Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity

The separation of high-viscosity oil–water emulsions remains a global challenge due to ultra-stable interfaces and severe membrane fouling. In this paper, SiO<sub>2</sub> micro–nanoparticles coated with polyethyleneimine (PEI) were initially loaded onto a stainless steel substrate. This...

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Main Authors: Mengxi Zhou, Peiqing Yuan, Xinru Xu, Jingyi Yang
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/8/1840
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author Mengxi Zhou
Peiqing Yuan
Xinru Xu
Jingyi Yang
author_facet Mengxi Zhou
Peiqing Yuan
Xinru Xu
Jingyi Yang
author_sort Mengxi Zhou
collection DOAJ
description The separation of high-viscosity oil–water emulsions remains a global challenge due to ultra-stable interfaces and severe membrane fouling. In this paper, SiO<sub>2</sub> micro–nanoparticles coated with polyethyleneimine (PEI) were initially loaded onto a stainless steel substrate. This dual-functional design simultaneously modifies surface roughness and wettability. Furthermore, a covalent crosslinking network was created through the Schiff base reaction between PEI and glutaraldehyde (GA) to enhance the stability of the membrane. The membrane exhibits extreme wettability, superhydrophilicity (WCA = 0°), and underwater superoleophobicity (UWOCA = 156.9°), enabling a gravity-driven separation of pump oil emulsions with 99.9% efficiency and a flux of 1006 L·m<sup>−2</sup>·h<sup>−1</sup>. Moreover, molecular dynamics (MD) simulations demonstrate that the SiO<sub>2</sub>-PEI-GA-modified membrane promotes the formation of a stable hydration layer, reduces the oil–layer interaction energy by 85.54%, and exhibits superior underwater oleophobicity compared to the unmodified SSM. Efficiency is maintained at 99.8% after 10 cycles. This study provides a scalable strategy that combines covalent crosslinking with hydrophilic particle modification, effectively addressing the trade-off between separation performance and membrane longevity in the treatment of viscous emulsions.
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spelling doaj-art-965b7689d6d843cfbc15f7bcbb2bb0da2025-08-20T02:18:15ZengMDPI AGMolecules1420-30492025-04-01308184010.3390/molecules30081840Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under GravityMengxi Zhou0Peiqing Yuan1Xinru Xu2Jingyi Yang3International Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, ChinaState Key Laboratory of Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, ChinaInternational Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, ChinaInternational Joint Research Center of Green Energy Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, ChinaThe separation of high-viscosity oil–water emulsions remains a global challenge due to ultra-stable interfaces and severe membrane fouling. In this paper, SiO<sub>2</sub> micro–nanoparticles coated with polyethyleneimine (PEI) were initially loaded onto a stainless steel substrate. This dual-functional design simultaneously modifies surface roughness and wettability. Furthermore, a covalent crosslinking network was created through the Schiff base reaction between PEI and glutaraldehyde (GA) to enhance the stability of the membrane. The membrane exhibits extreme wettability, superhydrophilicity (WCA = 0°), and underwater superoleophobicity (UWOCA = 156.9°), enabling a gravity-driven separation of pump oil emulsions with 99.9% efficiency and a flux of 1006 L·m<sup>−2</sup>·h<sup>−1</sup>. Moreover, molecular dynamics (MD) simulations demonstrate that the SiO<sub>2</sub>-PEI-GA-modified membrane promotes the formation of a stable hydration layer, reduces the oil–layer interaction energy by 85.54%, and exhibits superior underwater oleophobicity compared to the unmodified SSM. Efficiency is maintained at 99.8% after 10 cycles. This study provides a scalable strategy that combines covalent crosslinking with hydrophilic particle modification, effectively addressing the trade-off between separation performance and membrane longevity in the treatment of viscous emulsions.https://www.mdpi.com/1420-3049/30/8/1840superwetting membraneunderwater superoleophobicemulsion separationcrosslinkingmolecular dynamics simulation
spellingShingle Mengxi Zhou
Peiqing Yuan
Xinru Xu
Jingyi Yang
Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
Molecules
superwetting membrane
underwater superoleophobic
emulsion separation
crosslinking
molecular dynamics simulation
title Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
title_full Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
title_fullStr Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
title_full_unstemmed Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
title_short Construction of a Covalent Crosslinked Membrane Exhibiting Superhydrophilicity and Underwater Superoleophobicity for the Efficient Separation of High-Viscosity Oil–Water Emulsion Under Gravity
title_sort construction of a covalent crosslinked membrane exhibiting superhydrophilicity and underwater superoleophobicity for the efficient separation of high viscosity oil water emulsion under gravity
topic superwetting membrane
underwater superoleophobic
emulsion separation
crosslinking
molecular dynamics simulation
url https://www.mdpi.com/1420-3049/30/8/1840
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AT xinruxu constructionofacovalentcrosslinkedmembraneexhibitingsuperhydrophilicityandunderwatersuperoleophobicityfortheefficientseparationofhighviscosityoilwateremulsionundergravity
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