Regeneration of activated carbons saturated with pyridine or phenol using supercritical water oxidation method enhanced with hydrogen peroxide

Abstract

While activated carbon (AC) is widely employed for treating water resources contaminated with hazardous organic compounds, regeneration of AC after saturation has been a concerning issue. Supercritical water oxidation (SCWO) in a batch reactor was used to regenerate two commercial activated carbons (CAL and COCO) saturated with pyridine or phenol. BET surface area, pore volume and pore size distribution of CAL and COCO were characterized before and after their regeneration. Decomposition of pyridine and phenol was examined at 400, 450, 525 °C with the presence or absence of hydrogen peroxide. The SCWO regeneration efficiency was determined from the amount of pyridine or phenol adsorbed and desorbed in successive adsorption-regeneration cycles. Effects of SCWO on adsorption capacity of CAL and COCO were experimentally investigated. With SCWO enhanced by H 2O 2, adsorbed organic compounds could be converted to carbon dioxide, hydrogen and nitrogen.