Evaluation of exfoliation degree of montmorillonite in aqueous dispersions through turbidity measurement

Tianxing Chen; Yiming Yang; Yunliang Zhao; Feng Rao; Shaoxian Song

doi:10.1039/c8ra09042d

Evaluation of exfoliation degree of montmorillonite in aqueous dispersions through turbidity measurement

RSC Adv. 2018 Dec 5;8(71):40823-40828. doi: 10.1039/c8ra09042d. eCollection 2018 Dec 4.

Authors

Tianxing Chen^{1

2}, Yiming Yang^{1

2}, Yunliang Zhao^{1

2}, Feng Rao³, Shaoxian Song^{1

2

4}

Affiliations

¹ Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology Luoshi Road 122 Wuhan Hubei 430070 China zyl286@whut.edu.cn ssx851215@whut.edu.cn.
² School of Resources and Environmental Engineering, Wuhan University of Technology Luoshi Road 122 Wuhan Hubei 430070 China.
³ Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria Morelia Michoacán 58030 Mexico.
⁴ Hubei Provincial Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan University of Technology Luoshi Road 122 Wuhan Hubei 430070 China.

Abstract

In this work, the exfoliation of montmorillonite (MMT) in aqueous suspensions was investigated through the measurement of turbidity. The experimental results have shown that the turbidity is closely correlated to the exfoliation degree of MMT in aqueous suspensions. Below the solid concentration of 2% w/v and in the range of pH 4-10, the turbidity of aqueous dispersions of MMT without exfoliation appeared constant, while it decreased on increasing the exfoliation degree of MMT. The ratio of the turbidities before and after the exfoliation (τ ₀/τ) was directly proportional to the number of fresh MMT flakes formed from the exfoliation. τ ₀/τ was termed the exfoliation degree E. The larger the value of E, the more MMT flakes formed. It has been found that the exfoliation of MMT in aqueous dispersions was depressed due to the presence of electrolytic ions. This depression increased with the increase of ion concentration and valence.