title: Solar photocatalytic degradation of chlorophenols mixture (4-CP and 2,4-DCP): Mechanism and kinetic modelling.
abstract: The solar-photocatalytic degradation mechanisms and kinetics of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) using TiO2 have been investigated both individually and combined. The individual solar-photocatalytic degradation of both phenolic compounds showed that the reaction rates follow pseudo-first-order reaction. During the individual photocatalytic degradation of both 4-CP and 2,4-DCP under the same condition of TiO2 (0.5 g L(-1)) and light intensities (1000 mW cm(-2)) different intermediates were detected, three compounds associated with 4-CP (hydroquinone (HQ), phenol (Ph) and 4-chlorocatechol (4-cCat)) and two compounds associated with 2,4-DCP (4-CP and Ph). The photocatalytic degradation of the combined mixture (4-CP and 2,4-DCP) was also investigated at the same conditions and different 2,4-DCP initial concentrations. The results showed that the degradation rate of 4-CP decreases when the 2,4-DCP concentration increases. Furthermore, the intermediates detected were similar to that found in the individual degradation but with high Ph concentration. Therefore, a possible reaction mechanism for degradation of this combined mixture was proposed. Moreover, a modified Langmuir-Hinshelwood (L-H) kinetic model considering all detected intermediates was developed. A good agreement between experimental and estimated results was achieved. This model can be useful for scaling-up purposes more accurately as its considering the intermediates formed, which has a significant effect on degrading the main pollutants (4-CP and 2,4-DCP).
authors.affiliation: a Department of Chemical Engineering , Curtin University , Perth WA , Australia.
authors.forename: Abdulbasit M
authors.initials: AM
authors.lastname: Abeish
authors.forename: Ha Ming
authors.initials: HM
authors.lastname: Ang
authors.forename: Hussein
authors.initials: H
authors.lastname: Znad
mesh_terms: D002384:Catalysis; D002396:Catechols / Q000737:chemistry*; D002733:Chlorophenols / Q000737:chemistry*; D045424:Complex Mixtures / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D010782:Photolysis; D013472:Sunlight
chemical_list: D002396:Catechols; D002733:Chlorophenols; D045424:Complex Mixtures
keywords: 2; 4-CP; 4-DCP; chlorophenols mixture; degradation; kinetic modelling; mechanism; solar photocatalytic