Speciation of chromium in waters via sol-gel preconcentration prior to atomic spectrometric determination a thesis submitted to the graduate school of engineering and sciences of. References x lv, y hu, j tang, t sheng, g jiang, x xu, effects of co-existing ions and natural organic matter on removal of chromium (vi) from aqueous solution by nanoscale zero valent iron (nzvi)-fe 3 o 4 nanocomposites, chem eng j, 218 (2013) 55-64. Title of thesis: hexavalent chromium modified to prevent method-induced reduction of cr(vi) by not heating (95°c) but chromium (cr) is a transition element. Strengthening aluminum by zirconium and chromium by shi yan a thesis submitted to the faculty of the worcester polytechnic institute in partial fulfillment of the. Remediation of chromium(vi) in the vadose zone: stoichiometry and kinetics of chromium(vi) reduction by sulfur dioxide a thesis by min ahn submitted to texas a&m university.
A thesis submitted in 465 effect of biomass concentration on the reduction of arsenic cadmium, chromium and copper 86 466 effects of immobilization 88. It shown 7803% hexavalent chromium reduction when incubated in a nutritive medium at 30°c for 24 hours at ph 7 and the rate of reduction decreased from 7803 to 381% in a nonnutritive medium then the bacteria was selected for parametric studies and observed to exhibit highest reduction 85% at ph 80, temperature 30/ 24 hours. The potential for biological reduction of cr(vi) under acidic conditions was evaluated with the acidophilic, facultatively metal-reducing bacterium acidiphilium cryptum strain jf-5 to explore the role of acidophilic microorganisms in the cr cycle in low-ph environments.
I abstract hexavalant chromium (cr(vi)) poses an emerging concern in drinking water treatment with stricter regulations on the horizon photocatalytic reduction of cr(vi) was. Bachelor's thesis, spring 2015 iron based metal organic frameworks as photocatalysts for chromium (vi) degradation deliana dimitrova1 abstract the photocatalytic reduction of cr(vi) is investigated over iron(iii) based metal-organic frameworks (mofs) with. Reaction between nitrogen and spinel in chromium based in part on a thesis submitted by d m scruggs for and to an investigation by khan of the reduction. Abstract this project investigated the traditional treatment of chromium by oxidation-reduction reaction using fe (ii) and mn (ii) it was found that fe (ii) was a potential remediation to stabilise chromium and reduce cr (vi) to cr (iii), but mn (ii) oxidised cr (iii) to cr (vi) mobilising it to the leachate. Bacterial reduction of chromium (vi) has been seen as one of the biological means of detoxifying toxigenic chromium this study was designed to isolate cr(vi) tolerant bacteria from sewage.
The undersigned, appointed by the dean of the graduate school, have examined the thesis entitled photocatalytic reduction of hexavalent chromium in aqueous. The work for this thesis was carried out in the laboratory of industrial chemistry at helsinki university of technology between 1999 and 2004, and in the instituto de catálisis y petroleoquímica, csic, madrid, spain between may and june 2003. Miller, robert chromium (vi) reduction by shewanella oneidensis mr-1 in elevated chromium concentrations exhibited in corrosion resistant coatings electronic thesis or dissertation electronic thesis or dissertation. Tanning emu skins: an assessment of the processes, the leather properties, and the potential for chromium reduction by venkateswara reddy kotla, btech. Chromium, cr, was first discovered by a french chemist, vauquelin, in 1798 it is a block vi transition metal on the periodic table and is the 21 st most abundant element in.
Bioremediation of chromium contaminated environments chromium is known to undergo various chemical important microbes involved in chromium reduction. Putting chromium on the map for n 2 reduction diagrams etc contained in this article in third party publications or in a thesis or dissertation provided that the. Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel powder ola bergman licentiate thesis stockholm, sweden 2008. Isotopic fractionation of chromium and uranium during cr(vi) reduction by ascorbate and u(vi) reduction by sulfide by elizabeth l armstrong thesis.
Oxidation and reduction from organic chemistry by robert c neuman, jr professor of chemistry, emeritus chromium compound with cr in its +6 oxidation state (cr. Reduction of hexavalent chromium by soil humic substances paul r wittbrodt ms university of alaska, fairbanks, 1985 bs michigan technological university, 198 1 a thesis submitted to the faculty of the. Chromium is a chemical element with symbol cr and atomic number 24 it is the first element in group 6it is a steely-grey, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point. The concentration levels that caused a 50% reduction in the rate of cr(vi) reduction (ic 50) were 986, 1,526, and 5,263 mg/l for p‐cresol, 2‐chlorophenol, and phenol, respectively, in anaerobic cultures with higher ic 50 values noted in aerobic cultures.