to its receptor, STAT3 undergoes homodimerization to form an active dimer that can translocate to nucleus and mediates its transcriptional activity. Besides its well-described canonical signaling, STAT3 can be subjected to alternative post-translational modifications. In addition, recent studies assessed the involvement of STAT3, by means of both its canonical and non-canonical pathway, in the metabolic shift toward aerobic glycolysis known as Warburg Effect, which is typical of the more aggressive tumor phenotypes. On the basis of these premises, the existence of a link between PTMs and specific STAT3-mediated pathways was investigated in LNCaP (less aggressive PCa form) and DU-145 (more aggressive) cells performing experiments that simulated inflammatory and oxidative-stress conditions. Cells were treated with IL-6 to induce an inflammatory response, whereas tert-butyl hydroperoxide (t-BHP) was used to simulate oxidative stress. Obtained results on cellular models confirmed the relationship between STAT3 PTMs and cellular conditions, thereby reinforcing the hypothesis that PTMs can drive intracellular responses through STAT3-mediated signaling pathways. Thus, it is possible to identify STAT3 PTMs and STAT3 modulators as suitable markers or targets for PCa prevention, diagnosis and therapy. Then the role of STAT3 in prostate cancer energy metabolism was further investigated, with particular focus on the protein SHMT2 (Serine-Hydroxymethyltransferase). Results indicate that SHMT2 is an active player in STAT3 signaling and that its expression is upregulated by the JAK2/STAT3 canonical pathway upon IL-6 stimulation. Experiments were carried out on two different prostate cancer cell lines, LNCaP (less aggressive) and DU145 (more aggressive). The observation was extended to PCa formalin-fixed paraffin-embedded (FFPE) tissue sections obtained from total prostatectomies: collected specimens are characterized by a different Gleason score, ranging from 6 (less aggressive) to 9 (more aggressive). In both cell lines, STAT3 activation mode, the amount and distribution of PKM2, SHMT2, and HIF-1a proteins, as well as the cellular metabolic conditions, were evaluated in the presence or absence of IL-6-induced inflammation. Expression levels of PKM2, SHMT2, and HIF-1a, together with interleukin-6, were also analyzed utilizing normal and tumor FFPE tissues.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished

In this work a new method of production of MCM-41 was used which involved synthesis under mild conditions (room temperature) and shorter reaction times as well as reduced surfactant removal times (15 min) compared to the previously published methods that take approximately 10 h. This material was functionalised with an amine-based functional group to study the feasibility of separation of chromium (III) and chromium (VI) from aqueous solution. A maximum adsorption capacity calculated using Langmuir isotherms of 111.1 mg g-1 was achieved, which was higher than previously reported for competitive sorbents. Moreover, adsorbents containing silica nanoparticles with different porosity parameters were synthesized and evaluated for Cr (VI) uptake. The adsorption mechanism was defined by a two step adsorption mechanism for AP-MCM-41 while other sorbent exhibited a fast one step adsorption mechanism. The regeneration of MP-MCM-41 loaded with Hg (II) ions was also investigated with batch and dynamic methods using thiourea that was acidified using HNO3, H2SO4, or HCl; with HCl being the most efficient with recovery efficiency of over 90 %.A simple, rapid, bio-inspired green silica material was then developed producing a silica material with iron nanoparticles being incorporated into the framework (Fe-GN). The efficiency of Fe-GN material for the removal of arsenic ions from contaminated solution was evaluated. The material was found to be effective for the removal of arsenate ions with a maximum adsorption capacity of 69 mg/g of Fe-GN. Moreover, a method was developed to regenerate the Fe-GN allowing for full recovery and reuse of the adsorbent in subsequent extractions. Finally, the Fe-GNs material, along with other conventionally available materials, was assessed for the removal of naphthalene from aqueous solutions. The Fe-GN material was found to only have a slight affinity for the adsorption of naphthalene.

Carbon-based nanomaterials have attracted significant attention due to their unique optical, electrical, thermal and mechanical properties. In recent years, a large number of carbon-based nanomaterials have been investigated including carbon nanotubes, graphitic carbon nitride (g-C3N4), graphene, carbon nanofibers, carbon nanodots (CNDs), heteroatom-doped carbon, and carbon-based materials obtained from biomass etc. The unique and superior properties of such carbon-based materials make them useful for a wide range of applications in the fields such as environmental remediation and energy conversions. Although significant progress has been made over the past decade or so, few drawbacks of carbon-based materials still remain unresolved. For example, as a photocatalyst, the weak van der Waals interactions between adjacent conjugated planes of g-C3N4 and poor electronic properties affect negatively on the photocatalytic activity. Despite a variety of synthetic methods have been investigated, to fabricate undoped and doped carbon-based materials, the efficiency and level of control on the resultant products are far from satisfactory. Majority of these approaches either involve tedious and complex experimental procedures or require using harsh reaction conditions, or possessing low yield production. Furthermore, to achieve heteroatom-doped carbon-based materials, the reported approaches almost exclusively require the use of synthetic chemicals as carbon and heteroatom sources, respectively. The large-scale application of fuel cells and dye-sensitized solar cells (DSSCs) using Pt-based catalysts is hindered by the inherent disadvantages of Pt such as high cost, scarcity and low resistance to crossover effect of methanol molecule. It is therefore highly desirable to realize heteroatom doping by simple, low-cost, high yield and environmentally benign synthesis methods for fabrication of commercially viable carbon-based materials for applications in solar cells and fuel cells.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

The scope of this doctoral thesis is appropriate soil remediation methods for marginalized regions that go beyond pollution reduction targets and include strategies to support sustainable development. Contaminated soil from industrial or agricultural activities poses potential health threats to animals and humans and also threatens economic systems by making land unsuitable for agriculture and other economic purposes. Remediation of contaminated sites in marginalized regions such as rural areas in developing countries or sparsely populated regions in industrialized countries, need strategies that meet a different set of criteria compared to urban industrial sites in order to be appropriate. A pilot-scale experimental station was built to assess the feasibility of using organic by-products to enhance the degradation of diesel fuel. It was demonstrated that bioremediation based on the use of readily available organic by-products as amendments or phytoremediation based on locally present plants can be appropriate choices of technology in marginalized regions. Systematic sustainability assessments of the regions local environmental and social context of the contaminated site are necessary to design appropriate bioremediation projects. The inclusion of ecological engineering into the framework for strategic sustainable development, as an integrated planning guide, was demonstrated by two case studies to give valuable input to the strategic process when bioremediation is used as a tool to reach sustainability goals. Results from pilot-scale experiments confirm that whey can significantly increase the degradation rate of diesel fuel, but the slow overall degradation rates due to the high clay content in ultisol (a common tropical soil) could be a considerable constraint for efficient pollutant removal in full scale applications. Results from an experiment in soil cylinders show that the vertical migration of added microorganisms was limited in dense soils. Three species of amaranth tested in the field experiment effectively bioaccumulated toxaphene and other persistent organic pollutants which make them potentially interesting candidates for phytoremediation in the region.
Denna doktorsavhandling handlar om tillämplig marksanering i marginaliserade områden där målet går utöver saneringsmål och inkluderar strategier för främjande av hållbar utveckling. Förorenad jord från industri och jordbruksverksamheter innebär potentiella hälsorisker för djur och människor samtidigt som ekonomiska system hotas på grund av mark som blir obrukbar för jordbruk och andra ekonomiska syften. Återställande av förorenade platser i marginaliserade regioner som landsbygd i utvecklingsländer eller glesbefolkade delar av industrialiserade länder kräver strategier som möter andra kriterier än vad som krävs för urbana industriella miljöer för att kunna betecknas som tillämpliga. En försöksstation i pilotskala byggdes för att utvärdera användbarheten av att utnyttja organiska restprodukter för att öka nedbrytningshastigheten av dieselolja. Det påvisades att bioremediering baserad på användning av lättillgängliga organiska restprodukter och fytoremediering baserad på lokala växter kan vara tillämpliga teknikval i marginalisade områden. Systematiska hållbarhetsutvärderingar av den lokala situationen beträffande miljö och sociala frågor är nödvändiga för att kunna utforma tillämpliga bioremedieringsprojekt. Tillämpning av ekologisk ingenjörskonst inom ramverket för strategisk hållbar utveckling, som en integrerad planeringsguide, visade sig genom två fallstudier ge värdefulla riktlinjer för den strategiska processen då bioremediering används som ett redskap för att nå hållbarhetsmål. Resultat från ett experiment i pilotskala bekräftar att tillsatser av vassle signifikant kan öka nedbrytningen av dieselolja men den låga nedbryningshastigheten som tillskrivs den höga lerhalten i ultisol (en vanligt förekommande tropisk jord) kan vara en betydande begränsning för effektiv reduktion av föroreningar i fullskaliga tillämpningar. Resultat från ett experiment i jordcylindrar visar att den vertikala transporten av tillsatta mikroorganismer var begränsad i kompakta jordar. Tre arter av amarant som testades i ett fältexperiment visade sig effektivt kunna bioackumulera toxafen och andra  långlivade organiska föroreningar vilket gör dem till potentiellt intressanta kandidater för fytoremediering i regionen.

Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 1 och 2 inskickade, delarbete 4 accepterat.

At the time of the doctoral defence the following papers were unpublished: paper 1 and 2 submitted, paper 4 accepted.

The Nigerian economy has relied heavily on crude oil production since independence in 1960. As a consequence, it has seen an influx of multinational petroleum companies with oil exploration and associated activities having significant environmental impacts, particularly oil leakage and spillage into soil and the overall degradation of the ecosystem in the Niger Delta area. This study aims to find a viable solution to the remediation of polluted soil by comparing two thermal remediation techniques, namely microwave pyrolysis and traditional pyrolysis, which has been investigated using a Gray-King retort. The polluted soil was first examined to ascertain the distribution of the soil organic carbon (SOC) with 78% found to be solvent extractable in dichloromethane/methanol, while 95 % was thermally labile and removed under hydropyrolysis (HyPy) conditions at 550 °C. The remaining 5 % of the SOC was composed of a recalcitrant residue being defined as the black or stable polyaromatic carbon fraction. The solvent extractable organic matter (EOM) was then further separated into the maltene (free phase) and asphaltene (bound phase) fractions together for comparison with a sample of Nigerian crude oil provided by the Shell Petroleum Development Company (SPDC), Nigeria. The Nigerian crude oil is a light crude oil with the percentage of maltene (95.2 %) was far higher than the asphaltene (4.8 %). A closer margin was observed in the percentage between the maltene (88.3 %) and asphaltene (11.7 %) in the soil EOM due to biodegradation. The biomarker profile of the EOM was compared with that of a Nigerian crude oil to confirm that the EOM contains the crude oil in the soil. Their biomarker profiles revealed that the source inputs were terrigenous from deltaic settings, of Late Upper Cretaceous age and deposited under oxic conditions. Oleanane (a pentacyclic triterpene, abundant in oils from the Niger Delta) was present in both the crude oil and EOM and the hopane and the sterane distributions (m/z 191 and m/z 217 respectively) were similar in every respect, which indicates that the probable source of the pollutant crude oil in the soil is similar in composition to the Nigerian crude oil. Accordingly, the polluted soil was treated with microwave pyrolysis and Gray-King pyrolysis to remove the crude oil pollutant. The maximum average recovered products from the thermal remediation process with Gray-King pyrolysis is 99.4 % TOC and maximum crude oil pollutant removed by Gray-King pyrolysis was 85.3 % TOC with maximum oil recovery of 70 % TOC from all the different treatment conditions, while the shortest treatment time condition gave the lowest gas yield of 10.2 % TOC. This implies that 100 % removal with respect to EOM and 89 % removal with respect to HyPy as discussed above. Furthermore, the polluted soil was also treated with microwave pyrolysis with maximum pollutant removal of 77 % TOC, which is 98.7 % removal with respect to EOM and 81 % with respect to HyPy. In conclusion, Gray-King pyrolysis removed more of the soil organic carbon than microwave pyrolysis, but the latter does have advantages regarding operability and greater output within a short treatment time.