Synthesis and characterization of mesoporous activated carbon from rice husk for adsorption of glycine from alcohol-aqueous mixture

Activated carbon prepared from rice husk using phosphoric acid activation has been studied by chemical activation. The surface area, pore volume, and pore size distribution of carbon samples activated at 700, 800, and 900 °C (MAC₇₀₀, MAC₈₀₀ and MAC₉₀₀) were measured. Temperature 800 °C was found to be optimum for the increase production of pore volume especially mesopore volume. Hence detailed characterization of MAC₈₀₀ was carried out. The X-ray diffraction curve of MAC ₈₀₀ revealed the evolution of crystallites of carbon and silica during activation at higher temperature. The FTIR spectrum also provided evidence for the presence of silica in the carbon composite. Batch adsorption of glycine onto MAC₈₀₀ was carried out. The effect of time, temperature and initial concentration of glycine on the adsorption was studied. pH 6 was found to be optimum for adsorption reaction and the reaction was endothermic in nature. Adsorption isotherm models such as Langmuir, Freundlich and Redlich-Peterson were evaluated and their constants were derived. The pseudo first order and second order models were employed; the pseudo second order showed a good agreement when compared to pseudo first order.