The enhanced mechanism of Fe(III)/H2O2 system by N, S-doped mesoporous nanocarbon for the degradation of sulfamethoxazole

Abstract

Fenton-like technology has been widely used in the field of water treatment as an advanced oxidation processes (AOPs), and a multitude of non-homogeneous catalysts have been reported effectively to enhance it. Herein, nitrogen and sulfur co-doped nanocarbon materials (NSC) was designed and synthesized, which formed a unique mesoporous structure and abundant functional groups on the surface. It exhibits superior catalytic performance to enhance the Fe(III)/H2O2 system for sulfamethoxazole (SMX) degradation, kobs is 18 times higher than Fe(III)/H2O2 system after the introduction of NSC under the same experimental conditions. Also, the working pH of Fe(III)/H2O2 system was broadened by NSC. Quenching and probe experiments demonstrate that hydroxyl radical (∙OH) was the dominant active species. Both dissociative and surface-bound iron species were observed, which indicates direct reduction and in-situ binding of Fe(III), respectively. Further investigation found nitrogen and sulfur co-doped attribute to the formation of abundant functional groups, the CO bond and CSC bond on the surface of NSC result in the directly reduce of Fe(III), while –COOH contributes to the in-situ binding. The intermediates and possible degradation pathway of SMX degradation were proposed based on the results of liquid chromatography-quadrupole time of flight-mass spectrometer (LC-QTOF-MS). The results of cycling and co-existing ions experiments demonstrate that NSC has outstanding potential for application. This work provides a novel insight into the sustained removal of micropollutants from the aqueous environment based on the nanocarbon materials enhancing the Fenton-like oxidation.