College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, 100871, China; Center for Agricultural Water Research in China, China Agricultural University, Beijing 100083, China.
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States.
Environ Pollut. 2018 Jan;232:580-590. doi: 10.1016/j.envpol.2017.09.094. Epub 2017 Oct 6.
Bisphenol A (BPA) is a widely concerned endocrine disrupting chemical and hard to be removed through conventional wastewater treatment processes. In this study, we developed a TiO decorated titanate nanotubes composite (TiO/TNTs) and used for photocatalytic degradation of BPA. TEM and XRD analysis show that the TiO/TNTs is a nano-composite of anatase and titanate, with anatase acting as the primary photocatalytic site and titanate as the skeleton. TiO/TNTs exhibited excellent photocatalytic reactivity and its easy-settling property leaded to good reusability. After 5 reuse cycles, TiO/TNTs also could photo-degrade 91.2% of BPA with a high rate constant (k) of 0.039 min, which was much better than TiO and TNTs. Higher pH facilitated photocatalysis due to more reactive oxygen species produced and less material aggregation. The presence of NaCl and CaCl showed negligible effects on BPA degradation, but NaHCO caused an inhibition effect resulting from consumption of ·OH. Humic acid inhibited degradation mainly due to blockage of the active sites of TiO/TNTs. Degradation pathway was well interpreted through theoretical calculation. Hydroxyl radical played the dominate role in BPA photodegradation, and the atoms of BPA with high Fukui index based on density-functional theory (DFT) calculation are the radical easy-attacking (f) sites. Considering the good photocatalytic reactivity, reusability, stability and settle property, TiO/TNTs promises to be an efficient alternative for removal of organic compounds from wastewaters.
双酚 A (BPA) 是一种广泛关注的内分泌干扰化学物质，很难通过传统的废水处理工艺去除。在这项研究中，我们开发了一种 TiO 修饰的钛酸盐纳米管复合材料 (TiO/TNTs)，并将其用于 BPA 的光催化降解。TEM 和 XRD 分析表明，TiO/TNTs 是锐钛矿和钛酸盐的纳米复合材料，锐钛矿作为主要的光催化活性位，钛酸盐作为骨架。TiO/TNTs 表现出优异的光催化活性和易于沉降的特性，具有良好的可重复使用性。经过 5 次重复使用循环，TiO/TNTs 仍可光降解 91.2%的 BPA，其速率常数 (k) 为 0.039 min，远高于 TiO 和 TNTs。较高的 pH 值有利于光催化，因为产生了更多的活性氧物种，并且材料聚集较少。NaCl 和 CaCl 的存在对 BPA 的降解几乎没有影响，但 NaHCO 由于消耗了·OH，会产生抑制作用。腐殖酸主要通过阻止 TiO/TNTs 的活性位点来抑制降解。通过理论计算很好地解释了降解途径。羟基自由基在 BPA 的光降解中起主导作用，基于密度泛函理论 (DFT) 计算的具有高 Fukui 指数的 BPA 原子是自由基易攻击 (f) 位点。考虑到良好的光催化活性、可重复使用性、稳定性和沉降性，TiO/TNTs 有望成为从废水中去除有机化合物的有效替代品。
