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Biogeochemical and ecohydrologic controls on arsenic mobilization in groundwater of the Okavango DeltaEnriquez, Hersy J. January 1900 (has links)
Master of Science / Department of Civil Engineering / Natalie Mladenov / The detrimental health effects of arsenic (As) contamination have motivated the study of As mobility around the globe. The variability in naturally occurring As concentration is due to variation in geology and climate. In arid environments with high evaporation, ecohydrology and As desorption under alkaline pH are thought to be responsible for high As concentrations. In reducing groundwater, on the other hand, microbial iron (Fe) reductive dissolution is known to release As into solution. In such environments, As-sulfide minerals precipitation and vegetation uptake could contribute to re-distribution of As. The Okavango Delta is an arid-zone wetland punctuated by ten of thousands of islands, and the reducing groundwater beneath these islands have dissolved As as high as 3000 µg•L[superscript]-1. Ecohydrologic controls are thought to contribute to the elevated As level; however dissolution of Fe-containing sediments has been proposed as the initial step in releasing As from sediment to the groundwater. To test the consistency of the hypothesized mechanisms, four islands were sampled in January 2013. The goal of this thesis is to: 1) provide more evidence on the zones of elevated As in groundwater of four islands, 2) gain understanding on the influence ecohydrology (i.e., evapotranspiration) on high As in groundwater, 3) evaluate the sediment of microbial community composition, and 4) gain new insights into the behavior of DOM along the groundwater flow path. The findings show zones of elevated As in all four islands. The ecohydrologic controls provide information on the location of high As and solute accumulation. Microbial analyses suggest DNA sequences collected were grouped within lineages that contain organisms capable of dissimilatory Fe reduction and sulfate reduction. This supports evidence from previous study that sulfide produced by microbial sulfate reduction is available for As-sulfide mineral formation. The variation of DOM characteristics could influence As solubility and reactivity. In addition, carbonate alkalinity and increase pH may contribute to As mobility further along the flow path. In this arid and reducing groundwater, we find that ecohydrologic and biogeochemical processes have a fundamental role in As mobility.
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THE SURFACE CHEMISTRY OF CHROMIUM OXIDES IN AQUEOUS SOLUTIONSAli, Iqbal, 1948- January 1987 (has links)
A detailed study has been carried out to investigate the dissolution characteristics of unstabilized and stabilized CrO₂ particles. It has been found that on contact of CrO₂ with aqueous solutions, it dissolves by disproportionation reaction to HCrO₄ and Cr2O₃. XPS study has shown that stabilization of CrO₂ particles with bisulfite solution leads to the formation of Cr2O₃. However, because of agglomeration of the CrO₂ particles due to their magnetic properties, not all of the surface is completely stabilized. The electrokinetic characteristics of Cr(IV) and Cr(III) oxides in aqueous solutions have been investigated. Experiments suggest that sulfite ions chemisorb strongly on Cr₂O₃ particles. Experiments have also been carried out to study the adsorption of sodium dodecyl sulfate (SDS) on Cr₂O₃ particles. With increasing SDS concentration, Cr₂O₃ becomes less positively charged and ultimately negatively charged when the surfactant concentration exceeds 10⁻³ M. This suggests that SDS specifically adsorbs onto the oxide.
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Control of Listeria monocytogenes on frankfurters formulated with and without lactate by dipping in sodium lactate and acidified calcium sulfate before and after inoculation for shelf life extensionStohs, Buffy Ann January 1900 (has links)
Master of Science / Food Science Institute, Animal Science & Industry / Daniel Y.C. Fung / The objectives of these studies were to determine the antimicrobial effects of sodium lactate (SL) and acidified calcium sulfate (ACS) on frankfurters formulated with and without lactate in the frankfurter formulation. Two studies were performed, one which mimicked home storage, and the other evaluated the effectiveness of SL (12% v/v) and ACS (12% v/v) as antimicrobial dips when used prior to and after inoculation of Listeria monocytogenes on frankfurters formulated without lactate. In the first study, five peeled frankfurters with and without lactate in the formulation were either dipped in SL or in ACS, stabilized for 30 minutes, vacuum packaged and stored for 30 days at 4°C. Controls were also prepared by dipping in 0.1% peptone. After 30 days the packages were opened and frankfurters were dip inoculated, stabilized for 30 minutes, and one frankfurter from each treatment was sampled. All other frankfurters were then placed in storage at 7°C and sampled after an additional 7, 14, and 21 days. For the second study, treatments consisted of five frankfurters that were first inoculated with a five-strain cocktail of L. monocytogenes, stabilized for 30 minutes, then dipped in SL or acidified ACS; or were first dipped in SL or ACS, stabilized for 30 minutes then dip inoculated. Controls were prepared by dip inoculating frankfurters. One frankfurter from each treatment was sampled immediately. The remaining frankfurters were vacuum packaged, stored at 4°C and sampled after 30, 60, 90, and 120 days. For both studies, on sampling days one frankfurter from each treatment was pulsified and plated on Tryptic Soy Agar (TSA) for viable cell counts and Modified Oxford Medium (MOX) for L. monocytogenes counts. The results indicated that SL dipped frankfurters had lower total aerobic counts and L. monocytogenes counts compared with ACS treatments and the controls. Use of lactate formulation in frankfurters resulted in lower bacterial counts of both natural microflora and inoculated L. monocytogenes in frankfurters after prolonged storage at 4 °C. This research indicates that sodium lactate (12% v/v) may be effective as an antimicrobial dip on frankfurters for the reduction of natural microflora and L. monocytogenes.
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Recovery of dissolved platinum group metals from a pregnant copper sulphate leach solution by precipitationMulwanda, James 04 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: In Base Metal Refineries (BMRs), the copper sulphate leach solution produced during the final
pressure leaching stage contains impurities such as selenium and tellurium, as well as other
precious metals (OPMs, namely Rh, Ru, and Ir). Se and Te are removed by precipitation with
sulphur dioxide prior to electrowinning of Cu. While a small percentage of the dissolved OPMs
precipitate with the Se and Te, the largest portion remains in solution and is recycled to the first
stage leach. If a larger portion of the OPMs in solution can be recovered in the Se/Te
precipitation stage, OPM losses and the OPM inventory of the plant can be reduced. The aim of
this project was to determine operating conditions that would allow maximum OPM recovery
with minimal Cu and Ni co-precipitation in the Se/Te removal section of a BMR.
The effects that the operating temperature, pressure, stirring rate, reagent type, and reagent
quantity have on the metal precipitation behavior and precipitate characteristics were
determined experimentally. Thio-urea and sulphurous acid were evaluated as precipitation
reagents for temperatures of 80°C and 160°C, stirring rates of 250 rpm and 500 rpm, and
pressures equal to ambient pressure and 7 bar. 200 % and 320 % excess thio-urea and 720 %
and 960 % excess sulphur dioxide were used.
The precipitation of OPMs with sulphur dioxide was generally poor; the maximum percentage
Rh, Ru, and Ir precipitated were 35 %, 18 %, and 20 %, respectively. It was, however, found that
the OPM precipitation increased as the reagent amount was increased. Increasing the
temperature further increased Rh and Ir precipitation but affected the Ru precipitation
negatively. Thio-urea precipitated virtually all of the Rh contained in the solution irrespective of
the values of the process variables studied. As was the case with sulphur dioxide, increasing the
amount of thio-urea added resulted in increased Ru and Ir precipitation, while higher
temperatures favored Ir precipitation but not Ru precipitation. The maximum percentage Ru
and Ir precipitation achieved with thio-urea were 87 % and 60 %, respectively. Complete Se precipitation was observed at all process conditions, while Te precipitation
increased as the operating temperature and the reagent quantity were increased. Maximum Te
precipitation of 98 % and 90 % were achieved when using 320 % excess thio-urea and 960 %
sulphurous acid quantities, respectively, at 160°C and a stirring rate of 250 rpm. Increasing the
reagent quantity and temperature did, however, also result in increased copper and nickel
precipitation. The statistical analysis of the results allowed regression models to be fitted to predict the
percentage metal precipitation as a function of the investigated process variables. These models
were used to define an objective function to determine the optimal operating conditions. A
temperature of 80oC, a pressure of 7 bar, and 200 % excess thio-urea were proposed as the
optimum operating conditions that would yield 98 % Rh, 75 % Ru, and 48 % Ir precipitation
with less than 5 % Cu and Ni co-precipitation. Experimental validation tests confirmed the
model predicted values and proved repeatability of the experimental data. / AFRIKAANSE OPSOMMING: Die kopersulfaat logingsoplossing wat tydens die finale drukloging stadium in Basis Metaal
Raffinaderye (BMRe) produseer word, bevat onsuiwerhede soos selenium en tellurium sowel as
ander edelmetale (AEMe, naamlik Rh, Ru, en Ir). Se en Te word voor Cu elektrowinning
verwyder deur middel van presipitasie met swaweldioksied. Alhoewel ʼn klein persentasie van
die opgeloste AEMe saam met die Se en Te presipiteer, bly die grootste gedeelte in oplossing en
word gevolglik na die eerste loging stadium hersirkuleer. AEM verliese en die AEM inventaris
van die aanleg kan verminder word indien ʼn groter gedeelte van die AEMe in die Se/Te
presipitasie stadium herwin kan word. Die doel van hierdie projek was om bedryfstoestande te
bepaal om maksimum AEM herwinning met minimale Cu en Ni kopresipitasie in die Se/Te
verwyderingseksie van ʼn BMR te behaal.
Die effekte wat bedryfstoestande soos temperatuur, druk, roerder tempo, tipe reagens, en
hoeveelheid reagens op die metaal presipitasiegedrag en presipitaat eienskappe het, is
eksperimenteel bepaal. Tio-ureum en swaweligsuur is evalueer as presipitasie reagense vir
temperature van 80°C en 160°C, roerder tempo’s van 250 rpm en 500 rpm, en drukke gelyk aan
omgewingsdruk en 7 bar. 200 % en 320 % oormaat tio-ureum en 720 % en 960 % oormaat
swaweldioksied is gebruik. Die presipitasie van AEMe met swaweldioksied was swak in die algemeen; die maksimum
persentasie Rh, Ru, en Ir presipitasie wat behaal is, is 35 %, 18 %, en 20 %, onderskeidelik. Daar
is egter gevind dat die AEM presipitasie toeneem indien die hoeveelheid reagens toeneem. ʼn
Toename in die temperatuur het verder tot ʼn toename in Rh en Ir presipitasie gelei, maar dit het
Ru presipitasie negatief affekteer. Tio-ureum het basies al die Rh in oplossing laat presipiteer,
ongeag die waardes van die ander prosesveranderlikes wat ondersoek is. Soos wat die geval vir
swaweldioksied was, het ʼn toename in die hoeveelheid tio-ureum ʼn toename in die Ru en Ir
presipitasie tot gevolg gehad, terwyl hoër temperature Ir presipitasie bevoordeel en Ru
presipitasie benadeel het. Die maksimum persentasie Ru en Ir presipitasie wat met tio-ureum
behaal is, is 87 % en 60 %, onderskeidelik.
Volledige Se presipitasie is by alle proses toestande waargeneem, terwyl Te presipitasie
toegeneem het soos wat die temperatuur en die hoeveelheid reagens toegeneem het. Maksimum
Te presipitasie van 98 % en 90 % is behaal toe 320 % oormaat tio-ureum en 960 % oormaat
swaweligsuur, onderskeidelik, by 160°C en ʼn roerder tempo van 250 rpm gebruik is. ʼn
Toename in die hoeveelheid reagens en die temperatuur het egter ook meer koper en nikkel
presipitasie tot gevolg gehad. Die statistiese analise van die resultate het dit moontlik gemaak om regressie modelle te pas om
die persentasie metaal presipitasie as ʼn funksie van die ondersoekte veranderlikes te voorspel.
Hierdie modelle is gebruik om ʼn doelfunksie te definieer ten einde die optimale
bedryfstoestande te bepaal. ʼn Temperatuur van 80°C, ʼn druk van 7 bar, en 200 % oormaat tioureum
is voorgestel as die optimale bedryfstoestande wat 98 % Rh, 75 % Ru, en 48 % Ir
presipitasie met minder as 5 % Cu en Ni kopresipitasie tot gevolg sal hê. Eksperimentele
geldigheidsbepalingtoetse het die waardes wat deur die modelle voorspel is bevestig en die
herhaalbaarheid van die eksperimentele data bewys.
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Tellurium and selenium precipitation from copper sulphate solutionsBello, Yusuf O. 12 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: The copper sulphate leach solutions produced during the final pressure leach stages in base metal refinery processes contain low concentrations of other precious metals (OPMs, namely Rh, Ru and Ir ) and impurities in addition to the base metals (BMs) of interest. Se and Te impurities, in particular, must be removed from the leach solution before it is fed to copper electrowinning because these species have adverse effects on electrowinning efficiency.
Currently, these elements are being precipitated from the leach solution with sulphurous acid. Se precipitation is satisfactory but Te removal still proves challenging. Previous studies have shown that tellurium can either be precipitated as cuprous telluride from copper sulphate solutions by reduction with sulphurous acid alone, or by the addition of SO2 as a precipitating agent and metallic copper as an additional precipitating agent.
The objective of this study was to evaluate the effects of different process variables on Te and Se recovery in order to propose operating conditions at which increased tellurium precipitation can be achieved with minimal co-precipitation of base metals of interest (notably Cu and Ni). This would also aid in the development of a better understanding of tellurium and selenium precipitation mechanisms in CuSO4-H2SO4 medium. / AFRIKKANSE OPSOMMING: Die kopersulfaat logingsoplossing wat gedurende die finale druklogingstadia in basis metaal raffinaderye produseer word bevat, behalwe vir die basis metale van belang, ook lae konsentrasies ander edelmetale (AEM, naamlik Rh, Ru, en Ir) sowel as onsuiwerhede. Se en Te onsuiwerhede, in die besonder, moet vanuit die logingsoplossing verwyder word voordat die oplossing na die koper elektrowinning gevoer word omdat hierdie spesies negatiewe effekte op die elektrowinning effektiwiteit het.
Hierdie elemente word tans met swaweligsuur vanuit die logingsoplossing gepresipiteer. Se presipitasie is voldoende, maar die Te verwydering bly steeds problematies. Vorige studies het getoon dat tellurium as kuprotelluried vanuit kopersulfaat oplossings presipiteer kan word deur middel van reduksie met swaweligsuur alleen, of met die byvoeging van SO2 as presipiteermiddel en metallieke koper as addisionele presipiteermiddel.
Die doelwit van hierdie studie was om die effekte van verskillende prosesveranderlikes op Te en Se presipitasie te ondersoek ten einde bedryfstoestande voor te stel wat verbeterde tellurium presipitasie toelaat met minimale kopresipitasie van basis metale van belang (hoofsaaklik Cu en Ni). Dit sal ook bydra tot die ontwikkeling van ʼn beter begrip van die tellurium en selenium presipitasie meganisme in ʼn CuSO4-H2SO4 medium.
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Identification of extraction methods for the production of humic acids from black liquorMema, Vusumzi (Vusie) 12 1900 (has links)
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2006. / South Africa has a variety of sources for humic substances that may be utilised for the large-scale production of specialised fertilizers. Humic substances are dark coloured fully decomposed remains of plant and animal organic matter. Amongst the sources that were investigated in this study, a 5-weeks old compost (C5W), a 6-weeks old compost (C6W), a compost prepared by Medallion Mushroom farm for the production of mushrooms (CB1), a compost produced as waste material after mushroom production (CB2), recycled water used in compost (i.e. CB1) preparation for mushroom production (“Goodie water,” GW) and black liquor from pulp industry (BL), black liquor showed the best potential for the large scale production of humic acids in South Africa. The quantity and quality of humic acids in these materials were determined by using the basic acid-precipitation method and E6/E6 ratio analyses of the products.
Extracting humic acids from black liquor was optimised by comparing three possible variations to the standard humic acid-precipitation method (HAp), namely, lignin extraction/humic acid precipitation method (LHAp), humic acid precipitation/acid treatment method (HApA) and lignin extraction/humic acid precipitation/acid treatment method (LHApA). The method of extraction had a substantial impact on the quantity and quality of humic acids produced. Humic acid precipitation method followed by humic acid precipitation/acid treatment method (HApA) demonstrated high quantities of humic acids compared to lignin extraction/humic acid precipitation method (LHAp) and lignin extraction/humic acid precipitation/acid treatment method (LHApA).
Analyses such as Fourier Transform Infrared (FTIR) spectroscopy, Ultraviolet Visible Spectroscopy (UV-VIS), High Performance Liquid Chromatography (HPLC) and Elemental Analysis demonstrated that the quality of humic acids produced from black liquor was similar to those reported previously. The type of material (e.g. softwood, hardwood and bagasse) used for black liquor production significantly affected the elemental and molecular composition of humic acids produced. The quality of humic acids produced was affected by both lignin extraction and acid treatment. However, chemical analyses indicated that the features of the humic acids extracted from black liquor correlated with their lignin origin. Humic acids from hardwood and softwood black liquor had a low nitrogen and high sulphur content compared to those extracted from black liquor produced from bagasse material. Although chemical and instrumental analysis of humic acids was quite reasonable for all humic acids produced, LHAp method was favoured for the extraction of humic acids from pine liquor due to the high quantity of humic acids produced (low S and ash contents).
The humic acids extracted by means of HAp method and HApA had a positive effect on plant growth, when extracted from bagasse and Eucalyptus black liquors. Humic acids extracted by HAp from pine liquor had an inhibitory effect on plant growth. A possible process flow for the large-scale production of humic acids from black liquor was formulated. The possible process flow indicated that with the amounts of black liquor produced from pulp industry production of humic acids in South Africa is a possibility. Nevertheless, there is still more that needs to be done to investigate the cost effectiveness of this production prior its implementation. HAp method was most suitable for the production of humic acids from Eucalyptus and bagasse liquors in terms of quantity and plant response but LHAp method was more suitable for the production of humic acids from pine liquor in terms of both quantity and quality.
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LOCALIZATION AND FUNCTIONAL CHARACTERIZATION OF OATP4C1 TRANSPORTER IN <i>IN VITRO</i> CELL SYSTEMS AND HUMAN/RAT TISSUESKuo, Kuei-Ling 01 January 2012 (has links)
The organic anion transporting polypeptide 4c1 (Oatp4c1) was previously identified as a novel uptake transporter predominantly expressed at the basolateral membrane in the rat kidney proximal tubules. Its functional role was suggested to be a vectorial transport partner of an apically-expressed efflux transporter for the efficient translocation of physiological substrates into urine, some of which were suggested to be uremic toxins. In vitro studies in polarized cell lines showed that upon transfection rat Oatp4c1 localizes at the apical membrane. The objectives of this project were to further validate the subcellular localization of Oatp4c1/OATP4C1 in rat and human tissues as well as their localization and function in polarized cells.
Using several complementary biochemical, molecular and proteomic methods as well as antibodies amenable to immunohistochemistry, immunofluorescence, and immunoblotting, we investigated the expression pattern of Oatp4c1 in epithelial cell lines and in the rat kidney and mammary gland (MG). Collectively, these data demonstrated that rat Oatp4c1 localized at the apical cell surface of polarized epithelium and primarily in the proximal straight tubules, the S3 segment of proximal tubule, in the juxtamedullary cortex.
Drug uptake studies in Oatp4c1-expressing cells demonstrated that Oatp4c1- mediated estrone-3-sulfate (E3S) uptake was ATP-independent and pH-dependent. The increased E3S transport activity at acidic extracellular pH was ascribed to the increased maximum transport rate (Vmax). In addition, E3S transport inhibition by various substrates suggests that Oatp4c1 possesses multiple substrate binding sites.
The apical localization of Oatp4c1 in the rat kidney and MG is a novel finding and implies that this transporter protein plays a role in the reabsorption, not vectorial secretion, of its substrates. In addition, the upregulation of Oatp4c1 expression during lactation indicates that it is involved in reuptake of xenobiotic from the milk, resulting in their reduced exposure to the suckling infants, or that it functions as a scavenger system. Further, studies to identify physiological substrates are needed to better understand the significance of Oatp4c1 function in renal and mammary epithelium.
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Role of Heparan Sulfate Structure in FGF-Receptor Interactions and SignalingJastrebova, Nadja January 2008 (has links)
<p>Heparan sulfate (HS) belongs to the glycosaminoglycan family of polysaccharides and is found attached to protein cores on cell surfaces and in the extracellular matrix. The HS backbone consists of alternating hexuronic acid and glucosamine units and undergoes a number of modification reactions creating HS chains with alternating highly and low modified domains, where high degree of modification correlates with high negative charge. Fibroblast growth factors (FGFs) and their receptors (FRs) both bind to HS, which affect formation of the FGF–FR complexes on the cell surfaces. Activated FRs can trigger several intracellular signaling pathways leading thereby to diverse cellular responses. </p><p>Work presented in this thesis focuses on the effect of HS and its structures on FGF–FR complex formation and FGF-induced signaling. Studies with short, highly modified oligosaccharides and FGF1 and 2 combined with FR1c, 2c, 3c or 4 showed a correlation between the overall degree of modification and amount/stability of FGF–FR complexes. Our findings imply that several HS structures, differently modified but with the same negative charge density are equal in their ability to support complex formation. Co-application of oligosaccharides with FGF2 to HS-deficient cells and investigation of the thereby induced cell signaling confirmed our findings with a cell-free system. The oligosaccharide with the highest modification degree displayed the biggest impact on cell signaling, which was FGF2 concentration dependent. Studies with long HS polysaccharides with preserved high and low modified domains suggest that the proportion between these two types of domains and also the structure of the low modified domains are of importance for the FGF–HS–FR complex formation and cell activation capacity. </p><p>This work illuminates several aspects in how HS structure influences the interplay between FGFs and FRs and contributes to the understanding of what factors affect a cell’s response following FGF stimulation.</p>
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Cellular design of heparan sulfate : The NDST enzymes and their regulationCarlsson, Pernilla January 2008 (has links)
<p>Heparan sulfate proteoglycans are proteins with long, unbranched heparan sulfate (HS) polysaccharide chains attached to them. They are found on cell surfaces and in basement membranes where they exert their action by interacting with a wide range of enzymes and signaling molecules and are thereby involved in a range of various processes both during embryonic development and in adult physiology.</p><p>A great part of the biological functionality of proteoglycans can be directly related to the polysaccharide part. HS chains display very variable sulfation patterns where highly sulfated regions are responsible for a large part of the biological activity. The biosynthesis of HS is a complex process in which a number of enzymes are involved. Better comprehension of how this process is regulated could reveal clues to how formation of HS sulfation patterns occurs, and thereby how HS functionality is controlled.</p><p>This thesis is focusing on regulation of one of the enzymes responsible for HS sulfation, glucosaminyl N-deacetylase/N-sulfotransferase (NDST), in an attempt to understand these mechanisms better. Different aspects of NDST regulation were studied in three projects:</p><p>I) “Heparin/heparan sulfate biosynthesis: Processive formation of N-sulfated domains”, where the sulfate donor PAPS is shown to influence the manner in which NDST modifies the substrate, affecting the domain structure of the polysaccharide.</p><p>II) “Heparan sulfate biosynthesis: Characterization of an NDST1 splice variant”, where a splice variant of NDST1 which appears to influence NDST1 protein levels and affect HS structure is described.</p><p>III) “Heparan sulfate biosynthesis in zebrafish: Five NDST genes with distinct expression patterns during embryonic development”, in which five zebrafish NDSTs were cloned and shown to be expressed in a temporally and spatially regulated manner.</p>
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Dépollution des effluents industriels tunisiens chargés en polluants organiques persistants par les procédés d'oxydation avancéeTabelsi, Souhaila 15 December 2011 (has links) (PDF)
L'installation de décharges sanitaires représente la seule méthode de stockage des déchets ménagers solides dans plusieurs pays. Les lixiviats générés à partir de ces décharges présentent une grande toxicité aigüe et chronique. Lorsqu'ils ne sont pas traités, ces lixiviats peuvent pénétrer dans la nappe phréatique ou contaminer les eaux de surface et donc contribuer à la pollution des eaux. Divers procédés biologiques ont été appliqués au traitement des lixiviats de décharge. Cependant, ces procédés sont relativement inefficaces pour le traitement des lixiviats à cause de la présence de composés bioréfractaires. D'autre part, les procédés d'oxydation avancée représentent une excellente alternative pour le traitement des eaux polluées par les polluants toxiques et/ou persistants (bioréfractaires). Dans ce travail, quelques procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués au traitement de deux molécules modèles appartenant chacune à une famille de polluants présents dans la matrice du lixiviat tunisien de la décharge contrôlée de Jebel Chakir (identifiée dans ce travail), à savoir, l'anhydride phtalique et le 8-hydroxyquinoléine sulfate. Pour ces deux molécules, une étude de la dégradation et la minéralisation a été réalisée en optimisant les paramètres expérimentaux. L'étude cinétique montre que la dégradation oxydative des deux polluants étudiés suit une cinétique de réaction du pseudo-premier ordre, avec des temps de dégradation assez courts. Par exemple, avec une anode de Pt, l'oxydation complète de l'anhydride phtalique a été achevée en moins de 15 min sous un courant appliqué de 2,88 mA cm-2. L'identification des intermédiaires aromatiques et carboxyliques à courte chaîne carbonée a permis de proposer un mécanisme de dégradation de l'anhydride phtalique par les radicaux hydroxyles. Les valeurs des constantes de vitesse des réactions entre les *OH, et les deux polluants et leurs intermédiaires ont été déterminés par la technique de cinétique de compétition à l'aide d'un composé de référence; l'acide 4-hydroxybenzoique. Le suivi de la toxicité lors du traitement de la solution de 8-HQS par la méthode Microtox®, (une méthode basée sur la mesure de l'inhibition de la luminescence des bactéries marines Vibrio fischeri) a montré la formation des intermédiaires plus toxiques que les molécules mères. Une comparaison des procédés d'oxydation avancée appliqués a été réalisée pour chacun des polluants. Enfin, différents procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués à la dépollution du lixiviat tunisien de Jebel Chakir. Une étude comparative a été réalisée afin d'évaluer le coût des procédés. L'ensemble des résultats obtenus confirme l'efficacité du procédé électro-Fenton pour la dépollution des lixiviats.
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