Adsorption of chromium (VI) from the synthetic aqueous solution using chemically modified dried water hyacinth roots

Present study elaborates the development of chemically modified dried water hyacinth root (DWHR) as an adsorbent for the removal of chromium (VI) from the synthetic aqueous solution. The Batch-mode experiments were conducted to determine the effect of various parameters (i.e. Contact time, Adsorbent dose, pH of sample and Agitation speed) on the adsorption of chromium (VI). To understand the surface characteristics and to verify the adsorption of chromium (VI) onto DWHR, FTIR and SEM analysis were done for DWHR before and after the adsorption process. The DWHR removed chromium (VI) from the synthetic aqueous solution at maximum removal efficiency of 95.43% from the conducted batch adsorption at optimized parameters (i.e. pH = 3.0, adsorbent dose = 14.0 g L-1 , adsorbent size = 150 mu, adsorbate concentration = 10.0 mg L-1 temperature = 25 +/- 5 degrees C, agitation speed = 200 rpm) after 2 h contact time. The DWHR had a maximum adsorption capacity of 1.28 mg g(-1) and 0.828 mg g at 5.0 mg L-1 and 10.0 mg L-1 respectively. The conducted adsorption kinetics studies and the adsorption isotherms explained that data fitted well with Freundlich isotherm and correlated well with the pseudo second order. So, it can be concluded that DWHR is a satisfactory adsorbent for mitigation of chromium (VI) from small scale electroplating industries effluent at even low adsorption capacity.