title: UV/TiO₂ photocatalytic oxidation of recalcitrant organic matter: effect of salinity and pH.
abstract: Photocatalytic oxidation processes have interest for water treatment since these processes can remove recalcitrant organic compounds and operate at mild conditions of temperature and pressure. However, performance under saline conditions present in many water resources is not well known. This study aims to explore the basic effects of photocatalysis on the removal of organic matter in the presence of salt. A laboratory-scale photocatalytic reactor system, employing ultraviolet (UV)/titanium dioxide (TiO₂) photocatalysis was evaluated for its ability to remove the humic acid (HA) from saline water. The particle size and zeta potential of TiO₂ under different conditions including solution pH and sodium chloride (NaCl) concentrations were characterized. The overall degradation of organics over the NaCl concentration range of 500-2,000 mg/L was found to be 80% of the non-saline equivalent after 180 min of the treatment. The results demonstrated that the adsorption of HA onto the TiO₂ particles was dependent on both the pH and salinity due to electrostatic interaction and highly unstable agglomerated dispersion. This result supports UV/TiO₂ as a viable means to remove organic compounds, but the presence of salt in waters to be treated will influence the performance of the photocatalytic oxidation process.
authors.affiliation: College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia E-mail: Shobha.Muthukumaran@vu.edu.au; Institute for Sustainability and Innovation, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia.
authors.forename: Shobha
authors.initials: S
authors.lastname: Muthukumaran
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Song
authors.affiliation: Institute for Sustainability and Innovation, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Institute for Sustainability and Innovation, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia.
authors.forename: Darli
authors.initials: D
authors.lastname: Myat
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032, China.
authors.forename: Jin-Yuan
authors.initials: JY
authors.lastname: Chen
authors.affiliation: Institute for Sustainability and Innovation, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Gray
authors.affiliation: Institute for Sustainability and Innovation, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia.
authors.forename: Mikel
authors.initials: M
authors.lastname: Duke
mesh_terms: D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D010777:Photochemistry; D054712:Salinity; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D009930:Organic Chemicals; C009495:titanium dioxide; D014025:Titanium