title: Effects of acetylacetone on the photoconversion of pharmaceuticals in natural and pure waters.
abstract: Acetylacetone (AcAc) has proven to be a potent photo-activator in the degradation of color compounds. The effects of AcAc on the photochemical conversion of five colorless pharmaceuticals were for the first time investigated in both pure and natural waters with the UV/H2O2process as a reference. In most cases, AcAc played a similar role to H2O2. For example, AcAc accelerated the photodecomposition of carbamazepine, oxytetracycline, and tetracycline in pure water. Meanwhile, the toxicity of tetracyclines and carbamazepine were reduced to a similar extent to that in the UV/H2O2process. However, AcAc worked in a way different from that of H2O2. Based on the degradation kinetics, solvent kinetic isotope effect, and the inhibiting effect of O2, the underlying mechanisms for the degradation of pharmaceuticals in the UV/AcAc process were believed mainly to be direct energy transfer from excited AcAc to pharmaceuticals rather than reactive oxygen species-mediated reactions. In natural waters, dissolved organic matter (DOM) played a crucial role in the photoconversion of pharmaceuticals. The role of H2O2became negligible due to the scavenging effects of DOM and inorganic ions. Interestingly, in natural waters, AcAc first accelerated the photodecomposition of pharmaceuticals and then led to a dramatic reduction with the depletion of dissolved oxygen. Considering the natural occurrence of diketones, the results here point out a possible pathway in the fate and transport of pharmaceuticals in aquatic ecosystems.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
authors.forename: Guoyang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
authors.forename: Bingdang
authors.initials: B
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China. Electronic address: sjzhang@nju.edu.cn.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Zhang
mesh_terms: D002220:Carbamazepine; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D010422:Pentanones / Q000737:chemistry*; D055668:Photochemical Processes / Q000187:drug effects*; D010782:Photolysis; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010422:Pentanones; D014874:Water Pollutants, Chemical; D014867:Water; D002220:Carbamazepine; C008790:acetylacetone; D006861:Hydrogen Peroxide; D010100:Oxygen
keywords: Acetylacetone; PPCPs; Photolysis; Tetracycline; Toxicity