Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran.
Department of Nanochemistry, Faculty of Pharmaceutical Chemistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
Sci Rep. 2019 Jul 23;9(1):10605. doi: 10.1038/s41598-019-46816-2.
DFT-D3 calculations were carried out to investigate interaction of HS and CH between numerous functionalized CNTs (f-CNTs), including hydroxyl, carboxyl, and cyclodextrin groups as potential candidates for selective adsorption and elimination of toxic pollutants. It was found that pristine CNTs as well as nanotube surface of functionalized CNTs cannot stably adsorb the HS molecule (adsorption energy of -0.17 eV). However, HS adsorption was significantly enhanced with different magnitudes upon the functionalization of CNT. For f-CNTs, HS adsorption was accompanied by releasing energies in the range between -0.34 to -0.54 eV where the upper limit of this range belongs to the cyclodextrin-functionalized CNT (CD-CNT) as the consequence of the existence of both dispersion and electrostatic interactions between the adsorbate and substrate. Findings also demonstrated a significantly weaker interaction between CH and CD-CNT in comparison to the HS molecule with adsorption energy of -0.14 eV. Electronic properties of the selected substrates revealed no significant changes in the inherent electronic properties of the CNTs after functionalizing and adsorbing the gas molecules. Moreover, DFTB-MD simulation demonstrated high adsorption capacity as well as CD-CNT ability for HS molecules against the CH one under ambient condition.
采用 DFT-D3 计算方法研究了 HS 和 CH 与众多功能化 CNT（f-CNTs）之间的相互作用，这些 CNT 包括羟基、羧基和环糊精基团，它们是用于选择性吸附和去除有毒污染物的潜在候选物。结果表明，原始 CNT 以及功能化 CNT 的纳米管表面均不能稳定地吸附 HS 分子（吸附能为-0.17eV）。然而，经过 CNT 功能化后，HS 的吸附能力得到了显著增强。对于 f-CNTs，HS 的吸附伴随着能量的释放，范围在-0.34 到-0.54eV 之间，其中该范围的上限属于环糊精功能化 CNT（CD-CNT），这是由于吸附物和底物之间存在色散和静电相互作用。研究结果还表明，与 HS 分子相比，CH 与 CD-CNT 的相互作用明显较弱，吸附能为-0.14eV。所选底物的电子性质表明，在功能化和吸附气体分子后，CNT 的固有电子性质没有发生显著变化。此外，DFTB-MD 模拟表明，在环境条件下，CD-CNT 对 HS 分子具有高吸附能力，而对 CH 分子的吸附能力较弱。
