Kim Jihyun R, Kan Eunsung
Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
J Environ Manage. 2016 Sep 15;180:94-101. doi: 10.1016/j.jenvman.2016.05.016. Epub 2016 May 20.
The present study reports an effective heterogeneous photocatalytic degradation of sulfamethoxazole (SMX) in water using a biochar-supported TiO2 (biochar/TiO2). The biochar was used as a low cost and effective support for TiO2 to lower the recombination rate of electrons and electron holes during photocatalysis, allow efficient attachment of TiO2, increase adsorption capacity and help easy separation of the photocatalyst after use. The biochar/TiO2 showed much higher adsorption of SMX than the commercial TiO2 powder due to the hydrophobic interaction between the biochar and SMX. Particularly this study focused on the effects of water quality and operating conditions on the photocatalytic oxidation of SMX. The addition of low concentration of bicarbonate made drastic enhancement in SMX removal and mineralization while the final effluent showed high biotoxicity. On the contrary, the presence of nitrate exhibited slight enhancement in SMX removal efficiency. The photocatalyst loading and UV irradiation time also played their important roles in enhancement of SMX removal and mineralization. In overall the photocatalytic oxidation of SMX using the biochar/TiO2 at the selected catalyst loading and irradiation time (5 g biochar-supported TiO2 L(-1), 6 h) resulted in the high removal and mineralization of SMX and negligible toxicity.
本研究报道了一种利用生物炭负载二氧化钛（biochar/TiO₂）对水中磺胺甲恶唑（SMX）进行有效多相光催化降解的方法。生物炭被用作二氧化钛的低成本有效载体，以降低光催化过程中电子与电子空穴的复合率，使二氧化钛有效附着，提高吸附能力，并有助于使用后光催化剂的轻松分离。由于生物炭与SMX之间的疏水相互作用，biochar/TiO₂对SMX的吸附量远高于市售二氧化钛粉末。特别地，本研究着重考察了水质和操作条件对SMX光催化氧化的影响。低浓度碳酸氢盐的添加显著提高了SMX的去除率和矿化程度，然而最终出水显示出高生物毒性。相反，硝酸盐的存在对SMX去除效率有轻微提高。光催化剂负载量和紫外线照射时间在提高SMX去除率和矿化程度方面也发挥了重要作用。总体而言，在选定的催化剂负载量和照射时间（5 g生物炭负载二氧化钛L⁻¹，6 h）下，使用biochar/TiO₂对SMX进行光催化氧化，实现了SMX的高去除率和矿化程度，且毒性可忽略不计。
