Molybdenum disulfide (MoS 2 ) is viewed as a promising two-dimensional Fenton-like catalyst, but the basal plane could not be well applied in peroxides activation. In this study, Fe(III) species were atomically impregnated on the MoS 2 basal plane to enhance peracetic acid (PAA) activation. The surface Fe(III) up shifted the d-band centre of MoS 2 and acted as electron shuttles in breaking the O-O bonds of PAA. HO • , CH 3 COO • and Fe(V) were generated in the Fe(III)-MoS 2 /PAA system, whereas the 1 O 2 production was inhibited on the Fe(III)-MoS 2 surface. Sulfamethazine (SMT) was efficiently degraded by Fe(III)-MoS 2 /PAA during 15 min reaction, with the observed removal efficiencies of SMT by Fe(III)-MoS 2 ( k obs ) being 25-fold higher than that by MoS 2 . Increasing the dosages of PAA and Fe(III)-MoS 2 facilitated SMT degradation, and high removal rate of SMT was achieved in the pH range of 3–5. HO • and Fe(V) were identified as critical reactive species responsible for the SMT degradation. Nitrification and Smiles rearrangement were proposed as the degradation pathways of SMT based on the identified oxidation products. This study demonstrates that impregnating Fe species would be an effective strategy for strengthening the Fenton-like reactivity of MoS 2 .
This study aimed to investigate the degradation of triclosan (TCS) in the presence of p -aminobenzoic acid (PABA) under simulated sunlight irradiation ( λ ≥ 290 nm). The effect of PABA concentration, pH, dissolved organic matter (DOM), and DOM-hydrolytic Fe(III) species complexes on the photodegradation of TCS in the presence of PABA (TCS -PABA ) was also studied. The photolysis of TCS -PABA obeyed pseudo-first-order kinetics well, and the degradation of TCS -PABA enhanced with increasing solution pH (from 3.0 to 11.0). The presence of PABA inhibited the degradation of TCS -PABA , and the weakest inhibitory effect was observed while the concentration of PABA was 5 mg L −1 . The addition of DOM (Suwannee River fulvic acid standard I [SRFA], Suwannee River HA standard II [SRHA], and Suwannee River natural organic matter [SRNOM]) showed different inhibition effects on TCS -PABA degradation. However, higher Fe(III) concentration at the DOM concentration of 5 mg L −1 could favor the formation of DOM-hydrolytic Fe(III) species complexes, further accelerating the degradation of TCS -PABA . In comparison with deionized water (DI water), TCS -PABA could be better photodegraded in river water nearby the effluent of a wastewater treatment plant. This study provides useful information for understanding the natural behavior of TCS in the presence of other organic contaminants.
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