Direct conversion of wet sewage sludge to carbon catalyst for sulfamethoxazole degradation through peroxymonosulfate activation.

The high moisture content of wet sewage sludge generated from wastewater treatment process not only brings high cost of sewage disposal, but also limits its utilization as resource. In this study, an efficient strategy of directly utilizing wet sludge to develop advanced carbocatalyst via a hydrothermal coupled pyrolysis process was proposed. The possible application of as-synthesized carbocatalyst was evaluated by activating peroxymonosulfate (PMS) to degrade a model pollutant of sulfamethoxazole (SMX). Experimental results showed that about 100% of SMX and 59% of total organic carbon (TOC) could be removed within 15 min. Moisture content in wet sludge also affected the performances of as-obtained carbocatalysts. Further studies verified that singlet oxygen (1O2) dominated SMX degradation, which was generated in the process of PMS activation by CO groups on the surface of carbocatalyst. In the preliminary ecological test, a lower ecotoxicity of SMX degradation solution compared with the original solution was observed. This study demonstrated the feasibility of directly utilizing wet sludge for advanced carbocatalyst fabrication, which provided another solution for wet sludge treatment and utilization.