Wei Dongli, Zhang Anrui, Ai Yuejie, Wang Xiangke
MOE Key Lab of Resources and Environmental System Optimization College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China.
Chem Asian J. 2020 Apr 1;15(7):1140-1146. doi: 10.1002/asia.201901686. Epub 2020 Mar 9.
Considering the superior physiochemical property, increasing efforts have been devoted to exploiting the covalent organic frameworks (COFs) materials on the environmental remediation of heavy metal ions. Water pollution caused by Cr metal ions is of special concern for scientists and engineers. Notwithstanding all the former efforts made, it is surprising that very little is known about the interaction mechanisms between the hydrated Cr metal ions and COF materials. In present context, density functional theory (DFT) method is used to elucidate geometric and electronic properties with the purpose of putting into theoretical perspective the application values and interaction mechanisms for COF materials on Cr capture. The results showed that all the five selected Schiff-base COFs materials displayed good adsorption performance on Cr removal while the phenazine-linked and imine-COFs possessed the most favorable adsorption capacity due to the optimal chemical units and frameworks. The hydration effect was found to play a two-side role in the adsorption process and interaction mechanisms, involving coordination, hydrogen bonds, as well as weak non-covalent interactions, have been illuminated to explain the observed different adsorption behaviors. This study provides a general guidance for the design and selection of efficient COF materials as high-capacity Cr adsorbents.
鉴于共价有机框架（COF）材料具有优异的物理化学性质，人们越来越致力于开发其在重金属离子环境修复方面的应用。铬金属离子造成的水污染尤其受到科学家和工程师的关注。尽管此前已做出诸多努力，但令人惊讶的是，关于水合铬金属离子与COF材料之间的相互作用机制，人们所知甚少。在当前背景下，采用密度泛函理论（DFT）方法来阐明其几何和电子性质，目的是从理论角度探讨COF材料对铬的捕获应用价值及相互作用机制。结果表明，所选取的五种席夫碱COF材料对铬的去除均表现出良好的吸附性能，而吩嗪连接的COF和亚胺COF由于具有最佳的化学单元和骨架结构，因而具有最有利的吸附容量。研究发现水合作用在吸附过程中起到了双重作用，同时阐明了包括配位、氢键以及弱非共价相互作用在内的相互作用机制，以解释所观察到的不同吸附行为。本研究为设计和选择高效的COF材料作为高容量铬吸附剂提供了一般性指导。
