title: Surface acid-base properties and hydration/dehydration mechanisms of aluminum (hydr)oxides.
abstract: In this paper, surface physiochemical properties of three typical aluminas, gamma-Al(OH)3, gamma-Al2O3, and alpha-Al2O3, were investigated by means of XRD, SEM, TEM, BET surface area, TG/DTA, and potentiometric titration techniques. Based on the titration data, surface protonation and deprotonation constants were determined using the constant capacitance model (CCM). The emphasis of this research was laid on the comparison of the crystal structure, surface hydration/dehydration and acid-base properties of these three typical alumina minerals. The calculation results revealed that the surface acidity of the aluminas is in the order of alpha-Al2O3>gamma-Al(OH)3>gamma-Al2O3 after being hydrated for 1 h. The correlation between the hydration/dehydration mechanisms of alumina and its acid/base properties is discussed.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Yang
authors.forename: Zhongxi
authors.initials: Z
authors.lastname: Sun
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.forename: Willis
authors.initials: W
authors.lastname: Forsling