College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China.
Environ Pollut. 2019 Dec;255(Pt 1):113211. doi: 10.1016/j.envpol.2019.113211. Epub 2019 Sep 9.
Once released into the environment, engineered nanomaterials can significantly influence the transformation and fate of organic contaminants. To date, the abilities of composite nanomaterials to catalyze environmentally relevant abiotic transformation reactions of organic contaminants are largely unknown. Herein, we investigated the effects of two nanocomposites - consisting of anatase titanium dioxide (TiO) with different predominantly exposed crystal facets (i.e., {101} or {001} facets) anchored to hydroxylated multi-walled carbon nanotubes (OH-MWCNT) - on the hydrolysis of 1,1,2,2-tetrachloroethane (TeCA), a common groundwater contaminant, at ambient pH (6, 7 and 8). Both OH-MWCNT/TiO nanocomposites were more effective in catalyzing the dehydrochlorination of TeCA than the respective component materials (i.e., bare OH-MWCNT and bare TiO). Moreover, the synergistic effect of the two components was evident, in that the incorporation of OH-MWCNT increased the TeCA adsorption capacity of the nanocomposites, significantly enhancing the catalytic effect of the deprotonated hydroxyl and carboxyl groups on nanocomposite surfaces, which served as the main catalytic sites for TeCA hydrolysis. The findings may have important implications for the understanding of the environmental implications of composite nanomaterials and may shed light on the design of high-performance nanocomposites for enhanced contaminant removal.
一旦释放到环境中，工程纳米材料会显著影响有机污染物的转化和归宿。迄今为止，对于复合纳米材料催化环境相关的有机污染物非生物转化反应的能力，我们知之甚少。在此，我们研究了两种纳米复合材料的影响，它们由负载在羟基化多壁碳纳米管（OH-MWCNT）上的不同主要暴露晶面（即{101}或{001}面）的锐钛矿二氧化钛（TiO）组成，对环境 pH 值（6、7 和 8）下 1,1,2,2-四氯乙烷（TeCA）这种常见地下水污染物的水解作用。两种 OH-MWCNT/TiO 纳米复合材料在催化 TeCA 脱氯化氢方面都比各自的组成材料（即裸露的 OH-MWCNT 和裸露的 TiO）更有效。此外，两种成分的协同作用明显，即 OH-MWCNT 的掺入增加了纳米复合材料对 TeCA 的吸附能力，显著增强了纳米复合材料表面上脱质子的羟基和羧基的催化作用，它们是 TeCA 水解的主要催化位点。这些发现可能对理解复合纳米材料的环境影响具有重要意义，并为设计用于增强污染物去除的高性能纳米复合材料提供了思路。
