title: OH-initiated transformation and hydrolysis of aspirin in AOPs system: DFT and experimental studies.
abstract: Advanced oxidation processes (AOPs) are widely used in wastewater treatment of pharmaceutical and personal care products (PPCPs). In this work, the OH-initiated transformation as well as the hydrolysis of a typical PPCPs, aspirin, was investigated using density functional theory (DFT) calculations and laboratory experiments. For DFT calculations, the frontier electron densities and bond dissociation energies were analyzed. Profiles of the potential energy surface were constructed, and all the possible pathways were discussed. Additionally, rate constants for each pathway were calculated with transition state theory (TST) method. UV/H2O2experiments of aspirin were performed and degradation intermediates were identified by UPLC-MS-MS analysis. Different findings from previous experimental works were reported that the H-abstraction pathways at methyl position were dominated and OH-addition pathways on benzene ring were also favored. Meantime, hydroxyl ASA was confirmed as the main stable intermediate. Moreover, it was the first time to use DFT method to investigate the hydrolysis mechanisms of organic ester compound.
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: He
authors.affiliation: Environment Research Institute, Shandong University, Jinan 250100, PR China. Electronic address: sxmwch@sdu.edu.cn.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Fanping
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China.
authors.forename: Shaojie
authors.initials: S
authors.lastname: Ren
authors.affiliation: Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China. Electronic address: sgw@sdu.edu.cn.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Wang
mesh_terms: D001241:Aspirin / Q000737:chemistry*; D006861:Hydrogen Peroxide; D006868:Hydrolysis; D017665:Hydroxyl Radical; D007700:Kinetics; D010084:Oxidation-Reduction
chemical_list: D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D001241:Aspirin
keywords: Advanced oxidation processes; Aspirin; DFT; Hydrolysis; Transformation mechanism