Activation of persulfate for degradation of sodium dodecyl sulfate by a hybrid catalyst hematite/cuprous sulfide with enhanced FeIII/FeII redox cycling. (May 2022)

• Record Type: Journal Article
• Authors: You, Yingying; Huang, Shaobin; He, Zhen
• Is Part Of: Chemosphere. Volume 295(2022)
• Publication Date: 2022-05
• Subjects: Hematite -- Cuprous sulfide -- Persulfate -- Surfactant -- Iron redox cycling; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.133839
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Surfactants are recalcitrant compounds that require advanced treatment for their degradation. Heterogeneous advanced oxidation processes (AOPs) using iron-based catalysts can be a promising method for surfactant degradation. The acceleration of the Fe III /Fe II redox cycling is the key to enhance the catalytic degradation. Herein, a hybrid catalyst composed of α-Fe2 O3 and Cu2 S was synthesized to improve the reduction of Fe III in a heterogeneous persulfate-AOP system. The results of XRD, Raman and TEM demonstrated the successful preparation of the hybrid catalyst. Because of the optimized Fe II regeneration, the AOP containing the catalyst FC75 achieved 100.0% removal of sodium dodecyl sulfate (SDS) in a neutral aquatic environment, significantly higher than 22.9 ± 2.4% with pure α-Fe2 O3 or 39.6 ± 2.5% with pure Cu2 S. The catalyst FC75 demonstrated effective SDS removal in the recycling test (82.7 ± 7.0% after six recycling test) and in actual wastewater (84.4 ± 4.5%). The regeneration of Fe II was confirmed by the increased proportion of Fe II from 39.5% in the fresh catalyst to 42.6% in the used catalyst. The main active species was revealed to be sulfate radicals under an acidic condition and shifted to hydroxyl radicals under a basic condition. In the hybrid catalyst, α-Fe2 O3 provided Fe II to activate persulfate to radicals, with an oxidation product of Fe III, which was then reduced to Fe II by Cu I provided by Cu2 S, coupling with the oxidation of Cu I to Cu II . The S element in Cu2 S could directly or indirectly facilitate the Fe III /Fe II redox cycling as an electron donor. Those results have demonstrated that the developed hybrid catalyst is able to promote Fe II regeneration for effective SDS removal. Graphical abstract: Image 1 Highlights: A hybrid catalyst is successfully prepared from α-Fe2 O3 and Cu2 S. The hybrid catalyst shows greatly enhanced SDS removal performance. Improved Fe III /Fe II redox cycling is confirmed by the increased Fe II . The synergetic effect between Fe–Cu cycles promotes the catalytic activity.