Adsorption ( IF 1.949 ) Pub Date : 2020-01-08 , DOI: 10.1007/s10450-019-00194-3
Jian Zhao, Wei Gao, Xin-Zhan Qin, Man-Chao He

Abstract The environmental fate and behavior of arsenic (As) is receiving increased attention due to the As pollution all over the world. Kaolinite is a natural mineral resource that can be used for the removal of pollution as adsorbent. First-principles calculations based on density-functional theory was employed to explore the adsorption behavior of arsenic atoms adsorption on the kaolinite (001) and (00$$\bar {1}$$) surface. The one-fold top site was found to be energetically preferred for the kaolinite (001) and (00$$\bar {1}$$) surface, and the adsorption energy of the former is obviously higher than the latter. The coverage dependence of the adsorption energetics was systematically studied for a wide range of coverage Θ [from 0.11 to 1.0 monolayers (ML)]. The adsorption energy of As decreased with increasing coverage, thus indicating the lower stability of surface adsorption due to the repulsion of neighboring As atoms. The coverage has obvious effects on the arsenic adsorption process. Other properties of the As/kaolinite (001) system, including the lattice relaxation and changes of electronic density of states, were also studied and discussed in detail.

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