Efficient activation of peroxydisulfate (PDS) by rice straw biochar modified by copper oxide (RSBC-CuO) for the degradation of phenacetin (PNT)

In this study, rice straw biochar modified by copper oxide (RSBC-CuO) was successfully fabricated via a hydrothermal method and used as a catalyst for the degradation of organic pollutants by peroxydisulfate (PDS). RSBC-CuO-activated PDS exhibited an outstanding performance on the decomposition of phenacetin (PNT). Electron paramagnetic resonance (EPR) confirmed that the reactive oxygen species (ROS) included SO4−, OH, O2− radicals and singlet oxygen (1O2), which were in charge of the PNT destruction. Scavenger experiments further conformed that 1O2 and O2− played the crucial role in the PNT removal. RSBC-CuO also displayed an excellent stability and reusability. The rate of PNT removal after four consecutive cycles declined slightly. Furthermore, the combination of RSBC-CuO and PDS possessed a universal degradation potential towards various organic pollutants, and the degradation efficiencies of the pollutants such as paracetamol, aniline, p-chlorobenzoic acid, sulfamethazine and 2,4,6-Trichlorophenol reached a range of 86 to 100% within 10 to 30 min. Thus, it is concluded that RSBC-CuO-activated PDS is a novel and feasible approach to the removal of organic contaminants from aqueous solution.