title: Theoretical investigation of lead vapor adsorption on kaolinite surfaces with DFT calculations.
abstract: Kaolinite can be used as the in-furnace sorbent/additive to adsorb lead (Pb) vapor at high temperature. In this paper, the adsorptions of Pb atom, PbO molecule and PbCl2 molecule on kaolinie surfaces were investigated by density functional theory (DFT) calculation. Si surface is inert to Pb vapor adsorption while Al surfaces with dehydroxylation are active for the unsaturated Al atoms and the O atoms losing H atoms. The adsorption energy of PbO is much higher than that of Pb atom and PbCl2. Considering the energy barriers, it is easy for PbO and PbCl2 to adsorb on Al surfaces but difficult to escape. The high energy barriers of de-HCl process cause the difficulties of PbCl2 to form PbO·Al2O3·2SiO2 with kaolinite. Considering the inertia of Si atoms and the activity of Al atoms after dehydroxylation, calcination, acid/alkali treatment and some other treatment aiming at amorphous silica producing and Al activity enhancement can be used as the modification measures to improve the performance of kaolinite as the in-furnace metal capture sorbent.
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
authors.forename: Xinye
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China. Electronic address: heyyj@seu.edu.cn.
authors.forename: Yaji
authors.initials: Y
authors.lastname: Huang
authors.affiliation: College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
authors.forename: Yongxing
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
authors.forename: Changqi
authors.initials: C
authors.lastname: Liu
mesh_terms: D007616:Kaolin / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry*
chemical_list: D010087:Oxides; D007616:Kaolin; D007854:Lead; C029891:lead chloride; C047365:lead oxide
keywords: Adsorption; Chlorine; Density functional theory; Kaolinite; Lead vapor