title: Response surface modeling of Carbamazepine (CBZ) removal by Graphene-P25 nanocomposites/UVA process using central composite design.
abstract: Graphene-P25 (Gr-P25) nanocomposites were synthesized by a simple microwave hydrothermal method. The nanocomposites with different graphene loading were evaluated for the degradation of an important pharmaceutical water pollutant, Carbamazepine (CBZ) under UVA irradiation in a batch reactor. Response surface methodology (RSM) was used to optimize three key independent operating parameters, namely Gr-P25 nanocomposites dose (X1), CBZ initial concentration (X2) and UV light intensity (X3), for photocatalytic degradation of CBZ. The central composite design (CCD) consisting of 20 experiments determined by 2(3) full factorial designs with six axial points and six center points was used to conduct experiments. The results showed that CBZ removal was significantly affected by the synergistic effect of linear term of Gr-P25 dose (X1) and UV intensity (X3). However, the quadratic terms of Gr-P25 (X1(2)) and UV intensity (X3(2)) had an antagonistic effect on CBZ removal. The obtained RSM model (R(2) = 0.9206) showed a satisfactory correlation between experimental and predicted values of CBZ removal. The optimized conditions for achieving 100% CBZ removal with 5 min UVA irradiation were 25.14 mg/L, 167.68 ppb and 1.35 mW/cm(2) for Gr-P25 dose, initial concentration of CBZ and UV intensity, respectively.
authors.affiliation: Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, E1A 07-03, Singapore 117576, Singapore.
authors.forename: Initha
authors.initials: I
authors.lastname: Amalraj Appavoo
authors.affiliation: Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, E1A 07-03, Singapore 117576, Singapore. Electronic address: ceehujy@nus.edu.sg.
authors.forename: Jiangyong
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Sam Fong Yau
authors.initials: SF
authors.lastname: Li
authors.affiliation: Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, E1A 07-03, Singapore 117576, Singapore.
authors.forename: Say Leong
authors.initials: SL
authors.lastname: Ong
mesh_terms: D000927:Anticonvulsants / Q000737:chemistry / Q000528:radiation effects; D002220:Carbamazepine / Q000737:chemistry* / Q000528:radiation effects*; D002384:Catalysis; D004784:Environmental Monitoring; D006108:Graphite / Q000737:chemistry*; D008962:Models, Theoretical; D053761:Nanocomposites / Q000737:chemistry*; D010782:Photolysis; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000528:radiation effects*
chemical_list: D000927:Anticonvulsants; D014874:Water Pollutants, Chemical; D002220:Carbamazepine; D006108:Graphite
keywords: Graphene oxide; Heterogeneous photocatalysis; P25; Pharmaceutical degradation; Response surface methodology