為了生產純淨水，海水淡化過程中的超疏水薄膜扮演著關鍵的角色，它能顯著地減少薄膜蒸餾中的潤濕和結垢問題。然而，傳統的超疏水膜通常使用奈米材料和高毒性溶劑來製備，對自然環境造成了嚴重的負面影響。本研究的目的是利用環保的磷酸三乙酯（TEP）溶劑來製備薄膜，並採用最新的噴霧輔助非溶劑誘導相分離（SANIPS）方法來製造聚偏二氟乙烯（PVDF）超疏水薄膜。意外的是，在SANIPS方法下，使用PVDF/TEP和PVDF/n-甲基-2-吡咯烷酮（NMP）塗料系統製備的薄膜展示出截然不同的形態和疏水性。然而，在新生膜上噴水45秒後，成功製備了水接觸角（WCA）為154°且具有自清潔特性的PVDF超疏水薄膜。此外，我們也對PVDF/TEP系統中SANIPS方法的成膜機制進行了系統性的分析。最後，通過直接接觸膜蒸餾（DCMD）處理10 wt% NaCl高鹽度溶液，評估了超疏水薄膜的性能。超疏水薄膜表現出比傳統的非溶劑誘導相分離（NIPS）膜更高的通量（22與12 kg/m2 h），並且在100個小時長期測試中展現出穩定的性能。這些結果證明了在SANIPS方法中使用TEP製備用於海水和廢水薄膜蒸餾的超疏水膜的潛力，並且具有出色的性能和環境友善性。

To produce clean water from seawater desalination, superhydrophobic membranes are essential for membrane distillation to minimize wetting. However, superhydrophobic membranes are often prepared using nanomaterials and highly toxic solvents, posing significant concerns to the environment. This study has explored the use of triethyl phosphate (TEP) as a green solvent to fabricate PVDF membranes by the recently invented spray-assisted nonsolvent induced phase separation (SANIPS) method. Surprisingly, membranes fabricated from PVDF/TEP and PVDF/n-methyl-2-pyrrolidone (NMP) dope systems under SANIPS exhibited quite different morphology and hydrophobicity. Nevertheless, a superhydrophobic PVDF membrane with a water contact angle (WCA) of 154˚ and self-cleaning properties was successfully produced by spraying water on the nascent membrane for 45 seconds before completing phase inversion. The mechanism of SANIPS in the PVDF/TEP system was thoroughly investigated. The resultant superhydrophobic membrane was evaluated by direct contact membrane distillation (DCMD) to treat a high salinity solution of 10 wt% NaCl and showed a much higher flux than the nonsolvent induced phase separation (NIPS) membrane (i.e., 22 vs. 12 kg/m2 h). In addition, it exhibited stable long-term performance. These results demonstrate the potential of using TEP in SANIPS to produce superhydrophobic membranes for membrane distillation of seawater and wastewater with improved performance and environmental sustainability.

[1] M. Salehi, Global water shortage and potable water safety; Today's concern and tomorrow's crisis, Environ. Int. 158 (2022) 7.
[2] M. Laqbaqbi, M. García-Payo, M. Khayet, J. El Kharraz, M. Chaouch, Application of direct contact membrane distillation for textile wastewater treatment and fouling study, Sep. Purif. Technol. 209 (2019) 815-825.
[3] L.L. Zhu, M.M. Gao, C.K.N. Peh, G.W. Ho, Recent progress in solar-driven interfacial water evaporation: Advanced designs and applications, Nano Energy 57 (2019) 507-518.
[4] A. Deshmukh, C. Boo, V. Karanikola, S.H. Lin, A.P. Straub, T.Z. Tong, D.M. Warsinger, M. Elimelech, Membrane distillation at the water-energy nexus: limits, opportunities, and challenges, Energy Environ. Sci. 11(5) (2018) 1177-1196.
[5] P. Tao, G. Ni, C.Y. Song, W. Shang, J.B. Wu, J. Zhu, G. Chen, T. Deng, Solar-driven interfacial evaporation, Nat. Energy. 3(12) (2018) 1031-1041.
[6] E. Gontarek-Castro, R. Castro-Munoz, M. Lieder, New insights of nanomaterials usage toward superhydrophobic membranes for water desalination via membrane distillation: A review, Crit. Rev. Environ. Sci. Technol. 52(12) (2022) 2104-2149.
[7] D. Zou, Y.M. Lee, Design strategy of poly(vinylidene fluoride) membranes for water treatment, Prog. Polym. Sci. 128 (2022) 31.
[8] H. Chamani, J. Woloszyn, T. Matsuura, D. Rana, C.Q. Lan, Pore wetting in membrane distillation: A comprehensive review, Prog. Mater. Sci. 122 (2021) 43.
[9] E. Curcio, E. Drioli, Membrane distillation and related operations—a review, Sep. Purif. Rev. 34(1) (2005) 35-86.
[10] L. Eykens, K. De Sitter, C. Dotremont, L. Pinoy, B. Van der Bruggen, Membrane synthesis for membrane distillation: A review, Sep. Purif. Technol. 182 (2017) 36-51.
[11] H.C. Duong, M. Duke, S. Gray, P. Cooper, L.D. Nghiem, Membrane scaling and prevention techniques during seawater desalination by air gap membrane distillation, Desalination 397 (2016) 92-100.
[12] B.S. Lalia, E. Guillen-Burrieza, H.A. Arafat, R. Hashaikeh, Fabrication and characterization of polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) electrospun membranes for direct contact membrane distillation, J. Membr. Sci. 428 (2013) 104-115.
[13] P. Wang, T.-S. Chung, Recent advances in membrane distillation processes: Membrane development, configuration design and application exploring, J. Membr. Sci. 474 (2015) 39-56.
[14] N. Thomas, M.O. Mavukkandy, S. Loutatidou, H.A. Arafat, Membrane distillation research & implementation: Lessons from the past five decades, Sep. Purif. Technol. 189 (2017) 108-127.
[15] H.C. Duong, A.J. Ansari, R.H. Hailemariam, Y.C. Woo, T.M. Pham, L.T. Ngo, D.T. Dao, L.D. Nghiem, Membrane distillation for strategic water treatment applications: opportunities, challenges, and current status, Curr. Pollut. Rep. 6 (2020) 173-187.
[16] D.M. Warsinger, J. Swarninathan, E. Guillen-Burrieza, H.A. Arafat, J.H. Lienhard, Scaling and fouling in membrane distillation for desalination applications: A review, Desalination 356 (2015) 294-313.
[17] A. Alkhudhiri, N. Darwish, N. Hilal, Membrane distillation: A comprehensive review, Desalination 287 (2012) 2-18.
[18] M.O. Mavukkandy, S.A. McBride, D.M. Warsinger, N. Dizge, S.W. Hasan, H.A. Arafat, Thin film deposition techniques for polymeric membranes- A review, J. Membr. Sci. 610 (2020) 26.
[19] F. Tibi, A. Charfi, J. Cho, J. Kim, Fabrication of polymeric membranes for membrane distillation process and application for wastewater treatment: Critical review, Process Saf. Environ. Prot. 141 (2020) 190-201.
[20] F.E. Ahmed, B.S. Lalia, R. Hashaikeh, A review on electrospinning for membrane fabrication: Challenges and applications, Desalination 356 (2015) 15-30.
[21] J. Ravi, M.H.D. Othman, T. Matsuura, M.R. Bilad, T.H. El-badawy, F. Aziz, A.F. Ismail, M.A. Rahman, J. Jaafar, Polymeric membranes for desalination using membrane distillation: A review, Desalination 490 (2020) 19.
[22] Y.-H. Huang, M.-J. Wang, T.-S. Chung, Zwitterionic poly (sulfobetaine methacrylate-co-acrylic acid) assisted simultaneous anti-wetting and anti-fouling membranes for membrane distillation, Desalination 555 (2023) 116527.
[23] M.O. Aijaz, M.R. Karim, M.H.D. Othman, U.A. Samad, Anti-fouling/wetting electrospun nanofibrous membranes for membrane distillation desalination: A comprehensive review, Desalination 553 (2023) 25.
[24] W. Zhang, Y. Li, J. Liu, B.A. Li, S.C. Wang, Fabrication of hierarchical poly (vinylidene fluoride) micro/nano-composite membrane with anti-fouling property for membrane distillation, J. Membr. Sci. 535 (2017) 258-267.
[25] M. Pagliero, A. Bottino, A. Comite, C. Costa, Novel hydrophobic PVDF membranes prepared by nonsolvent induced phase separation for membrane distillation, J. Membr. Sci. 596 (2020) 9.
[26] H.Q. Chang, B.C. Liu, Z.W. Zhang, R. Pawar, Z.S. Yan, J.C. Crittenden, R.D. Vidic, A critical review of membrane wettability in membrane distillation from the perspective of interfacial interactions, Environ. Sci. Technol. 55(3) (2021) 1395-1418.
[27] N.F. Himma, N. Prasetya, S. Anisah, I.G. Wenten, Superhydrophobic membrane: progress in preparation and its separation properties, Rev. Chem. Eng. 35(2) (2019) 211-238.
[28] E. Drioli, A. Ali, F. Macedonio, Membrane distillation: Recent developments and perspectives, Desalination 356 (2015) 56-84.
[29] A. Bratovcic, Different applications of nanomaterials and their impact on the environment, SSRG Int. J. Mater. Sci. and Engineering 5(1) (2019) 1-7.
[30] N.J. Niemuth, B.J. Curtis, M.N. Hang, M.J. Gallagher, D.H. Fairbrother, R.J. Hamers, R.D. Klaper, Next-generation complex metal oxide nanomaterials negatively impact growth and development in the benthic invertebrate Chironomus riparius upon settling, Environ. Sci. Technol. 53(7) (2019) 3860-3870.
[31] K.J. Lu, C.Z. Liang, Y.M.L. Chen, T.S. Chung, Unlock the secret of air blowing in developing high strength and superhydrophobic membranes for membrane distillation, Desalination 527 (2022) 12.
[32] K.J. Lu, D.L. Zhao, Y.M.L. Chen, J. Chang, T.S. Chung, Rheologically controlled design of nature-inspired superhydrophobic and self-cleaning membranes for clean water production, NPJ Clean Water 3(1) (2020) 10.
[33] A. Figoli, T. Marino, S. Simone, E. Di Nicolò, X.-M. Li, T. He, S. Tornaghi, E. Drioli, Towards non-toxic solvents for membrane preparation: a review, Green Chem. 16(9) (2014) 4034-4059.
[34] D. Zou, S.P. Nunes, I.F. Vankelecom, A. Figoli, Y.M. Lee, Recent advances in polymer membranes employing non-toxic solvents and materials, Green Chem. 23(24) (2021) 9815-9843.
[35] F.P. Byrne, S. Jin, G. Paggiola, T.H. Petchey, J.H. Clark, T.J. Farmer, A.J. Hunt, C. Robert McElroy, J. Sherwood, Tools and techniques for solvent selection: green solvent selection guides, Sustain. Chem. Process. 4 (2016) 1-24.
[36] M. Cvjetko Bubalo, S. Vidović, I. Radojčić Redovniković, S. Jokić, Green solvents for green technologies, J. Chem. Technol. Biotechnol. 90(9) (2015) 1631-1639.
[37] J. Chang, J. Zuo, L.L. Zhang, G.S. O'Brien, T.S. Chung, Using green solvent, triethyl phosphate (TEP), to fabricate highly porous PVDF hollow fiber membranes for membrane distillation, J. Membr. Sci. 539 (2017) 295-304.
[38] S. Fadhil, T. Marino, H.F. Makki, Q.F. Alsalhy, S. Blefari, F. Macedonio, E. Di Nicolo, L. Giorno, E. Drioli, A. Figoli, Novel PVDF-HFP flat sheet membranes prepared by triethyl phosphate (TEP) solvent for direct contact membrane distillation, Chem Eng Process. 102 (2016) 16-26.
[39] D.-M. Wang, J.-Y. Lai, Recent advances in preparation and morphology control of polymeric membranes formed by nonsolvent induced phase separation, Curr. Opin. Chem. Eng. 2(2) (2013) 229-237.
[40] M.M. Tao, F. Liu, B.R. Ma, L.X. Xue, Effect of solvent power on PVDF membrane polymorphism during phase inversion, Desalination 316 (2013) 137-145.
[41] S. Nejati, C. Boo, C.O. Osuji, M. Elimelech, Engineering flat sheet microporous PVDF films for membrane distillation, J. Membr. Sci. 492 (2015) 355-363.
[42] J. Chang, J. Zuo, L.L. Zhang, G.S. O'Brien, T.S. Chung, Using green solvent, triethyl phosphate (TEP), to fabricate highly porous PVDF hollow fiber membranes for membrane distillation, J. Membr. Sci. 539 (2017) 295-304.
[43] J.T. Jung, J.F. Kim, H.H. Wang, E. di Nicolo, E. Drioli, Y.M. Lee, Understanding the non-solvent induced phase separation (NIPS) effect during the fabrication of microporous PVDF membranes via thermally induced phase separation (TIPS), J. Membr. Sci. 514 (2016) 250-263.
[44] T.H. Xiao, P. Wang, X. Yang, X.H. Cai, J. Lu, Fabrication and characterization of novel asymmetric polyvinylidene fluoride (PVDF) membranes by the nonsolvent thermally induced phase separation (NTIPS) method for membrane distillation applications, J. Membr. Sci. 489 (2015) 160-174.
[45] H. Strathmann, K. Kock, P. Amar, R. Baker, The formation mechanism of asymmetric membranes, Desalination 16(2) (1975) 179-203.
[46] N. Widjojo, T.S. Chung, Thickness and air gap dependence of macrovoid evolution in phase-inversion asymmetric hollow fiber membranes, Ind. Eng. Chem. Res. 45(22) (2006) 7618-7626.
[47] T. Marino, S. Blefari, E. Di Nicolo, A. Figoli, A more sustainable membrane preparation using triethyl phosphate as solvent, Green Process. Synth. 6(3) (2017) 295-300.
[48] K.-Y. Chan, C.-L. Li, D.-M. Wang, J.-Y. Lai, Formation of porous structures and crystalline phases in poly (vinylidene fluoride) membranes prepared with nonsolvent-Induced phase separation—roles of solvent polarity, Polymers 15(5) (2023) 1314.
[49] Y. Li, C. Jin, Y. Peng, Q. An, Z. Chen, J. Zhang, L. Ge, S. Wang, Fabrication of PVDF hollow fiber membranes via integrated phase separation for membrane distillation, J. Taiwan Inst. Chem. Eng. 95 (2019) 487-494.
[50] H. Karkhanechi, M. Vaselbehagh, S. Jeon, A.R. Shaikh, D.-m. Wang, H. Matsuyama, Preparation and characterization of polyvinylidenedifluoride-co-chlorotrifluoroethylene hollow fiber membranes with high alkaline resistance, Polymer 145 (2018) 310-323.
[51] N. AlQasas, A. Eskhan, D. Johnson, Hansen solubility parameters from surface measurements: A comparison of different methods, Surf. Interfaces 36 (2023) 102594.
[52] L. Yilmaz, A.J. McHugh, Analysis of nonsolvent solvent polymer phase-diagrams and their relevance to membrane formation modeling, J. Appl. Polym. Sci. 31(4) (1986) 997-1018.
[53] C.M. Hansen, Hansen solubility parameters: a user's handbook, CRC press2007.
[54] D.R. Lide, CRC handbook of chemistry and physics, CRC press2004.
[55] M.O. Mavukkandy, M.R. Bilad, J. Kujawa, S. Al-Gharabli, H.A. Arafat, On the effect of fumed silica particles on the structure, properties and application of PVDF membranes, Sep. Purif. Technol. 187 (2017) 365-373.
[56] R. Shimizu, H. Tanaka, A novel coarsening mechanism of droplets in immiscible fluid mixtures, Nat. Commun. 6(1) (2015) 7407.
[57] F. Wang, P. Altschuh, L. Ratke, H.D. Zhang, M. Selzer, B. Nestler, Progress report on phase separation in polymer solutions, Adv Mater. 31(26) (2019) 14.
[58] S. Kooij, R. Skis, M.M. Denn, E. Villermaux, D. Bonn, What Determines the Drop Size in Sprays?, Phys. Rev. X. 8(3) (2018) 13.
[59] M. Yao, L.D. Tijing, G. Naidu, S.-H. Kim, H. Matsuyama, A.G. Fane, H.K. Shon, A review of membrane wettability for the treatment of saline water deploying membrane distillation, Desalination 479 (2020) 114312.
[60] L. Fortunato, Y. Jang, J.-G. Lee, S. Jeong, S. Lee, T. Leiknes, N. Ghaffour, Fouling development in direct contact membrane distillation: Non-invasive monitoring and destructive analysis, Water Res. 132 (2018) 34-41.
[61] T. Horseman, Y.M. Yin, K.S.S. Christie, Z.X. Wang, T.Z. Tong, S.H. Lin, Wetting, scaling, and fouling in membrane distillation: State-of-the-art insights on fundamental mechanisms and mitigation strategies, Acs Es&T Engineering 1(1) (2021) 117-140.
[62] M.R. Choudhury, N. Anwar, D. Jassby, M.S. Rahaman, Fouling and wetting in the membrane distillation driven wastewater reclamation process - A review, Adv. Colloid Interface Sci. 269 (2019) 370-399.