Enhancing Fenton-like reaction through a multifunctional molybdenum disulfide film coating on nano zero valent iron surface (MoS2@nZVI): Collaboration of radical and non-radical pathways.

ABSTRACT

In this study, we synthesized nano zero-valent iron incorporated with a multifunctional molybdenum disulfide film (MoS2@nZVI). The material exhibited a 100.00 % removal efficiency for sulfamethoxazole (SMX) and achieved a kobs of 0.4485 min-1 within 10 min. The excellent degradation performance can be attributed to the incorporation of the MoS2 film, which facilitated Fe2+ regeneration. Simultaneously, the MoS2 film assisted in proton accumulation and electron transfer, thereby amplifying the efficiency of SMX degradation across a wide pH range. Comprehensive experimental examinations and characterizations confirmed the selectivity and stability of the MoS2@nZVI catalysts, encompassing both degradation efficiency and structural stability. Interestingly, the MoS2@nZVI/PMS system for SMX degradation significantly involved a non-radical mechanism (1O2), along with radicals (SO4·-, ·OH, and O2·-). The direct oxidation of PMS by Fe2+ not only facilitated the generation of ·OH and SO4·- but also actively engaged in a reaction with O2, leading to the production of O2·-. The primary pathway for 1O2 production was established through the interplay between Mo6+ and O2·-, in conjunction with the direct electron transfer (DET) mechanism between PMS and SMX. The contributions of these active species to SMX degradation occurred in the following precedence SO4·- > 1O2 > ·OH > O2·-. Notably, the primary pathways for radicals and non-radicals were studied during separate reaction periods. This investigation proposed a promising approach for mitigating pharmaceutical pollutants using a transition metal sulfide-modified nZVI catalyst.