Korea Institute of Construction Technology, Water Resource & Environment Research Department, Republic of Korea.
J Hazard Mater. 2013 Dec 15;263 Pt 2:569-74. doi: 10.1016/j.jhazmat.2013.10.017. Epub 2013 Oct 17.
The feasibility of nano-ZnO/Laponite composites (NZLc) as a valid alternative to TiO2 to mineralize trichloroethylene (TCE) without difficulties for recovery of photocatalysts was evaluated. Based on the experimental observations, the removal of TCE using NZLc under UV irradiation was multiple reaction processes (i.e., sorption, photolysis, and photocatalysis). Sorption of TCE was thermodynamically favorable due to the hydrophobic partitioning into crosslinked poly vinyl alcohol, and the adsorption onto high-surface-area mineral surfaces of both ZnO and Laponite. The degradation efficiency of TCE can be significantly improved using NZLc under UV irradiation, indicating that ZnO-mediated heterogeneous photocatalytic degradation occurred. However, the degradation efficiency was found to vary with experimental conditions (e.g., initial concentration of TCE, loading amount of NZLc, the intensity of light and initial solution pH). Although the removal of TCE by NZLc was found to be a complex function of sorption, photolysis, and photocatalysis, the photocatalytic degradation of TCE on the surface of ZnO was critical. Consequently, developed NZLc can be applied as a valid alternative to suspended TiO2 powder, and overcome drawbacks (e.g., filtration and recovery of photocatalysts) in degradation of TCE for various water resources.
评估了纳米氧化锌/膨润土复合材料（NZLc）作为一种有效替代 TiO2 来矿化三氯乙烯（TCE）的方法的可行性，同时不会对光催化剂的回收造成困难。根据实验观察，在 UV 照射下，使用 NZLc 去除 TCE 是通过多个反应过程（即吸附、光解和光催化）实现的。由于疏水分配到交联的聚乙烯醇中，以及 ZnO 和膨润土的高表面积矿物表面的吸附，TCE 的吸附在热力学上是有利的。在 UV 照射下使用 NZLc 可以显著提高 TCE 的降解效率，表明发生了 ZnO 介导的非均相光催化降解。然而，降解效率发现会随实验条件（例如 TCE 的初始浓度、NZLc 的负载量、光强和初始溶液 pH 值）而变化。尽管 NZLc 对 TCE 的去除是吸附、光解和光催化的复杂函数，但 ZnO 表面上 TCE 的光催化降解是关键的。因此，开发的 NZLc 可以作为悬浮 TiO2 粉末的有效替代品，并克服在降解各种水资源中的 TCE 时存在的缺点（例如过滤和光催化剂的回收）。
