MoS2 co-catalysis promoted CaO2 Fenton-like process: Performance and mechanism

Abstract

• A Fenton-like process using CaO 2 as oxidant and MoS 2 as co-catalyst was proposed. • MoS 2 promoted Fe 3+ /Fe 2+ circulation during CaO 2 based Fenton-like reaction. • HO was dominant radical, and both O 2 2 and 1 O 2 worked in CaO 2 /Fe 2+ /MoS 2 . • CaO 2 /Fe 2+ /MoS 2 was efficient to remove diverse organics and treat real wastewater. Fenton reaction is widely applied to treat organic contaminant through hydroxyl radicals (HO ), which is formed from the catalytic reaction of hydrogen peroxide (H 2 O 2 ) and Fe 2+ . Nevertheless, its well application for actual wastewater has been confined by the narrow range of pH, disproportionation of H 2 O 2 and inefficiency of Fe 2+ /Fe 3+ circulation. To overcome these shortcomings, an improved Fenton-like method applying calcium peroxide (CaO 2 ) as the substitution of H 2 O 2 and molybdenum disulfide (MoS 2 ) as the co-catalyst was proposed. The results indicated the efficient rhodamine B (RhB) removal (98.6%) was achieved under the conditions of 1 mmol L −1 CaO 2 , 0.5 mmol L −1 Fe 2+ , 0.3 g L −1 MoS 2 , and initial pH 5.85 within 5 min, and this system could well degrade other dyes, antibiotic, and phenol. The MoS 2 addition could promote the Fe 2+ /Fe 3+ conversion and H 2 O 2 disintegration. The radical masking tests and electron paramagnetic resonance demonstrated that the HO was the main active substances during this process. The decomposition intermediates of RhB were identified through the mass spectra analysis, and their ecotoxicities were assessed by the toxicity estimation software. Finally, this process also presented a favorable performance for the real wastewater treatment, which is a potential route to promote the development of Fenton method.