Studies on the Adsorption of 2-Chlorophenol onto Rice Straw Activated Carbon from Aqueous Solution and its Regeneration

M. Mahapatra and A. Kumar

Abstract
For this study a low-cost adsorbent, rice straw activated carbon (RSAC) was prepared via thermochemical routes after being impregnated with ZnCl2. Characterization studies performed on RSAC have revealed that RSAC is a mesoporous adsorbent with significant affinity towards 2-chlorophenol (2-CP). The optimal values for process parameters were investigated via experimental runs. The optimal values of process parameters such as RSAC dose, pH of 2-CP solution, contact time, and temperature were found to be; 1.25 g L–1, 8, 125 min, and 303 K, respectively. The Langmuir isotherm and pseudo-first-order kinetics models were found to be in good agreement with the experimental data for this adsorption system. The adsorption thermodynamics studies have revealed that the adsorption of 2-CP onto RSAC is exothermic and spontaneous. Regeneration studies of RSAC using hydrogen peroxide have revealed that RSAC was effectively regenerated for four consecutive cycles. This research has proved the potential of RSAC for abating 2-CP from aqueous solutions.

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Keywords
adsorption, 2-chlorophenol abatement, rice straw activated carbon, adsorption kinetics, adsorption equilibrium, regeneration