Regeneration of hexamminecobalt(II) under the catalysis of activated carbon treated with K2S2O8 solution



The combined elimination of NO and SO2 can be realized by hexamminecobalt(II) solution. Activated carbon is utilized to catalyze the reduction of hexamminecobalt(III) (Co(NH3)63+) to hexamminecobalt(II) (Co(NH3)62+), so as to maintain a high NO removal efficiency for a long time. K2S2O8 solution has been tried to modify coconut activated carbon to enhance its catalytic capability in the reduction of hexamminecobalt(III). The experiments have been performed in a stirred cell to investigate the effects of K2S2O8 concentration, impregnation temperature, and impregnation time on the catalytic ability of activated carbon. The results showed that the best K2S2O8 concentration for the improvement of activated carbon is 0.3 mol L−1. The optimal impregnation temperature was 40°C. The optimum impregnation duration was 9 h. After treated with K2S2O8 solution, the surface area of activated carbon decreased. But the acidity on its surface was enhanced, which played a crucial role in improving the catalytic capacity of activated carbon in the reduction of Co(NH3)63+. The experimental results showed that the modified carbon could obtain a higher NO removal efficiency than the original carbon. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 65–73, 2015