Segui questo link per vedere altri tipi di pubblicazioni sul tema: Iron removal.
Tesi sul tema "Iron removal"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Iron removal".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
1
Leake, Thomas Russell. "Zinc removal using biogenic iron oxides". Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/T_Leake_120409.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in enviromental engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 28, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 27-31).
2
Moridani, Majid Yousefi. "Hydroxpyridinone iron chelators". Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243728.
Testo completo
3
Swarna, Anitha. "Removal of Arsenic Using Iron Coated Limestone". TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1342.
Testo completoAbstract (sommario):
Arsenic contamination in drinking water is a severe problem worldwide. The best way to prevent hazardous diseases from chronic arsenic exposure is to remove the exposure. Efforts to remediate arsenic in drinking water have taken two tracks. One is to provide surface or shallow well water sources as an alternative to the arsenic contaminated deep wells. Another approach is to remove arsenic from the contaminated water. Different removal technologies like oxidation, chemical coagulation, precipitation, adsorption and others are available. There are problems and benefits associated with each of these approaches that can be related to cultural, socio-economic and engineering influences. The method proposed in this research is adsorption of arsenic to iron coated limestone. Different iron coated limestone samples were prepared. Standard solutions of 100ppb arsenic were prepared and batch and kinetic experiments were conducted. The final solution concentrations were analyzed by Graphite Furnace Atomic Adsorption Spectroscopy (GFAAs) and the results showed that iron coated limestone removed arsenic below 10ppb with 5 grams of material. Variations in iron coverage impacted efficiency of arsenic removal.
4
Ahmed, F. "Low cost iron removal for handpump tubewells". Thesis, University of Strathclyde, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382316.
Testo completo
5
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.
Testo completoAbstract (sommario):
Nanoscale zero-valent iron (NZVI) particles and iron cross-linked alginate (FCA) beads were successfully used for the first time for phosphate removal and recovery. NZVI was successfully used for phosphate removal and recovery. Batch studies indicated a removal of ~96 to 100% phosphate in 30 min (1, 5, and 10 mg PO43--P/L with 400 mg NZVI/L). Phosphate removal efficiency by NZVI was 13.9 times higher compared to Microscale ZVI (MZVI) particles. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters. The presence of sulfate, nitrate, and humic substances and the change in ionic strength in the water marginally affected phosphate removal by NZVI. A maximum phosphate recovery of ~78% was achieved in 30 min at pH 12.
Novel iron cross-linked alginate (FCA) beads were synthesized, characterized and used for phosphate removal. The beads removed up to 37-100% phosphate from aqueous solution in 24 h. Freundlich isotherm was found to most closely fit with experimental data and the maximum adsorption capacity was found to be 14.77 mg/g of dry beads. The presence of chloride, bicarbonate, sulfate, nitrate, and natural organic matters in aqueous solution did not interfere in phosphate removal by FCA beads. The phosphate removal efficacy FCA beads was not affected due to change in pH (4-9).
Nanosacle zero-valent iron (NZVI) and iron cross-linked alginate beads were also tested for phosphate removal using actual wastewater treatment plant effluent and animal feedlot runoff. The FCA beads could remove ~63% and ~77% phosphate from wastewater and feedlot runoff in 15 min, respectively.
Bioavailability of phosphate was examined using algae and higher plants. Phosphate and iron bioavailability of the NZVI sorbed phosphate was examined by supplying spent particles (NZVI with sorbed phosphate) to Tyee Spinach (Spinacia oleracea) and algae (Selenastrum capricornutum). Results revealed that the phosphate was bioavailable for both the algae and spinach. Also, presence of the nanoparticles enhanced the algae growth and plant growth and increases in biomass and plant length were observed. Iron (from spent NZVI) was found to be bioavailable for spinach.
6
Iatrou, Angela. "Removal of chlorite by reaction with ferrous iron". Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/42223.
Testo completoAbstract (sommario):
The use of chlorine dioxide as an oxidant and/or
disinfectant for drinking water treatment has been an
alternative considered when utilities seek to control
trihalomethane concentrations. However, concern regarding
residual concentrations of chlorite and chlorate have
resulted in limitations on applied chlorine dioxide dosages.
This study describes the use of ferrous iron as a possible
reducing agent for the elimination of residual chlorite from
drinking water.
Master of Science
7
Cordray, Antoine. "Phosphorus removal characteristics on biogenic ferrous iron oxides". Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Thesis/Fall2008/a_cordray_111708.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in environmental engineering)--Washington State University, December 2008.Title from PDF title page (viewed on Dec. 23, 2008). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 69-72).
8
Xie, Li. "Factors and mechanisms controlling bromate removal by zerovalent iron /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202005%20XIE.
Testo completo
9
Isaeva, Margarita, e Castro Natasha Montes. "Water Treatment for the Removal of Iron and Manganese". Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-5357.
Testo completoAbstract (sommario):
The purpose of the study is to find a suitable method for removal of iron and manganese considering local economic and environmental aspects. El Salvador is situated in Central America with a coast line towards the Pacific Ocean. The country borders Guatemala and Honduras. Aguilares is a town situated in the department of San Salvador, with a population of approximately 33,000 people. Currently, the population is provided with water for about two hours per day, since it is the highest capacity of the existing wells. During these two hours many households fill a small tank with water to use for the remainder of the day. The water is not safe to use for oral consumption because of the levels of bacteria and other contamination. One of the wells, situated in the community of Florída is not in use at this date because of the high levels of Iron and Manganese in the ground water which cannot be removed with the present technique.Ground water is naturally pure from bacteria at a depth of 30 m or more, however solved metals may occur and if the levels are too high the water is unsuitable to drink. The recommended maximum levels by WHO (2008) [1] for Iron and Manganese are 2 mg/l and 0.5 mg/l respectively.Literature and field studies led to the following results; Iron and manganese can be removed by precipitation followed by separation. Precipitation is achieved by aeration, oxygenation or chemical oxidation and separation is achieved by filtration or sedimentation.The different methods all have advantages and disadvantages. However the conclusion reached in this report is that aeration and filtration should be used in the case of Florída. What equipment and construction that should be used depends on economic and resource factors as well as water requirements, which is up to the council of Aguilares to deliberate.
10
Vercellotti, Joseph M. "Kinetics of iron removal using potassium permanganate and ozone". Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182873479.
Testo completo
11
Al-Zahrani, Abdulnaser A. "Chloride ion removal from archaeological iron and #beta#-FeOOH". Thesis, Cardiff University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313137.
Testo completoAbstract (sommario):
The stabilisation of archaeological iron is considered as one of the major problems facing the archaeological conservator today. Free chlorides, held as counter ions at the metallic anode, act as electrolytes and promote corrosion of metallic iron This study examines and compares the efficiency of a range of aqueous wash methods currently used to remove chloride ions from archaeological iron and determines how these various treatments work. It also investigates the effect of selected aqueous wash treatments on the chloride rich metastable corrosion product 0-FeOOH. The amount of Cl'removed from 0-FeOOH and any transformations to new compounds are recorded. Iron objects were treated using aqueous Soxhlet extraction with nitrogen, aqueous sodium hydroxide and aqueous alkaline sulphite solutions. Synthetic O-FeOOH and PFeOOH1Fe3Om4 ixtures were washed in aqueouss odium hydroxide, aqueousa lkaline sulphite solution, aqueous sodium sulphite, hot and cold deionised water. The outcome of the work showed that: (1) For archaeological iron objects: O. SM nitrogen de-aerated aqueous NaOH solutions are very efficient chloride extractors, often approaching a 100% efficiency. Almost as efficient were 0.5M aqueous... NaOH/Na2SO3 treatment solutions. Nitrogen de-aeration of treatment solutions improves their cr extraction efficiency, by freeing Cl' from its counter ion role. Hydroxide ions improve extraction efficiency of Cl- from iron objects in nitrogen and Na2S03 de-aerated environments. The de-aerated aqueous Soxhlet extraction method, as suggested by Scott and Seeley (1986), is a less efficient chloride extractor than either nitrogen de-aerated 0.5M NaOH or 0.5M NaOH/Na2SO3. De-aerated NaOH treatment solutions are to be preferred to NaOH/Na2SO3 solutions, as they do not introduce residual electrolyte ions (SO 42). (2) For O-FeOOH samples: Pure O-FeOOH and P-FeOOH/Fe3O4 mixtures reacted differently during washing. Pure 0-FeOOH completely transformed to cc-FeOOH in the alkaline environments provided by NaOH and NaOH/Na2SO3. This released all the chloride from the PFeOOH. In NaOH solutions within the range pH8.5 to 10.5 0-FeOOH/Fe3O4 transformed mostly to Fe304. Above pH1 1 there was limited conversion. Improved release of Cl' from P-FeOOII/Fe3O4 mixture correlated with the transformation of PFeOOH to Fe304.
12
Zhang, Liping. "Removal and inactivation of waterborne viruses using zerovalent iron". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 87 p, 2008. http://proquest.umi.com/pqdweb?did=1601514831&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Delaware, 2008.Principal faculty advisors: Yan Jin, Dept. of Plant & Soil Sciences; and Pei C. Chiu, Dept. of Civil & Environmental Engineering. Includes bibliographical references.
13
Falconer, Haley Ryanne Watson. "Column filter studies phosphorus removal using biogenic iron oxides /". Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/H_Falconer_100709.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in environmental engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 12, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 52-53).
14
Weatherill, Joshua. "Iron oxyhydroxide formation in the enhanced actinide removal plant". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/iron-oxyhydroxide-formation-in-the-enhanced-actinide-removal-plant(6e42dca7-48be-4261-8178-5413bc172f40).html.
Testo completoAbstract (sommario):
The Enhanced Actinide Removal Plant (EARP), located on the Sellafield site, is one of the UK's most crucial radioactive effluent treatment plants. EARP removes actinides and select fission products from routine reprocessing effluents by association with a ferric iron oxyhydroxide floc, which is precipitated from acidic effluent streams by the addition of NaOH. The effluent compositions that EARP receives will change in character as the Sellafield site transitions from its current routine reprocessing operations to post-operational clean-out and accelerated decommissioning activities over the next few years. An enhanced understanding of the iron oxyhydroxide formation processes occurring in EARP would help underpin optimisation of current plant efficiency and allow better prediction of changes in efficiency as effluent composition varies. In this study, iron oxyhydroxide formation, properties and evolution with time under EARP-relevant conditions were characterized. These processes were investigated in a pure ferric nitrate system and systems with added sulfate, phosphate and boric acid using a range of techniques including SAXS, TEM and FTIR. In all the experimental systems the iron oxyhydroxide floc was composed of nanoparticulate ferrihydrite aggregated into extensive mass fractal structures. In situ SAXS experiments showed that formation proceeded via a precursor cluster pathway whereby Fe(III) clusters ~ 0.45 nm in radius form rapidly at pH 0.12 - pH 1.5 upon dropwise addition of strong NaOH to the acidic effluent simulants. Further analysis indicates these clusters are Fe13 Keggin clusters, which have previously been shown to be an important structural motif in the ferrihydrite structure. With further pH increase, cluster aggregation occurs along with precipitation of low molecular weight Fe(III) species (mostly monomers), leading to formation of ferrihydrite nanoparticles which preserve the Keggin cluster in the core. Phosphate, sulfate and boric acid exhibit varying interactions with the solid phase throughout the formation process, with both inner and outer sphere adsorption observed for different species. Ageing experiments show that the ferrihydrite floc readily undergoes transformation leading to predominantly hematite formation, except in the presence of phosphate (concentrations > 10 ppm) where transformation is entirely inhibited due to phosphate adsorption to the floc. These results progress the fundamental understanding of the iron oxyhydroxide formation and ageing processes occurring in EARP.
15
Yang, Yang. "Removal Mechanisms of Protective Iron Carbonate Layer in Flowing Solutions". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1339731278.
Testo completo
16
Faulkner, David W. S. "Electrokinetics and iron precipitation for ground engineering and metal removal". Thesis, University of Brighton, 2010. https://research.brighton.ac.uk/en/studentTheses/e4fe05a6-93a7-40d4-9065-7a04e9188395.
Testo completoAbstract (sommario):
Passing an electric current through a wet mass of soil results in the net movement of pore water, and charged species in solution, whose direction of movement is controlled by the polarisation of the electrodes, and the charge on the dissolved species. The use of electric fields for the movement of soil components is termed electrokinetics.
17
Diz, Harry Richard. "Chemical and Biological Treatment of Acid Mine Drainage for the Removal of Heavy Metals and Acidity". Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30713.
Testo completoAbstract (sommario):
This dissertation reports the design of a process (patent
pending) to remove iron from acid mine drainage (AMD)
without the formation of metal hydroxide sludge. The
system includes the oxidation of ferrous iron in a packed
bed bioreactor, the precipitation of iron within a
fluidized bed, the removal of manganese and heavy metals
(Cu, Ni, Zn) in a trickling filter at high (>9) pH, with
final neutralization in a carbonate bed. The technique
avoided the generation of iron oxyhydroxide sludge.
In the packed bed bioreactor, maximum substrate oxidation
rate (R,max) was 1500 mg L-1 h-1 at dilution rates of 2
h-1, with oxidation efficiency at 98%. The half-saturation
constant (similar to a Ks) was 6 mg L-1. The oxidation
rate was affected by dissolved oxygen below 2 mg L-1, with
a Monod-type Ko for DO of 0.33 mg L-1. Temperature had a
significant effect on oxidation rate, but pH (2.0 to 3.25)
and supplemental CO2 did not affect oxidation rates.
Iron hydroxide precipitation was not instantaneous when
base was added at a OH/Fe ratio of less than 3. Induction
time was found to be a function of pH, sulfate
concentration and iron concentration, with a multiple R2
of 0.84. Aqueous [Al (III)] and [Mn (II)] did not
significantly (a = 0.05) affect induction time over the
range of concentrations investigated.
When specific loading to the fluidized bed reactor exceeded
0.20 mg Fe m-2 h-1, dispersed iron particulates formed
leading to a turbid effluent. Reactor pH determined the
minimum iron concentration in the effluent, with an optimal
at pH 3.5. Total iron removals of 98% were achieved in
the fluidized bed with effluent [Fe] below 10 mg L-1.
Further iron removal occurred within the calcium carbonate
bed.
Heavy metals were removed both in the fluidized bed reactor
as well as in the trickling filter. Oxidation at pH >9
caused manganese to precipitate (96% removal); removals of
copper, nickel, and zinc were due primarily to sorption
onto oxide surfaces. Removals averaged 97% for copper,
70% for nickel and 94% for zinc.
The treatment strategy produced an effluent relatively
free of iron (< 3 mg/L), without the formation of iron
sludge and may be suitable for AMD seeps, drainage from
acidic tailings ponds, active mine effluent, and acidic
iron-rich industrial wastewater.Ph. D.
18
Kumar, Arun Gurian Patrick L. "Arsenic removal effectiveness of iron oxide-based fibrous adsorbents and stability of granular iron oxide media /". Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2929.
Testo completo
19
Conley, LuAnne Simpson. "Removal of complexed iron by chemical oxidation and/or alum coagulation". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-03172010-020643/.
Testo completo
20
Gui, Minghui. "IRON AND IRON OXIDE FUNCTIONALIZED MEMBRANES WITH APPLICATIONS TO SELECTED CHLORO-ORGANIC AND METAL REMOVAL FROM WATER". UKnowledge, 2014. http://uknowledge.uky.edu/cme_etds/37.
Testo completoAbstract (sommario):
The development of functionalized membranes with tunable pores and catalytic properties provides us an opportunity to manipulate the membrane pore structure, selectivity and reactivity. By introducing the functional groups into membrane pores, dissolved metal ions and reactive particles can be effectively immobilized within the polymer matrix for toxic chloro-organic and heavy metal remediation in water.
A polyelectrolyte functionalized membrane platform with tunable pore size and ion exchange capacity has been developed for iron/iron oxide nano-catalyst synthesis and chlorinated organic compound (trichloroethylene, TCE and polychlorinated biphenyls, PCBs) degradation. Highly robust polyvinylidene fluoride (PVDF) microfiltration membranes are used as the support with cross-linked polyacrylic acid (PAA) filled in the pores. By varying the environmental pH, PAA hydrogels have either swelling or collapsing behavior, resulting in different effective membrane pore sizes for different separation purposes. Cation exchange groups (i.e. carboxyl groups) in PAA chains prevent the aggregation and leaching of nanoparticles (NPs) during in-situ synthesis and reaction. Depending on the catalyst loading and residence time, TCE and PCBs can be completely degraded by reduction of zero-valent iron and bimetallic iron/palladium NPs, or iron oxide catalyzed free radical oxidation at near-neutral pH. Biphenyl from PCB dechlorination can be further oxidized by hydroxyl radicals (OH•) generated from hydrogen peroxide (H2O2) decomposition. Hydroxybiphenyls and benzoic acid are identified as oxidation products. Line scan and elemental mapping in transmission electron microscopy (TEM) and X-ray photo electron spectroscopy (XPS) characterizations are conducted to understand the effect of iron surface transformation on NP reactivity, and to optimize the membrane functionalization.
The same platform can also be used to remove toxic metal selenium in the scrubber water of coal-fired power plants. By reducing the salt concentration in water or increasing the residence time and temperature, the concentration of selenium oxyanions in functionalized membrane permeate can be reduced to less than 10 µg/L. Selenium is captured in membranes by both iron reduction to metallic selenium and iron oxide adsorption. The full-scale flat sheet functionalized membrane and spiral wound modules have also been developed. Iron NPs with alterable loadings are successfully synthesized inside the membrane module for real water applications.
21
Vaughan, Ronald L. "Modeling AS(V) removal in iron oxide impregnated activated carbon columns". free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060150.
Testo completo
22
Hurst, Gregory H. "Evaluation of the use of ferrous iron for chlorite removal under alkaline pH conditions". Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/42148.
Testo completoAbstract (sommario):
Chlorine dioxide has gained much attention for use as a
possible alternative disinfectant in water treatment plants
due to concerns regarding trihalomethane formation in
drinking waters which utilize chlorine as the primary
disinfectant and the strict regulations regarding THM's and
THMFP (MCL of 0.080 mg/L for TTHMs) (Pontius, 1993).
Although the use of Cl02 as a disinfectant prevents the
formation of THM's, concern exists regarding the potential
health risks due to the disinfection-by-products of chlorite
and chlorate.
The main objective of this project was to study the
removal of chlorite by reaction with ferrous iron under
elevated pH conditions. The stoichiometry of the reaction
was evaluated under the following conditions: solution pH
of 6.0 to 10.0, 02(aq) concentration of 0.5 to 10 mg/L, and
solution DOC concentrations of 0 to 15 mg/L. Mass balances
were conducted to define the speciation of the oxychlorine
residuals associated with the reduction of Cl02 by Fe(II).
Master of Science
23
Sun, Qingyun. "Iron and acid removal from acid mine drainage in open limestone systems". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1315.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains ix, 112 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 56-57).
24
Mamtaz, Rowshan. "Low cost technology for removal of arsenic from water : with particular reference to Bangladesh". Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21155.
Testo completoAbstract (sommario):
The contamination of groundwater by arsenic is currently a major concern in Bangladesh. Arsenic in groundwater was first detected in 1993 following reports of many people suffering from arsenical diseases. Further investigations showed the extent of the problem with large areas of the country's water supply being affected and millions of people at serious risk of arsenic poisoning. Technology for arsenic removal from water already exists. However, the socioeconomic conditions which prevail in Bangladesh, do not permit implementation of this type of technology on grounds of cost. The main objective of this study was to develop a low cost technique for the removal of arsenic from contaminated groundwater using the naturally occurring iron, which is another water quality constraint in Bangladesh. The approach was to form arsenic-iron complexes by coprecipitation and adsorption of arsenic on iron. It has been demonstrated that provided the iron levels are sufficiently high (say >_ 1.2 mg/1), simple shaking of a container and allowing the arsenic-iron complex to settle out for 3 days could reduce the concentration of arsenic from 0.10 mg/l to Bangladesh standard (0.05 mg/1). In experimental program, As(III) form of arsenic was used as this form is more likely to be present in groundwater. From laboratory studies, it was shown that the removal rate was largely controlled by the Fe/As ratio, pH and the As concentration. Arsenic removal increases with increasing Fe/As ratio and is favoured by increasing pH in the range of 5 to 8. Separation of the precipitates was achieved by settlement. Following prolonged settlement, it was found that arsenic removal could exceed the removal achieved by filtration through a 0.45 μm filter paper. The experiments demonstrated that about 77% arsenic removal could be achieved from water containing 0.2 mg/l As(III), 4.0 mg/1 Fe at pH 7.5 by manual flocculation (1 min manual mixing) and 3 days settlement. The use of ordinary charcoal, which is cheap and easily available, was investigated for removal of arsenic and was found to be ineffective. From maps of the known distributions of As, Fe and pH, it was evident that 63% of the area in Bangladesh complied with the Bangladesh standard for arsenic. By interpreting the maps and applying the potential removal by coprecipitation-adsorption and settlement technique, it was estimated that a further 8% of area would comply with the Bangladesh standard freeing an additional 7 million people from arsenic contamination.
25
Beheshti, Reza. "Sustainable Aluminum and Iron Production". Doctoral thesis, KTH, Kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196547.
Testo completoAbstract (sommario):
Aluminium recycling requires 95% less energy than primary production with no loss of quality. The Black Dross (BD) produced during secondary aluminium production contains high amounts of water-soluble compounds, therefore it is considered as a toxic waste. In the present work, salt removal from BD by thermal treatment has been investigated in laboratory scale. The optimum conditions for treatment were established, i.e., temperature, gas flow rate, holding time, rotation rate, and sample size. The overall degree of chloride removal was established to increase as a function of time and temperature. Even Pretreated Black Dross (PBD) was evaluated as a possible raw material for the production of a calcium aluminate-based ladle-fluxing agent to be used in the steel industry. The effects of different process parameters on the properties of the produced flux were experimentally investigated, i.e. CaO/Al2O3 ratio, temperature, holding time, and cooling media. The utilization of PBD as the alumina source during the production of a calcium aluminate fluxing agent shows promising results. The iron/steel industry is responsible for 9% of anthropogenic energy and process CO2 emissions. It is believed that the only way to a long-term reduction of the CO2 emissions from the iron/steel industry is commercialization of alternative processes such as Direct Reduction (DR) of iron oxide. Detailed knowledge of the kinetics of the reduction reactions is, however, a prerequisite for the design and optimization of the DR process. To obtain a better understanding of the reduction kinetics, a model was developed step-by-step, from a single pellet to a fixed bed with many pellets. The equations were solved using the commercial software COMSOL Multiphysics®. The final model considers the reaction rate and mass transfer inside the pellet, as well as the mass transfers and heat transfer in the fixed bed. All the models were verified against experimental results, and where found to describe the results in a satisfying way.QC 20161128
26
Abedin, Md Anwarul. "Mitigation of Arsenic in Groundwater Using Zero Valent Iron: removal mechanism and application". 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142484.
Testo completo
27
Canas, Carlos Gonzalo. "Hydrogen sulfide removal from biogas with a fixed bed of rusted iron turnings". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26220.
Testo completoAbstract (sommario):
Biogas produced at farm level has many applications, however the hydrogen sulfide must be eliminated from the biogas to prevent any possible damage to equipment, users and operators, and the environment. Among the various options available to the farmer to clean hydrogen sulfide from biogas a fixed-bed of rusted iron turnings seems appropriate.
This study investigated the effectiveness of a fixed bed of rusted iron turnings in eliminating hydrogen sulfide. For that purpose, dynamic bench scale test were done to study the effects of flow rate (0.5 l/min, 0.75 l/min and 1.0 l/min) and hydrogen sulfide concentration (100 ppm and 200 ppm). The gas used was a mixture of saturated carbon dioxide and hydrogen sulfide. The iron turnings were made with a uniform thickness and width and allowed to oxidize under atmospheric conditions for 8 weeks.
The resulting breakthrough curves were well described by sigmoidal curves. The breakpoint time was affected by flow rate and hydrogen sulfide concentration. At the higher flows and concentrations the breakpoint times were smaller. In contrast, the mass of hydrogen sulfide removed up to breakpoint time was independent of flow rate and hydrogen sulfide concentration (0.83 g). Nevertheless, the maximum removal capacity was independent of hydrogen sulfide concentration but dependent on flow rate. The rate data conformed well to a surface rate model, however the calculated pseudo-rate constants were different for the flow rates and hydrogen sulfide concentrations used in this study. Thus it was not possible to define a mechanism control for the rate of reaction.
The fixed-bed was able to eliminate hydrogen sulfide from the gas mixture, however only 30 to 44% of the iron oxide reacted.Applied Science, Faculty of
Graduate
28
Gu, Zhimang. "Development and evaluation of innovative iron-containing porous carbon adsorbents for arsenic removal". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/5864.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 10, 2007) Vita. Includes bibliographical references.
29
Sinsabaugh, Robert L. "Removal of dissolved organic matter from surface waters by coagulation with trivalent iron". Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/49777.
Testo completo
30
Masters, Erika N. "Colloid Formation for the Removal of Natural Organic Matter during Iron Sulfate Coagulation". Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/43756.
Testo completoAbstract (sommario):
Removal of organic matter is increasingly important to drinking water utilities and consumers. Organic matter is a significant precursor in the formation of disinfection by-products (DBPs). The maximum contaminant levels for (DBPs) are decreasing and more DBPs are believed carcinogenic. Traditional coagulation focuses on the removal of particulate matter and in the last decade soluble species have also been targeted with high coagulant doses. However, colloidal matter is smaller than particulate matter and therefore not easily removed by conventional drinking water treatment. This research focused on the conversion of soluble organic matter to colloids using relatively low doses of ferric sulfate coagulant and the subsequent removal of the colloids by filtration during drinking water treatment. The goal is to achieve enhanced removal of soluble organic matter with minimal chemical costs and residual formation.
This study investigated the effects of pH, iron coagulant dose, turbidity, organic matter concentration, and temperature on colloid formation. Characterization of the colloidal organic matter was attempted using zeta potential and sizing analyses. Cationic low molecular weight, nonionic high molecular weight, and cationic medium molecular weight polymers were evaluated on their removal of colloidal organic matter.
Colloidal organic matter formation was affected by changes in coagulation pH, coagulant dose, and organic matter concentration, whereas turbidity and temperature did not significantly impact colloid formation. Decreased coagulation pH caused increased organic carbon removal. As coagulant dose was increased, colloid formation initially increased to maximum and subsequently rapidly decreased. Colloid formation was increased as the organic matter concentration increased. Due to low sample signal, the colloids could not be characterized using zeta potential and sizing analyses. In addition, polymers were ineffective for aggregating colloidal organic matter when used as flocculant aids.Master of Science
31
Saracusa, Emily L. "A Mathematical Model for Acid Mine Drainage Removal and Iron Hydroxide Crust Formation". University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1302448347.
Testo completo
32
Chaudhuri, Mahua. "Removal of hydrogen sulfide from groundwater using ozone and iron oxide-coated sand /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422983.
Testo completo
33
Ofverstrom, Svetlana. "Research and evaluation of iron impact on sludge digestion process". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140219_152012-51144.
Testo completoAbstract (sommario):
Research and evaluation of effect of traditional (iron salts) and alternative iron source (ochre) on anaerobic digestion of sludge mixture process have been made in dissertation. Research has been made in two European countries: Lithuania and Sweden. Sludge mixture used for the experiments was from biological phosphorus removal plants; ochre originated from groundwater treatment plants. Case study, laboratory and pilot-scale experiments have been made for the complex evaluation of impact of ochre on sludge digestion process. Standard and specific methodics were used for the evaluation of results. Based on results technology for using of ochre for the improving of the anaerobic digestion process at the treatment plants with biological phosphorus treatment has been proposed.Disertacijoje nagrinėjamas ir vertinamas tradicinio (geležies druskų) ir alternativaus geležies šaltinio (geležies paplavų) poveikis anaerobinio dumblo mišinio pūdymo procesui. Tyrimai buvo atlikti dviejose Europos Sąjungos šalyse: Lietuvoje ir Švedijoje. Tyrimams dumblo mišinys imtas iš biologinio fosforo šalinimo įrenginių; geležies paplavos – iš požeminio vandens gerinimo įrenginių. Siekiant kompleksiškai įvertinti geležies paplavų įtaką dumblo pūdymo procesui, buvo atlikti natūriniai, laboratoriniai ir pusiau gamybiniai tyrimai. Darbe panaudotos standartinės ir specifinės pūdymo proceso kokybės nustatymo metodikos. Remiantis gautais rezultatais buvo pasiūlyta technologinė geležies paplavų panaudojimo dumblo apdorojimo ūkyje, skirta nuotekų valymo įrenginiams su biologiniu fosforo šalinimu.
34
Ahn, Se Chang. "Removal of perchlorate in ammunition wastewater by zero-valent iron and perchlorate respiring bacteria". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 138 p, 2008. http://proquest.umi.com/pqdweb?did=1601522481&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Testo completo
35
Shiono, Yuhta, Hisao Hayashi, Shinnya Wakusawa, Fujiko Sanae, Toshikuni Takikawa, Motoyoshi Yano, Kenntaro Yoshioka e Hiros Saito. "Body iron stores and Iron restoration rate in Japanese patients with chronic Hepatitis C as measured during therapeutic Iron removal revealed neither Increased body iron stores nor effects of C282y and H63d mutations on iron indices". Nagoya University School of Medicine, 2001. http://hdl.handle.net/2237/5367.
Testo completo
36
Zhang, R. (Ruichi). "Investigation on modification conditions of iron-modified biomass and its use for phosphate removal". Master's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201710112970.
Testo completoAbstract (sommario):
Abstract
Increasing discharged anionic pollutants discharged into water has been a subject of concern worldwide. Although numerous conventional methods are used to treat these anion contaminated wastewater, most of them have their own limitations such as high investment cost, sensitive operation conditions, and sludge handling problems. Low-cost biosorbents have attracted a lot of attention for anion removal due to their abundance source, high availability, renewability and environmental sustainability. Four type of iron–modified biomaterials: sawdust, CA-sawdust (citric acid modified sawdust), peat and peat moss residue (PMR) were tested in the preliminary experiment for phosphate sorption. PMR was then selected as optimum biomass for phosphate removal based on its good phosphate removal efficiency. The effect of modification conditions: initial Fe(III) concentration (0.067 g Fe³⁺/50 mL, 0.133 g Fe³⁺/50 mL, and 0.201 g Fe³⁺/50 mL) and modification pH (5, 7 and 9) were investigated. Modification pH 5 and initial Fe(III) concentration (0.201 g Fe³⁺/50 mL) was observed to be the optimal condition for PMR modification, and then was selected for further studies. Phosphate sorption tests were carried out at room temperature as a function of solution pH (3–9) and contact time (30 mins, 60 mins, 1 h, 6 h and 24 h) at an initial phosphate (P) concentration of 15 mg/L. The removal efficiency decreased with increasing pH within the range of 3–9 and the maximum removal efficiency (82%) was observed at pH 3 after 24 hours contact time. However, considering low pH is not always practical to be applied in real industrial activities, thus the pH 4 was perceived as optimal pH in this study. The effect of the contact time on phosphate sorption was conducted at pH 4. With the increased contact time, the phosphate removal efficiency increased and reached to 70% at 24 hours contact time. Two batches (batch 1 and batch 2) were used to obtain the maximum capacity of iron-modified PMR at the initial phosphate (P) concentration in the range of 10 to 175 mg/L at pH 4 under the room temperature. Batch 1 was used also for all the sorption tests, while batch 2 was used only for maximum capacity tests. The maximum capacity was 9 mg/g and 13 mg/g for batch 1 and batch 2 at initial phosphate (P) concentration of 104 mg/L and 175 mg/L, respectively. The sorption followed the Langmuir isotherm but the results were opposite for non-linear model. Results showed that iron-modified PMR can be used effectively as a biosorbent for phosphate removal from aqueous solutions. XRD analyses showed that iron compound loaded on the PMR was amorphous iron oxyhydroxide, which was supposed to be two-line ferrihydrite. XPS analyses supported this finding.
37
Yahaya, Sani. "Bacterial removal of iron impurities to increase the quality and value of industrial minerals". Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1346.
Testo completoAbstract (sommario):
Kaolin, silica sand and high grade carbonates are industrial minerals widely and extensively used as fillers and coating agents in the manufacture of paper, ceramics, glass, paint and cosmetics. When mined, kaolin and silica sand are generally not pure, often associated with iron hydroxide and oxy-hydroxide impurities (ranging between 0.074 up to 44.2mg Fe per gram of mineral) usually in the form of Fe3+-phases adsorbed onto the mineral surface, covering the entire mineral surface, or admixed as a separate iron bearing phase. The ironbearing impurities associated with calcium carbonate are mostly ferrous (Fe2+) in the form of siderite (FeCO3). In all cases, the presence of iron affects the colour and the physical properties of the mineral, and so lowers the industrial value and limits the application and uses. Due to the environmental, economic and operational disadvantages associated with conventional physical and chemical refining processes, this thesis considers a microbial refining process in a closed non-growth system as an alternative for iron removal from these minerals. Bioreduction was initially optimised using 80ml microcosm batch experiments and subsequently up-scaled to a 4.5L closed system bioreactor with continuous monitoring of pH, Eh and temperature. The anaerobic removal of Fe(III)-bearing impurities from these minerals was investigated using different iron-reducing Shewanella strains (S. putrefaciens CIP8040, S. putrefaciens CN32, S. oneidensis MR-1, S. algae BrY and S. loihica) in the presence of anthraquinone 2,6 disulphonate (AQDS) serving as electron shuttling mediator. The efficiency of natural organic matter (NOM) was also investigated as a substitute for AQDS. In the microcosm experiments, up to 4.4% of the insoluble Fe(III) in kaolin (as determined by XRF) was successfully reduced to more soluble and leachable Fe(II) by the five different iron reducing bacteria (except S. loihica) after 5 days. This was equivalent to 46.6mg of bioreducible Fe2O3 per 100g of kaolin. After bioreduction, the colour value of the biotreated kaolin mineral improved, with a substantial increase in brightness from 76.1% to 79.7% and whiteness from 57.7% to 67.8%. For the silica sand, up to 17.6% of the iron bearing impurities (~117mg of bioreducible Fe2O3 per 100g of silica sand) was successfully removed after 15 days. In both cases, addition of AQDS as electron transport mediator enhanced the rate and extent of bioreduction by facilitating the exchange of electrons between the ironreducing bacteria and the iron-bearing phase in the mineral. Natural organic matter also increased the rate and extent of Fe(III) reduction when compared with experiments without electron shuttling mediators. Because iron-bearing impurities present in the carbonate (chalk) were mostly ferrous, biotreatment by iron reduction was unable to improve significantly the iron content and colour properties in this mineral. Another microbial bioleaching method was tested for the carbonate using Desulfovibrio desulfuricans. Desulfovibrio desulfuricans, which is a sulphate reducing bacterium, was able to leach Fe from the chalk but the Fe immediately precipitated as a different iron phase (probably iron sulfide) giving a dark coloration to the chalk. The colour properties did not improve, with the colour value decreasing below the initial value after sequential centrifugation. The 4.5L batch bioreactors designed to upscale the bioleaching process successfully supported the bioreduction of Fe(III)-oxide in both kaolin and silica sand. Up to 5.9% of the total iron bearing impurities of the same kaolin material was removed (equivalent to 62.2mg of bioreducible Fe2O3 per 100g of kaolin material) with appreciable improvement in brightness from 75.79% to 79.06% and whiteness from 55.69% to 66.01%), similar to what was observed in the small scale microcosm study. Bioleaching of silica sand (King’s Lynn) in the batch reactors successfully removed up to 53.9% of Fe-bearing impurities (~89.03mg of Fe2O3 per 100g of silica material) on day 4. The bioreduction did not cause any unfavourable modification in the mineralogy of either kaolin or silica sand, and no apparent crystalline byproduct was formed after biotreatment.
38
Bok-Badura, J., A. Jakóbik-Kolon, M. Turek, S. Boncel, K. Karoń, J. Laskowski e P. Ceglarski. "Differences in Iron Removal from Carbon Nanoonions and Multiwall Carbon Nanotubes for Analytical Purpose". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42517.
Testo completoAbstract (sommario):
The paper describes the differences between wet iron removal from carbon nanoonions and from multiwall carbon nanotubes for analytical purpose. Nowadays, both carbon nanoonions and multiwall carbon nanotubes are one of the most interesting materials with applicability in electronics, medicine and biotechnology. Medical applications of those nanomaterials require not only recognition of their structure but also measurement of metal impurities concentration. Inductively coupled plasma optical emission spectrometry as a method for Fe-determination requires liquid samples. Hence, we propose various protocols for leaching of iron from studied materials. Our results proved that structure of nanomaterials have an impact on the efficiency of iron removal.
39
Beard, Kelly Marie. "Role of oxidants in the removal of iron and organics from Harwood's Mill Reservoir". Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/104292.
Testo completo
40
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.
Testo completoAbstract (sommario):
Dissolved metalloids, such as arsenic (As), antimony (Sb) and boron (B), are often found in contaminated surface waters or groundwater. Their removal is essential for protecting the water environment. This MEngSci research project investigated the use of magnetite (Fe3O4) nanoparticle – polymethylmethacrylate (PMMA) composites, as a reusable adsorbent toremove dissolved As andSb.
Comparative experiments were carried out to examine the effectiveness ofcommercial magnetite nanoparticles, lab synthesized nanoparticles, and the composites of synthesed Fe3O4nanoparticle-PMMA, for adsorbing As (III) and Sb (III) ions. The effects of major environmental and operating parameters (e.g. pH and adsorbent dosage) were investigated.Four cycles of adsorption-desorption experiment were conducted; the results demonstrating significant capability of the composites of removing the dissolved metalloids. In addition, the competitive adsorption of As and Sb to the composites was studied in batch experiments. It was found that the affinity of antimony to the adsorbents was generally greater than arsenic ions. A variety of analytical methods, such as X-Ray Diffraction (XRD), microwave plasma atomic emission spectrometry (MP-AES) and Malvern Zetasizer, were used to characterise the properties of the composites and analyze dissolved As and Sb concentrations. Details of the experimentalprocedures and results have been presented in this MEngSci thesis. Overall, this research validated: (a) a process to synthesize Fe3O4 nanoparticle-PMMA composites; and (b) the efficiency of using the composites to remove dissolved metalloids from contaminated water.
41
Calderón, Roca Blanca. "Application of iron-based nanostructures to contaminant remediation". Doctoral thesis, Universidad de Alicante, 2017. http://hdl.handle.net/10045/69809.
Testo completoAbstract (sommario):
This thesis focuses on the synthesis and applications of nanoscale zero valent iron (nZVI) in the environmental remediation of contaminants. The polyvalent characteristics of this nanomaterial are evaluated in this work with the study of its application in a wide range of contaminants: heavy metals and pesticides in water medium, and malodorous sulfur compounds present in air streams. Moreover, a novel method of synthesis of encapsulated nZVI from a waste material is presented, which meets the principles of green chemistry and at the same time represents a low-cost method of obtaining nZVI with improved characteristics. Chapter 1 describes the current state of the topics that will be discussed in the rest of the thesis. Specifically, the different mechanisms of contaminant remediation by nZVI are discussed, a summary of the current synthesis methods is presented and the principal modifications of nZVI to improve its characteristics are described. Finally, the limitations of the current techniques are assessed, which will be the starting point of the thesis. In Chapter 2, the application of nZVI to heavy metal removal during long time periods is explored. The contaminants studied are Zn, Cd, Ni, Cu and Cr, which are the most common heavy metals found in ground and wastewater. A delivery-effect of the heavy metal ions that had already been attached to nZVI surface is observed after long reaction times, which is a consequence of the nZVI aging and oxidation. The conditions that influence the delivery-effect are assessed and possible solutions to this detected problem are presented. In Chapter 3, nZVI is applied to the removal of sulfur-based odorous compounds in air streams. The compounds studied are hydrogen sulfide and dimethyl disulfide (DMDS), which are commonly found in wastewater treatment plants. Both nZVI loading and pH are varied to assess their influence on the process. Bimetallic nanoscale particles of Cu/Fe, Ni/Fe and Pd/Fe are synthesized in order to improve the DMDS abatement by the nZVI. The advantages of this new method for odor removal are discussed at the look of the experimental results. Lastly, a pilot scale test was performed in a wastewater treatment plant in order to test the effectiveness of the nZVI in a real application. The nZVI were applied in a scrubber to eliminate the sulfurous compounds from the pre-treatment area of the wastewater treatment plant. Chapter 4 deals with the application of nZVI to the oxidation of non-biodegradable pollutants by the Fenton reaction. Specifically, the effect of pH on the degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is studied. The advantages of using nZVI as a Fenton reagent compared to homogeneous Fenton are described. Furthermore, the addition of UV-light to the process is investigated. Finally, the main degradation intermediates of the reaction are identified and a degradation mechanism is accordingly proposed. In Chapter 5, the presence of polychlorinated dioxins and furans (PCDD/Fs) in the nZVI surface is addressed. Studies have shown that nZVI enhances the formation of such chlorinated compounds during thermal processes, but it is unclear which the origin of the compounds is. It has been suggested that nZVI could possess impurities such as PCDD/Fs in its surface. Therefore, the concentration of PCDD/Fs in both commercial and laboratory-synthesized nanoparticles is analyzed. PCDD/Fs pattern and WHO-TEQ concentrations are also obtained. As an outcome of the results obtained in this chapter, a recommendation for preventing the PCDD/Fs presence in nZVI is given. Chapter 6 is dedicated to the synthesis of carbon-encapsulated nanoparticles using hydrothermal carbonization (HTC) of an agricultural waste, particularly, olive mill wastewater (OMW). This novel method, in addition to meet the green chemistry principles, makes profit of the high polyphenol content of OMW to maximize the fraction of incorporated iron into the nZVI. Moreover, the carbon layer surrounding the nZVI protects it against oxidation and avoids its aggregation. Several HTC conditions are explored to study their implications in the characteristics of the material obtained. A deep characterization of the encapsulated nZVI is also presented in this chapter. In Chapter 7, the applications of the encapsulated nZVI synthesized in Chapter 6 are explored and compared for the same contaminants that have been studied in the previous chapters. Then, the advantages of encapsulated nZVI in comparison with common nZVI are discussed at the end of the chapter, and an estimation of the synthesis costs with this method is addressed. Lastly, in Chapter 8, the main conclusions of the thesis are summarized and suggestions for future work are presented.
42
Qin, Hongye. "Investigation of Direct-Reduced Iron as a Filter Media for Phosphorus Removal in Wastewater Applications". Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39973.
Testo completoAbstract (sommario):
Passive reactive filters have the potential to provide effective phosphorus (P) removal from stormwater or agricultural drainage, or to act as an add-on P-removal technology for decentralized or small community wastewater treatment systems. Passive filters require minimal energy consumption and human maintenance. Direct-reduced iron (DRI), a steel-making intermediate, was investigated as a passive filter media for wastewaters phosphorus reduction.
Phosphorus is a biologically active element that is in excess in many natural waterways due to intensive human activity. Eutrophication can occur when P concentrations exceed 0.02 mg/L in freshwater lakes and rivers. The harmful consequence of this phenomenon includes oxygen deprivation, fish death and cyanobacteria-produced toxins. There is a pressing need to limit phosphorus over-discharge into natural waterways.
DRI is a novel media in the application of wastewater treatment and was characterized to have a porous structure with high metallic iron content. The phosphorus retaining mechanisms in batch and column studies suggest a combination of adsorption and surface crystal formation as the dominant removal mechanisms. Batch studies demonstrated increasing removal capacity with P concentration with a plateau observed at 21 mg P/g DRI relating to initial 3000 mg P/L. Media rejuvenation was investigated through chemical treatment with two iron solutions (Fe2(SO4)3, FeCl3) and two acidic solutions (H2SO4 and HCl) at varying molarity. P removal capacity could be fully recovered with 0.05 M Fe3+ or 0.4 N H+ (HCl/H2SO4), while a 37.6% P recovery was also achieved in an acidic solution at 1.2 N H+ (HCl/H2SO4).
A column study utilizing three media sizes of DRI (3.5, 11, 19 mm) and one media size of activated alumina (AA) (7.5 mm) was conducted for 315 days using synthetic P solution varying from 2 to 10 mg/L and hydraulic retention times (HRTs) varying from 0.7 – 15 h. The results demonstrated that removal efficiency increased with HRT and decreased with increasing media size and concentration with minimum HRTs to maintain an 80% removal efficiency varying from 4.4 to 15 hrs for DRI and 3.9 hrs for AA for influent P concentrations of 10 mg/L and below. After 1 year of column operation, the DRI media had demonstrated a minimum removal capacity of 1.82 mg P/g DRI, which can be used as a conservative design parameter. A short duration column study (34 days) utilizing municipal lagoon effluent exhibited similar removal efficiencies to the synthetic column study under the same operational conditions. The 10 years lifespan DRI filter with 80% removal rate in the treatment of stormwater, municipal lagoon effluent, septic tank effluent and dairy wastewater application would have been estimated to have filter volumes of 0.24, 4.69, 15.3 and 36.2 m3, respectively.
43
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.
Testo completoAbstract (sommario):
In this study, a magnetic nanomaterial was used for the binding of anionic arsenic species from contaminated groundwater. Iron oxide (Fe3O4) magnetic nanoparticles (NPs) and the surface modified Fe3O4 NPs with 3-aminopropyl-triethoxysilane (3-APTES), Trisodium citrare (TSC) and Chitosan were synthesized with the co-precipitation method. Structural characterizations showed that the four kinds of NPs had different sizes an average particle range size of 15-20 nm was observed with Transmission Electron Microscopy. X-ray diffraction was used to identify the crystalline structure of synthesized Fe3O4 and surface modified NPs. Molecular structure and functional groups present in synthesized magnetic NPs Fe3O4 were identify with infrared analysis. The synthesized Fe3O4 NPs and surface coated NPs were used for determine the binding capacity of Arsenic ions from the synthetic groundwater. The binding of As(III) increased as the dissolved As(III) concentration increased in the solution. From the experiments it was found chitosan-coated NPs are best than other coated and uncoated NPs for arsenite removal from the solution. It was found that if only As(III) ions were present in the water without other anions and cations the binding capacity of the magnetic NPs is very high. The binding capacity of As ions was decreased with presence of other anions and cations in the groundwater because they interfere with arsenic binding sites which presence on the magnetic NPs.
44
McKevitt, Bethan Ruth. "Removal of iron by ion exchange from copper electrowinning electrolyte solutions containing antimony and bismuth". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/427.
Testo completoAbstract (sommario):
In order to increase the current efficiency in copper electrowinning tankhouses, iron can be removed from the electrolyte using ion exchange. While this is a proven technology, very little data is available for the application of this technology to copper electrowinning electrolytes containing antimony and bismuth.
The feasibility of utilizing iron ion exchange for the removal of iron from copper electrowinning electrolytes containing antimony and bismuth was studied in the laboratory. Apicolylamine, a sulphonated diphosphonic, an aminophosphonic and three sulphonated monophosphonic resins were tested. The picolylamine resin was found to be completely impractical as it loaded high levels of copper. All the phosphonic resins tested loaded an appreciable amount of antimony, however, only the aminophosponic resin loaded an appreciable amount of bismuth.
Tests to determine whether or not the sulphonated monophosphonic Purolite S957 resin would continue to load antimony with time and, hence, reduce the resin's ability to remove iron gave inconclusive results. In the event that the resin's ability to remove iron is hampered due to antimony loading, testing has shown that the resin performance may be restored via a regeneration with a solution containing sulphuric acid and sodium chloride.
A case study for the application of this technology to the CVRD Inco CRED plant has shown that, while iron removal by ion exchange is technically feasible, it will upset the plant's acid balance in electrolyte. Therefore, an acid removal process would need to be implemented in tandem with an iron ion exchange system. Additionally, preliminary calculations suggest that a system with a single ion exchange column may have difficulty removing sufficient iron for the CRED design conditions. Therefore, consideration should be given to the possibility of utilizing a two column system (one column loading, one column stripping).
45
Okazaki, T. "The removal of copper and tin from molten pig iron and steel using sulphide slags". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37809.
Testo completo
46
McBeath, Sean T. "Pilot capacity iron electrocoagulation scale-up for natural organic matter removal for drinking water treatment". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60562.
Testo completoAbstract (sommario):
Canadian remote communities are most often those who are affected by poor water quality and boil water advisories. A major issue is the applicability of traditional water treatment technologies to unconventional applications (small-scale and inaccessible communities). Their inaccessibility presents difficulties for supplying needed chemicals involved in traditional treatment processes such as coagulations and flocculation. Electrocoagulation (EC), an electrochemical process producing coagulant chemicals on-site and on-demand, may be an alternative technology to traditional coagulation suitable for small and remote communities. The following work investigated a continuous iron EC process for natural organic matter (NOM) removal. EC experiments were undertaken in the laboratory at 1.35 and 5 LPM, using synthetic surface water, monitoring the effect of flocculation, metal loading (ML), current density and inter-electrode gap. At both flow rates, flocculation was found to have no effect on the reduction of DOC or UV-abs-254. ML was found to have the greatest effect on both DOC and UV-abs-254 reductions, where the highest ML tested yielded reductions >90% and >60%, respectively. Increases in UV-abs-254 at low ML were found to be due to dissolved residual iron. It was determined that humic acid and chloride functioned as ligands and increased the solubility of iron. Operations were scaled-up to 10 LPM and integrated into a water treatment plant in the community of Van Anda, using raw surface water. Average DOC and UV-abs-254 reductions at the greatest ML were 37.2±4.2% and 54.7±0.9%, respectively. EC was found to have low energy requirements at a pilot-scale, whereby 0.480-0.621 kWh per cubic meter of water treated was required to operate at the conditions that yielded the greatest NOM reductions. Finally, an investigation to determine the current density distribution was undertaken. Current distribution results yielded increased current uniformity with the increase of the inter-electrode gap. This increased uniformity can be attributed to the water velocity profiles in the reactor. Through computational fluid dynamic (CFD) models, it was demonstrated that fluid flow uniformity also increased with an increasing inter-electrode gap. Regions of the electrode that were observed to be occupied by high fluid velocity were also areas yielding greater current density.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
47
Lungu, Radu. "Amendment of constructed wetland substrates with iron (hydr)oxide coatings for enhanced removal of phosphorus /". Connect to online version, 1996. http://hdl.handle.net/1989/3569.
Testo completo
48
Carr, Stephen Thomas David. "Investigation into phosphorus removal by iron ochre for the potential treatment of aquatic phosphorus pollution". Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7663.
Testo completoAbstract (sommario):
Phosphorus (P) pollution of waterbodies is a global issue with detrimental environmental, social and economic impacts. Low-cost and sustainable P removal technologies are therefore required to tackle P pollution, whilst also offering a technique for reclaiming P. Ochre, a waste product from minewater treatment plants (MWTPs), has been proposed as a suitable material for the removal of P from enriched waters due to a high content of Fe, Al, Ca and Mg, which have high affinities for P removal. Whilst a range of studies have been conducted investigating ochre as a P adsorbent, most of these are large-scale field experiments and lack understanding of the underlying processes of P removal by ochre. There have also been very few detailed comparisons of different ochre types. The primary focus of this thesis is thus to provide a process-based understanding of P removal by various ochres, in order to investigate the optimal conditions for the use of ochres in the treatment of aquatic P pollution. Seven ochres from six MWTPs in the UK and Ireland were investigated, one of which was in a pelleted form. The ochres were largely comprised of Al, Ca, Fe and Mg (42-68 % by dry weight), had a high B.E.T. surface area, 56-243 m2 g-1, and contained mineral surfaces with a high affinity for P adsorption, such as goethite and calcite. A novel batch experiment methodology was utilised to calculate the adsorption characteristics of ochre at discrete pH conditions. The variation of these characteristics with pH indicates the importance and requirement for such a method to study adsorption by materials at the expected pH conditions of application. At the pH conditions of wastewater streams (~pH 7), the P adsorption capacities of the ochres, determined from fitting adsorption isotherms, was 11.8–43.1 mg P g-1. Results of P adsorption batch experiments were modelled in ORCHESTRA, wherein P removal by the ochres was described well by adsorption onto hydrous ferric oxides. Three of the ochres contain relatively high calcite contents and due to a poor fit of the model to the observed datasets at high pH conditions, with equilibrium P concentrations lower in the batch experiments than the modelled result, adsorption onto calcite is suggested as a P removal mechanism for these ochres at pH > 7. Environmental application of ochre filters will require P removal under flow-through transport conditions. Column experiments were therefore conducted using two ochres, coarse-grained Polkemmet ochre and Acomb pellets (column volume 1055 cm3, pore space 490-661 cm3, typical pore volumes of experiments: 220-400). P removal efficiency increased with contact time, and the presence of competing ions had only marginal effects on P removal. Resting the column substrate for 48 hours between P applications greatly increased the P removal efficiency of a packed column of Polkemmet ochre, resulting in 81 % of influent P removed over 1000 pore volumes of operation (7.68 mg P g-1). Acomb pellets had a lower P removal efficiency than Polkemmet ochre. It is suggested that the high calcium content of the pellets, as a result of the pelletisation process, has created a substrate where the dominant P removal mechanism at neutral pH conditions is adsorption to calcite, which has slower reaction kinetics than adsorption onto goethite. Therefore, this pelleted ochre requires a higher contact time for adsorption reactions to occur. It is suggested that ochre filters are most suitable for application in situations where flow rate is constant or can be controlled e.g. septic tank effluent. Ochres which dry to a coarse particle size are preferred for use as a substrate as pelletisation requires capital, expertise and can produce substrates with slower P sorption kinetics. Resting the filter substrate between P application regenerates surface sites for adsorption, and filters should be run in parallel to maximise P removal efficiency. Acomb pellets, which are a mix of iron hydroxides and alkaline materials, may have potential application as a permeable reactive barrier substrate to treat P enriched ground waters. Further research utilising fine-grained ochres as an additive to P rich fertilisers or for use in continuously stirred tank reactors is recommended.
49
Zhao, Kang, e 趙鈧. "An iron-facilitated chemical and biological process for phosphorus removal and recovery during wastewater treatment". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196027.
Testo completoAbstract (sommario):
Phosphorus (P) is an important pollutant of concern in wastewater that causes eutrophication and algal blooms in water body. On the other hand, P is a valuable natural resource for agricultural and industrial use. With the rapid depletion of mineral phosphorus on earth, there is a need to recover phosphorus from wastewater. In this study, a new chemical and biological process facilitated with iron dosing has been developed for P removal and recovery during wastewater treatment. The system consists of a main stream identical to the conventional activated sludge process in an aerobic sequencing batch reactor (SBR) for P removal and a side stream of sludge recirculation through an anaerobic SBR (AnSBR) for P release and recovery from the P-rich sludge.
In the aerobic SBR treating a synthetic domestic wastewater, Fe(III) (FeCl3) was dosed to remove P by precipitation and adsorption. Fe(III) dosing at a Fe/P molar ratio of 1.5:1 could reduce the P concentration from more than 10 mg/L to below 1 mg/L in the final effluent. Compared to other dosing periods, dosing Fe(III) right before the SBR settling could achieve the best result in sludge flocculation and P removal. Meanwhile, organic removal was well maintained as 90% of the chemical oxygen demand (COD) was degraded in the aerobic SBR. In the AnSBR, phosphate precipitated with ferric iron in the sludge was released owing to microbial Fe(III) reduction, and a positive correlation was found between the phosphate and ferrous iron concentrations in the sludge suspension. Chemical tests showed that significant P release from Fe(III)-P occurred only if the acidic condition and the reducing condition were combined. For the AnSBR sludge, a higher organic loading, lower pH and higher biomass concentration resulted in a higher level of Fe(III) reduction and P release. Organic acidogenesis prevailed in the reactor and lowered the pH to ~4.5, which facilitated the P release from the solid phase into the liquid phase. With a solids retention time (SRT) of 10 days, the anaerobic supernatant contained a phosphate concentration of up to 70 mg/L, while the settled sludge was returned to the aerobic SBR. The phosphate could be readily recovered from the supernatant with Fe-induced precipitation by aeration and pH adjustment, and the overall P recovery could be achieved at about 70%. In addition to the treatment performance, the speciation of P in the aerobic sludge and the anaerobic sludge also was investigated. A significant change in the immediately available P and the redox-sensitive P was found in the sludge through the aerobic-anaerobic cycle. Such chemical transformation is believed to be crucial to the P removal and recovery during the wastewater treatment process.published_or_final_version
Civil Engineering
Master
Master of Philosophy
50
Chowdhury, Md Abu Raihan. "Removal of Select Chlorinated Hydrocarbons by Nanoscale Zero-valent Iron Supported on Powdered Activated Charcoal". Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496150130687849.
Testo completo