Adsorption of phenol from aqueous solutions using mesoporous carbon prepared by two-stage process

Abstract

Porous carbon prepared from rice husk using phosphoric acid activation through precarbonization and chemical activation has been examined for the adsorption of phenol from aqueous solutions. The method adopted could produce carbons with micro and mesoporous structure. The surface area, pore volume and pore size distribution of carbon samples activated at three different temperatures 700, 800 and 900 °C have been carried out using nitrogen adsorption isotherms at 77 K. The production yield was observed to decrease with increase in activation temperature. Adsorption behavior of phenol onto the porous carbon was studied by varying the parameters such as agitation time, phenol concentration, pH and temperature. Studies showed that the adsorption decreased with increase in pH and temperature. The sorption process was found to be exothermic in nature. The kinetic models such as pseudo first order, pseudo second order and intra particle diffusion model were fitted to identify the mechanism of adsorption process. The isotherm data were fitted to Langmuir and Freundlich models. The maximum uptake of phenol was found to be 2.35 × 10−4 mol/g at 20 °C and final pH 2.7.