title: Degradation of sunscreen agent p-aminobenzoic acid using a combination system of UV irradiation, persulphate and iron(II).
abstract: Increased usage and discharge of sunscreens have led to ecological safety crisis, and people are developing the advanced oxidation processes (AOPs) to treat them. The present study aimed to determine the degradation efficiency and mechanism of the sunscreen agent p-aminobenzoic acid (PABA) using the UV/Fe(2+)/persulphate (PS) method. A series of irradiation experiments were conducted to optimise the system conditions and to study the impacts of the natural anion. Free radicals and degradation products were identified in order to clarify the degradation mechanism. Initial PS and Fe(2+) concentrations showed significant impacts on PABA degradation. Natural anions, such as Cl(-), NO3 (-), H2PO4 (-) and HCO3 (-), impeded PABA degradation because of ion (Fe(2+)) capture, radical scavenging or pH effects. Hydroxyl (HO·) and sulphate (SO4 (·-)) radicals were two main radicals observed in the UV/Fe(2+)/PS system; of these, SO4 (·-) showed greater effects on PABA degradation. Over 99 % of the available PABA was completely degraded into carbon dioxide (CO2) and water (H2O) by the UV/Fe(2+)/PS system, and the remaining PABA participated in complex radical reactions. By-products were identified by total ion chromatography and mass spectrometry. Our research provides a treatment process for PABA with high degradation efficiency and environmental safety and introduces a new strategy for sunscreen degradation.
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
authors.forename: Yicen
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China. wbdong@fudan.edu.cn.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Dong
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Bi
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Zhai
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China. lihongjing@fudan.edu.cn.
authors.forename: Hongjing
authors.initials: H
authors.lastname: Li
authors.affiliation: Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
authors.forename: Minghua
authors.initials: M
authors.lastname: Nie
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry* / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D013431:Sulfates / Q000737:chemistry; D013473:Sunscreening Agents / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014867:Water
chemical_list: D013431:Sulfates; D013473:Sunscreening Agents; D014867:Water; D017665:Hydroxyl Radical; D007501:Iron; D010129:4-Aminobenzoic Acid
keywords: Ferrous ion; Free radicals; Natural anions; Persulphate; UV irradiation; p-Aminobenzoic acid