Exploring the roles of ascorbic acid/L-cysteine in boosted carbamazepine degradation by biochar-CuFe2O4/Fe2O3/CuO/peroxymonosulfate: Taguchi optimization and mechanistic studies

The present research aimed to improve the efficiency of a novel walnut shell biochar-CuFe2O4/Fe2O3/CuO (BC-CuFeO) nanocomposite for the activation of peroxymonosulfate (PMS) for the degradation of carbamazepine (CBZ), as a recalcitrant organic pollutant. Ascorbic acid (H2A) and L-cysteine (LC) were utilized to significantly increase CBZ removal efficiency in the BC-CuFeO/PMS system. An L-16 Taguchi design was applied to identify the relative significance of the operating parameters for the degradation of CBZ. In addition, both the BC-CuFeO/PMS/H2A and BC-CuFeO/PMS/LC systems demonstrated outstanding CBZ degradation performance in the presence of humic acid, sodium chloride, and sodium nitrate, respectively. The scavenging experiments indicated that 1O2, ·OH, O2•−, and SO4•− were responsible for CBZ degradation in the BC-CuFeO/PMS/H2A system, while O2•−, 1O2, and ·OH contributed to CBZ degradation in the BC-CuFeO/PMS/LC system. Furthermore, the intermediates and pathways of CBZ degradation were determined via Q-TOF-MS analysis, and the potential toxicity of the products was assessed via Toxicity Estimation Software Tool analysis. The practicality of the nanocomposites was also evaluated through the fabrication of catalytic balls and catalytic membranes, followed by the study of their stability for wastewater treatment. In conclusion, this study provides novel and promising PMS activation methods for the efficient removal of recalcitrant pollutants from wastewater.