Coal-based activated carbon is oxidatively modified by(NH4)2S2O8 to improve its electrosorption performance.The activated carbon materials are prepared into electrodes for experiments under EST technique.The changes in surface morphology,surface functional groups and pore structure of the activated carbon before and after modification are compared and analyzed.Results show that the activated carbons modified by 1.5 mol·L-1(NH4)2S2O8 exhibits the largest specific capacitance value.The specific capacitance of the activated carbon electrode increases after modification,but its pore capacity and average pore size decrease.The modified material has a smooth surface,less impurities,a developed pore structure and more oxygen-containing functional groups.Through using the single-factor and Box-Behnken response surface methods,the best process conditions for the preparation of the modified material are as follows:1.59 g of activated carbon has been oxidatively modified at 54.22 ℃ for 4.93 h.The specific capacitance of the electrode is 259.850 F·g-1.The CV curves of the electrode proves that its electrochemical properties are improved because it contains pseudo capacitance.
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