Facile synthesis of magnetic ZnFe2O4/AC composite to activate peroxydisulfate for dye degradation under visible light irradiation

• Published in: Environmental science and pollution research international 2022-10, Vol.29 (50), p.76321-76338
• Main Authors: Song, Tingting, He, Quanbao, Meng, Xiaoyan, He, Zhangxing, Ge, Ming
• Format: Article
• Language: English
• Subjects: Activated carbon; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Calcium ions; Catalysts; Contaminants; Copper; Drinking water; Dyes; Earth and Environmental Science; Ecotoxicology; Efficiency; Environment; Environmental Chemistry; Environmental Health; Environmental science; Hydrogen; Iron; Irradiation; Light irradiation; Oxidation; Oxidation process; pH effects; Photocatalysis; Photodegradation; Pollutant removal; Radiation; Research Article; Rhodamine; Rivers; Waste Water Technology; Water Management; Water Pollution Control; X ray photoelectron spectroscopy; Zinc ferrites
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-022-21253-3

Heterogeneous photocatalysis/persulfate oxidation process has been considered as a promising technology for dye contaminants removal. The magnetic ZnFe 2 O 4 /active carbon (AC) composites were hydrothermally synthesized and firstly used to activate peroxydisulfate (PDS) for rhodamine B (RhB) degradation under visible LED light irradiation. The optimized Vis-ZnFe 2 O 4 /AC(4/1)-PDS system can enhance the RhB degradation efficiency by 32.01% and 13.87% compared with Vis-ZnFe 2 O 4 -PDS and Vis-AC-PDS systems, respectively. The influence of operational parameters such as catalyst dosage (0.2 − 0.4 g L −1 ), PDS concentration (1.0 − 2.0 g L −1 ), temperature (25 − 45 °C), solution pH (2.7 − 10.9), and coexisting inorganic ions (Cl − , NO 3 − , HCO 3 − , PO 4 3− , Cu 2+ , Fe 3+ , and Ca 2+ ) on RhB degradation was studied, and 100% of RhB (20 mg L −1 ) was degraded after 80 min at operational condition: 0.30 g L −1 of ZnFe 2 O 4 /AC(4/1) and 1.5 g L −1 of PDS, solution pH of 2.74, reaction temperature of 25 °C. The quenching experiments, EPR test, and XPS analysis were employed to reveal the proposed mechanism, which demonstrated that 1 O 2 played a more important role than other reactive species (SO 4 •− , •OH, O 2 •− , and h + ) in RhB degradation. The generation of 1 O 2 via the two routes was as follows: (i) the in situ formed active oxygen (O * ) reacted with HSO 5 − to produce 1 O 2 ; (ii) O 2 •− was oxidized by h + to form 1 O 2 . After five consecutive cycles, the photodegradation efficiency of RhB by ZnFe 2 O 4 /AC(4/1) catalyst slightly decreased from 88.52 to 83.92%, indicating the excellent reusability of ZnFe 2 O 4 /AC(4/1) photocatalyst. As designed, Vis-ZnFe 2 O 4 /AC-PDS oxidation system can effectively remove RhB from the different real water matrices, and the degradation efficiency of RhB in tap water, river water, and secondary effluent was 78.24%, 79.55%, and 74.53% after 80 min of reaction, respectively.