Department of Civil and Environmental Engineering, University of Cyprus, 75 Kallipoleos St., 1678 Nicosia, Cyprus.
Water Res. 2010 Mar;44(6):1737-46. doi: 10.1016/j.watres.2009.11.044. Epub 2009 Nov 29.
The conversion of the antibiotic ofloxacin and the beta-blocker atenolol by means of TiO(2) photocatalysis was investigated. Irradiation was provided by a UVA lamp at 3.37x10(-6)einstein/s photon flux, while emphasis was given on the effect of catalyst type and loading (50-1500mg/L), initial substrate concentration (5-20mg/L), initial pH (3-10) and the effect of H(2)O(2) (0.07-1.4mM) as an additional oxidant on substrate conversion and mineralization in various matrices (i.e. pure water, groundwater and treated municipal effluent). Conversion was assessed measuring sample absorbance at 288 and 224nm for ofloxacin and atenolol, respectively, while mineralization measuring the dissolved organic carbon. Degussa P25 TiO(2) was found to be more active than other TiO(2) samples for either substrate degradation, with ofloxacin being more reactive than atenolol. Conversion generally increased with increasing catalyst loading, decreasing initial substrate concentration and adding H(2)O(2), while the effect of solution pH was substrate-specific. Reaction rates, following a Langmuir-Hinshelwood kinetic expression, were maximized at a catalyst to substrate concentration ratio (w/w) of 50 and 15 for ofloxacin and atenolol, respectively, while higher ratios led to reduced efficiency. Likewise, high concentrations of H(2)O(2) had an adverse effect on reaction, presumably due to excessive oxidant scavenging radicals and other reactive species. The ecotoxicity of ofloxacin and atenolol to freshwater species Daphnia magna was found to increase with increasing substrate concentration (1-10mg/L) and exposure time (24-48h), with atenolol being more toxic than ofloxacin. Photocatalytic treatment eliminated nearly completely toxicity and this was more pronounced for atenolol.
采用 TiO(2) 光催化法对抗生素氧氟沙星和β受体阻滞剂阿替洛尔进行了转化研究。通过 UVA 灯在 3.37x10(-6)einstein/s 光子通量下进行辐照，重点研究了催化剂类型和负载量（50-1500mg/L）、初始底物浓度（5-20mg/L）、初始 pH 值（3-10）以及作为额外氧化剂的 H(2)O(2)（0.07-1.4mM）对不同基质（即纯水、地下水和处理后的城市污水）中底物转化和矿化的影响。通过测量样品在 288nm 和 224nm 处的吸光度来评估转化情况，分别用于氧氟沙星和阿替洛尔，而矿化则通过溶解有机碳进行测量。结果表明，Degussa P25 TiO(2) 比其他 TiO(2) 样品对两种底物的降解都更具活性，其中氧氟沙星的反应性更强。转化率通常随着催化剂负载量的增加、初始底物浓度的降低和 H(2)O(2)的添加而增加，而溶液 pH 的影响则与底物有关。根据 Langmuir-Hinshelwood 动力学表达式，反应速率在催化剂与底物浓度比（w/w）分别为 50 和 15 时达到最大值，而更高的比值会降低效率。同样，高浓度的 H(2)O(2)对反应产生不利影响，可能是由于过量的氧化剂会清除自由基和其他活性物质。研究发现，氧氟沙星和阿替洛尔对淡水生物大型溞的生态毒性随着底物浓度（1-10mg/L）和暴露时间（24-48h）的增加而增加，其中阿替洛尔比氧氟沙星毒性更大。光催化处理几乎完全消除了毒性，对阿替洛尔的消除效果更为显著。
