نتایج جستجو برای: chromium vi ions
تعداد نتایج: 197985 فیلتر نتایج به سال:
Chromium ions released into aquatic environments pose major environmental risks, particularly in developing countries. Here, a low-cost N-cetyltrimethylammonium bromide (CTAB)-modified fly ash-based zeolite Na-A (CTAB@FZA) was prepared for the treatment of industrial wastewater contaminated with Cr(VI). CTAB@FZA evaluated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (F...
The wood preservative chromated copper arsenate (CCA) contains hexavalent chromium [Cr(VI)] and the conversion of Cr(VI) to trivalent chromium [Cr(III)] drives fixation of the treatment chemicals to the wood fibers. Since the toxicity of Cr depends on its valence state, an assessment of the Cr species occurring in CCA-treated wood, as well as leachates and ashes from CCA-treated wood, is helpfu...
Aqueous plant leaves extract (PLE) of an abundant shrub, Sorbaria sorbifolia, was explored for the reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). The effect of contact time, pH, PLE quantity, ionic strength, hardness, temperature and effective initial Cr(VI) ion concentration were tested; Cr(VI) reduction followed the pseudo-first order rate kinetics and maximum reduc...
The effect of pretreatment with ascorbic acid (vitamin C) on chromate-induced DNA damage, cytotoxicity, and enzyme inhibition as well as on the cellular reduction of chromium(VI) was investigated using Chinese hamster V-79 cells. Cellular pretreatment with nontoxic levels of 1 mM ascorbic acid for 24 h prior to exposure resulted in a significant increase (1.7-fold) in cellular levels of this vi...
This paper reports on enzyme-like catalytic properties of polyethylene glycol-functionalized poly(N-phenylglycine) (PNPG-PEG) nanoparticles, which have not been explored to date. The developed nanoparticles the ability display great inherent peroxidase-like activity at very low concentrations, and are able catalyze oxidation 3,3′,5,5′-tetramethylbenzidine (TMB) substrate in presence hydrogen pe...
Hexavalent chromium-resistant Ochrobactrum intermedium BCR400 was isolated from chromium contaminated soil collected from Vadodara, Gujarat. It reduced 100 mg Cr(VI)/L completely in 52 h with initial Cr(VI) reduction rate of 1.98 mg/L/h. The Cr(VI) reduction rate decreased with increase in Cr(VI) concentration from 100 to 500 mg/L. The addition of anthraquinone-2-sulphonic acid (AQS) to culture...
Background and Objectives:Groundwater treatment by nano particles has received increasing interest in recent years. Chromium is a commonly identified contaminant in soils and groundwater. Zero-valent iron, as a natural reduction agent can be used in controlling of contaminated sites. The aim of this research is investigation of hexavalent chromium removal from aqueous solutions by using of iron...
Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI) in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI) from MS...
Chromium (VI) Considered as a serious health hazard and it has attracted attention as a pollutant in natural waters. The sources of contamination of chromium in natural waters and in the Environment are from electroplating, tanning industries and waste solution from oxidative dyeing and leaching from sanitary land – fills, In view of this the separation and determination of chromium has been re...
A method is described for assessing occupational exposures to chromium aerosols; it involves four procedures. The first, proton induced X-ray emission (PIXE), measures the total chromium. The second, electron spectroscopy for chemical analysis (ESCA), measures the oxidation state of the particle surfaces, and the third, which uses sym-diphenylcarbazide (DPQ, measures the proportion of water-sol...
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