TY - JOUR

T1 - Membrane Contact Demulsification

T2 - A Superhydrophobic ZIF-8@rGO Membrane for Water-in-Oil Emulsion Separation

AU - Gu, Jiahui

AU - Qu, Zhou

AU - Zhang, Xiangning

AU - Fan, Hongwei

AU - Li, Chunxi

AU - Caro, Jürgen

AU - Meng, Hong

N1 - Funding Information: This work was financially supported by the National Natural Science Foundation of China ( 51773012 ), Fundamental Research Funds for the Central Universities (buctrc202135), and China Scholarship Council Program ( 201906880031 ).

PY - 2023/4

Y1 - 2023/4

N2 - Achieving a water–oil interface imbalance has been identified as a critical factor in the demulsification of water-in-oil emulsions. However, conventional demulsifying membranes generally break the interface balance by depending on a relatively high transmembrane pressure. Here, we present a “contact demulsification” concept to naturally and quickly achieve disruption of the water–oil interface balance. For this purpose, a novel demulsifying membrane with a high flux of the organic component has been developed via the simple vacuum assembly of zeolitic imidazolate framework-8 (ZIF-8)@reduced graphene oxide (rGO) microspheres (ZGS) on a polytetrafluoroethylene (PTFE) support, followed by immobilization processing in a polydimethylsiloxane (PDMS) crosslinking solution. Due to the micro-nano hierarchies of the ZGS, the prepared ZIF-8@rGO@PDMS/PTFE (ZGPP) membranes feature a unique superhydrophobic surface, which results in a water–oil interface imbalance when a surfactant-stabilized water-in-oil emulsion comes into contact with the membrane surface. Under a low transmembrane pressure of 0.15 bar (15 kPa), such membranes show an excellent separation efficiency (∼99.57%) and a high flux of 2254 L·m−2·h−1, even for surfactant-stabilized nanoscale water-in-toluene emulsions (with an average droplet size of 57 nm). This “contact demulsification” concept paves the way for developing next-generation demulsifying membranes for water-in-oil emulsion separation.

AB - Achieving a water–oil interface imbalance has been identified as a critical factor in the demulsification of water-in-oil emulsions. However, conventional demulsifying membranes generally break the interface balance by depending on a relatively high transmembrane pressure. Here, we present a “contact demulsification” concept to naturally and quickly achieve disruption of the water–oil interface balance. For this purpose, a novel demulsifying membrane with a high flux of the organic component has been developed via the simple vacuum assembly of zeolitic imidazolate framework-8 (ZIF-8)@reduced graphene oxide (rGO) microspheres (ZGS) on a polytetrafluoroethylene (PTFE) support, followed by immobilization processing in a polydimethylsiloxane (PDMS) crosslinking solution. Due to the micro-nano hierarchies of the ZGS, the prepared ZIF-8@rGO@PDMS/PTFE (ZGPP) membranes feature a unique superhydrophobic surface, which results in a water–oil interface imbalance when a surfactant-stabilized water-in-oil emulsion comes into contact with the membrane surface. Under a low transmembrane pressure of 0.15 bar (15 kPa), such membranes show an excellent separation efficiency (∼99.57%) and a high flux of 2254 L·m−2·h−1, even for surfactant-stabilized nanoscale water-in-toluene emulsions (with an average droplet size of 57 nm). This “contact demulsification” concept paves the way for developing next-generation demulsifying membranes for water-in-oil emulsion separation.

KW - Demulsification

KW - Oil/water separation

KW - Superhydrophobic membrane

KW - Water-in-oil emulsion

UR - http://www.scopus.com/inward/record.url?scp=85151458719&partnerID=8YFLogxK

U2 - 10.1016/j.eng.2022.02.017

DO - 10.1016/j.eng.2022.02.017

M3 - Article

AN - SCOPUS:85151458719

VL - 23

SP - 73

EP - 81

JO - Engineering

JF - Engineering

SN - 2095-8099

ER -