Author/Authors :
Asgari, A. R. tehran university of medical sciences tums - School of Public Health - Department of Environmental Health Engineering, تهران, ايران , Vaezi, F. tehran university of medical sciences tums - School of Public Health - Department of Environmental Health Engineering, تهران, ايران , Dehghani Fard, E. tehran university of medical sciences tums - School of Public Health - Department of Environmental Health Engineering, تهران, ايران , Nasseri, S. tehran university of medical sciences tums - School of Public Health and Center for Environmental Research - Department of Environmental Health Engineering, تهران, ايران , Mahvi, A. H. tehran university of medical sciences tums - School of Public Health and Center for Environmental Research - Department of Environmental Health Engineering, تهران, ايران , Dordelmann, 0 . Institute for Water Research - Department of Water Technology, Germany
Abstract :
Removal of chromium can be accomplished by various methods but none of them is cost-effective in meeting drinking water standards. For this study, granular ferric hydroxide was used as adsorbent for removal of hexavalent chromium. Besides, the effects of changing contact time, pH and concentrations of competitive anions were determined for different amounts of granular ferric hydroxide. It was found that granular ferric hydroxide has a high capacity for adsorption of hexavalent chromium from water at pH 7 and in 90 min contact time. Maximum adsorption capacity was determined to be 0.788 mg Cr+6fg granular ferric hydroxide. Although relatively good adsorption of sulfate and chloride had been specified in this study, the interfering effects of these two anions had not been detected in concentrations of 200 and 400 mg/L. The absorbability of hexavalent chromium by granular ferric hydroxide could be expressed by Freundlich isotherm with R2 O.968. However, the disadvantage was that the iron concentration in water was increased by the granular ferric hydroxide. Nevertheless, granular ferric hydroxide is a promising adsorbent for chromium removal, even in the presence of other interfering compounds, because granular ferric hydroxide treatment can easily be accomplished and removal of excess iron is a simple practice for conventional water treatment plants. Thus, this method could be regarded as a safe and convenient solution to the problem of chromium-polluted water resources.
