Chromium (VI) Ions Removal from Tannery Effluent using Chitosan-Microcrystalline Cellulose Composite as Adsorbent

The bio-adsorbent chitosan-microcrystalline was synthesized from waste materials of shrimp processing industries, and waste cotton rags of garments industries for removal of chromium (VI) ion from tannery effluent. The chitosan was extracted from shrimp shell through the deproteinization, demineralization and deacetylation steps and microcrystalline cellulose was extracted from waste cotton rags by acid hydrolysis. The composite was prepared by simple solution evaporation method. The functional groups, responsible for adsorption and the chemical interaction in the composite formation were evidenced from FTIR results. The observed SEM results indicate that the prepared composite has a rough and porous surface. Batch adsorption experiments were conducted and removal of Cr(VI) was found to be reliant on pH and maximum adsorption was observed at pH 5.0. For 2 ppm Cr(VI) stock solution, the optimum dose and contact time treatment was 2 g/L and 240 minutes respectively and the maximum removal efficiency of chromium was found 93%. Tannery effluent was treated with optimum conditions required for maximum removal of Cr(VI). Langmuir isotherm and Freundlich isotherm model were plotted against the adsorption data and found that Langmuir Isotherm was well fitted with R2 value of 0.997.