کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1694994 1519089 2013 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Adsorption and diffusion of Pb(II) on the kaolinite(001) surface: A density-functional theory study
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Adsorption and diffusion of Pb(II) on the kaolinite(001) surface: A density-functional theory study
چکیده انگلیسی


• We investigate the adsorption and diffusion of Pb(II) on kaolinite(001) surface.
• The most stable adsorbed site for Pb(II) is the bridge site.
• Increasing the coverage will increase the adsorption energy in Θ ≤ 1.
• The Pb(II) atoms are easy to diffuse on kaolinite(001) surface.

The adsorption and diffusion of Pb(II) atom on the hydroxylated (001) surface of kaolinite were investigated using density-functional theory within the generalized gradient approximation and a supercell approach. The coverage dependence of the adsorption structures and energetics was systematically studied for a wide range of coverage Θ [from 0.11 to 1.0 monolayers (ML)] and adsorption sites. The most stable among all possible adsorption sites was the two-fold bridge site followed by the one-fold top site, and the adsorption energy increased with the coverage, thus indicating the higher stability of surface adsorption and a tendency to the formation of Pb(II) islands (clusters) with increasing coverage. Moreover, the energy barrier for diffusion of Pb(II) atom between the one-fold top and the two-fold bridge adsorption sites on kaolinite(001) surface was 0.23 (0.31) eV, implying that the Pb(II) atom is prone to diffusing on kaolinite(001) surface. The other properties of the Pb(II)/kaolinite(001) system including the different charge distribution, the lattice relaxation, and the electronic density of states were also studied and discussed in detail.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Clay Science - Volume 85, November 2013, Pages 74–79
نویسندگان
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