Microwave regeneration characteristics of activated carbon for flue gas desulfurization

Microwave regeneration of SO2-loaded activated carbon (AC) and its consequent adsorption characteristics were studied. The effects of microwave regeneration on the pore texture and surface chemistry of activated carbon were examined by scanning electron microscopy, low-temperature N2 adsorption, elemental analysis and Boehm titration, and its effect on the adsorption of SO2 contained in flue gas passing over activated carbon was analyzed. The results show that increasing microwave regenerative power produces a narrower SO2 regeneration curve with higher peak concentrations, which aids both the regeneration of activated carbon and recovery of a high concentration of SO2. The carbon pores become elongated during the regeneration process. With increasing microwave power, the micropore specific surface area, volume, and the proportion of surface acidic functional groups all increase, while the surface alkaline functional groups decrease. Incomplete regeneration occurrs at 100 W due to the inhibiting effect of residual H2SO4 on adsorptive capacity. At 200, 300 and 400 W, the adsorptive capacity for SO2 exceeds that of the original AC.