A Review of Two-Dimensional Membrane Material：Structural Design and Performance for Demulsification and Emulsion Separation AITranslate

［1］He Y，Jiang Z W. Technology review：treating oilfield wastewater［J］. Filtration & Separation，2008，45（5）：14.

［2］Wang Z M，Lun Q Y，Wang J，Han X，Zhu W，Zhang J，Song G L. Corrosion mitigation behavior of an alternately wetted steel electrode in oil/water media［J］. Corrosion Science，2019，152：140.

［3］Tulayakul P，Boonsoongnern A，Kasemsuwan S，Wiriyarampa S，Pankumnoed J，Tippayaluck S，Hananantachai H，Mingkhwan R，Netvichian R，Khaodhiar S. Comparative study of heavy metal and pathogenic bacterial contamination in sludge and manure in biogas and non-biogas swine farms［J］. Journal of Environmental Sciences，2011，23（6）：991.

［4］Beyer J，Trannum H C，Bakke T，Hodson P V，Collier T K. Environmental effects of the deepwater horizon oil spill：a review［J］. Marine Pollution Bulletin，2016，110（1）：28.

［5］Chen C L，Weng D，Mahmood A，Chen S，Wang J D. Separation mechanism and construction of surfaces with special wettability for oil/water separation［J］. ACS Applied Materials & Interfaces，2019，11（11）：11006.

［6］Chen W M，Gu Z P，Ran G，Li Q B. Application of membrane separation technology in the treatment of leachate in China：a review［J］. Waste Management，2021，121：127.

［7］Lee C H，Tiwari B，Zhang D Y，Yap Y K. Water purification：oil-water separation by nanotechnology and environmental concerns［J］. Environmental Science-Nano，2017，4（3）：514.

［8］Tian Y，Zhou J J，He C Q，He L，Li X G，Sui H. The formation，stabilization and separation of oil-water emulsions：a review［J］. Processes，2022，10（4）：738.

［9］Raya S A，Saaid I M，Ahmed A A，Umar A A. A critical review of development and demulsification mechanisms of crude oil emulsion in the petroleum industry［J］. Journal of Petroleum Exploration and Production Technology，2020，10（4）：1711.

［10］Zuo J H，Zhou Y，Chen Z H，Zhao T，Tan Q，Zhou C L，Zeng X J，Xu S P，Cheng J，Wen X F，Pi P H. A superwetting stainless steel mesh with Janus surface charges for efficient emulsion separation［J］. Journal of Hazardous Materials，2022，430：128378.

［11］Lin X D，Heo J，Jeong H J，Choi M Y，Chang M，Hong J. Robust superhydrophobic carbon nanofiber network inlay-gated mesh for water-in-oil emulsion separation with high flux［J］. Journal of Materials Chemistry A，2016，4（46）：17970.

［12］Yang C，Han N，Wang W J，Zhang W X，Han C Y，Cui Z Y，Zhang X X. Fabrication of a PPS microporous membrane for efficient water-in-oil emulsion separation［J］. Langmuir，2018，34（36）：10580.

［13］He B，Ding Y J，Wang J Q，Yao Z K，Qing W H，Zhang Y J，Liu F，Tang C Y. Sustaining fouling resistant membranes：membrane fabrication，characterization and mechanism understanding of demulsification and fouling-resistance［J］. Journal of Membrane Science，2019，581：105.

［14］Wang J Q，He B，Ding Y J，Li T T，Zhang W L，Zhang Y J，Liu F，Tang C Y. Beyond superwetting surfaces：dual-scale hyperporous membrane with rational wettability for "nonfouling" emulsion separation via coalescence demulsification［J］. ACS Applied Materials & Interfaces，2021，13（3）：4731.

［15］Wang D，Yang D L，Huang C，Huang Y Y，Yang D Z，Zhang H，Liu Q，Tang T，Gamal El-Din M，Kemppi T，Perdicakis B，Zeng H. Stabilization mechanism and chemical demulsification of water-in-oil and oil-in-water emulsions in petroleum industry：a review［J］. Fuel，2021，286：119390.

［16］Zhang L，Wei L X，Shi L J，Dai X，Guo S J，Jia X L，Liu C. Synthesis and characterization of a novel reticulated multi-branched fluorinated polyether demulsifier for w/o emulsion demulsification［J］. Journal of Polymer Research，2022，29（5）：164.

［17］Ma L L，Chen Y B，Liu Y C，Chen M Y，Yang B，Zhang B，Ding Y. Investigation on the performance of a block polyether demulsifier based on polysiloxane for the treatment of aged oil［J］. Energy & Fuels，2017，31（9）：8886.

［18］Hassanshahi N，Hu G J，Li J B. Application of ionic liquids for chemical demulsification：a review［J］. Molecules，2020，25（21）：4915.

［19］Ye F，Mi Y Z，Liu H Y，Zeng G X，Shen L W，Feng X N，Yang Y，Zhang Z J，Yuan H K，Yan X M. Demulsification of water-in-crude oil emulsion using natural lotus leaf treated via a simple hydrothermal process［J］. Fuel，2021，295：120596.

［20］Wang H，Zhang X Y，Fang Y，San K N E，Fan Y. Smart and recyclable admicelle-coated Fe3O4 nanoparticles for treating oily wastewater［J］. Journal of Environmental Chemical Engineering，2022，10（3）：107445.

［21］Mu Y，Liu J，Liu J，Ren S L. Preparation and demulsification performance of modified attapulgite nanoparticle demulsifier［J］. Fuel，2022，313：123038.

［22］Li H N，Yang J，Xu Z K. Hollow fiber membranes with Janus surfaces for continuous deemulsification and separation of oil-in-water emulsions［J］. Journal of Membrane Science，2020，602：117964.

［23］Wang R，Zhu X，Zhu L，Li H，Xue J W，Yu S F，Liu X L，Gan S P，Xue Q Z. Multifunctional superwetting positively charged foams for continuous oil/water emulsion separation and removal of hazardous pollutants from water［J］. Separation and Purification Technology，2022，289：120683.

［24］Zhu X，Zhu L，Li H，Xue J W，Ma C，Yin Y Y，Qiao X R，Sun D F，Xue Q Z. Multifunctional charged hydrogel nanofibrous membranes for metal ions contained emulsified oily wastewater purification［J］. Journal of Membrane Science，2021，621：118950.

［25］Wang H C，Gao F，Ren R L，Wang Z W，Yue R R，Wei J F，Wang X L，Kong Z Y，Zhang H，Zhang X Q. Caffeic acid polymer rapidly modified sponge with excellent anti-oil-adhesion property and efficient separation of oil-in-water emulsions［J］. Journal of Hazardous Materials，2021，404：124197.

［26］Chen L H，Ye F，Liu H J，Jiang X B，Zhao Q M，Ai G S，Shen L W，Feng X N，Yang Y，Mi Y Z. Demulsification of oily wastewater using a nano carbon black modified with polyethyleneimine［J］. Chemosphere，2022，295：133857.

［27］Wormuth K R，Zushma S. Phase behavior of branched surfactants in oil and water［J］. Langmuir，1991，7（10）：2048.

［28］Wang S T，Liu K S，Yao X，Jiang L. Bioinspired surfaces with superwettability：new insight on theory，design，and applications［J］. Chemical Reviews，2015，115（16）：8230.

［29］Liu J，Li X C，Jia W H，Li Z Y，Zhao Y P，Ren S L. Demulsification of crude oil-in-water emulsions driven by graphene oxide nanosheets［J］. Energy & Fuels，2015，29（7）：4644.

［30］Liu J，Liu J，Zhong J P，Shen J L，Ren S L. Preparation of graphene oxide/attapulgite composites and their demulsification performance for oil-in-water emulsion［J］. Energy & Fuels，2021，35（6）：5172.

［31］Dorn P B，Salanitro J P，Evans S H，Kravetz L. Assessing the aquatic hazard of some branched and linear nonionic surfactants by biodegradation and toxicity［J］. Environmental Toxicology and Chemistry，1993，12（10）：1751.

［32］（沈如翠，安邦，王亚强，张金钰，刘刚，孙军. 纳米金属多层膜微观结构及其力学性能研究进展［J］. 稀有金属，2023，47（4）：555.）

R C Shen，B An，Y Q Wang，J Y Zhang，G Liu，J Sun. Research progress in microstructure and mechanical properties of nanostructured metallic multilayers［J］. Chinese Journal of Rare Metals，2023，47（4）：555.

［33］（丁成，蔚志红，巩春龙，乔瞻，张谷平. 黄金纳米复合材料工业化生产工艺设计及应用［J］. 黄金，2023，44（5）：32.）

C Ding，Z H Wei，C L Gong，Z Qiao，G P Zhang. Design and application of industrial production process for nano-gold composite materials［J］. Gold，2023，44（5）：32.

［34］（冯蓉，吴静. 基于共价有机框架材料的电化学传感器研究进展［J］. 分析试验室，2024，43（2）：179.）

R Feng，J Wu. Advances of electrochemical sensors based on covalent organic framework materials［J］. Chinese Journal of Analysis Laboratory，2024，43（2）：179.

［35］Zhang S X，Jiang G S，Gao S J，Jin H L，Zhu Y Z，Zhang F，Jin J. Cupric phosphate nanosheets-wrapped inorganic membranes with superhydrophilic and outstanding anticrude oil-fouling property for oil/water separation［J］. ACS Nano，2018，12（1）：795.

［36］He H Q，Wu Y，Wang Y，Zhang T J，Zhang T C，Yuan S J. Constructing a Janus membrane with extremely asymmetric wettability for water unidirectional permeation and switchable emulsion separation［J］. Separation and Purification Technology，2022，303：122254.

［37］（杨程，赵占霞，张承龙，王瑞雪，马恩. 水溶液中低温电沉积法制备锗薄膜工艺［J］. 有色金属工程，2022，12（10）：38.）

C Yang，Z X Zhao，C L Zhang，R X Wang，E Ma. Preparation process of low-temperature electrodeposition of germanium thin film in aqueous solution［J］. Nonferrous Metals Engineering，2022，12（10）：38.

［38］Zhang S X，Jiang G S，Gao S J，Jin H L，Zhu Y Z，Zhang F，Jin J. Cupric phosphate nanosheets-wrapped inorganic membranes with superhydrophilic and outstanding anticrude oil-fouling property for oil/water separation［J］. ACS Nano，2018，12（1）：795.

［39］He H Q，Liu Y J，Zhu Y M，Zhang T C，Yuan S J. Underoil superhydrophilic CuC2O4@Cu-MOFs core-shell nanosheets-coated copper mesh membrane for on-demand emulsion separation and simultaneous removal of soluble dye［J］. Separation and Purification Technology，2022，293：121089.

［40］Usman J，Othman M H D，Ismail A F，Rahman M A，Jaafar J，Raji Y O，Gbadamosi A O，El Badawy T H，Said K A M. An overview of superhydrophobic ceramic membrane surface modification for oil-water separation［J］. Journal of Materials Research and Technology-Jmr&T，2021，12：643.

［41］（王海霞，王洪建，邱柯卫，宋阳阳，刘营，李文良. 聚醚砜-TiO2复合膜及其水气交换性能研究［J］. 稀有金属，2023，47（9）：1243.）

H X Wang，H J Wang，K W Qiu，Y Y Song，Y Liu，W L Li. Polyether sulfone-TiO2 composite membranes and performances of water-gas exchange［J］. Chinese Journal of Rare Metals，2023，47（9）：1243.

［42］Dong Y C，Wu H，Yang F L，Gray S. Cost and efficiency perspectives of ceramic membranes for water treatment［J］. Water Research，2022，220：118629.

［43］Zhao Y，Gu Y N，Gao G D. Piezoelectricity induced by pulsed hydraulic pressure enables in situ membrane demulsification and oil/water separation［J］. Water Research，2022，215：118245.

［44］Zhou H，Xie J W，Yan F Y，Guo W M，Gao P Z，Qin H，Xiao H N. Porous Al2O3 ceramics with directional gradient pore structure modified by cobweb-bridged WO3 nanowires for oil/water emulsions separation［J］. Ceramics International，2022，48（13）：18753.

［45］Mousa H M，Fahmy H S，Ali G A M，Abdelhamid H N，Ateia M. Membranes for oil/water separation：a review［J］. Advanced Materials Interfaces，2022，9（27）：2200557.

［46］Kang G D，Cao Y M. Application and modification of poly（vinylidene fluoride） （PVDF） membranes-a review［J］. Journal of Membrane Science，2014，463：145.

［47］Yuan S S，Strobbe D，Kruth J P，Van Puyvelde P，Van der Bruggen B. Super-hydrophobic 3D printed polysulfone membranes with a switchable wettability by self-assembled candle soot for efficient gravity-driven oil/water separation［J］. Journal of Materials Chemistry A，2017，5（48）：25401.

［48］Otitoju T A，Ahmad A L，Ooi B S. Recent advances in hydrophilic modification and performance of polyethersulfone （PES） membrane via additive blending［J］. RSC Advances，2018，8（40）：22710.

［49］Kassa S T，Hu C C，Liao Y C，Chen J K，Chu J P. Thin film metallic glass as an effective coating for enhancing oil/water separation of electrospun polyacrylonitrile membrane［J］. Surface & Coatings Technology，2019，368：33.

［50］Lai X，Wang C，Xiao C F，Wang L M，Xin B J. Progress in preparation and application of aromatic polyamide separation membrane［J］. Journal of Textile Research，2021，42（10）：172.

［51］Ma W J，Guo Z F，Zhao J T，Yu Q，Wang F，Han J Q，Pan H，Yao J F，Zhang Q L，Samal S K，De Smedt S C，Huang C B. Polyimide/cellulose acetate core/shell electrospun fibrous membranes for oil-water separation［J］. Separation and Purification Technology，2017，177：71.

［52］Zhu X，Zhu L，Zhang J Q，Li H，Yu S F，Wang R，Yan Z C，Xue J W，Xue Q Z. Robust modified nylon mesh for the separation of crude-oil/water emulsion based on the coupling of squeezing coalescence demulsification and sieving separation［J］. Separation and Purification Technology，2022，295：121319.

［53］Li F R，Wang Z R，Huang S C，Pan Y L，Zhao X Z. Flexible，durable，and unconditioned superoleophobic/superhydrophilic surfaces for controllable transport and oil-water separation［J］. Advanced Functional Materials，2018，28（20）：1706867.

［54］Cheng X Q，Jiao Y，Sun Z K，Yang X B，Cheng Z J，Bai Q，Zhang Y J，Wang K，Shao L. Constructing scalable superhydrophobic membranes for ultrafast water-oil separation［J］. ACS Nano，2021，15（2）：3500.

［55］Wang M L，Yu D G，Bligh S W A. Progress in preparing electrospun Janus fibers and their applications［J］. Applied Materials Today，2023，31：101766.

［56］Qin Y，Shen H，Han L，Zhu Z M，Pan F，Yang S W，Yin X Z. Mechanically robust Janus poly（lactic acid） hybrid fibrous membranes toward highly efficient switchable separation of surfactant-stabilized oil/water emulsions［J］. ACS Applied Materials & Interfaces，2020，12（45）：50879.

［57］Jin K L，Hou K R，Wang J，Zhai S X，Fan Z Z，Zhao Y P，Xie K L，Cai Z S，Feng X S. Composite membranes with multifunctionalities for processing textile wastewater：simultaneous oil/water separation and dye adsorption/degradation［J］. Separation and Purification Technology，2023，320：124176.

［58］Che W B，Zhou L Y，Zhou Q R，Xie Y J，Wang Y G. Flexible Janus wood membrane with asymmetric wettability for high-efficient switchable oil/water emulsion separation［J］. Journal of Colloid and Interface Science，2022，629（Pt B）：719.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY24090027

Chinese Library Classification Number:X-1

Citation Information:

Oil-water emulsion is a stable colloidal dispersion made of microscopic droplets dispersed in an immiscible continuous phase，which is widely used in the fields of petrochemicals，food processing，clinical pharmaceuticals，and cosmetics production. Generally，oil-water emulsion is obtained from wastewater，and if it is discharged without proper treatment，it will cause great harm to life and the environment. Compared with traditional separation technology，membrane separation technology has several advantages，such as high separation efficiency，no phase change，low energy consumption，low cost，and simple device，thus becoming the researchers' first choice to treat oily wastewater. Common two-dimensional demulsification separation membrane materials have the unique advantages of uniform pore size，high demulsification efficiency，and controllable wettability，which can realize efficient demulsification and separation of oil-water emulsion through the synergistic effect of nanopores and surface properties. This review firstly classified and introduced the demulsification mechanism of the demulsification materials. Demulsification mechanisms could be divided into four main categories：sieving demulsification，physical demulsification，chemical demulsification，and electrostatic demulsification. Sieving demulsification used the pore size of the material to screen the droplets，and then intercepted them into a narrow space to contact each other and combine，which ultimately separated the droplets of emulsion，with a smaller pore size，wettability with numerous different advantages. Physical demulsification used a particular form of the material （various micro and nanostructures） or irregular pores on the emulsion droplets to physically destroy the droplets，leading to the deformation and destabilization of the emulsion. Chemical demulsification was the use of chemical components on the substrate or chemical demulsifiers and oil droplets or surfactants to react，reducing the stability of the oil/water boundary membrane，to break the emulsion. Electrostatic demulsification was based on the electrostatic interactions between charged substances and charged droplets to destabilize droplets for demulsification，which was usually defined as the charge shielding effect，and had the advantages of simplicity，rapidity，and non-introduction of external contaminants. Secondly，the design principles and critical parameters of two-dimensional demulsification separation membrane materials were described in detail. The design principles mainly included：（1） selection of a suitable demulsification mechanism，when designing membrane materials，the characteristics of specific emulsions should be considered comprehensively，and the appropriate demulsification mechanism should be selected according to the desired demulsification effect；（2） good hydrophilic and hydrophobic properties，so that the membrane material could be adsorbed at the oil/water interface，reduced the interfacial tension，and promoted the aggregation，fragmentation and separation of oil droplets in the emulsion；（3） good biodegradability and environmental friendliness，could be biodegraded in the natural environment，and would not cause pollution or harm to the environment. Important design parameters included，but were not limited to：pore size，porosity，surface properties，material morphology，particle size，and chemical composition. Finally，four types of two-dimensional demulsification separation membrane materials and the corresponding typical cases were comprehensively reviewed. Two-dimensional demulsification membrane materials could be classified into metal-based membranes，inorganic oxide membranes，electrostatically spun polymer membranes，and biomass-based fiber membranes according to the different membrane-forming materials. Through in-depth analysis and discussion of the cutting-edge research in this field，it aimed to provide references and help for the related research，promote the development of oil-water emulsion wastewater treatment technology，and realize efficient and environmentally friendly wastewater treatment and resource recovery.