Enhanced Catalytic Activity of a Coal-Based Powdered Activated Carbon by Thermal Treatment

Thermal treatment is simple and has high potential in activated carbon (AC) modification because its functional groups, structures, and pores can be significantly modified. However, the changes in characteristics of ACs, affecting catalytic activity, have not been investigated enough. Therefore, in this study, a coal-based powdered AC (PAC) was thermally treated, characterized, and subjected to the removal of an antibiotic (oxytetracycline, OTC). The PAC treated at 900 °C (PAC900) showed the best OTC removal compared to the PACs treated under lower temperatures via both adsorption and catalytic oxidation in the presence of peroxymonosulfate (PMS). The results of N2 adsorption/desorption, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, and Boehm titration showed increases in basicity, specific surface area, graphitic structures with higher crystallinity and more defects, and C=O in PAC900 compared to PAC. Stronger signals of DMPO-X and TEMP-1O2 were shown for PAC900+PMS compared to PAC+PMS in electron paramagnetic resonance spectroscopy. It is suggested that a simple thermal treatment can significantly change the characteristics of a PAC, which improves organic micropollutants removal. The changes in the properties, affecting the performance, would provide important information about the improvement of carbonaceous catalysts.