Department of Power Engineering, School of Energy, Power and Mechanical Engineering, North China Electric Power University, Baoding 071003, China.
CNOOC Research Institute of Refining and Petrochemicals, Beijing, 102200, P. R. China.
Phys Chem Chem Phys. 2022 Jun 1;24(21):13156-13170. doi: 10.1039/d1cp02170b.
Integrated gasification combined cycle (IGCC) is a promising clean technology for coal power generation; however, the high volatility and toxicity of arsenic pollutants (As, As, AsO and AsH) released from an IGCC coal plant cause serious damage to human health and the ecological environment. Therefore, highly efficient adsorbents for simultaneous treatment of multiple arsenic pollutants are urgently needed. In this work, the adsorption characteristics and competitive adsorption behaviors of As, As, AsO, and AsH on four kinds of graphene-based single-atom iron adsorbents (Fe/GA) were systematically investigated through density functional theory (DFT) and molecular dynamics (AIMD) simulations. The results suggest that single-vacancy Fe/GA doped with three nitrogen atoms has the largest adsorption ability for As, As, AsO and AsH. The adsorption energies of As, AsO and As on Fe/GA depend on both charge transfer and orbital hybridization, while the adsorption energy of AsH is mainly decided by electronic transfer. The adsorption differences of As, As, AsO and AsH on four Fe/GA adsorbents can be explained through the obvious linear relationship between the adsorption energy and Fermi softness. As, As, AsO and AsH will compete for adsorption sites when they exist on the same adsorbent surface simultaneously, and the adsorption capacities of AsO and As are relatively stronger. After the competitive adsorption between AsO and As, AsO occupies the adsorption site at 300-900 K. This theoretical work suggests that Fe/GA is a promising adsorbent for the simultaneous removal of multiple arsenic pollutants with high adsorption capacity and low cost.
整体煤气化联合循环（IGCC）是一种很有前途的清洁煤发电技术；然而，来自 IGCC 燃煤电厂的砷污染物（As、As、AsO 和 AsH）具有高挥发性和高毒性，对人类健康和生态环境造成严重危害。因此，迫切需要高效的吸附剂来同时处理多种砷污染物。在这项工作中，通过密度泛函理论（DFT）和分子动力学（AIMD）模拟系统地研究了 As、As、AsO 和 AsH 在四种基于石墨烯的单原子铁吸附剂（Fe/GA）上的吸附特性和竞争吸附行为。结果表明，掺杂三个氮原子的单空位 Fe/GA 对 As、As、AsO 和 AsH 具有最大的吸附能力。Fe/GA 对 As、AsO 和 As 的吸附能取决于电荷转移和轨道杂化，而 AsH 的吸附能主要由电子转移决定。通过吸附能与费米柔软度之间的明显线性关系，可以解释 As、As、AsO 和 AsH 在四种 Fe/GA 吸附剂上的吸附差异。当它们同时存在于同一吸附剂表面时，As、As、AsO 和 AsH 会争夺吸附位，而 AsO 和 As 的吸附容量相对较强。在 AsO 和 As 之间的竞争吸附后，AsO 在 300-900 K 时占据吸附位。这项理论工作表明，Fe/GA 是一种很有前途的吸附剂，可同时去除多种砷污染物，具有高吸附容量和低成本的特点。
