IMMOBILIZATION OF SELENIUM IN WASTE WATER BY LOW COST BIOMASS
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Date
2017
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Department of Chemistry Faculty of Science Sam Higginbottom University of Agriculture, Technology and Sciences Allahabad-211007 (2017)
Abstract
Selenium is one of the important element playing a most important role in human and animal health and is essential to all other organisms. The permissible level of selenium in drinking water is 10μg/L. Therefore even very low concentration of selenium in water it is toxic. For this reason it is essential to develop economical and ecofriendly method for the removal of selenium ions from aqueous solution. The rice husk, sweet lime peel and saw dust are naturally occurring adsorbents used for the removal of selenium. The adsorbents sweet lime peel, rice husk and saw dust were characterized by scanning electron microscopy and FTIR techniques. Sweet lime peel showed maximum removal of selenium as compared to rice husk and saw dust and these adsorbents followed the order that sweet lime peel is better adsorbent than rice husk and saw dust. At initial concentration of 1ppm the adsorbents showed maximum removal at pH 4.0 with amount of adsorbents 1.0g at 450C.The agitation speed was kept at 170 rpm. The adsorption kinetics was studied for pseudo first order, pseudo second order, intra particle diffusion, liquid film diffusion model and Elovich equation. The kinetics for these adsorbents fitted best was pseudo second order which confirmed that the adsorption was chemisorption in nature. The adsorption isotherm studied were Langmuir, Freundlich, Temkin, D-R, and Halsey for the adsorbents sweet lime peel, rice husk and saw dust. Thermodynamically the process was spontaneous and endothermic in nature. The maximum desorption %(69.09%) was showed in HNO3 and the minimum desorption%(36.10%) was showed in HCl. The results suggested that the sweet lime peel was proved to be the better adsorbent as compared to rice husk and saw dust. These adsorbents have high possibility to be used as effective and economical adsorbent for selenium removal.
Description
Ph. D. Thesis
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