A comprehensive review on the behavior and evolution of oil droplets during oil/water separation by membranes

Jialu Zhang; Kaiming Peng; Zhi-Kang Xu; Yongjiao Xiong; Jia Liu; Chen Cai; Xiangfeng Huang

doi:10.1016/j.cis.2023.102971

A comprehensive review on the behavior and evolution of oil droplets during oil/water separation by membranes

Adv Colloid Interface Sci. 2023 Sep:319:102971. doi: 10.1016/j.cis.2023.102971. Epub 2023 Aug 2.

Authors

Jialu Zhang¹, Kaiming Peng², Zhi-Kang Xu³, Yongjiao Xiong¹, Jia Liu⁴, Chen Cai⁴, Xiangfeng Huang⁵

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China.
² State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China; Institute of Carbon Neutrality, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China. Electronic address: pengkaiming@tongji.edu.cn.
³ MOE Key Laboratory of Macromolecular Synthesis and Functionalization, and Key Lab of Adsorption and Separation Materials & Technologies of Zhejiang Province, Department of Polymer Science and Engineering, Zhejiang University, No.38 Zheda Road, Hangzhou 310027, PR China.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China; Institute of Carbon Neutrality, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China; Institute of Carbon Neutrality, Tongji University, No.1239 Siping Road, Shanghai 200092, PR China. Electronic address: hxf@tongji.edu.cn.

PMID: 37562248
DOI: 10.1016/j.cis.2023.102971

Abstract

Membrane separation technology has significant advantages for treating oil-in-water emulsions. Understanding the evolution of oil droplets could reveal the interfacial and colloidal interactions, facilitate the design of advanced membranes, and improve the separation performances. This review on the characteristic behavior and evolution of oil droplets focuses on the advanced analytical techniques, and the subsequent fouling as well as demulsification effects during membrane separation. A detailed introduction is provided on microscopic observations and numerical simulations of the dynamic evolution of oil droplets, featuring real-time in-situ visualization and accurate reconstruction, respectively. Characteristic behaviors of these oil droplets include attachment, pinning, wetting, spreading, blockage, intrusion, coalescence, and detachment, which have been quantified by specific proposed parameters and criteria. The fouling process can be evaluated using Hermia and resistance models. The related adhesion force and intrusion pressure as well as droplet-droplet/membrane interfacial interactions can be accurately quantified using various force analysis methods and advanced force measurement techniques. It is encouraging to note that oil coalescence has been achieved through various effects such as electrostatic interactions, mechanical actions, Laplace pressure/surface free energy gradients, and synergistic effects on functional membranes. When oil droplets become destabilized and coalesce into larger ones, the functional membranes can overcome the limitations of size-sieving effect to attain higher separation efficiency. This not only bypasses the trade-off between permeability and rejection, but also significantly reduces membrane fouling. Finally, the challenges and potential research directions in membrane separation are proposed. We hope this review will support the engineering of advanced materials for oil/water separation and research on interface science in general.

Keywords: Interfacial interaction; Membrane fouling; Numerical simulation; Oil coalescence; Oil droplet behavior; Oil/water separation.

Publication types

Review