hexavalent chromium Articles

  • Deadly Hexavalent Chromium in Soil

    Merging technologies will change over Hexavalent Chromium in soil to Trivalent Chromium, effectively stopping Hexavalent Chromium from becoming dangerously airborne or becoming even more deadly by migrating into the water table. There are three valences of Chromium: 1) Chromium—safe to humans, 2) Trivalent Chromium—safe and an essential element in humans and 3) Hexavalent ...


    By ABCOV Companies

  • Adsorption of hexavalent chromium on dunite

    The paper presents and discusses the effect of various physicochemical parameters (e.g. pH, ionic strength, Cr(VI) initial concentration, amount of the adsorbent, temperature and contact time between metal ion and adsorbent) on the adsorption efficiency of Cr(VI) on dunite in aqueous solutions under atmospheric conditions. Evaluation of the experimental data shows that dunite presents increased ...


    By IWA Publishing

  • Removal of hexavalent chromium using coffee husk

    The potential to remove chromium(VI) from aqueous solutions through biosorption using coffee husk was investigated. The effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(VI) were studied. The data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity was found to be 44.95 mg/g. The Freundlich constants Kf and n were ...


    By Inderscience Publishers

  • Is Hexavalent Chromium (Hex Chrome; Chrome VI) a carcinogen?

    In 1990, the International Agency for Research on Cancer (IARC), an agency of the World Health Organization (WHO), published their findings on chromium and chromium compounds as carcinogens.  Chromium may be isolated in any of three volume states: Chrome 0 or metallic chromium; Chrome III called “Chrome 3” or Chrome VI called “Chrome 6,” also called hexavalent ...


    By Atlantic Environmental, Inc.

  • Biological Treatment of Hexavalent Chromium Treatability Study Report

    A former XXXX was found to be impacted by hexavalent chromium [Cr(VI)]. The site Cr(VI) plume has groundwater concentrations as high as 1,150,000 μg/L in the hot spot(s). Treatability studies were conducted at Shaw Environmental & Infrastructure, Inc.’s Technology Development Laboratory (TDL) in Knoxville, Tennessee, to evaluate treatment technologies to decrease the concentration of Cr(VI) ...


  • Immobilised microbial reactor for the biotransformation of hexavalent chromium

    Out of an array of bacterial strains isolated from soil contaminated with effluents from electroplating wastewater, Bacillus coagulans exhibited the maximum Cr(VI) reduction potential. The feasibility of an immobilized B. coagulans bioreactor for hexavalent chromium reduction was investigated. Experimental results demonstrated that near complete removal of Cr(VI) was achieved in the reactor with ...


    By Inderscience Publishers

  • Osha issues final standard on hexavalent Chromium

    After years of trying to craft an exposure standard for hexavelant chromium that would stand up under expected court challenges, the Occupational Safety and Health Administration (OSHA) issued a final standard on February 28, 2006 which became effective on May 29, 2006. Under the standard, the Permissible Exposure Limit (PEL) for exposure to hexavalent chromium will be lowered from 52 to 5 ...


    By Atlantic Environmental, Inc.

  • Morphological and transcriptional responses of Lycopersicon esculentum to hexavalent chromium in agricultural soil

    The carcinogenic, teratogenic and mutagenic effects of hexavalent chromium [Cr(VI)] to living organisms through food chain raise the immediate need to assess the potential toxicological impacts of Cr(VI) on human health. Therefore, the concentration‐dependent responses of 12 Cr(VI)‐responsive genes selected from the high‐throughput Lycopersicon esculentum cDNA microarray were examined at ...


    By John Wiley & Sons, Ltd.

  • Adsorption of hexavalent chromium from aqueous solutions by wheat bran

    In this research, adsorption of chromium (VI) ions on wheat bran has been studied through using batch adsorption techniques. The main objectives of this study are to 1) investigate the chromium adsorption from aqueous solution by wheat bran, 2) study the influence of contact time, pH, adsorbent dose and initial chromium concentration on adsorption process performance and 3) determine appropriate ...

  • Nitrite interference and elimination in diphenylcarbazide (DPCI) spectrophotometric determination of hexavalent chromium

    Cr(VI) is highly noted as a carcinogenic, mutagenic, and teratogenic pollutant. However, accurate determination of Cr(VI) in aqueous samples is difficult using the conventional diphenylcarbazide (DPCI) spectrophotometric method upon being interfered by co-existed nitrite. This paper illustrates how to eliminate the nitrite influence in a simple but efficient method based on a detailed analysis ...


    By IWA Publishing

  • Characteristics and kinetics of hexavalent chromium reduction by gallic acid in aqueous solutions

    Gallic acid (GA) is a naturally occurring plant polyphenol compound. Experiments were conducted to study the kinetics and effects of pH, temperature, irradiation, and initial hexavalent chromium (Cr(VI)) concentration on Cr(VI) reduction by GA. Results indicated that Cr(VI) could be reduced to chromium oxide (Cr(III)) with GA in a wide range of pH values from 2.0 to 8.5. The reaction followed a ...


    By IWA Publishing

  • Reduction remediation of hexavalent chromium by bacterial flora in Cr(VI) aqueous solution

    Chromium(VI) is a priority pollutant in soils and wastewaters and reduction of Cr(VI) to Cr(III) is a solution to this problem. In this study a low-cost method was proposed to adapt indigenous bacteria and use them to reduce Cr(VI) in solutions. The experiment results show that Cr(VI) could be efficiently reduced by indigenous bacteria under anaerobic and pH-unadjusted conditions. After about ...


    By IWA Publishing

  • Removal of hexavalent chromium from aqueous solution by calcined Zn/Al-LDHs

    In this study, Zn/Al-layered double hydroxides (Zn/Al-LDHs) were synthesized by a co-precipitation method and characterized with X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Then the hexavalent chromium Cr(VI) adsorption experiments on calcined Zn/Al-LDHs were carried out to analyze the effects of pH, temperature, adsorption time, initial Cr(VI) ...


    By IWA Publishing

  • Removal of hexavalent chromium from aqueous solution by lignocellulosic solid wastes

    The batch removal of Cr(VI) from aqueous solution using lignocellulosic solid wastes such as sawdust and pine leaves under different experimental conditions was investigated in this study. The influence of pH, temperature, contact time, initial concentration of Cr(VI) and particle size on the chromium removal was investigated. Adsorption of Cr(VI) is highly pH-dependent and the results indicate ...

  • Control of Welding Fume Particulates Using Cleanable Filter Media: Hexavalent Chromium

    Herein, a Sentry Air Systems product study of hexavalent chromium particles, [Cr(VI)], is reported. Due to the popularity of extended life cleanable filter media and health concerns regarding hexavalent chromium exposure in the work place, Sentry Air Systems conducted a study of the efficacy of cleanable filter systems for the maintenance of safe breathing conditions during welding operations ...


    By Sentry Air Systems, Inc.

  • Determination of hexavalent chromium in toys by using UV/Vis Spectrometry

    Toy safety is a joint responsibility among governments, the toy industries, regulatory bodies and parents. The toy safety regulations are intended to reduce potential risks children could be exposed to when playing with toys. Enforcement of the regulations aims to identify those toys that do not comply with the legislation and remove them from the market. The toxic elements that may be present in ...


    By PerkinElmer, Inc.

  • Assessment of the removal mechanism of hexavalent chromium from aqueous solutions by olive stone

    The objectives of this study were to study the removal mechanism of Cr(VI) by natural olive stone (OS) and to present a sequential-batch process for the removal of total chromium (original Cr(VI) and Cr(III) derived from reduction of Cr(VI) during biosorption at acidic conditions). First, experiments were conducted varying pH from 1 to 4, and showed that a combined effect of biosorption and ...


    By IWA Publishing

  • Adsorption of hexavalent chromium by crosslinked chitosan–iron(III) in an air-lift reactor

    Column experiments were conducted in an airlift reactor containing a certain amount of crosslinked chitosan–iron(III) (Ch-Fe), to examine the effects of adsorbent mass, flow rate, and influent concentrations on Cr(VI) removal. The breakthrough time increased with an increase in Ch-Fe mass, but decreased with an increase in initial Cr(VI) concentration. The exhaustion time decreased with an ...


    By IWA Publishing

  • Effective detoxification of hexavalent chromium using sulfate-crosslinked chitosan

    A sulfate-crosslinked chitosan (SCC) was prepared for effective detoxification of hexavalent chromium (Cr(VI)) from effluents. SCC was characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray studies. The maximum adsorption of Cr(VI) was observed at pH 6.0 with adsorption capacity of 157 mg/g in accordance with the Langmuir ...


    By IWA Publishing

  • Behavior of hexavalent chromium in the water supply system by IC-ICP-MS method

    The analysis conditions for measuring trace concentration of Cr(VI) based on the ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) method was examined. By optimizing the analysis conditions, the measurement of 0.02 μg-Cr(VI)/L was achieved with a high degree of accuracy. The behavior of Cr(VI) through the water treatment process in Osaka city was investigated and ...


    By IWA Publishing

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