Preparation of activated carbon by molten salt electrochemical method and adsorption and recovery on chromium

Given the substantial health hazards linked to hexavalent chromium Cr(VI), the utilization of bamboo-based activated carbon (BAC) prepared through molten salt electrochemical technology enables effective adsorption of Cr(VI), thereby mitigating environmental pollution. The effects of reaction temperature, reaction time, and current density on the yield of activated carbon and iodine adsorption value were initially investigated. Under the optimal reaction conditions, BAC exhibited a substantial pore structure, with a specific surface area of 1280.39 m2/g and an iodine adsorption value of 1270.8 mg/g. The activated carbon demonstrated effective removal of Cr(VI) in wastewater with a high adsorption capacity of 185.68 mg/g for an initial concentration of 200 mg/L, achieving a removal rate of 92.84 %. In the preparation process, electrolysis enhanced the molten salt pyrolysis and activation, promoting the formation of mesopores, while also generating activated gases inside activated carbon through decarboxylation and oxidation reactions of carbonate ions, facilitating the formation of micropores and enhancing the rate of gas activation. Research on recycling has shown that the removal efficiency of Cr(VI) using activated carbon recovered from molten salt electrochemical systems reached 97.92 %. Further reactions could be carried out to obtain metallic chromium, enabling the resourceful utilization of chromium.