Carbonaceous composite membranes for peroxydisulfate activation to remove sulfamethoxazole in a real water matrix. (February 2022)

• Record Type: Journal Article
• Authors: Qian, Feiyue; Luo, Junpeng; Yin, Honggui; Liu, Feng; Gao, Shiqian; Gu, Xinyu
• Is Part Of: Chemosphere. Volume 288:Part 2(2022)
• Publication Date: 2022-02
• Subjects: Carbonaceous composite membranes -- In-situ catalytic oxidation -- Peroxydisulfate activation -- Sulfamethoxazole -- Real water matrix -- Non-radical pathway; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.132597
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study, we fabricated carbonaceous composite membranes by loading integrated mats of nitrogen-doped graphene, reduced graphene oxide, and carbon nanotubes (NG/rGO/CNTs) on a nylon microfiltration substrate and employed it for in-situ catalytic oxidation by activating peroxydisulfate (PDS) for the removal of sulfamethoxazole (SMX) in a real water matrix. The impact of coexisting organics on the performance of carbonaceous catalysis was investigated in the continuous filtration mode. Reusability testing and radical quenching experiments revealed that the non-radical pathways of surface-activated persulfate mainly contributed to SMX degradation. A stable SMX removal flux ( r SMX ) of 22.15 mg m −2 ·h −1 was obtained in 24 h when tap water was filtered continuously under a low pressure of 1.78 bar and in a short contact time of 1.4 s, which was slightly lower than the r SMX of 23.03 mg m −2 ·h −1 performed with deionized water as the control group. In addition, higher contents of protein-, fulvic acid-, and humic acid-like organics resulted in membrane fouling and significantly suppressed SMX removal during long-term filtration. Changes in the production of sulfate ions and the Raman spectra of carbon mats indicated that organics prevent the structural defects of the carbon matrix from participating in PDS activation. Moreover, NG/rGO/CNTs composite membranes coupled with activated persulfate oxidation exhibited good self-cleaning ability, because membrane fouling could be partly reversed by restoring filtration pressure during operation. This study provides a novel and effective oxidation strategy for efficient SMX removal in water purification, allowing the application of carbonaceous catalysis for the selective degradation of emerging contaminants. Graphical abstract: Image 1 Highlights: In-situ carbonaceous catalysis was used to remove SMX in a real water matrix. Composite membranes were fabricated by loading the NG/rGO/CNTs mats. Non-radical pathways of surface-activated persulfate dominated in the reaction. Stable SMX removal flux was obtained when tap water was filtered continuously.