Factors Influencing Al(III) Adsorption onto Silicate Clay Minerals
Wencui Chai, Yanfang Huang, Guihong Han∗, Jiongtian Liu
School of Chemical Engineering and Energy, Zhengzhou University, Zhouzheng 450001, Henan Province,
P.R.China
(*Corresponding author: guihong-han@hotmail.com)
ABSTRACT
In the beneficiation process, the metal ions could adsorb onto clay mineral surface or interact with flotation
chemicals, and then result in changing the flotation behavior of desired minerals. Al3+ is a dominating ion
existing in the bauxite flotation system. In this research, the adsorption behavior of Al 3+ on two silicate
clay minerals (including bentonite and kaolin) were investigated by means of UV-Vis spectra, Zeta
potential testing, and SEM analysis. The adsorption experiment results show that the amount of Al3+
adsorption increases with initial metal ion concentration, contact time, and solution pH. Moreover, there
are some different adsorption behaviours for different clays. Increasing the clay amount decreases the
adsorption amount for bentonite, while increases first then decreases for kaolin. The temperature of the
system also has a distinct effect on adsorption amount. Higher temperature favours the adsorption of Al3+
on bentonite but goes against for kaolin. The adsorption amounts of Al3+ on bentonite and kaolin reach to
12.48 mg·g-1 and 0.875mg·g-1 under the condition of the initial pH 5. Zeta potential results show that the
adsorption of Al3+ on two clays is characterized by electrostatic attraction and ion exchange.
Figure 1 – Adsorption rate of Al(III) and Zeta potential changing of clay minerals with solution pH
KEYWORDS
Bentonite, Kaolin, Al(Ⅲ), Adsorption, Clay Minerals