Janus sand filter with excellent demulsification ability in separation of surfactant-stabilized oil/water emulsions: An experimental and molecular dynamics simulation study

Yuanyang Yan; Xinjuan Zeng; Kangquan Yang; Peizhang Zhou; Shouping Xu; Pihui Pi; Hao Li; Jing Fang; Shengnian Wang; Xiufang Wen

doi:10.1016/j.jhazmat.2021.126346

Janus sand filter with excellent demulsification ability in separation of surfactant-stabilized oil/water emulsions: An experimental and molecular dynamics simulation study

J Hazard Mater. 2021 Sep 15:418:126346. doi: 10.1016/j.jhazmat.2021.126346. Epub 2021 Jun 8.

Authors

Yuanyang Yan¹, Xinjuan Zeng², Kangquan Yang¹, Peizhang Zhou¹, Shouping Xu¹, Pihui Pi¹, Hao Li³, Jing Fang³, Shengnian Wang⁴, Xiufang Wen⁵

Affiliations

¹ School of Chemical and Chemical Engineering, Guangdong Engineering Technology Research Center of Advanced Insulating Coating, South China University of Technology, Guangzhou 510640, PR China.
² Guangdong Key Laboratory for Hydrogen Energy Technologies, School of Materials Science and Energy Engineering, Foshan University, Foshan 528000, PR China.
³ School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, PR China.
⁴ Chemical Engineering, Center of Biomedical Engineering and Rehabilitation Science, Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana 71272, USA.
⁵ School of Chemical and Chemical Engineering, Guangdong Engineering Technology Research Center of Advanced Insulating Coating, South China University of Technology, Guangzhou 510640, PR China. Electronic address: xfwen@scut.edu.cn.

PMID: 34329000
DOI: 10.1016/j.jhazmat.2021.126346

Abstract

Developing efficient separation materials for surfactant-stabilized oil/water emulsions is of great importance while significantly challenging. In this work, a sand filter with Janus channels was prepared by simply mixing superhydrophilic and superhydrophobic quartz sand in a mass ratio of 1:1. Due to the imbalanced force of droplets in those Janus channels, better separation performance under gravity was achieved for both surfactant-stabilized oil-in-water and water-in-oil emulsions than the superhydrophilic or superhydrophobic sand filter alone. It also received high flux (1080.13 L m^-2 h^-1 for dichloroethane-in-water emulsion and 1378.07 L m^-2 h^-1 for water-in-dichloroethane emulsion) and high separation efficiency (99.80% for dichloroethane-in-water emulsion and 99.98% for water-in-dichloroethane emulsion). Molecular dynamics based computational work and experimental studies revealed that the Janus channels of mixed sand layer exhibited greater interaction energy with emulsion droplets for more efficient adsorption, resulting in better demulsification capability and separation performance. The as-prepared Janus sand filters retained excellent separation performance after 50 cycles of the stability test. Together with the needs on only cheap and easily accessible raw materials and its environmentally friendly preparation method, this Janus sand filtration process exhibits its great potential for the separation of surfactant-stabilized oil/water emulsions.

Keywords: Interaction energy; Janus channel; Oil/water emulsion separation; Quartz sand.