Synergistic adsorption of Cu(II) and photocatalytic degradation of phenanthrene by a jaboticaba-like TiO2/titanate nanotube composite: An experimental and theoretical study
Synergistic adsorption of Cu(II) and photocatalytic degradation of phenanthrene by a jaboticaba-like TiO2/titanate nanotube composite: An experimental and theoretical study
复制标题
类jaboticaba TiO2/钛酸盐纳米管复合材料对Cu(II)的协同吸附和光催化降解菲：实验和理论研究
DOI：
10.1016/j.cej.2018.10.114
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发表时间：
2019-02-15
影响因子：
15.1
通讯作者：
Liu, Wen
中科院分区：
文献类型：
--
作者：
Cheng, Kaiyu;Cai, Zhengqing;Liu, Wen
重金属和有机污染物并存的复合水污染是实际废水处理中备受关注的问题。本研究采用两步水热法制备了一种新型的纳米复合材料--钛酸盐纳米管负载二氧化钛(TiO2TiO2TiO4/TnTS)。TiO2Tints具有较大的比表面积、丰富的-ONa/H基团和细小的锐钛矿晶相，对Cu2+表现出良好的吸附性能，对菲的降解也表现出较高的光催化活性。在pH为5时，TiO2TINTS对Cu2+的最大吸附容量为115.0 mg/g，在紫外光照射下4h内菲的降解率可达95%。与未改性颜料相比，二氧化钛/颜料对菲降解的观察速率常数(k(Obs))提高了约10倍。更重要的是，铜(II)的存在促进了菲的光催化降解，因为掺杂在染料晶格中的铜(II)可以捕获光致电子，从而抑制电子-空穴复合。密度泛函理论(DFT)计算表明，菲的Fukui指数(f(0))较高的位置倾向于被中心点羟基自由基攻击。定量构效关系(QSAR)分析表明，降解中间体的急性毒性和致突变性均低于菲。TiO2TINTS也具有较高的稳定性，即使在重复使用4次后，铜(II)和菲的去除效率也只有轻微的损失。本研究所开发的材料在处理多污染物的水或废水方面具有很大的应用潜力，这项工作有助于我们更好地了解钛基纳米材料与不同类型污染物的反应机理。
Combined water pollution with the coexistence of heavy metals and organic contaminants is of great concern for practical wastewater treatment. In this study, a jaboticaba-like nanocomposite, titanate nanotubes supported TiO2 (TiO2/TiNTs), was synthesized by a two-step hydrothermal treatment. TiO2 /TiNTs had large surface area, abundant of -ONa/H groups and fine crystal anatase phase, thus exhibited both good adsorptive performance for Cu(II) and high photocatalytic activity for phenanthrene degradation. The maximum Cu(II) adsorption capacity on TiO2/TiNTs was 115.0 mg/g at pH 5 according to Langmuir isotherm model, and > 95% of phenanthrene was degraded within 4 h under UV light. TiO2/TiNTs showed about 10 times higher observed rate constant (k(obs) ) for phenanthrene degradation compared to the unmodified TiNTs. More importantly, the coexistence of Cu(II) promoted photocatalytic degradation of phenanthrene, because the incorporated Cu(II) in the lattice of TiNTs could trap photo-excited electron and thus inhibited the electron-hole recombination. Density functional theory (DFT) calculation indicated that the sites of phenanthrene with high Fukui index (f(0)) preferred to be attacked by center dot OH radicals. The quantitative structure-activity relationship (QSAR) analysis revealed that the degradation intermediates had lower acute toxicity and mutagenicity than phenanthrene. TiO2/TiNTs also owned high stability, as only slight loss of Cu(II) and phenanthrene removal efficiency was observed even after four reuse cycles. The developed material in this study is of great application potential for water or wastewater treatment with multi-contaminants, and this work can help us to better understand the mechanisms on reaction between Ti-based nanomaterials and different kinds of contaminants.