Bogazici University, Institute of Environmental Sciences, Bebek Istanbul, Turkey.
Water Sci Technol. 2010;61(10):2581-90. doi: 10.2166/wst.2010.174.
The present study investigated the removal efficiency of aqueous humic acid solutions by TiO(2) photocatalytic degradation in the presence of Cu(II) species. The pseudo-first-order kinetics revealed rate constants as 9.87 x 10(-3), 7.19 x 10(-3), 3.81 x 10(-3) min(-1) for Color(436), UV(254) and TOC, respectively. Comparatively, lower rate constants were attained with respect to photocatalytic degradation of humic acid. Considering the source-dependent diverse chemical and spectral characteristics of NOM, a particular interaction would be expected for humic acid with Cu(II) species (0.1 mg L(-1)). The presence of copper ions significantly altered the photocatalytic degradation kinetics of humic acids in relation to the concentration effects of humic acid as expressed by spectroscopic parameters and TOC. Batch equilibrium adsorption experiments revealed a distinct Langmuirian-type adsorptive behavior of humic acid onto TiO(2) both in terms of UV(254) and Color(436) and a C-type adsorption isotherm was attained for TOC. K(F) values displayed an inconsistent effect of Cu(II) species, while adsorption intensity factor 1/n<1 denoted a prevailing favorable type of adsorption for Color(436) and UV(254). Because of the role of intra- and intermolecular interactions between copper ions and humic molecular size fractions, spectroscopic techniques were also employed for the assessment of the adsorption as well as photocatalytic degradation efficiencies.
本研究考察了 TiO(2)光催化降解在 Cu(II)物种存在下对水合腐殖酸溶液的去除效率。准一级动力学揭示了 Color(436)、UV(254)和 TOC 的速率常数分别为 9.87×10(-3)、7.19×10(-3)和 3.81×10(-3)min(-1)。相比之下，对于腐殖酸的光催化降解，获得的速率常数较低。考虑到 NOM 的来源依赖性多样的化学和光谱特性，腐殖酸与 Cu(II)物种（0.1mgL(-1)）之间预计会有特殊的相互作用。铜离子的存在显著改变了腐殖酸的光催化降解动力学，这与腐殖酸的浓度效应有关，表现在光谱参数和 TOC 上。批量平衡吸附实验表明，腐殖酸在 TiO(2)上具有明显的 Langmuir 型吸附行为，无论是在 UV(254)还是在 Color(436)上，并且对于 TOC 获得了 C 型吸附等温线。K(F)值显示出 Cu(II)物种的不一致影响，而吸附强度因子 1/n<1 表示 Color(436)和 UV(254)上主要是有利的吸附类型。由于铜离子和腐殖质分子大小分数之间的分子内和分子间相互作用的作用，还采用光谱技术评估了吸附和光催化降解效率。
