Alkali Activated Cedar Wood as an Efficient Adsorbent for Pb2+ Removal from Aqueous Solutions: Optimization, Kinetic and Thermodynamic Study

Abstract

In the present study, activated carbon prepared from cedar wood was synthesized, \u200evia NaOH activation, and optimized to be used as the adsorbent for Pb2+ removal \u200efrom aqueous solutions in a batch process mode. The physicochemical properties \u200eof the synthesized adsorbent were examined by SEM, FTIR and BET analysis. In \u200eorder to determine the optimum operational conditions, the effects of different \u200eparameters including pH, adsorbent dosage, contact time, temperature, and initial \u200ePb2+concentration on the adsorptive performance of synthesized samples were also \u200einvestigated. According to the obtained results, the highest Pb2+ ion adsorption \u200ecapacity (971.9 mg/g) took place at the optimum operational condition of pH=4, \u200eadsorbent dosage of 0.025 g/L, contact time of 60 minutes, 300 ppm of Pb2+ and \u200e\u200e30 ℃. The results showed that among Langmuir, Freundlich, and Temkin \u200eisotherms, the obtained data were fitted the best with the Freundlich model. \u200eAdditionally, the process of Pb2+ adsorption was consistent with the pseudo-\u200esecond-order kinetics model, indicating that chemical adsorption was the dominant \u200emechanism of adsorption. Finally, according to the calculated thermodynamic \u200eparameters, i.e., ∆H°, 〖∆S〗^° & 〖∆G〗^°, Pb2+ adsorption on activated cedar \u200ewood can be considered as an exothermic and spontaneous process.\u200e