Effects of common inorganic anions on the rates of photocatalytic degradation of sodium dodecylbenzenesulfonate over illuminated titanium dioxide

Article type: Research Article

Authors: Xia, Xing-hui | Xu, Jia-lin | Yun, Ying

Affiliations: Institute of Environmental Sciences, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Beijing Normal University,Beijing 100875, China. E-mail: xiaxh@bnu.edu.cn

Abstract: Experiments were carried out to study the effects of several anions on the photocatalytic degradation rates of sodium dodecylbenzene sulphonate (DBS) with TiO_2 as catalyst. The anions were added as Na_2 SO_4, NaNO_3, NaCl, NaHCO_3, NaH_2 PO_4 and Na_3 PO_4, and two levels of anion content, i.e. 12 mmol/L and 36 mmol/L in terms of Na^+ , were studied. The results revealed that: Cl^- , SO^2_4^- , NO^-_3 and HCO_3^-retarded the rates of DBS degradation to different degrees; PO_4^3 - increased the DBS degradation rate at low concentration and decreased the rate at high concentration; H_2PO^-_4 accelerated the rate of DBS degradation. The mechanism of the effects of anions on DBS degradation was concluded as the following three aspects: anions compete for the radicals; anions are absorbed on the surface of catalyst and block the active site catalyst.

Keywords: surfactant, anion, photocatalytic degradation, water environment

Journal: Journal of Environmental Sciences, vol. 14, no. 2, pp. 188-194, 2002