title: Oxidative decomposition of atrazine in water in the presence of hydrogen peroxide using an innovative microwave photochemical reactor.
abstract: The simultaneous application of microwave (MW) power and UV light leads to improved results in photochemical processes. This study investigates the oxidative decomposition of atrazine in water using an innovative MW and UV photochemical reactor, which activates a chemical reaction with MW and UV radiation using an immersed source without the need for a MW oven. We investigated the influence of reaction parameters such as initial H(2)O(2) concentrations, reaction temperatures and applied MW power and identified the optimal conditions for the oxidative decomposition of atrazine. Atrazine was completely degraded by MW/UV/H(2)O(2) in a very short time (i.e. t(1/2) = 1.1 min for 20.8 mg/L in optimal conditions). From the kinetic study, the disappearance rate of atrazine can be expressed as dX/dt = k(PH)[M](0)(b-X)(1-X), where b ≡ [H(2)O(2)](0)/[M](0)+k(OH)[·OH]/k(PH)[M](0), and X is the atrazine conversion, which correlates well with the experimental data. The kinetic analysis also showed that an indirect reaction of atrazine with an OH radical is dominant at low concentrations of H(2)O(2) and a direct reaction of atrazine with H(2)O(2) is dominant when the concentration of H(2)O(2) is more than 200 mg/L.
authors.affiliation: Department of Environmental Engineering, Civil & Environment Engineering School, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
authors.forename: Huilun
authors.initials: H
authors.lastname: Chen
authors.forename: Emilia
authors.initials: E
authors.lastname: Bramanti
authors.forename: Iginio
authors.initials: I
authors.lastname: Longo
authors.forename: Massimo
authors.initials: M
authors.lastname: Onor
authors.forename: Carlo
authors.initials: C
authors.lastname: Ferrari
mesh_terms: D001280:Atrazine / Q000737:chemistry*; D002244:Carbon / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D007202:Indicators and Reagents; D007700:Kinetics; D008872:Microwaves; D009930:Organic Chemicals / Q000032:analysis; D010084:Oxidation-Reduction; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: D006540:Herbicides; D007202:Indicators and Reagents; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D014867:Water; D017665:Hydroxyl Radical; D002244:Carbon; D006861:Hydrogen Peroxide; D001280:Atrazine