Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (5): 829-835.doi: 10.3866/PKU.WHXB201403211

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Adsorption Mechanism of Hydrated Pb(OH)+ on the Kaolinite (001) Surface

WANG Juan1,2, XIA Shu-Wei1, YU Liang-Min1   

  1. 1 Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, Shandong Province, P. R. China;
    2 College of Chemistry and Pharmacy, Qingdao Agricultural University, Qingdao 266109, Shandong Province, P. R. China
  • Received:2014-01-21 Revised:2014-03-20 Published:2014-04-25
  • Contact: XIA Shu-Wei E-mail:shuweixia@ouc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20677053) and Natural Science Foundation of Shandong Province, China (ZR2012CQ015).

Abstract:

The adsorption behavior of Pb(OH)+ on the basal octahedral (001) surface of kaolinite has been investigated using the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) of density functional theory with periodic slab models, where the water environment was considered. The coordination geometry, coordination number, preferred adsorption position, and adsorption type were examined, with binding energy estimated. All the monodentate and bidentate complexes exhibited hemi- directed geometry with coordination numbers of 3-5. Site of "Ou" with "up" hydrogen was more favorable for monodentate complex than site of "Ol" with "lying" hydrogen. Monodentate complexation of "Ou" site with a high binding energy of -182.60 kJ·mol-1 should be the most preferred adsorption mode, while bidentate complexation on "OuOl" site of single Al center was also probable. The stability of adsorption complex was found closely related to the hydrogen bonding interactions between surface Ol and H in aqua ligands of Pb(Ⅱ). Mulliken population and density of states analyses showed that coupling of Pb 6p with the antibonding Pb 6s―O 2p states was the primary orbital interaction between Pb(Ⅱ) and the surface oxygen. Hydrogen complexation occupied a much large proportion in the joint coordination structure of bidentate complex, where bonding state filling predominated for the Pb―Ol interaction.

Key words: Pb(OH)+, Kaolinite, Chemical adsorption, Density functional theory, Coordination number

MSC2000: 

  • O647