نتایج جستجو برای: chromium vi
تعداد نتایج: 64211 فیلتر نتایج به سال:
Reaction of chromium(VI) with one equivalent of ascorbate was studied by electron paramagnetic resonance spectroscopy in the presence of 0.10 M 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) at room temperature in 0.10 M (N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid]) (HEPES) and 0.05 M tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffers (pH 7.0 room temperature). Chromium(V), a...
Heavy metals have significant importance in altering the immune response. Chromium is found in the environment commonly in trivalent, Cr (III), and hexavalent, Cr (VI), forms. The reduction of Cr (VI) to Cr (III) results in the formation of reactive intermediates (ROS) that contribute to the cytotoxicity and genotoxicity. In this study mice were treated with chromium (VI) oxide (24 mg /kg body ...
abstract background: heavy metals in industrial wastewater especially chromium (vi) are considered as the main environmental pollutants. methods: electrochemical cell made of plexiglass with a volume of 1.95 lit was used. iron and graphite electrodes, electricity conductor, each with dimensions of 0.1×3×10 cm (width×length×height) were designed and built. tests were carried out in various condi...
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...
The activated sludge has been acclimatized with chromium (VI) ions from 5 mg/L to 20 mg/L. It is observed that the chromium removal percentage, COD removal and mixed liquor suspended solid (MLSS) decrease with the increase in dilution rate. Maximum food to microorganisms ratio (F/M) is found to be 0.19. When initial metal ion concentration increases from 5 mg/L to 20 mg/L, the chromium removal ...
the biosorption of hexavelent chromium from saline solutions by posidonia oceanica, a marinebiomass, was studied as a function of ph, initial chromium (vi) and salt (nacl) concentrations in batchsystem. the sorbent exhibited the maximal chromium (vi) uptake at ph 2 regardless of the presence ofincreasing salt concentration. equilibrium uptake increased with chromium (vi) concentration up to 250...
Chromium exists in sediments in two oxidation states: Cr(III), which is relatively insoluble and nontoxic, and Cr(VI), which is much more soluble and toxic. Chromium(VI) is thermodynamically unstable in anoxic sediments, and acid-volatile sulfide (AVS) is formed only in anoxic sediments; therefore sediments with measurable AVS concentrations should not contain toxic Cr(VI). If this hypothesis h...
Hexavalent chromium reduction by sulfide in the presence of goethite was studied through several batch experiments. Under our specific experimental conditions including 20 μM of hexavalent chromium, 560–1117 μM of sulfide and 10.61– 37.13 m2/L of goethite at pH of 8.45 controlled by 0.1 M borate buffer, the obtained hexavalent chromium disappearance rate was –d[Cr(VI)]/dt = k[surface area of go...
Diabetes mellitus is growing in prevalence worldwide. Uncontrolled industrialization has released heavy metal pollutants and toxic agents that may play a role in the islet function and development of diabetes mellitus. Among the toxic metals, chromium (Cr) is widely used in industries and is considered a major cause of environmental pollution. Cr (III) constitutes an essential nutrient, while C...
Nine bacterial colonies were screened for the Cr(VI) removal efficiency and out of these three bacterial strains Pseudomonas putida, Pseudomonas aeruginosa and Bacillus sp. were isolated from soil and used to remove Cr(VI) from aqueous solution. The effect of time and concentrations on the removal rate of hexavalent chromium were studied using batch experiment. Maximum Cr (VI) removal was noted...
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