Study on The Preparation of Magnetic Sorbent from Bagasse for Chromium Ion Removal

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2015-06

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Addis Ababa University

Abstract

Heavy metals in the environment are hazardous to human health and require better methods for detection and remediation. Industrial effluent often contains the significant amount of hexavalent chromium. The discharge of wastewater without proper treatment into water streams consequently enters the soil and disturbs the aquatic and terrestrial life. A range of wastewater treatment technologies have been proposed which can efficiently reduce Cr(VI) to less toxic form such, as biodegradation, sorption, bioaccumulation, and nanotechnology. In this study, bagasse coated iron oxide magnetic sorbent were prepared using iron salts in presence of NH3 by co- precipitation process and then the magnetic sorbent is used as an adsorbent for chromium removal. All the adsorption experiments were carried out in batch mode to optimize process parameters using response surface methodology. Based on central composite design, quadratic model was developed to correlate the variables to the response. The effect of different parameters on optimum function of this process has been analysed. The results showed that maximum chromium adsorption of 91.95% occurs at pH levels of about 4. Optimum dosage of sorbent, chromium concentration and contact time are 1.1g, 20mg/l and 90min, respectively. Adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to Langmuir isotherm. Results show that the kinetic model of pseudo-first order provided a good description of the experimental data. Thus, the chromium adsorption by magnetic sorbent can be considered as a potential treatment process for chromium removal in which the adsorbents and the adsorbed pollutant can be quickly recycled by the application of magnet.

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Mechanical Engineering

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