title: Photocatalytic ozonation of pesticides in a fixed bed flow through UVA-LED photoreactor.
abstract: In this study, a fixed bed flow through UVA-LED photoreactor was used to compare the efficiency of ozone, photocatalysis and photocatalysis-ozone degradation, and mineralization of two pure pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA), and a commercial one, Killex®. For the degradation of the parent compounds, ozone-based processes were more effective. While for mineralization, photocatalytic processes were more effective. Photocatalytic ozonation was the most efficient process for both the degradation and mineralization of the parent compounds. The degradation rates and mineralization by photocatalytic ozonation were higher than the summation of the corresponding rates by ozonation and photocatalysis, indicating a symbiotic relationship.Overall, the photocatalytic ozonation process with the fixed bed TiO2reduces the time needed for the degradation and mineralization of the pesticides, reduces the costs of powder catalyst separation and overcomes the reduced efficiency of immobilized catalysts, which makes the process quite attractive for practical applications.
authors: Department of Civil Engineering, National Research Centre, 33 El Bohouth St, Dokki, P.O. 12622, Giza, Egypt. emadk80@gmail.com.
authors: Emad K
authors: EK
authors: Radwan
authors: Department of Civil Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada.
authors: Linlong
authors: L
authors: Yu
authors: Department of Civil Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada.
authors: Gopal
authors: G
authors: Achari
authors: Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada.
authors: Cooper H
authors: CH
authors: Langford
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis / Q000737:chemistry; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000032:analysis / Q000737:chemistry; D002384:Catalysis; D010126:Ozone / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D055668:Photochemical Processes; D012666:Semiconductors; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D015084:2,4-Dichlorophenoxyacetic Acid; D010126:Ozone; D014025:Titanium; D008456:2-Methyl-4-chlorophenoxyacetic Acid
keywords: 2,4-Dichlorophenoxyacetic acid; 2-Methyl-4-chlorophenoxyacetic acid; Anodized TiO2 sheets; Light-emitting diode (LED)