Extraction of trivalent chromium from tannery effluent by ion exchange with indion 790 resin

Extraction of chromium(III) from a model tanning effluent has been studied by ion exchange using Indion 790 resin. The resin has been found to be selective for the sorption of chromium(III) in the pH range 0.5-3.5 from a model solution containing 500 ppm chromium(III). Beyond pH 3.5 extraction of chromium(III) drastically decreases from 92% to 76.5%. Sorption of chromium(III) on Indion 790 follows Freundlich isotherm indicating strong chemical interaction of the metal ion with the resin. Desorption of chromium(III) from the loaded resin increases with the increase in concentration of eluant (5-20% H2SO4). With 20% sulfuric acid solution 89% chromium(III) was eluted in two stages. The bench scale results are also validated in continuous mode in a fixed bed column for the recovery of chromium(III) from tannery effluent.