نتایج جستجو برای: bioreduction of hexavalent chromium
تعداد نتایج: 21165796 فیلتر نتایج به سال:
Some compounds of hexavalent chromium are well-established carcinogens. Chromium enters mammalian cells in the hexavalent form and is reduced to chromium (III). Treatment of purified DNA with chromium (III) produces DNA-DNA interstrand crosslinks (DDC) which obstruct the progression of DNA polymerases in vitro. DDC were also detected in chromate-treated cultured normal human lung cells using th...
The United States Environmental Protection Agency (EPA) intends to add either chromium or hexavalent chromium to the list of hazardous air pollutants under Section 112 of the Clean Air Act. A preliminary assessment performed by EPA has identified several categories of stationary sources as emitters of significant quantities of chromium to the atmosphere and for which the proposal o f national e...
abstract chromium is among the metals that has numerous applications in various industries due to its specifications. widespread use of this metal in different industries has unfortunately been accompanied by its increased release into environment and this entails numerous environmental hazards. in the first phase of the research that was conducted to evaluate the effect of the leather processi...
A trivalent chromium electroplating process has been io use commercially in North America since its introduction in 1975. Based upon years of laboratory and in-plant experience and testing, many process performance characteristics and physical properties of deposits have been determined. This paper compares the performance of trivalent chromium with hexavalent chromium processes. Factors such a...
II ADIOACTIVE hexavalent chromium is a widely used agent for labeling platelets and studying their survival. Since platelet viability appears to be unaffected by chromium labeling, it is assumed that platelet function also remains intact. This assumption is basic to interpretation of platelet survival studies with chromium labeling. Accordingly, we examined the in vitro function of platelets th...
Quantitative electron microscopy was used to evaluate interactive effects of chromium additions and phosphate nutrient status on the diatom Cyclotella meneghiniana. Cells of differing phosphate status were exposed to hexavalent chromium for 7 days and morphological changes in both phosphate alone and phosphate and chromium treatments were observed. Changes in chloroplast relative volume and num...
Chromium (vi) – tolerant bacterial strains, namely, Bacillus sp., Pseudomonas sp., Escherichia coli and Staphylococcus sp. were isolated from the oxidation ditch of a sewage treatment plant. All the isolates tolerated high concentrations of up to 500 μg/ml chromium (vi) in nutrient broth. The growth responses of the bacterial isolates to different concentrations of chromium (vi) were carried ou...
absorptive characteristics of polyaniline synthesized in different solvents were studied. water and mixture of water with other solvents were implemented for polyaniline synthesis. synthesized polyanilines in powder shape is used as an adsorbent to remove toxic hexavalent chromium from aqueous solutions. experiments were conducted in batch mode. removal mechanism involving polyaniline is the co...
The toxicity of chromium (Cr) to biota is related to its chemical forms and consequently to the redox conditions of soils. Hexavalent Cr[Cr(VI)] may undergo natural attenuation through reduction processes. In this study, the reduction kinetics of Cr(VI) in seven soils and its relationships with soil properties were investigated with laboratory incubation experiments. The results indicate that t...
Several low cost biomaterials such as rice husk, sugar cane bagasse, Tulsi Leaf &branches, coconut shell & coir and fly ash were tested for removal of chromium. All the experiments were carried out in batch process. The adsorbent, which had highest chromium (VI) removal, was coconut shell. An influence of chromium concentration, contact time on removal of chromium from effluent was investigated...
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