Adsorption capacity of Cr(VI) onto activated carbon, almond and apricot shells was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH , temperature, agitation speed, absorbent dose and particle size. The adsorption was solution pH dependent and the maximum adsorption was observed at solution pH of 2.0. The amounts of Cr(VI) adsorbed increased with increase in dose of both adsorbents and their contact time. A contact time of 30 min was found to be optimum. Experimental results show low cost biosorbent was effective for the removal of pollutants from aqueous solution. The pseudo-second-order kinetic model gave a better fit of the experimental data compared to the pseudo-first-order kinetic model. Experimental data showed a good fit with the Freundlich isotherm model.

Keywords