Dissertations / Theses on the topic 'Nanoparticles removal'
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MANTOVANI, MARCO. "Nanoparticles for the removal of contaminants from wastewaters." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/305614.
This thesis is part of PerFORM WATER 2030 (Platform for Integrated Operation Research and Management of Public Water towards 2030), a project financed by the Lombardy region and the European Regional Development Fund. The objective is to produce laboratory-scale zero valent iron nanoparticles encapsulated in a carbonaceous matrix (ME-nFe), a material with reducing properties and high adsorption capacity that can be used in wastewater treatment. The synthesis of the nanoparticles is achieved through hydrothermal carbonization (HTC) starting from microalgal biomass grown in the pilot plant located at the Bresso-Niguarda (MI) treatment plant. Specifically, the first phases of work focused on collecting biomass directly from the plant and on its characterization in terms of elemental composition and polyphenol content. Subsequently, the conditions that could influence the synthesis of ME-nFe were studied: two types of salt were tested as an iron source (ammonium iron sulphate and iron nitrate), four Fe/C ratios to be put in the reactor (0.02, 0.05, 0.1, 0.2) and three different temperatures of the synthesis process (180°C, 200°C and 225°C). The characterization of the produced nanoparticles in terms of zero-valent and total iron content, specific surface area and nanoscale morphological structure, allowed the selection of the prototypes with the best properties. Once the best operating conditions were identified, the ME-nFe were tested in the removal of five heavy metals (Zn, Cu, Ni, Cd, Cr), first under ideal conditions and then in more realistic ones. At the end of the treatment, the possibility of recovering the CE-nZVI and reusing it them for multiple removal cycles was also assessed. The best results were achieve using a sorbent concentration of 3 gL-1 on a starting solution of the five heavy metals with a starting concentration of 1 mg L-1. The removal for Zn, Cu, Ni e Cd were higher than 96%. However, Cr was never affected during the tests. Hereafter, the toxicity of the liquid by-product of the HTC process was studied, both towards Aliivibrio fischeri, a luminescent bacterium used as an indicator in ecotoxicology, and towards the microalgae themselves. Microtox Basic tests were performed on the raw liquid by-product, showing a very strong effect even on very diluted samples (EC50= 1.8% after 15 min). The test was than repeated after a pretreatment step (precipitation of dissolved iron after pH adjustment) but the final toxicity was still very high, proving that the problem was not the dissolved iron but probably the presence of some toxic organic compounds (EC50= 6.8% after 15 min). Adsorption with activated carbons (using two different adsorbent doses of 2 and 3gL-1) was then performed as an alternative pretreatment. Both concentrations were able to sensibly reduce the wastewater toxicity, with the best result achieved using the 3gL-1 dose (EC50= 60% after 15 min). Finally, the possibility of cultivating microalgae on a dilution of the HTC wastewater was assessed, in order to study their decontamination capacity and simultaneously evaluating the possibility of closing the cycle, enhancing the by-product and obtaining new biomass for other syntheses of CE-nZVI. Microalgae were grown on a 20% dilution of the liquid by-product using the centrate as the diluent, both in batch and continuous mode, making the process to produce the microalgal base nanoparticles more sustainable.
Ng, Dedy. "Nanoparticles removal in post-CMP (Chemical-Mechanical Polishing) cleaning." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/4159.
Zhai, Chunhao. "Polyimide Aerogels and Their Applications in Removal of Airborne Nanoparticles." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1464284202.
Walrod, John Hamilton II. "ARSENIC REMOVAL WITH A DITHIOL LIGAND SUPPORTED ON MAGNETIC NANOPARTICLES." UKnowledge, 2017. http://uknowledge.uky.edu/chemistry_etds/83.
Almeelbi, Talal Bakheet. "Phosphate Removal and Recovery Using Iron Nanoparticles and Iron Cross-Linked Biopolymer." Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26517.
Seyedi, Seyed Mojtaba. "Engineered iron oxide nanoparticle-polymer composites for the removal of dissolved arsenic and antimony." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2017. https://ro.ecu.edu.au/theses/2038.
Hu, Jing. "Fundamental investigation on removal and recovery of heavy metals from synthetic wastewater using magnetic nanoparticles /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202005%20HU.
Farkas, Kata. "Mimicking virus removal and transport in aquifer media using surface-modified silica nanoparticles." Thesis, University of Canterbury. School of Biological Sciences, 2014. http://hdl.handle.net/10092/9349.
Verdugo, Gonzalez Brenda. "Regenerable Adsorbents for Removal of Arsenic from Contaminated Waters and Synthesis and Characterization of Multifunctional Magnetic Nanoparticles for Environmental and Biomedical Applications." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202532.
Clarke, Emma Victoria Faye. "An investigation into silver nanoparticles removal from water during sand filtration and activated carbon adsorption." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/29959.
Cisse, Seydou. "Use of Biopolymer Entrapped Sulfate Reducing Bacteria and Metal Nanoparticles for Effective Aqueous Sulfate Removal." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/27234.
Fulbright Program Fellowship
National Science Foundation (NSF, Grant: CCMI-1125674)
Gomez-Rivera, Francisco. "Exploration of Biological Treatment Systems for the Removal of Persistent Landfill Leachate Contaminants and Nanoparticles." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145311.
Rottman, Jeffrey J. "Fundamentals and Application of Porous Media Filtration for the Removal of Nanoparticles from Industrial Wastewater." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/255157.
Kumar, Rajender. "Development and potential applications of nanomaterials for arsenic removal from contaminated groundwater." Thesis, KTH, Miljögeokemi och ekoteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96106.
Martinson, Carol A. "Evaluation of cupric oxide (CuO) nanoparticles in the removal of arsenic species from groundwater across a wide range of natural conditions." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1594490421&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Molinari, Simone. "Chromium and arsenic removal from contaminated water: environmental application of maghemitenanoparticles (samns)." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3424791.
L'arsenico (AsIII-V) e cromo (CrVI) sono classificati come cancerogeni di classe A se inalati o ingeriti con acqua. l'Organizzazione Mondiale della sanità (OMS) ha fissato come limite nelle acque per l’As 10 µg l-1 e 50 µg l-1 per il Cr. La riduzione della loro concentrazione è quindi di vitale importanza. I metodi di bonifica convenzionali sono basati su riduzione chimica, adsorbimento e scambio di anioni. Essi sono influenzati da elevati costi, uso di grandi quantità di reagenti e generazione di fanghi con potenziali pericoli di lisciviazione in discarica. Tecniche a basso costo e sostenibili devono essere identificate come alternative o per implementare i metodi di trattamento convenzionali. Le nanoparticelle sono una delle tecniche più promettenti per ridurre le attività ex situ, migliorare la selettività e l'efficienza di bonifica del sottosuolo. Il progetto di ricerca si basa sull'applicazione di nanoparticelle superparamagnetiche di maghemite chiamate SAMNs (Surface Active Maghemite Nanoparticles) per la rimozione di metalli tossici (As e CrVI) dalle acque, con l'obiettivo di ridurre le attività ex situ, aumentare l'efficienza di bonifica e ottenere un migliore selettività per soddisfare la crescente domanda di bonifiche sostenibili. Le SAMNs sono caratterizzate da un'elevata stabilità colloidale e dalla capacità di legare selettivamente CrVI, As e altre macromolecole a causa della topografia dei siti di FeIII non coordinati sulla superficie. Il compendio di caratteristiche, dalla sintesi in acqua, la reattività superficiale, la specificità e biocompatibilità, rendono le SAMNs un promettente candidato per la bonifica a larga scala. I risultati hanno evidenziato che le SAMNs sono un materiale ideale a basso costo per la bonifica ex situ e in situ di As e CrVI. L'efficienza di rimozione è stata dimostrata con variabili concentrazioni di SAMNs ed inquinanti, pH della soluzione. Inoltre, i risultati di studi cinetici e termodinamici, associati ad una dettagliata caratterizzazione strutturale e chimica dei complessi SAMN@metallo, hanno confermato l'insorgenza di diversi e complessi meccanismi di legame, rivelando specifici processi superficiali. Le SAMNs possono rimuovere alte concentrazioni di CrVI (22 mg L-1) in acqua con una forte dipendenza dal pH; inoltre i test per la rimozione di CrVI su campioni reali dal sito Ex-Stoppani con concentrazioni nell'intervallo 0,5-19 mg L-1 di CrVI, hanno mostrato un grande potenziale per applicazioni a larga scala su livello industriale. I risultati hanno confermato l'elevata efficienza di adsorbimento delle SAMNs (>80% di CrVI rimosso) riscontrata anche a valori di pH neutri, condizioni tipiche delle acque sotterranee. Allo stesso tempo, non sono stati trovati anioni interferenti. Per l'arsenico, oltre a dimostrare la capacità di sequestramento fino alla totale rimozione, è stato trovata una diversa affinità di legame delle due specie AsIII e AsV. La massima capacità di legame per l’AsIII (~ 24 mg g-1) risulta costante in tutto il range di pH investigato, mentre per l’AsV (~32 mg g-1 a pH 3,0) è stato osservato un rapido decremento con pH. Lo studio dell'interazione delle SAMNs con AsIII-V mediante spettroscopia fotoelettronica a raggi X ha rivelato una correlazione tra la specificità di legame, modifica degli ossigeni strutturali e ripristino della cristallinità superficiale. Queste reazioni superficiali sono attribuite alla topografia superficiale dei siti FeIII non coordinati. Anche se le nanoparticelle di ossido di ferro sono state a fondo investigate, la presente tesi, oltre ad arricchirne la conoscenza, apre le porte a nuovi approcci di sintesi per investigare nuove opportunità dagli ossidi di ferro. Nuove sintesi possono portare a nanomateriali caratterizzati da peculiari caratteristiche superficiali, offrendo novità e caratteristiche promettenti che possono essere molto utili per una vasta gamma di applicazioni, dalla bonifica dell'acqua alla biotecnologia.
Calderón, Roca Blanca. "Application of iron-based nanostructures to contaminant remediation." Doctoral thesis, Universidad de Alicante, 2017. http://hdl.handle.net/10045/69809.
Al, Anazi Abdulaziz H. "Synthesis of Recyclable Magnetic Metal-ferrite Nanoparticles for the Removal of Contaminants of Emerging Concern in Water." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543922143864275.
Barrabés, Rabanal Noelia. "Selective Hydrogenation Catalysts For Environmental Processes: Nitrate And Chlorocompounds Removal." Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/8573.
La contaminación por nitratos en las aguas subterráneas es un problema importante en determinadas regiones. Esta problemática ha impulsado el estudio de la eliminación catalítica de los nitratos, en la que se enfoca la primera parte de la tesis. Este estudio se realizó en un reactor en continuo de lecho fijo. Se sintetizaron, caracterizaron y ensayaron, varios catalizadores monometálicos, bimetálicos y de nanopartículas soportadas. Una vez determinada la actividad y la estabilidad de los catalizadores se procedió a optimizar los materiales con el fin de mejorar la selectividad de éstos hacia nitrógeno. El presente trabajo ha sido el punto de partida para la puesta en marcha de una planta piloto para el tratamiento de aguas subterráneas reales contaminadas con nitratos. Próximamente será inaugurada una planta de eliminación catalítica de nitratos de aguas subterráneas con capacidad 500m3/día en las proximidades de El Morell (Tarragona).
La segunda parte de la tesis se enfoca en el proceso de hidrodecloración catalítica de compuestos orgánicos clorados como el tricloroetileno. Los experimentos se llevaron a cabo en fase gas utilizando diferentes tipos de catalizadores, los cuales fueron sintetizados y caracterizados. Se emplearon diferentes catalizadores, mono y bimetálicos, para la transformación del tricloroetileno a un producto de valor añadido, como es el etileno.
El presente trabajo, además de aportar conocimientos fundamentales en la catálisis heterogénea, contribuye a forjar soluciones a problemas medioambientales reales que afectan a la salud humana.
In the present study have been designed, synthesised and characterised heterogeneous catalysts. Their activities and selectivity have been studied in the treatment of compounds that present environmental problems. For the catalysts preparation different protocols such as incipient-wetness impregnation, co-impregnation, redox and combustion have been followed. In addition, metal nanoparticles were synthesized and deposited on several materials as well as tested their catalytic behaviour. The activity and the selectivity of nanoparticle catalysts with that of other catalysts in different processes were compared. On the other hand, different materials such as alumina, active carbon, ceria and hydrotalcites were used to study the role of them as catalyst supports.
In the light of the current demand for drinking water, the first part of this thesis studies the catalytic hydrogenation of nitrates. The study is carried out in a fixed bed continuous reactor. Several bimetallic, monometallic and supported nanoparticle catalysts have been synthesised, characterized and tested in order to improve their activity and stability and to optimise their selectivity to nitrogen. The present study was further extended and some of the catalysts have been used as a starting point for a Pilot Plant investigation into eliminating nitrate in real ground water. At this moment, a plant is being constructed in the vicinity of El Morell, Tarragona, which can use catalysis to reduce nitrates in 500 m3/day of groundwater.
The second part of the thesis deals with the catalytic hydrodechlorination of chlorinated organic compounds such as TCE. The experiments were done in gas phase. Different types of catalysts have been synthesised, characterized and tested and the final objective is to obtain an active and stable catalyst that is selective toward valuable products such as ethylene.
This research aims to use catalytic technologies to contribute to solving real environmental problems that affect human life.
JASPER, ANTHONY JOHN. "Impact of Nanoparticles and Natural Organic Matter on the Removal of Organic Pollutants by Activated Carbon Adsorption." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1218743967.
Salih, Hafiz H. M. "The Implications of Nanoparticles on the Removal of Volatile Organic Compounds from Drinking Water by Activated Carbon." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321366798.
Meduri, Kavita. "Carbon-Supported Transition Metal Nanoparticles for Catalytic and Electromagnetic Applications." Thesis, Portland State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10933285.
Recently, there has been growing interest in using transition metals (TM) for catalytic and electromagnetic applications, due to the ability of TMs to form stable compounds in multiple oxidation states. In this research, the focus has been on the synthesis and characterization of carbon-supported TM nanoparticles (NPs), specifically palladium (Pd) and gold (Au) NPs, for catalytic applications, and transition metal oxides (TMO) NPs, specifically Fe3O4 NPs for electromagnetic applications. Carbon supports have several advantages, such as enabling even distribution of particles, offering large specific surface area with excellent electron conductivity, and relative chemical inertness.
In this dissertation, for catalytic applications, emphasis was on removal of trichloroethylene (TCE) from groundwater. For this application, carbon-supported Pd/Au NP catalysts were developed. Pd was chosen because it is more active, stable and selective for desired end-products, and Au has shown to be a good promotor of Pd’s catalytic activity. Often, commercially available Pd-based catalysts are made using harsh chemicals, which can be harmful to the environment. Here, an environmentally friendly process with aspects of green chemistry was developed to produce carbon-supported Pd/Au NP catalysts. This process uses a combination of sonochemistry and solvothermal syntheses. The carefully designed carbon-supported Pd/Au NP catalyst material was systematically characterized, tested against TCE, and optimized for increased rate of removal of TCE. Electron microscopy and spectroscopy techniques were used to study the material including structure, configuration and oxidative state. The Pd/Au NPs were found mainly to form clusters with an aggregate-PdShellAuCore structure. Using state-of-the-art direct detection with electron energy loss spectroscopy, the Pd NPs were found to have an oxidative state of zero (0). The formation of the catalyst material was studied in detail by varying several synthesis parameters including type of solvent, sonication time, synthesis temperature etc. The most optimized catalyst was found remove TCE at double the rate of corresponding commercial Pd-based catalysts in a hydrogen headspace. This material was found to catalyze the removal of TCE via traditional hydrodehalogenation and shows promise for the removal of other contaminants such as trichloropropane (TCP), carbon tetrachloride (CT).
This green approach to make and optimize TM materials for specific applications was extended to TMOs, specifically magnetite (Fe3O4) and further developed for the application of electromagnetism. As catalysts, Fe3O4 is used for removal of p-nitrophenol from water. However, since the carbon-supported Pd/Au material system was developed and optimized for catalysis, here, carbon-supported Fe3O 4 NPs were developed for electromagnetic applications. There has been growing interest in tuning the magnetic properties of materials at room temperature with the use of external electric fields, for long-term applications in data storage and spintronic devices. While a complete reversible change of material properties has not yet been achieved, some success in partial switching has been achieved using multiferroic spinel structures such as Fe3O 4. These materials experience a change in magnetic moment at room temperature when exposed to the electric fields generated by electrochemical cells such as lithium ion batteries (LIBs) and supercapacitors (SC). In the past, a 1% reversible change was observed in Fe3O4 using LIBs. Here, building on the developments from previous material system, Fe 3O4 NPs were directly hybridized onto the graphene support in order to increase the observable change in magnetic moment. The material was systematically designed and tested for this application, including a study of the material formation. A simple, environmentally friendly synthesis using the solvothermal process was implemented to make the graphene-supported Fe 3O4 NPs. This new material was found to produce a reversible change of up to 18% in a LIB. In order to overcome some of the difficulties of testing with a LIB, a corresponding hybrid SC was designed, built and calibrated. The graphene-supported Fe3O4 NPs were found to produce a net 2% reversibility in the SC, which has not been reported before. The results from both the LIB and SC were analyzed to better understand the mechanism of switching in a spinel ferrite such as Fe3O4, which can help optimize the material for future applications.
The focus of this dissertation was on the development of a methodology for carbon-supported TM and TMO NPs for specific applications. It is envisioned that this approach and strategy will contribute towards the future optimization of similar material systems for a multitude of applications.
Eduok, Samuel. "Evaluation of the impact of engineered nanoparticles on the operation of wastewater treatment plant." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8261.
Pretorius, Chantelle. "Covalent immobilisation of β-Galactosidase from Escherichia coli to commercially available magnetic nanoparticles for the removal of lactose from milk." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71958.
ENGLISH ABSTRACT: ß-Galactosidase of Escherichia coli is the equivalent of lactase in humans and has the ability to bind and hydrolyse lactose. Lactase de ciency is a common phenomenon present in almost 70% of the world's population. This has resulted in greater than before demands on the food processing industry to develop a method that will allow for the hydrolysis of the disaccharide lactose in milk but will also allow for the removal of the remaining active enzyme. In this thesis, a new method, that is bio-speci c and well characterized for the removal of lactose from a lactose containing solution, is described. The E537D mutated version of ß-Galactosidase, which has a much lower activity compared to the wildtype and is able to bio-speci cally bind lactose for longer periods, was covalently immobilised to commercially available magnetic nanoparticles (fl uidMAG-Amine) via two coupling strategies. Glutaraldehyde is a cross-linking agent that reacts with amine groups, while N- (3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) is a coupling agent that activates carboxylic groups. These agents are widely used for the coupling of biomolecules to solid supports. The covalently coupled fluidMAG-E537D ß-Galactosidase particles were characterized regarding retained enzymatic activity and ability to bind and physically remove lactose from a lactose containing solution by applying an external magnetic eld, after lactose binding, to the enzyme-particle complex in solution. Each component aimed at yielding this functionally immobilised enzyme complex was studied and optimized to contribute to the development of this novel technique, which is a ordable and simple, for the removal of lactose from solution for the ultimate production of lactose free milk. Results indicated the glutaraldehyde method of ß-Gal cross-linking to fluidMAG-Amine to be the preferred strategy since it allowed an increased carrier capacity of protein to the particles. The glutaraldehyde cross-linked protein also exhibited a two-fold higher activity than the EDC coupled protein. Furthermore, the glutaraldehyde cross-linked fluidMAG-E537D ß-Gal was able to physically remove 34 % of the lactose from a 0.2 nmol/L lactose in solution. This, therefore, con rmed the potential use of this novel technique in the food processing industry.
AFRIKAANSE OPSOMMING: ß-Galaktosidase vanaf Escherichia coli is dieselfde as laktase in mense en beskik oor die vermoë om laktose te bind en te hidroliseer. 'n Gebrek aan laktase kom algemeen voor en ongeveer 70 % van die wêreldbevolking ly hieraan. Laasgenoemde het daartoe gelei dat daar meer druk as vantevore op die voedselproduksie industrie is om 'n metode te ontwikkel waarmee die hidrolise van die disakkaried laktose in melk moontlik sal wees asook die verwydering van die oorblywende aktiewe ensiem. In hierdie tesis word 'n nuwe metode beskryf wat biospesi ek en goed gekarakteriseer is vir die verwydering van laktose vanuit 'n laktose bevattende oplossing. Die E537D gemuteerde weergawe van ß-Galaktosidase, wat beskik oor 'n baie laer aktiwiteit as die wildetipe asook die vermoë om laktose biospesi ek vir langer periodes te bind, is kovalent geïmmobiliseer op kommersieel beskikbare magnetiese nanopartikels (fluidMAG-Amine) via twee koppelingsstrategieë. Glutaraldehied is 'n kruisbindingsagent wat met amino groepe reageer, terwyl EDC 'n koppelingsagent is wat karboksie groepe aktiveer. Hierdie agente word algemeen gebruik vir die binding van biomolekules aan soliede matrikse. Die kovalent gekoppelde fluidMAG-E537D ß-Galaktosidase partikels is gekarakteriseer met betrekking tot behoue ensimatiese aktiwiteit en vermoë om laktose te bind en sies te verwyder vanuit 'n oplossing wat laktose bevat deur 'n eksterne magneetveld op die ensiem-partikel kompleks in oplossing toe te pas, nadat die binding van laktose plaasgevind het. Elke komponent van hierdie funksioneel geïmmobiliseerde ensiemkomplekse is ondersoek en geoptimaliseer met die doel om by te dra tot die ontwikkeling van 'n nuwe tegniek wat bekostigbaar en eenvoudig is vir die verwydering van laktose vanuit 'n oplossing vir die uiteindelike gebruik in die produksie van laktose-vrye melk. Resultate het getoon dat die glutaraldehied metode van ß-Gal kruisbinding op fluidMAG-Amine verkies word aangesien dit 'n verhoogde draerkapasiteit van proteïene op die partikels moontlik maak. Die glutaraldehied gekoppelde proteïene beskik ook oor twee keer meer aktiwiteit as die EDC gekoppelde proteïene. Die glutaraldehied gekoppelde fluidMAG-E537D ß -Gal kon 34 % van die laktose teenwoordig in 'n 0.2 nmol/L laktose oplossing sies verwyder. Hierdie het dus die potensiële gebruik van hierdie nuwe metode in die voedselproduksie industrie bevestig.
Lallart, Adeline. "Ultra propreté : des microgouttes aux nanoparticules." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY019/document.
With the evolution of microelectronics and the miniaturization of the various components at the nanoscale, the size of the critical particles to be removed during the manufacturing process has been drastically reduced. Indeed, this critical size is currently of the order of 10 nm. Cleaning processes must therefore be able to remove these particles without surfaces damage. In order to answer this challenge, two methods are studied in this work: the use of a spray and the joint application of a polymer layer and a spray.The spray has been used for many years in the microelectronics field. However, the mechanism of particles detachment by this method is still not assimilated. The purpose of this study is to better understand it. Thus, different parameters will be studied leading to the development of a detachment model, showing new variables related to the cleaning process, contamination (nature and particle size) or the storage conditions of surfaces.For its part, the process by using a combination of polymer layer and spray is in full development, but little information is available today. Nevertheless, early studies have demonstrated its ability to clean surfaces with patterns and its effectiveness regardless of the size of the contamination. In this work, different methods of the polymer layer removal will be compared as well as some physicochemical properties specific to it. The objective is to detect key parameters influencing particle removal and to propose a premise of elucidation of the physical mechanisms involved
Vaughan, Lisa Ann. "Enviromentally benign synthesis and application of some spinel ferrite nanopartilces." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44876.
Westphal, Emily Nicole. "Lignin-Magnetite Nanoparticles Aiding in Pickering Emulsions and Oil Manipulation and Their Rheological Properties." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1619710097550949.
Busse, Marta Julia. "Bionanocomposites of Fe3O4/SiO2 and alginate for magnetic removal of Cr(III) species from water." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14196.
The aim of the present work was to study the removal of Cr (III) species from aqueous solutions by adsorption process, using magnetic nanoparticles functionalized with amine groups and with the polysaccharide alginate. Heavy metal pollution is serious environmental and public health problem worldwide. Chromium is one of the most toxic metal endangering human life. Cr(III) is often used in industry which caused water pollution. Therefore, increased interest by the researchers to employ nanomaterials for the removal contamination and explore adsorbents to replace expensive materials, particularly low-cost raw materials such as, residual polymers materials or agricultural by-products. The work included the preparation of magnetic nanoparticles, coating them with amorphous silica shell functionalized with amine groups and the covalent attachment of alginate to the magnetic nanoparticle. The properties of the nanoparticles were assessed by a number of experimental techniques namely x-ray diffraction, infrared spectroscopy, elemental analysis, thermogravimetry and zeta potential measurements. Silica coated magnetic nanoparticles functionalized with amine groups were investigated for the uptake of Cr(III)/EDTA complexes from water, while the nanoparticles attached to the alginate molecules were tested for the removal of aqueous Cr(III) ions. The kinetic results were fitted to models of pseudo first and pseudo second order and the equilibrium adsorption results were adjusted to suitable isotherm models such as Langmuir and Freundlich. The composite nanoparticles revealed affinity to the Cr(III) species. Due to its properties, this new composite nanoparticles may find interesting applications in purification of water.
O objectivo do presente trabalho foi o de estudar a eliminação de Cr (III), a partir de soluções aquosas, por processo de adsorção, utilizando nanopartículas magnéticas funcionalizadas com grupos amina e com o polissacarídeo alginato. A poluição causada por metais pesados está na base de graves problemas de saúde pública e ambientais em todo o mundo. O crómio é um dos metais mais tóxicos, pondo em perigo a vida humana. O Cr (III) é frequentemente usado na indústria, causando a poluição da água. Por esta razão, aumentou o interesse dos investigadores na utilização de nanomateriais para a remoção de poluentes e no estudo de adsorventes para substituir materiais caros, nomeadamente matérias-primas de baixo custo, tais como, materiais provenientes de polímeros residuais ou subprodutos agrícolas. Este trabalho incluiu a preparação de nanopartículas magnéticas, o seu revestimento com uma capa de sílica amorfa funcionalizada com grupos de amina e a ligação covalente do alginato à nanopartícula magnética. As propriedades das nanopartículas foram avaliadas utilizando várias técnicas experimentais nomeadamente difracção de raios-X, espectroscopia de infravermelho, análise elementar, termogravimetria e medições do potencial zeta. As nanopartículas magnéticas revestidas com sílica e funcionalizadas com grupos de amina foram investigadas para a adsorção de Cr (III) / complexos de EDTA de águas, enquanto que as nanopartículas ligadas às moléculas de alginato foram testadas para a remoção de iões Cr (III) em meio aquoso. Os resultados de cinética foram ajustados aos modelos de pseudo-primeira e pseudo-segunda ordem, e os resultados de equilíbrio de adsorção foram ajustados aos modelos adequados, tais como a isotérmica de Langmuir e a de Freundlich. As nanopartículas compósitas revelaram ter afinidade para as espécies de Cr (III). Devido às suas propriedades, estas nova nanopartículas compósitas podem encontrar aplicações interessantes na purificação de águas.
Lee, Jung Ju. "Removal of Microcystin-LR from Drinking Water Using Adsorption and Membrane Processes." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1229026536.
Cordier, Marie. "Outdoor bronze conservation: assessment of protective treatments by accelerated aging and of treatment removal procedures by laser cleaning." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5731/.
Morrill, Samuel. "Combined Metal-Enhanced Fluorescence-Surface Acoustic Wave (MEF-SAW) Biosensor." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5081.
Xu, Yinhui Zhao Dongye. "Removal of copper(II) and lead(II) from soils by poly(amidoamine) dendrimers and reductive immobilization of chromium(VI) by stabilized zero-valent iron nanoparticles." Auburn, Ala., 2006. http://repo.lib.auburn.edu/Send%208-7-07/XU_YINHUI_21.pdf.
Mercadier, Thomas. "Retrait particulaire par étalement et retrait d’un film de résine." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALT095.
Efficient particle contamination removal is crucial in maximizing yield within the microelectronics industry. However, conventional particle removal techniques may become impractical when dealing with complex and fragile surface structures, as their application can potentially cause physical damage. This challenge has led to the development of new cleaning processes based on innovative concepts, such as a resist film lift off approach. The resist film lift-off leads to the particle removal due to the particle surface bonded to the resist. One of these particle removal processes is studied in this manuscript. In this process, the resist film is composed of two immiscible organic polymers. The process consists of the resist spin-coating followed by a diluted ammonia dispense at room temperature. Thanks to the latter chemical step, one of the polymers is dissolved inducing the delamination and lift-off of the remaining polymer with drag and lift forces.This manuscript sheds light on the critical role of the organization of two immiscible polymers within the resist film in the context of film lift-off. The organization of these polymers was shown to depend on the substrate surface energy through Tof SIMS analysis. For instance, on a hydrophilic substrate, the soluble polymer exhibits a pronounced affinity for the interface. Such an organization on hydrophilic surface minimizes the interfacial area that needs to be delaminated during the resist removal step. Consequently, the effectiveness of ammonia-based film removal relies on the substrate’s surface energy and is only achievable if the substrate surface energy is below 66mN/m.This manuscript provides valuable insights into the modification of the polymers’ organization. The tuning of some parameters from the resist formulation as the blend ratio or the resist thickness and the addition of a bake after the coating are shown to modify this surface energy peeling limit. Additionally, a Particle Removal Efficiency study was conducted on blanket wafers to determine and understand how these three parameters influence cleaning efficiency. It has led to the optimization of process efficiency. This optimized process efficiency was evaluated on structured surfaces. The results showcased its capability to efficiently remove particles while preserving the integrity of delicate structures.This PhD project has contributed to broadening the comprehension of particle removal using a resist peeling process. Moreover, it has demonstrated the potential application of this method in an industrial context
Ezzatahmadi, Naeim. "Synthesis and characterisation of mineral based composite materials for the remediation of contaminated aqueous solutions." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/131822/1/Naeim%20Ezzatahmadi%20Thesis.pdf.
Shanbhogue, Sai Sharanya. "Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene Remediation." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26675.
Department of Civil Engineering, North Dakota State University
Gustafsson, Olof. "Nanoparticle Removal and Brownian Diffusion by Virus Removal Filters: Theoretical and Experimental Study." Thesis, Uppsala universitet, Nanoteknologi och funktionella material, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-335802.
Oliveira, Fernanda Gandra de. "S?ntese e caracteriza??o do comp?sito ferro zero-valente nanoparticulado/carv?o ativado granulado (nFZV-CAG) e sua aplica??o para remo??o do f?rmaco nimesulida pelos processos adsor??o/redu??o e ozoniza??o catal?tica heterog?nea." UFVJM, 2016. http://acervo.ufvjm.edu.br/jspui/handle/1/1313.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)
O comp?sito nFZV-CAG foi empregado para a ozoniza??o catal?tica heterog?nea da NMS em meio aquoso. O oz?nio foi gerado por uma central geradora de oz?nio IPABRAS, alimentada com ar. Foram avaliados diferentes processos catal?ticos como O3, CAG, O3-CAG, O3-nFZV- CAG, e a varia??o da concentra??o das nFZV para remo??o da NMS. Os resultados mostraram que a combina??o do O3-nFZV-CAG foi muito eficiente levando ? mineraliza??o de aproximadamente 70% da NMS em 120 min de rea??o. Tal efici?ncia pode estar atribu?da ao processo de eletr?lise, em que o Fe0 origina Fe2+ levando ? produ??o do radical hidroxila que ? altamente oxidante, levando a destrui??o do contaminante. As rea??es seguiram a cin?tica pseudo-primeira ordem para remo??o do f?rmaco. Ap?s realizada a coleta as amostras foram submetidas a an?lise qu?mica, empregando-se as t?cnicas de espectrofotometria de UV-Vis, cromatografia l?quida de alta efici?ncia (CLAE) e a determina??o da demanda qu?mica de oxig?nio (DQO) tamb?m foi realizada.
As nanopart?culas de FZV imobilizadas sobre a superf?cie do carv?o ativado (nFZV-CAG) foram sintetizadas e caracterizadas para remo??o do f?rmaco Nimesulida (NMS) em sistemas aquosos. Os estudos foram realizados em bateladas com agita??o de 250 rpm durante 120 minutos, onde foram avaliadas a efici?ncia, concentra??o (20, 25 e 30% do comp?sito) e diferentes dosagens (0,1 a 10g) de nFZV-CAG. Os resultados mostraram que a dosagem de 10 g de 20%nFZV-CAG removeu cerca de 80% da NMS 50 mg L-1 em apenas 30 minutos de rea??o, e atingindo 100% em 120 minutos. Foi observada ainda uma remo??o de 80% da DQO ao final da rea??o. As velocidades de rea??o aumentaram na medida em que foram aumentadas as dosagens do comp?sito, o que seria esperado. Por?m, com o aumento da concentra??o (%) de nFZV n?o houve aumento na velocidade das rea??es. As rea??es seguiram uma cin?tica de pseudo-primeira ordem em rela??o ? remo??o da NMS. Ap?s realizada a coleta, as amostras foram submetidas a an?lise qu?mica, empregando-se as t?cnicas de espectrofotometria de UV- VIS, cromatografia l?quida de alta efici?ncia (CLAE) e a determina??o da demanda qu?mica de oxig?nio (DQO) tamb?m foi realizada. Para caracteriza??o do comp?sito foram empregadas as t?cnicas Microscopia Eletr?nica de Varredura acoplada ? Espectrometria de Energia Dispersiva de Raios-X (MEV-EDS), que mostraram claramente a presen?a da nanopart?culas sobre a superf?cie do carv?o, e analise de superf?cie do nFZV-CAG e do CAG tamb?m foram realizadas.
Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.
The FZV nanoparticles immobilized onto the surface of the activated charcoal (nFZV-CAG) were synthesized and characterized for the removal of the pharmaceutical Nimesulide (NMS) in aqueous systems. The studies were performed in batch mode with stirring speeds of 250 rpm during 120 minutes, so that it was possible to evaluate efficiency, concentration (20, 25 and 30% of the composite) and different dosages (0,1 to 10g) of nFZV-CAG. The results showed that the dosage of 10g of 20%nFZV-CAG removed approximately 80% of NMS 50 mg L-1 in just 30 minutes of reaction, and reaching 100% in 120 minutes. It was still observed a removal of 80% of the COD (Chemical Oxygen Demand) at the end of the reaction. The reaction rates increased with the dosage of the composite, which was expected. Though, increasing the concentration (%) of nFZV did not result in higher reaction rates. The reactions followed a pseudo-first order kinetics for the removal of NMS. After the samples were collected, they were submitted to chemical analysis, employing the techniques of UV-VIS spectroscopy, high performance liquid chromatography (HPLC) and chemical oxygen demand (COD). In order to characterize the composite, the following techniques were used: Scanning Electron Microscopy (SEM) coupled with Energy Dispersive x-Ray spectroscopy (EDS), which showed clearly the presence of nanoparticles onto the charcoal surface. Analysis of the surface of nFZV-CAG were also performed.
The composite nFZV-CAG was used for the catalytic ozonation of NMS in aqueous media. The ozone was generated by an ozone generator IPABRAS, fuelled with air. Different catalytic processes were evaluated such as O3, CAG, O3-CAG, O3-nFZV-CAG, and the variation of the nFZV concentration for the removal of NMS. The results showed that the combination of O3- nFZV-CAG was very efficient, leading to the mineralization of approximately 70% of NMS in 120 minutes of reaction. Such efficiency can be attributed to the electrolysis process, in which the Fe0 generates Fe2+ which generates hydroxyl radicals that are highly oxidant, leading to the destruction of the contaminant. The reactions followed the pseudo-first order kinetics for the removal of the pharmaceutical. After the samples were collected, they were submitted to chemical analysis such as, UV-VIS spectroscopy, high performance liquid chromatography (HPLC) and chemical oxygen demand (COD).
Martin, Benjamin David. "Removal and recovery of phosphorus from municipal wastewaters using a ferric nanoparticle adsorbent." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5767.
Ownby, Miles. "Phosphorus removal and recovery from wastewater via nano-enhanced adsorptive media." Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/40140.
Rapid increases in the world’s population and to-date industrial and agricultural practices have exacerbated the depletion of essential nutrients in today’s society. After years of environmentally lax agricultural and mining processes, society finds itself trapped between increasing nutrient shortage and the increased frequency of harmful algal blooms (HABs) caused by phosphorus leaching into water systems. New technologies that allow for removal and subsequent recovery and reuse of phosphorus from polluted streams is imperative. One such technology is nanoenhanced adsorption, which may allow to produce a valuable nutrient-rich solution upon desorption of the saturated media. This study evaluated the potential of four regeneration chemistries to desorb phosphorus from a commercially available ion exchange resin hybridized with iron-oxide nanoparticles using a Design of Experiments (DoE) approach. Novel regeneration solutions using a KOH/K2SO4 blend and a recovered NH4OH alkaline solution proved to be comparable to the "control" solution of KOH and H2SO4. Among the four regeneration methods studied, using the NH4OH solution shows the highest potential because: i) it is a valorized waste stream, ii) it showed a desorption efficiency comparable to the control solution, and iii) it did not demonstrate any dampening of the resin longevity after five adsorption and desorption cycles. Based on the DoE data, a series of regression models was developed to generate understanding with regard to expected phosphorus concentration from a regeneration process considering the regeneration chemistry, the treatment volume, the rinse speed, and the strength of the alkaline solution. Nutrient-rich regeneration solutions post-desorption show promising for subsequent use as hydroponic fertilizers or precursors for the P fertilizer industry. Future work should include the development of mechanistic process models to gain an even better understanding of the mechanics behind the desorption. Overall, the nano-enhanced adsorptive technology proposes a cost-effective and sustainable solution to the phosphorus problem in wastewater treatment applications across the globe.
Nawotka, Alexis. "Evaluation of Small Unilamellar Vesicles as a Removal Method of Benzo[a]pyrene from Humic Substances in Soils." Master's thesis, Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/592708.
M.S.
Polycyclic aromatic hydrocarbons (PAHs) are highly hydrophobic and lipophilic and are readily retained by soil surfaces and organic matter. Hence, several techniques have been developed in an effort to economically and effectively remove them from soil solids. Their strong affinity to soil organic matter limits their biodegradation processes by microorganisms, making them persistent in the soil environment. Recently, the use of “small unilamellar vesicles” (SUVs), nano-scale lipid aggregates, has been proposed as a means to enhance these microbial degradations, by effectively solubilizing lipophilic PAHs from the soil solids. In this thesis, laboratory-scale batch experiments were performed to examine this potential by measuring the uptake of benzo[a]pyrene (BaP), a model PAH compound, by SUVs from a simulated soil organic matter. This environmental surface was created by coating silica (SiO2) nanospheres with a layer of poly-L-lysine, followed by humic acid, and characterized by dynamic light scattering for particle size and zeta potential values. Then, these humic acid-bound SiO2 particles were saturated with BaP and then equilibrated with SUVs. The uptake of BaP by SUVs was measured through fluorescence spectroscopy, and the average amount of BaP concentrated in the 1 mg/L humic acid-bound SiO2 particles was found to be 1.77 µg/L. After one week of equilibration with SUVs, 94.4% and 83.6% of the added BaP was solubilized by SUVs (in solutions containing 50 mg/L and 100 mg/L of vesicles, respectively), indicating an excellent ability to extract BaP from the soil organic particles. SUVs can therefore be an effective vehicle to enhance the biodegradability of PAHs in soils, with potential as an environmentally sustainable and affordable method.
Temple University--Theses
Sarina, Sarina. "New catalysts for organic synthesis driven by light and efficient sorbents for removal of radioactive ions from water." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/63963/2/Sarina_Sarina_Thesis.pdf.
Zhang, Ming. "Elimination de nanoparticules par des procédés de flottation." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0012/document.
The removal of nanoparticles (NPs) from waters is a serious challenge in the water treatment field owing to the high stability and colloidal nature of particles. This study is devoted to develop effective flotation processes for NP separation. The investigation is firstly conducted to get a good knowledge of features and colloidal behaviors of NPs in suspension. Surface modification tests and adsorption-aggregation experiments are then carried out to understand the interaction mechanisms between NPs and flotation assisting reagents. Two types of flotation (dissolved air flotation (DAF) and colloidal gas aphrons (CGAs) involved flotation) were specially focused on: the former aims at using air bubbles to remove NP aggregates with the assistance of humic acid (HA), while the later employs the surface functionalized microbubbles, CGAs, to enhance the interaction of NP-bubble for the sake of high treating efficiency. Results show that, on mixing with the highly basic HA solution (pH12.9), the surface charge of TNPs is primarily neutralized by and then screened by polyanions of HA. When the pH of TNP-HA suspension is lower than 3 by adding HA stock solutions at pH4.0~9.0, the electrostatic attraction between TNPs and anions becomes insufficient but the aggregation of TNPs-colloidal HA occurs. In continuous DAF trials, the appropriate pH of HA stock solution (pH ≦ 9) and optimum HA concentration (11.1 mg/L DOC) for high TNP removals (> 95 %) are determined. The residual HA concentration remained in a low level even when HA is overdosed. When the pH of the TNP-HA suspension is highly acidic, most HA molecules are not really soluble and uncharged, and they may aggregate themselves and form hydrophobic colloidal precipitates to minimize the contact with the aqueous environment. As for the study of CGAs, the characterization results denote that introducing air flow during the CGA generation process can slow down the liquid drainage speed and may facilitate the particle separation performance; the stirring speed is a crucial parameter to create micron scale bubbles, and CGAs can be positively or negatively surface charged by using different surfactants. Different SiO2 NP (SNPs) can be efficiently separated from aqueous suspensions by the continuous CGA generation-flotation process with the highest SNP removal close to 100 %. The comparison tests between CGA-flotation and DAF denote that the former take the greater advantage because of its better treating effect and less surfactant demand
Abutin, Megan P. "Effects of Using Clay Nanoparticles as a Soil Amendment to Remove Nitrate from Stormwater." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1908.
He, Wenyan. "Coupling of an electrochemical process and a biological treatment for specific pollutant removal-Electrode surface functionalization." Rennes, Ecole nationale supérieure de chimie, 2016. http://www.theses.fr/2016ENCR0035.
The electrocatalytic reduction coupled to a biological process is a promising alternative for the degradation of chlorinated compounds. The selective cleavage of the carbon-chlorine bond in aqueous media was implemented for detoxification and to improve the biodegradability of chlorinated compounds. The mineralization of the electrolyzed solution can then be achieved by a biological treatment. The dechlorination was studied with the aid of transition metal complexes and Ag nanoparticles because of their high catalytic activity, leading to a total degradation of the organohalogenated studied compounds with good selectivity. The modification of graphite felt with Ni(tmc)Br2 or [Co(bpy(CH2OH)2)2]2+ complex highlighted the catalyst stability and current efficiency for dechlorination of 1,3-dichloropropane and alachlor , respectively, compared to the homogeneous process. Deschloroalachlor, was the main by-product of the electroreduction of alachlor, indicating the high selectivity of the Co complex system. The biodegradability of the solution was improved to 0. 31±0. 04 using Ag nanoparticles modified Ni foam in 0. 05 M NaOH solution with production of other dechlorinated by-products apart from deschloroalachlor, highlighting the interest of this new material. The new Ag nanoparticles modified graphite felt with Ni layer aimed at improving the catalytic performance of cathode by increasing the surface area of the support
Shipley, Heather J. "Magnetite nanoparticles for removal of arsenic from drinking water." Thesis, 2007. http://hdl.handle.net/1911/20649.
Sousa, Vânia Sofia Serrão de. "Development of drinking water treatment processes for nanoparticles removal." Doctoral thesis, 2020. http://hdl.handle.net/10400.1/15245.
A capacidade de controlar e manipular a forma e o tamanho de estruturas à escala nanométrica veio revolucionar diversas áreas industriais, possibilitando a criação de produtos adaptáveis, mais eficientes e de baixo custo através da integração de nanomateriais manufaturados, especialmente nanopartículas (NPs). Contudo, o crescimento exponencial de produtos do quotidiano contendo NPs leva à introdução destas nanoestruturas no meio aquático, originando potenciais riscos toxicológicos tanto para o ambiente como para a saúde humana. As características intrínsecas das NPs, tais como tamanho reduzido, forma variada, área superficial elevada, assim como as suas capacidades de agregação e dissolução, proporcionam uma maior reatividade, podendo ampliar o seu efeito tóxico e tornando-as responsáveis por efeitos nocivos nos organismos vivos. A introdução de NPs manufaturadas em águas superficiais utilizadas para a produção de água para consumo apresenta um elevado risco para a saúde humana, uma vez que pode levar à exposição direta às NPs através da ingestão de água contaminada. A ingestão de NPs pode causar efeitos adversos à saúde humana, tais como problemas renais, inflamações gastrointestinais, implicações ao nível do sistema neurológico e doenças cancerígenas. Embora ainda existam algumas dúvidas relacionadas com a toxicidade destas nanoestruturas, algumas NPs já foram identificadas como tóxicas para a saúde humana, nomeadamente as de origem metálica, onde se incluem as NPs de TiO2, Ag e CuO. Atualmente, já foram detetadas NPs em águas superficiais, águas para consumo humano e em água da torneira com concentrações entre os ng/L e os μg/L. Embora o tratamento de água seja uma das principais estratégias para evitar a exposição humana às NPs através da ingestão, os poucos estudos existentes descrevem os tratamentos convencionais como sendo ineficientes na sua remoção. Estes estudos, para além de mostrarem uma elevada variabilidade nas eficiências de remoção, foram maioritariamente realizados usando elevadas concentrações de NPs dispersas em água ultrapura, da torneira ou soluções sintéticas, sem considerarem a complexidade das águas superficiais naturais. Assim sendo, este trabalho pretendeu estudar a capacidade dos tratamentos de água convencionais e avançados para remover nanopartículas de águas superficiais. Para tal, a remoção de NPs de origem metálica foi explorada e avaliada usando diversas estratégias de tratamento, de modo a garantir uma eficiente remoção de NPs e de iões provenientes da sua dissolução. Os tratamentos propostos tiveram também por base a minimização do impacte da requalificação das estações de tratamento de águas para consumo humano recuperando os processos mais utilizados na produção de água potável. Para os ensaios foram escolhidas nanopartículas manufaturadas disponíveis comercialmente, TiO2, Ag e CuO, com base na sua elevada produção e aplicação em produtos do quotidiano. De modo a compreender os mecanismos de remoção, as NPs foram usadas individualmente e em conjunto dispersas em águas sintéticas (águas modelo) e águas naturais provenientes de barragens (Alentejo e Algarve) atualmente utilizadas para a produção de água para consumo humano. Em todas as opções de tratamento estudadas, os processos foram sempre otimizados tendo em vista a maximização da remoção das NPs, aplicando condições operacionais típicas em contexto real de tratamento de água. O tipo e doses de coagulante e carvão ativado testados são também usados em contexto real. O tratamento convencional coagulação/floculação/sedimentação (C/F/S) demonstrou ter capacidade para remover NPs, tanto em águas sintéticas como naturais, utilizando um coagulante polimérico de alumínio. Este processo apresentou eficiências elevadas (ca. 95%) tanto na remoção das NPs individualmente, como na sua remoção simultânea (variando entre 93% e 99% dependendo da NP e das características da água. Contudo, foi observado que para alcançar remoções semelhante de NPs de TiO2, as águas hidrofóbicas necessitam de uma dose de coagulante mais elevada do que as hidrofílicas. Ao contrário das características das águas, a presença de diferentes NPs em conjunto não afetou a dose de coagulante necessária. Determinou-se que o mecanismo de remoção de NPs mais provável foi a neutralização de cargas. No final do processo, as concentrações residuais de NPs nas águas tratadas foram, 6.5±2.1 e 2.5±0.7 μg Ti/L, 15.0±1.4 e 6.0±1.4 μg Ag/L, e 18.8±8.8 e 0.5±0.1 μg Cu/L, para a água natural com menor turvação e matéria orgânica natural (NOM) e para a água natural com maior turvação e NOM, respetivamente. De modo a diminuir as concentrações residuais de NPs na água tratada, o processo convencional C/F/S foi combinado com a adsorção por carvão ativado em pó (C/F/S+PAC) e integrado com o tratamento avançado ultrafiltração (UF) num processo de tratamento híbrido (C/F/S→UF). O processo C/F/S+PAC foi mais eficiente na remoção das NPs de TiO2 (>99.9%), com o Ti a apresentar concentrações inferiores ao limite de deteção na água tratada. Para o mesmo tratamento as remoções de Ag e Cu foram superiores a 99.2%. Com a aplicação do tratamento híbrido (C/F/S→UF), não foram detetadas concentrações residuais nem de Ti nem de Cu na água filtrada. Contudo, foram detetadas concentrações entre 5.0 e 7.0 μg/L para a Ag. Este resultado foi associado à dissolução das AgNPs, uma vez que, tendo em conta o menor tamanho do poro da membrana comparado com o tamanho individual das NPs e dos agregados formados, a parte nanoparticulada foi removida. Com o intuito de remover tanto AgNPs, como os iões provenientes da dissolução foi utilizado o tratamento avançado de nanofiltração (NF). Com este tratamento os agregados e as nanopartículas individuais foram completamente removidas por exclusão de tamanho, tendo a remoção de Ag dissolvida chegado aos 99.9%, dependendo do conteúdo de sais e matéria orgânica natural das águas testadas. Os resultados obtidos permitem concluir que é possível remover de forma eficaz NPs durante o tratamento de água para consumo humano, utilizando uma combinação/sequência de tratamentos convencionais e avançados, sem prejudicar a qualidade da água final. Tal foi demonstrado pela comparação dos valores residuais de turvação, carbono orgânico dissolvido, SUVA (absorvência específica) e alumínio com os valores paramétricos nacionais e internacionais para a água para consumo humano. Uma linha de tratamento integrando C/F/S+PAC, seguido de UF ou até mesmo NF, apresenta-se como uma solução segura para eliminar a ameaça de ingestão de NPs através de água potável.
PhD Grant (SFRH/BD/100402/2014) from the Portuguese Foundation of Science and Technology, trough the European Social Found from European Union. CENSE – Center for Environmental and Sustainability Research which financed by national funds FCT/MCTES (UID/AMB/04085/2019).
Wei, Chao-Yuan, and 韋朝源. "The synthesis of zero valent copper nanoparticles for hexabromocyclododecane removal." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/zhsu8x.
國立臺灣大學
農業化學研究所
105
Because of flooding and microbial metabolism, humic acid in some natural reduction environments could be reduced and then interact with metal ions; moreover, the copper ion is easily to be reduced. To understand whether a reduced condition can facilitate the formation of zero valent Cu NPs and then interact with persistent organic pollutant (POP), HBCD, one of POP, is chosen as a target compound. First, Cu NPs were synthesized by sodium borohydride. The removal of HBCD by Cu NPs was increased with the Cu NPs dosage increased but with the initial HBCD concentration decreased. The highest rate constant presented in 3.5 g/L Cu NPs, moreover the mass-normalized rate constant was 14.4 min-1g-1. The removal of HBCD was also increased with the temperature increased. The estimated activation energy was about 32.21 kJ/mol, which is considered as surface controlled reaction. The removal of HBCD was decreased with the initial pH increased. However, with pH increased the passivation of Cu NPs such as copper (hydro)oxide was found and then contributed to the increase of HBCD adsorption efficiency. On the other hand, the pHzpc of Cu NPs is 8.1, the Cu NPs would aggregate with the increased pH and then reduce the rate constant. To understand the transformation of complexes of reduced humic acid and cupric ion, humic acid was chemically reduced by sodium borohydride, and cupric ion was well-mixed with the reduced humic acid (RHA) under different Cu(II) ion dosages and incubation period. The copper species of RHA-Cu were organic acid-copper complexes after the reacting time of 12 hours. Metallic copper was observed for the reacting time of 48 hours in the condition of 0.9 g/L RHA with 175 mmol/kg Cu(II) which were analyzed by X-ray adsorption near edge structure. The spatial distribution of zero valent copper in the humic acid were investigated by scanning photoemission microscopy. There were two peaks at 1384 and 1598 cm-1 owning to the carboxylate vibrations, indicating that the HA complexes with Cu(II) via chemical bonding which were investigated by Fourier transform infrared spectroscopy. The particle size of metallic copper of RHA-Cu was around 50 nm was analyzed by single particle-inductively coupled plasma-mass spectrometry. The removal efficiency of HBCD by RHA-Cu was 34.5% after 24 hours and bromide ions were detected, indicating a reduction and debromination reaction of HBCD. Our results demonstrate the metallic copper can be synthesized by humic substances in a redox condition, which could provide a potential for HBCD removal through this abiotic chemical process.
Shih, Cheng-Jhih, and 石承治. "Heavy Metal Removal from Wastewater Using Zero-Valent Iron Nanoparticles." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/08799452939922399615.
國立高雄第一科技大學
環境與安全衛生工程所
95
The purpose of this study was aimed to investigate the reaction behavior of heavy metals (Cu、Zn、Pb、Ni、Cr) with zero-valent iron (ZVI) nanoparticles in the wastewater. The influence factors, such as initial pH, dosage of nanoscale ZVI and initial concentration of heavy metal, on the removal efficiency of heavy metals by ZVI in the wastewater were examined by the batch experiments in this study.Furthermore, the analysis of X-ray diffraction (XRD) was carried out to observe the products on the ZVI surface after the treatment of heavy metals from the wastewater. The results showed that the removal of heavy metals was affected by initial pH. The rate and efficiency of metal removal increased with decreasing initial pH. Higher than 90 % of the heavy metals (Cu、Zn、Pb、Cr) was removed when the initial pH was controlled at 2. The removal efficiency of heavy metal were in the decreasing order: Cu = Cr > Zn = Pb > Ni. In addition, the rate and efficiency of metal removal increased as the dosage of nanoscale ZVI increased. The removal efficiency of heavy metal was higher than 80% when 2.0 g/L of ZVI was added in the wastewater. On the other hand, the slow rate and low efficiency of metal removal from the wastewater treated by nanoscale ZVI was found in the wastewater with high concentration of heavy metal. Generally, the removal kinetic of heavy metals from the wastewater by nanoscale ZVI was well described by the pseudo-first order reaction. The XRD analysis revealed that iron corrosion products including r-FeOOH、 Fe6(OH)12SO4.nH2O and/or Fe(II)Fe(III)3(OH)12Cl3.H2O were formed at the surface of nanoscale ZVI particles after the treatment of heavy metals from the wastewater.
Desai, Ishan. "Mercury Removal from Aqueous Systems Using Commercial and Laboratory Prepared Metal Oxide Nanoparticles." 2009. http://hdl.handle.net/1969.1/ETD-TAMU-2009-08-6973.
Yean, Su Jin. "Arsenic removal using iron oxides: Application of magnetite nanoparticles and iron salts." Thesis, 2008. http://hdl.handle.net/1911/22252.