Electrokinetic potential reduction of fine particles induced by gas nucleation

Weiguang Zhou; Liming Liu; Baonan Zhou; Li Weng; Junguo Li; Cheng Liu; Siyuan Yang; Changning Wu; Ke Liu

doi:10.1016/j.ultsonch.2020.105167

Electrokinetic potential reduction of fine particles induced by gas nucleation

Ultrason Sonochem. 2020 Oct:67:105167. doi: 10.1016/j.ultsonch.2020.105167. Epub 2020 May 8.

Authors

Weiguang Zhou¹, Liming Liu², Baonan Zhou³, Li Weng⁴, Junguo Li⁴, Cheng Liu⁵, Siyuan Yang⁵, Changning Wu⁶, Ke Liu⁷

Affiliations

¹ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address: csupaper@163.com.
² School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen 518055, China.
³ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
⁴ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China.
⁵ School of Resources and Environment Engineering, Wuhan University of Technology, Wuhan 430070, China.
⁶ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address: Wucn@sustech.edu.cn.
⁷ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China; School of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen 518055, China; Clean Energy Institute, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address: Liuk@sustech.edu.cn.

PMID: 32442929
DOI: 10.1016/j.ultsonch.2020.105167

Abstract

Electrokinetic potential of particles has been extensively studied in colloidal systems over the past century, while up to date, the influence of gas on electrokinetic behaviors of particles has not been fully understood yet. In this study, the electrokinetic response of particles to gas nucleation was systematically investigated with coal as the object. The results showed that the nucleation of gas (both on particle surfaces and in water) significantly changed the particle' electrokinetic behaviors. Higher gas content and particle's surface hydrophobicity normally trigger more intensive gas nucleation, thus inducing more significant reduction of particle zeta potential. After gas nucleation, numerous nanobubbles (NBs) appear in the suspensions mainly in two forms: NBs adhering onto solid surfaces (ANBs) and NBs stagnating in bulk solutions (BNBs). ANBs not only enhance the surface heterogeneity, but also cause the "steric hindrance" effect, and electric double layer (EDL) overlapping and associated ions shielding towards charged particles, which significantly decrease their electrokinetic potentials. Although BNBs can also reduce the zeta potential of particles by EDL compressing, their functions are rather limited.

Keywords: Degassing; Electrokinetic; Gas nuclei; Nanobubbles; Zeta potential.