Bamboo-Activated Carbon Synthesized by One-Pot Pyrolysis and FeCl2 Activation for the Removal of Cr(VI) in Aqueous Solutions

Abstract

The present study utilized a FeCl2-based environmentally sustainable activation technique to produce activated carbon from bamboo. The research aimed to evaluate the influence of activation temperature on the physical and chemical characteristics of the activated carbon and its ability to adsorb Cr(VI). The results of the experiment indicated that the yield of activated carbon prepared by this method was in the range of 25.5–37.5%, which was comparatively higher than the yield obtained through traditional KOH and steam activation techniques. Moreover, this method resulted in a well-developed pore structure with pore sizes primarily ranging from 0.5 nm to 1.0 nm. A gradual increase in the specific surface area and pore volume was observed with an increase in the activation temperature. The maximum values of 1290.9 m2/g and 0.67 m3/g for specific surface area and pore volume, respectively, were achieved at an activation temperature of 900 °C. The adsorption capacity of Cr(VI) was subject to variation in correspondence with alterations in the pore structure of activated carbon. The maximum adsorption capacity recorded was 13.65 mg/g. This suggested that the adsorption capability was predominantly influenced by the pore configuration. The study of kinetics and isothermal adsorption indicates that the quasi-second-order kinetic model was a more effective approach for characterizing the adsorption process of Cr(VI) on activated carbon. Additionally, the Freundlich model demonstrated superior fitting performance compared to the Langmuir model.