Preparation of mesoporous activated carbon by preliminary oxidation of petroleum coke with hydrogen peroxide and its application in capacitive deionization

Abstract

Capacitive desalination is a very promising method for the supply of high-tech industrial water in the future. In this study, activated carbon with both specific surface area and mesopores developed at the same time was prepared by preliminarily oxidized petroleum coke with hydrogen peroxide and then activating it with KOH. Hydrogen peroxide used for preliminary oxidation penetrates deep to the inside as well as the surface of petroleum coke to increase reactivity upon activation, forming pores to the depth of petroleum coke to create high specific surface area activated carbon with developed mesopores. Activated carbon prepared by preliminarily oxidized petroleum coke had high specific surface area and mesopores. In particular, OMC-35 had a specific surface area of 3032 m2/g and the highest mesopores of 0.82 cm3/g. As a result, OMC-35 had an excellent capacitance of 196.9 F/g at a scan rate of 5 mV/s. In addition, OMC-35 showed a salt adsorption capacity (SAC) of 19.5 mg/g and excellent desalination performance with a salt removal efficiency of 98.5 % in 250 ppm of NaCl solution. Thus, this work supports OMC-35 as a promising candidate for desalination of industrial water and large-scale application.