CuO nanosheets incorporated scrap steel slag coupled with persulfate catalysts for high-efficient degradation of sulfonamide from water

A highly efficient and magnetically recoverable persulfate (PS) catalyst was prepared for the removal of sulfonamide (SMD) from wastewater, which is difficult to be degraded by the conventional biological treatment. In this study, the scrap steel slag (SSS) was used as supporting carrier and the CuO nanosheet was incorporated on the surface of SSS. The optimal conditions were determined as follows: the dosage of CuO/SSS was 1 g L-1, the PS concentration was 4 mM and the optimal initial pH was 6.85. Under the optimal conditions, the maximum SMD removal efficiency of 80.29% was achieved within 30 min by using CuO/SSS + PS. In addition, the CuO/SSS + PS system had a wide pH range (5-9) and more than 60% removal efficiency of SMD could be obtained with the pH between 3 and 11. The mechanism based on the phase transformation of Cu(I/II), Cu(II/III) and Fe(II/III) was elucidated by using different analytical techniques, such as SEM, XRD, XPS, BET, FTIR, VSM characterization and free radical analysis. This study provided a new pathway for the SSS resource utilization and the effective degradation of SMD from the refractory wastewater by using CuO/SSS catalyst coupled with PS system.