Journal of Research in Environmental Sciences and Engineering

Authors: Sameera N., Dr. Kiran S., Dr. S. M. Desai

Abstract: Hexavalent chromium is a major component of many industrial effluents and is toxic and carcinogenic even at very low concentrations. The present study aimed at evaluating the efficiency of coconut husk as an adsorbent for removal of Cr(VI)from solutions in a Packed Bed Adsorption Column. Batch adsorption studies were conducted to determine the effect of factors on removal of chromium from aqueous solutions by three forms of the biomass – untreated, acid-treated and alkali-treated. The acid-treated form of coconut husk was found to be the best with maximum chromium removal capacity of 84.06% at 2.35 pH and 34.3oC temperature, with highest initial metal concentration of 165.47 mg/L and lowest adsorbent usage of 4.89 g/100mL.Fixed bed column adsorption studies were conducted by varying flow rate of inlet stream (0.5 mL/min to 1.2 mL/min) while keeping the feed concentration at 250 mg/L, solution pH at 2.5 and bed height at 10 cm. Breakthrough curve was plotted and maximum value of adsorption capacity was obtained as 5.77 mg/g for flow rate of 1.2 mL/min. The observations were fit into well-established fixed-bed adsorption models namely, AdamsBohart, Thomas and Yoon-Nelson models. Thomas and Yoon-Nelson models were found to fit the adsorption data to good extent, with correlation coefficient R2≥ 0.96..