title: Enhanced photocatalytic ozonation of organics by g-C₃N ₄ under visible light irradiation.
abstract: Graphitic carbon nitride (g-C3N4) was employed as the active photocatalyst in the photocatalytic ozonation coupling system in the present study. g-C3N4 was prepared by directly heating thiourea in air at 550°C. XRD, FT-IR, UV-vis was used to characterize the structure and optical property. Oxalic acid and bisphenol A were selected as model substances for photocatalytic ozonation reactions to evaluate the catalytic ability of g-C3N4 (g-C3N4/Vis/O3). The results showed that the degradation ratio of oxalic acid with g-C3N4/Vis/O3 was 65.2% higher than the sum of ratio when it was individually decomposed by g-C3N4/Vis and O3. The TOC removal of biphenol A with g-C3N4/Vis/O3 was 2.17 times as great as the sum of the ratio when using g-C3N4/Vis and O3. This improvement was attributed to the enhanced synergistic effect between photocatalysis and ozonation by g-C3N4. Under visible light irradiation, the photo-generated electrons produced on g-C3N4 facilitated the electrons transfer owing to the more negative conduction band potential (-1.3V versus NHE). It meant that the photo-generated electrons could be trapped by ozone and reaction with it more easily. Subsequently, the yield of hydroxyl radicals was improved so as to enhance the organics degradation efficiency. This work indicated that metal-free g-C3N4 could be an excellent catalyst for mineralization of organic compounds in waste control.
authors.affiliation: Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China. Electronic address: liaogaozu@m.scnu.edu.cn.
authors.forename: Gaozu
authors.initials: G
authors.lastname: Liao
authors.affiliation: Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
authors.forename: Dongyun
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China. Electronic address: llsh@scnu.edu.cn.
authors.forename: Laisheng
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment, South China Normal University, Higher Education Mega Center, Guangzhou 510006, China.
authors.forename: Bingyan
authors.initials: B
authors.lastname: Lan
mesh_terms: D001559:Benzhydryl Compounds; D008027:Light; D009570:Nitriles / Q000138:chemical synthesis*; D019815:Oxalic Acid; D010126:Ozone / Q000737:chemistry*; D010636:Phenols; D010782:Photolysis; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D009570:Nitriles; D019815:Oxalic Acid; D010126:Ozone; D010636:Phenols; D014874:Water Pollutants, Chemical; C011206:cyanogen; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Carbon nitride; Hydroxyl radical; Photocatalytic ozonation; Synergistic effect