نتایج جستجو برای: chromium iii
تعداد نتایج: 279746 فیلتر نتایج به سال:
Several low cost biomaterials such as baggase, charred rice husk, activated charcoal and eucalyptus bark (EB) were tested for removal of chromium. All the experiments were carried out in batch process with laboratory prepared samples and wastewater obtained from metal finishing section of auto ancillary unit. The adsorbent, which had highest chromium(VI) removal was EB. Influences of chromium c...
Ten years have elapsed since the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of chromium and chromium compounds. Further studies performed during the last decade have provided further epidemiological, experimental and mechanistic data which support the IARC conclusions. A wealth of results indicate that, at variance with chromium(0) and chromium(III), chromi...
Chromium contamination in the area of the Radomka river basin in Poland has lead to significant environmental problems. Therefore, chromium redox transformations were investigated in the aquatic environment under conditions as close to natural as possible at intermediate pH and in the presence of original bottom sediment and dissolved oxygen. Reduction of Cr(VI) in the Radomka river water occur...
Chromium has been proposed to be an essential trace element useful in the treatment of diabetes, and several chromium(III) compounds have been used as nutritional supplements. However, the fate of the chromium from nutritional supplements has been investigated solely by techniques, such as radio-labeling, which allow only the chromium atom to be traced, not its chemical form. This investigation...
Chromium is one of the 25 most widespread elements in the Earth’s crust and occurs as an indelible non-volatile trace element in raw materials used in cement clinker production (clay, limestone and iron additives in particular). Chromium in raw materials mentioned above is mainly in form of trivalent chromium. Naturally occurring chromium (III) is not initially harmful, since it is chemically s...
Reduction of chromium(VI) to chromium(Ill) by thiourea between pH 3.0 and 5.5 is a key aspect of the chrominm(VI)/thiourea/polyacrylamide gel polymer system used in enhanced oil recovery processes. A method has been developed to determine chromium(Vl) concentration during the reduction of chromium(VI) to chromium(III) in this pH range. The reduction reaction is run in the presence of an acetic ...
Increased DNA-protein cross-linking (DPX) in circulating leukocytes has been proposed as a potential biomarker for exposure and genotoxic damage caused by inhalation of certain reactive chemicals, such as hexavalent chromium [Cr(VI)]. This study was designed to determine whether ingestion of a single dose of potassium dichromate alone [Cr(VI)] or potassium dichromate fully reduced to Cr(III) wi...
BACKGROUND Chromium (VI) has toxic and carcinogenic effects. So, determination and speciation of chromium in environmental samples is very important in view of health hazards. In this study, solid phase extraction (SPE) based on bulky amine-functionalized bimodal mesoporous silica nanoparticles (NH2-UVM-7) as a novel nanoadsorbent was applied for preconcentration and speciation of chromium (III...
Coconut husk fibre and rice straw were found to be able to remove significant amount of Cr (III) ions from aqueous solutions. Its removal is a function of pH and concentration. The optimum pH range for maximum uptake is between 4 and 6 for both substrates. The adsorption capacity was found to be 0.55 and 0.30 millimole Cr (III) / g substrate for coconut husk and rice straw respectively. The ads...
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