MOF in-situ growth modified poly(p-chloromethyl styrene)-polyvinylidene fluoride forward osmosis composite membrane and its anti-fouling performance for emulsified oil wastewater
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摘要: 金属-有机框架(MOF)材料有望提高正渗透(FO)膜的水通量和抗污染性,以提高其对乳化油废水的分离性能。为将MOF引入FO膜,首先通过相转化法制备聚对氯甲基苯乙烯-聚偏氟乙烯(PCMS-PVDF)共混底膜,以底膜中的氯甲基基团(—CH2Cl)为反应位点与2-甲基咪唑(Hmim)中的仲胺或叔胺反应,接着与硝酸锌(Zn(NO3)2)反应,以在膜表面原位生长金属有机骨架沸石咪唑酯骨架-8 (ZIF-8),最后经界面聚合制备抗污染FO复合膜。通过SEM、XPS、FTIR和接触角测定仪等对底膜和FO膜的表面化学结构及膜亲/疏水性能等进行表征。结果表明:ZIF-8均匀生长在PCMS-PVDF底膜表面,且该纳米粒子为形状较规则的立方晶体。由于ZIF-8的存在使底膜表面较疏水,但界面聚合后形成的聚酰胺层重新使膜表面变为亲水。对膜的渗透分离和抗污染性研究表明,在FO模式下,以1 mol/L的NaCl为汲取液时,未经ZIF-8改性的FO膜(PCMS-PVDF-FO)水通量仅为12.4 L·m−2·h−1,而经过ZIF-8改性后的FO膜(ZIF-8/PCMS-PVDF-FO)水通量可达到20.7 L·m−2·h−1。对乳化油模拟废水分离实验表明,经过4次纯水-乳化油分离循环后,正渗透膜ZIF-8/PCMS-PVDF-FO的纯水通量恢复率仍保持在89.9%,总污染率为27.5%;而相同情况下PCMS-PVDF-FO的通量恢复率仅为66.9%,总污染率上升为66.2%。综上,经过ZIF-8原位生长改性的正渗透复合膜在乳化油废水分离方面表现出较优异的性能。Abstract: Metal-organic framework (MOF) material is expected to improve the water flux and antifouling property of forward osmosis (FO) membrane, and improves its separation performance to emulsified oil wastewater. In order to introduce MOF into FO membrane, poly(p-chloromethyl styrene)-polyvinylidene fluoride (PCMS-PVDF) blend substrate was prepared by phase inversion method. The chloromethyl group (—CH2Cl) in the substrate reacted with secondary or tertiary amine in 2-methylimidazole (Hmim), and then reacted with zinc nitrate (Zn(NO3)2). The antifouling FO membrane was prepared by in-situ growth of metal-organic zeolite imidazolium ester skeleton-8 (ZIF-8) and interfacial polymerization. The surface chemical structures and hydrophilic/hydrophobic property of substrate membrane and FO membrane were characterized by SEM, XPS, FTIR, contact angle analyzer and so on. The results show that ZIF-8 grows uniformly on the surface of PCMS-PVDF substrate, and the nanocrystals are cubic crystals with regular shape. Due to the presence of ZIF-8, the substrate surface is hydrophobic, but the new polyamide layer formed by interfacial polymerization makes the membrane surface hydrophilic again. The results show that the water flux of the FO membrane (PCMS-PVDF-FO) without ZIF-8 modification is only 12.4 L·m−2·h−1, but the FO membrane (ZIF-8/PCMS-PVDF-FO) modified with ZIF-8 reach 20.7 L·m−2·h−1 when using 1 mol/L NaCl as the drawing solution in FO mode. The separation experiment of emulsified oil simulated wastewater shows that the recovery ratio of pure water flux of FO membrane (ZIF-8/PCMS-PVDF-FO) is remained 89.9%, the total fouling ratio is 27.5% after running four cycles for pure water-emulsified oil separation. But under the same condition, the flux recovery rate of PCMS-PVDF-FO is only 66.9%, and the total fouling ratio increases to 66.2%. Based on the above, it can be seen that the FO composite membrane modified by in-situ growth of ZIF-8 exhibits excellent performance in emulsified oil wastewater separation.
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图 1 ZIF-8/聚对氯甲基苯乙烯-聚偏氟乙烯正渗透复合膜(ZIF-8/PCMS-PVDF-FO)制备流程示意图
Figure 1. Schematic diagram of preparation process of ZIF-8/poly(p-chloromethyl styrene)-polyvinylidene fluoride forward osmosis composite membrane (ZIF-8/PCMS-PVDF-FO)
Hmim—2-methylimidazole; MPD—m-phenylenediamine; TMC—Trimesoyl chloride; PA—Polyamide
表 1 XPS测定的PCMS-PVDF和ZIF-8/PCMS-PVDF表面元素比重
Table 1. Specific gravity of elements on the surface of membranes PCMS-PVDF and ZIF-8/PCMS-PVDF by XPS determination
Membrane ID C/at% N/at% Cl/at% PCMS-PVDF 99.15 — 0.85 ZIF-8/PCMS-PVDF 93.73 5.94 0.33 表 2 文献报道不同FO膜的正渗透性能
Table 2. Permeability of different FO membrane reported by the literature
Membrane Jw/( L·m−2·h−1) Js/(g·m−2·h−1) Js/Jw/(g·L−1) Ref. ZIF-8/PVDF-PCMS 20.7 3.1 0.15 This work PSU-UiO-66 20.7 4.3 0.21 [26] PES-GO 16.1 7.5 0.47 [27] ZIF-8/PDA/PS* 9.6 3.8 0.40 [28] PES-GQDs@UiO-66-NH2 59.3 19.1 0.32 [29] PSF-UiO-PDA 22.2 5.72 0.26 [30] Notes: Jw—Water flux; Js—Salt flux; PSU-UiO-66—Polysulfon-UiO-66; PES-GO—Polyethersulfone-graphene oxide; ZIF-8/PDA/PS—ZIF-8/poly(dopamine)/polysulfone; PES-GQDs@UiO-66-NH2—Polyethersulfone-graphene quantum dots@UiO-66-NH2; PSF-UiO-PDA—Polysulfone-UiO-66-(COOH)2-poly(dopamine); The draw solution for FO membrane is 1 mol/L NaCl, * represents 1 mol/L MgCl2. -
[1] LEE W J, GOH P S, LAU W J, et al. Antifouling zwitterion embedded forward osmosis thin film composite membrane for highly concentrated oily wastewater treatment[J]. Separation and Purification Technology,2019,214:40-50. doi: 10.1016/j.seppur.2018.07.009 [2] CHAKRABARTY B, GHOSHAL A K, PURKAIT M K. Cross-flow ultrafiltration of stable oilin-water emulsion using polysulfone membranes[J]. Chemical Engineering Journal, 2010, 165(2): 447-456. [3] DAS P, SINGH K K K, DUTTA S. Insight into emerging applications of forward osmosis systems[J]. Journal of Industrial and Engineering Chemistry,2019,72:1-17. doi: 10.1016/j.jiec.2018.12.021 [4] HU B, JIANG M, ZHAO S, et al. Biogas slurry as draw solution of forward osmosis process to extract clean water from micro-polluted water for hydroponic cultivation[J]. Journal of Membrane Science,2019,576:88-95. doi: 10.1016/j.memsci.2019.01.029 [5] LAMBRECHTS R, SHELDON M S. Performance and energy consumption evaluation of a fertiliser drawn forward osmosis (FDFO) system for water recovery from brackish water[J]. Desalination,2019,456:64-73. doi: 10.1016/j.desal.2019.01.016 [6] KIM D I, GWAK G, ZHAN M, et al. Sustainable dewatering of grapefruit juice through forward osmosis: Improving membrane performance, fouling control, and product quality[J]. Journal of Membrane Science,2019,578:53-60. doi: 10.1016/j.memsci.2019.02.031 [7] GONZALES R R, PARK M J, BAE T H, et al. Melamine-based covalent organic framework-incorporated thin film nanocomposite membrane for enhanced osmotic power generation[J]. Desalination,2019,459:10-19. doi: 10.1016/j.desal.2019.02.013 [8] ZHENG K, ZHOU S, ZHOU X. A low-cost and high-performance thin-film composite forward osmosis membrane based on an SPSU/PVC substrate[J]. Scientific Reports,2018,8(1):1-13. [9] WU X, FIELD R W, WU J J, et al. Polyvinylpyrrolidone modified graphene oxide as a modifier for thin film composite forward osmosis membranes[J]. Journal of Membrane Science,2017,540:251-260. doi: 10.1016/j.memsci.2017.06.070 [10] ZHAO X, LI J, LIU C. A novel TFC-type FO membrane with inserted sublayer of carbon nanotube networks exhibiting the improved separation performance[J]. Desalination,2017,413:176-183. doi: 10.1016/j.desal.2017.03.021 [11] XU L, YANG T, LI M, et al. Thin-film nanocomposite membrane doped with carboxylated covalent organic frameworks for efficient forward osmosis desalination[J]. Journal of Membrane Science,2020,610:118111. doi: 10.1016/j.memsci.2020.118111 [12] TIRAFERRI A, KANG Y, GIANNELIS E P, et al. Highly hydrophilic thin-film composite forward osmosis membranes functionalized with surface-tailored nanoparticles[J]. ACS Applied Materials & Interfaces,2012,4(9):5044-5053. [13] ZHENG J, LI M, YU K, et al. Sulfonated multiwall carbon nanotubes assisted thin-film nanocomposite membrane with enhanced water flux and anti-fouling property[J]. Journal of Membrane Science,2017,524:344-353. doi: 10.1016/j.memsci.2016.11.032 [14] LI M P, ZHANG X, ZHANG H, et al. Hydrophilic yolk-shell ZIF-8 modified polyamide thin-film nanocomposite membrane with improved permeability and selectivity[J]. Separation and Purification Technology,2020,247:116990. doi: 10.1016/j.seppur.2020.116990 [15] FU W, CHEN J, LI C, et al. Enhanced flux and fouling resistance forward osmosis membrane based on a hydrogel/MOF hybrid selective layer[J]. Journal of Colloid and Interface Science,2021,585:158-166. doi: 10.1016/j.jcis.2020.11.092 [16] HUNG W S, AN Q F, HU C C, et al. Non-destructive means of probing a composite polyamide membrane for characteristic free volume, void, and chemical composition[J]. RSC Advances,2016,6(88):85019-85025. doi: 10.1039/C6RA16047F [17] BEH J J, OOI B S, LIM J K, et al. Development of high water permeability and chemically stable thin film nanocomposite (TFN) forward osmosis (FO) membrane with poly(sodium 4-styrenesulfonate)(PSS)-coated zeolitic imidazolate framework-8 (ZIF-8) for produced water treatment[J]. Journal of Water Process Engineering,2020,33:101031. doi: 10.1016/j.jwpe.2019.101031 [18] DU C H, ZHANG X Y, WU C J. Chitosan-modified graphene oxide as a modifier for improving the structure and performance of forward osmosis membranes[J]. Polymers for Advanced Technologies,2020,31(4):807-816. doi: 10.1002/pat.4816 [19] 刘和秀, 刘冬林, 周媛, 等. 对氯甲基苯乙烯及其聚合物的合成研究[J]. 广东化工, 2014, 41(22):16-17.LIU Hexiu, LIU Donglin, ZHOU Yuan, et al. Studies on synthesis of 4-chloro-alpha-methylstyrene and its homopolymer[J]. Guangdong Chemical Industry,2014,41(22):16-17(in Chinese). [20] SHAMSAEI E, LOW Z X, LIN X, et al. Rapid synthesis of ultrathin, defect-free ZIF-8 membranes via chemical vapour modification of a polymeric support[J]. Chemical Communications,2015,51(57):11474-11477. doi: 10.1039/C5CC03537F [21] CHIAO Y H, SENGUPTA A, CHEN S T, et al. Zwitterion augmented polyamide membrane for improved forward osmosis performance with significant antifouling characteristics[J]. Separation and Purification Technology,2019,212:316-325. doi: 10.1016/j.seppur.2018.09.079 [22] LINDER-PATTON O M, DE PRINSE T J, FURUKAWA S, et al. Influence of nanoscale structuralisation on the catalytic performance of ZIF-8: A cautionary surface catalysis study[J]. CrystEngComm,2018,20(34):4926-4934. doi: 10.1039/C8CE00746B [23] NAGARAJU D, BHAGAT D G, BANERJEE R, et al. In situ growth of metal-organic frameworks on a porous ultrafiltration membrane for gas separation[J]. Journal of Materials Chemistry A,2013,1(31):8828-8835. doi: 10.1039/c3ta10438a [24] LUO F, WANG J, YAO Z, et al. Polydopamine nanoparticles modified nanofiber supported thin film composite membrane with enhanced adhesion strength for forward osmosis[J]. Journal of Membrane Science,2021,618:118673. doi: 10.1016/j.memsci.2020.118673 [25] LEI Z, DENG Y, WANG C. Multiphase surface growth of hydrophobic ZIF-8 on melamine sponge for excellent oil/water separation and effective catalysis in a Knoevenagel reaction[J]. Journal of Materials Chemistry A,2018,6(7):3258-3263. doi: 10.1039/C7TA10566E [26] MA D, PEH S B, HAN G, et al. Thin-film nanocomposite (TFN) membranes incorporated with super-hydrophilic metal-organic framework (MOF) UiO-66: Toward enhancement of water flux and salt rejection[J]. Applied Materials & Interfaces,2017,9(8):7523-7534. [27] SONG X, ZHANG Y, ABDEL-GHAFAR H M, et al. Polyamide membrane with an ultrathin GO interlayer on macroporous substrate for minimizing internal concentration polarization in forward osmosis[J]. Chemical Engineering Journal,2021,412:128607. doi: 10.1016/j.cej.2021.128607 [28] WANG X P, HOU J W, CHEN F S, et al. In-situ growth of metal-organic framework film on a polydopamine-modified flexible substrate for antibacterial and forward osmosis membranes[J]. Separation and Purification Technology,2019,236:116239. [29] BAGHERZADEH M, BAYRAMI A, AMINI M. Enhancing forward osmosis (FO) performance of polyethersulfone/polyamide (PES/PA) thin-film composite membrane via the incorporation of GQDs@UiO-66-NH2 particles[J]. Journal of Water Process Engineering,2020,33:10110. [30] EGHBALAZAR T, SHAKERI A. High-performance thin-film nanocomposite forward osmosis membranes modified with poly(dopamine) coated UiO66-(COOH)2[J]. Separation and Purification Technology,2021,277:119438. doi: 10.1016/j.seppur.2021.119438