Fabrication of polyvinylidene fluoride blending membranes filled by La-TiO2-reduced graphene oxide with photocatalytic activity
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摘要: 为提高聚偏氟乙烯(PVDF)超滤膜的通量及抗污染性能，首先利用吸附相反应技术耦合乙醇热处理制备La掺杂TiO2-还原氧化石墨烯(La-TiO2-RGO)，再将其与PVDF共混制备La-TiO2-RGO/PVDF抗污染超滤膜。结果表明，均匀分散于PVDF高分子中表面亲水的La-TiO2-RGO增多，La-TiO2-RGO/PVDF共混膜的水通量和抗污染性能也显著提升。当La-TiO2-RGO/PVDF共混膜中出现团聚体，则会削弱其膜通量和抗污染性。在La-TiO2-RGO填充量(与PVDF质量比)为2.0%时，La-TiO2-RGO/PVDF共混膜具有最优纯水通量。La-TiO2-RGO/PVDF共混膜最高纯水通量可达171.5 L·m−2·h−1，是PVDF膜的5倍以上，其通量衰减速率也明显低于PVDF膜。另外，由于La-TiO2-RGO具有可见光催化活性，被污染后的La-TiO2-RGO/PVDF共混膜经过光照处理后用水清洗，其膜通量恢复率较直接用水清洗后的通量恢复率大幅提高；热处理温度升高，La-TiO2-RGO弱可见光活性增强，光照后La-TiO2-RGO/PVDF共混膜通量恢复率变大。但过高热处理温度抑制了La-TiO2-RGO中Ti3+形成，且削弱其光活性，La-TiO2-RGO/PVDF共混膜通量恢复率反而下降；对于La-TiO2-RGO填充量为2.0%的La-TiO2-RGO/PVDF共混膜，被污染后分别采用直接水清洗、仅光照处理2 h、先光照处理2 h后水清洗的膜通量恢复率分别为79.28%、52.42%、90.01%。
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关键词:
- 聚偏氟乙烯(PVDF)共混膜 /
- 抗污染性 /
- 通量恢复率 /
- 弱可见光催化活性 /
- La掺杂TiO2-还原氧化石墨烯
Abstract: To improve the flux and antifouling performance of polyvinylidene fluoride (PVDF) ultrafiltration membrane, La doped TiO2-reduced graphene (La-TiO2-RGO) was first synthesized by the adsorption phase reaction coupled with alcohol solvothermal reduction processes. Followed that, La-TiO2-RGO was blended with PVDF to fabricate a La-TiO2-RGO/PVDF ultrafiltration membrane with high anti-fouling performance. The results show that the water flux and antifouling performance of the La-TiO2-RGO/PVDF blending membrane increase, when more well-distributed La-TiO2-RGO with hydrophilic groups added. The aggregations generate in the La-TiO2-RGO/PVDF blending membranes will depress their water flux and antifouling performance. When the loading content (mass ratio to PVDF) of La-TiO2-RGO is 2.0%, the La-TiO2-RGO/PVDF blending membrane has the best pure water flux. The optimum pure water flux of the La-TiO2-RGO/PVDF blending membrane reaches 171.5 L·m−2·h−1, which is 5 times as high as that of the PVDF membrane. And the flux decay rate of the La-TiO2-RGO/PVDF blending membrane is significantly lower than that of the PVDF membrane. The flux recovery of the contaminated La-TiO2-RGO/PVDF blending membrane treated by illumination then washing is obviously higher than that just treated by washing, due to the addition of La-TiO2-RGO with photocatalytic activity. The increase in the solvothermal temperature enhances the photocatalytic activity of La-TiO2-RGO, thus improving the flux recovery rate of the La-TiO2-RGO/PVDF membranes after light irradiation. However, too high solvothermal temperature inhibites the formation of Ti3+ in La-TiO2-RGO, which weakens its photoactivity and decreases the flux recovery rate of the resulting La-TiO2-RGO/PVDF blending membranes. For the La-TiO2-RGO/PVDF blending membrane filled with La-TiO2-RGO loading of 2.0%, the flux recovery rates of contaminated membrane are 79.28%, 52.42% and 90.01%, respectively, after washing, illumination for 2 h and illumination for 2 h then washing. -
图 1 不同温度热处理后La-TiO2-RGO的HRTEM图像(内插图为TEM图像)
Figure 1. HRTEM images of La-TiO2-RGO treated by solvothermal reduction under different temperatures (Inset are TEM images)
图 2 不同温度热处理后La-TiO2-RGO的XRD图谱
Figure 2. XRD patterns of La-TiO2-RGO treated by solvothermal reduction under different temperatures
图 3 不同温度热处理后La-TiO2-RGO的FTIR图谱
Figure 3. FTIR spectra of La-TiO2-RGO treated by solvothermal reduction under different temperatures
图 4 不同温度热处理后La-TiO2-RGO的XPS图谱
Figure 4. XPS spectra of La-TiO2-RGO treated by solvothermal reduction under different temperatures
图 5 不同温度热处理后La-TiO2-RGO可见光激发光电流响应曲线
Figure 5. Visible light excitation photocurrent response curves of La-TiO2-RGO treated by solvothermal reduction under different temperatures
图 6 PVDF膜和La-TiO2-RGO/PVDF共混膜表面的SEM图像
Figure 6. SEM images of surface of PVDF membrane and La-TiO2-RGO/PVDF blending membranes
图 7 PVDF膜和La-TiO2-RGO/PVDF共混膜断面的SEM图像
Figure 7. SEM images of cross-section of PVDF membrane and La-TiO2-RGO/PVDF blending membranes
图 8 光照对PVDF膜和La-TiO2-RGO(170)/PVDF-2混合膜通量衰减过程的影响
Figure 8. Effect of irradiation on flux decay process of PVDF membrane and La-TiO2-RGO(170)/PVDF-2 blending membrane
图 9 PVDF膜和及La-TiO2-RGO/PVDF共混膜的抗污染性能
Figure 9. Anti-fouling performance of PVDF membrane and La-TiO2-RGO/PVDF blending membranes
表 1 La-TiO2-还原氧化石墨烯(RGO)/聚偏氟乙烯(PVDF)共混膜各组分含量
Table 1. Contents of components of La-TiO2-reduced graphene oxide(RGO)/ polyvinylidene fluoride(PVDF) blending membranes
Membrane La-TiO2-RGO VDMAc/
mLMass of
PVDF/gMass of
PEG2000/gMass ratio of La-TiO2-
RGO to PVDF/%Emax/
MPaPVDF — 50 7.5 2.5 0 75.3 La-TiO2-RGO(160)/PVDF-1 La-TiO2-RGO(160) 50 7.5 2.5 1.0 86.7 La-TiO2-RGO(160)/PVDF-2 La-TiO2-RGO(160) 50 7.5 2.5 2.0 98.9 La-TiO2-RGO(160)/PVDF-3 La-TiO2-RGO(160) 50 7.5 2.5 3.0 88.1 La-TiO2-RGO(170)/PVDF-1 La-TiO2-RGO(170) 50 7.5 2.5 1.0 87.2 La-TiO2-RGO(170)/PVDF-2 La-TiO2-RGO(170) 50 7.5 2.5 2.0 101.1 La-TiO2-RGO(170)/PVDF-3 La-TiO2-RGO(170) 50 7.5 2.5 3.0 89.5 Notes: Emax—Maximum tensile strength of membrane; La-TiO2-RGO(160)/PVDF-(1/2/3)—Blending membrane in which mass ratio of La-TiO2-RGO(160) to PVDF is 1%, 2%, 3%, respectively, La-TiO2-RGO(170)/PVDF-(1/2/3) is also understood like this; VDMAc—Volume of N,N-dimethyl acetamide. 
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表 2 PVDF膜和La-TiO2-RGO/PVDF共混膜的孔隙结构、表面亲水角和膜通量
Table 2. Porosities, mean pore sizes, water contact angles and flux of PVDF membrane and La-TiO2-RGO/PVDF blending membranes
Membrane Porosity/% Mean pore size/nm Water contact angle/(°) Jw/(L·m−2·h−1) Jp/(L·m−2·h−1) PVDF 30.2 35.1 91.3 37.9 7.4 La-TiO2-RGO(160)/PVDF-1 61.3 51.5 66.7 145.3 31.5 La-TiO2-RGO(160)/PVDF-2 71.1 62.3 65.3 169.2 39.6 La-TiO2-RGO(160)/PVDF-3 68.8 49.7 61.2 119.1 22.4 La-TiO2-RGO(170)/PVDF-1 65.3 57.2 56.4 149.2 33.4 La-TiO2-RGO(170)/PVDF-2 70.7 65.3 55.8 171.5 42.8 La-TiO2-RGO(170)/PVDF-3 69.7 59.7 58.9 155.1 38.7 Notes: Jw—Water flux; Jp—Bull serum albumin (BSA) flux.
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表 3 PVDF膜和La-TiO2-RGO/PVDF共混膜的抗污染性能
Table 3. Anti-fouling performance of PVDF membrane and La-TiO2-RGO/PVDF blending membranes
Membrane R/% RE/% REr/% PVDF 32.65 14.19 34.86 La-TiO2-RGO(160)/PVDF-1 77.40 34.70 82.22 La-TiO2-RGO(160)/PVDF-2 79.79 48.47 84.51 La-TiO2-RGO(160)/PVDF-3 63.69 33.55 72.09 La-TiO2-RGO(170)/PVDF-1 78.59 43.78 86.00 La-TiO2-RGO(170)/PVDF-2 79.28 52.42 90.01 La-TiO2-RGO(170)/PVDF-3 66.12 40.87 72.81 Notes: R—Flux recovery rate of contaminated membrane after washing; RE—Flux recovery rate after illumination for 2 h; REr—Flux recovery rate after illumination for 2 h then washing.
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[1] 朱振亚, 白成玲, 王磊, 等. 氧化石墨烯-氨基酰化酶/聚偏氟乙烯复合膜的制备及特性[J]. 复合材料学报, 2019, 36(11):2495-2501.ZHU Zhenya, BAI Chengling, WANG Lei, etal. Preparation and characteristic of graphene oxide-acylase/poly(vinylidenefluoride) composite membrane[J]. Acta Materiae Compositae Sinica,2019,36(11):2495-2501(in Chinese). [2] 朱振亚, 白成玲, 王磊, 等. 磺化氧化石墨烯/聚砜复合膜的制备及抗污染性能[J]. 复合材料学报, 2019, 36(11):2515-2521.ZHU Zhenya, BAI Chengling, WANG Lei, et al. Preparation and antifouling property of sulfonated graphene oxide/polysulfone composite membrane[J]. Acta Materiae Compositae Sinica,2019,36(11):2515-2521(in Chinese). [3] 冯雪婷, 杨盛, 文晨, 等. Ag2CO3@PVDF/氧化石墨烯超滤膜及其分离性能[J]. 化工学报, 2017, 68(5):2169-2176.FENG Xueting, YANG Sheng, WEN Chen, et al. Ag2CO3@PVDF/GO ultrafiltration membrane for water purification[J]. CIESC Journal,2017,68(5):2169-2176(in Chinese). [4] VENAULT A, CHOU Y N, WANG Y H, et al. A combined polymerization and self-assembling process for the fouling mitigation of PVDF membranes[J]. Journal of Membrane Science,2018,547:134-145. doi: 10.1016/j.memsci.2017.10.040 [5] SUN C G, FENG X S. Enhancing the performance of PVDF membranes by hydrophilic surface modification via amine treatment[J]. Separation and Purification Technology,2017,185:94-102. [6] OTITOJU T A, AHMAD A L, OOI B S. Polyvinylidene fluoride (PVDF) membrane for oil rejection from oily wastewater: A performance review[J]. Journal of Water Process Engineering,2016,14:41-59. doi: 10.1016/j.jwpe.2016.10.011 [7] MA N, CAO J J, LI H Y, et al. Surface grafting of zwitterionic and PEGylated cross-linked polymers toward PVDF membranes with ultralow protein adsorption[J]. Polymer,2019,167:1-12. [8] RANA D, MATSUURA T. Surface modifications for antifouling membranes[J]. Chemical Reviews,2010,110(4):2448-2471. doi: 10.1021/cr800208y [9] FARAHANIA M H D A, VATANPOUR V. A comprehensive study on the performance and antifouling enhancement of the PVDF mixed matrix membranes by embedding different nanoparticulates: Clay, functionalized carbon nanotube, SiO2 and TiO2[J]. Separation and Purification Technology,2018,197:372-381. doi: 10.1016/j.seppur.2018.01.031 [10] BET-MOUSHOUL E, MANSOURANAH Y, FARHADI K, et al. TiO2 nanocomposite based polymeric membranes: A review on performance improvement for various applications in chemical engineering processes[J]. Chemical Engineering Journal,2016,283:29-46. [11] CHEN F T, SHI X X, CHEN X B, et al. Preparation and characterization of amphiphilic copolymer PVDF-g-PMABS and its application in improving hydrophilicity and protein fouling resistance of PVDF membrane[J]. Applied Surface Science,2018,427:787-797. doi: 10.1016/j.apsusc.2017.08.096 [12] YUAN H K, REN J. Preparation of poly(vinylidene fluoride) (PVDF)/acetalyzed poly(vinyl alcohol) ultrafiltration membrane with the enhanced hydrophilicity and the anti-fouling property[J]. Chemical Engineering Research and Design,2017,121:348-359. doi: 10.1016/j.cherd.2017.03.023 [13] LIU F, XU Y Y, ZHU B K, et al. Preparation of hydrophilic and fouling resistant poly(vinylidene fluoride) hollow fiber membranes[J]. Journal of Membrane Science,2009,345(1-2):331-339. doi: 10.1016/j.memsci.2009.09.020 [14] 李妍, 周晓吉, 沈舒苏, 等. 一种两亲性共聚物的合成及其对 PVDF膜的改性研究[J]. 膜科学与技术, 2016, 36(6):70-77.LI Yan, ZHOU Xiaoji, SHEN Shusu, et al. Synthesis of a new type of amphiphilic copolymer and its effects on the properties of the modified poly-vinylidene fluoride membrane[J]. Membrane Science and Technology,2016,36(6):70-77(in Chinese). [15] HEGAB H M, ZOU L. Graphene oxide-assisted membranes: Fabrication and potential applications in desalination and water purification[J]. Journal of Membrane Science,2015,484:95-106. doi: 10.1016/j.memsci.2015.03.011 [16] ONG C S, GOH P S, LAU W J, et al. Nanomaterials for biofouling and scaling mitigation of thin film composite membrane: A review[J]. Desalination,2016,393:2-15. doi: 10.1016/j.desal.2016.01.007 [17] XU Z W, WU T F, SHI J, et al. Photocatalytic antifouling PVDF ultrafiltration membranes based on synergy of graphene oxide and TiO2 for water treatment[J]. Journal of Membrane Science,2016,520:281-293. doi: 10.1016/j.memsci.2016.07.060 [18] DAMODAR R A, YOU S J, CHOU H H. Study theself cleaning, antibacterial and photocatalytic properties of TiO2 entrapped PVDF membranes[J]. Journal of Hazardous Materials,2009,172(2-3):1321-1328. doi: 10.1016/j.jhazmat.2009.07.139 [19] MOGHADAM M T, LESAGE G, MOHAMMADI T, et al. Improved antifouling properties of TiO2/PVDF nanocomposite membranes in UV-coupled ultrafiltration[J]. Journal of Applied Polymer Science,2015,132(21):41731. [20] LIAO C J, YU P, ZHAO J Q, et al. Preparation and characterization of NaY/PVDF hybrid ultrafiltration membranes containing silver ions as antibacterial materials[J]. Desalination,2011,272(1-3):59-65. [21] WU L G, ZHANG X Y, WANG T, et al. Enhanced performance of polyvinylidene fluoride ultrafiltration membranes by incorporating TiO2/graphene oxide[J]. Chemical Engineering Research and Design,2019,141:492-501. [22] 许智勇, 李冰蕊, 潘家豪, 等. TiO2复合催化剂弱光催化降解模拟海水中苯酚及其催化活性的影响[J]. 环境科学学报, 2017, 37(12):4593-4601.XU Zhiyong, LI Bingrui, PAN Jiahao, et al. Photodegradation of phenol in artificial seawater by TiO2 composite catalysts under weak UV irradiation[J]. Acta Scientiae Circumstantiae,2017,37(12):4593-4601(in Chinese). [23] LI J F, XU Z L, YANG H. Microporous polyethersulfone membranes prepared under the combined precipitation conditions with non-solvent additives[J]. Polymers for Advanced Technologies,2008,19(4):251-257. doi: 10.1002/pat.982 [24] FENG C S, SHI B L, LI G M, et al. Preparation and properties of microporous membrane from poly(vinylidene fluoride-co-tetrafluoroethylene) (F2.4) for membrane distillation[J]. Journal of Membrane Science,2004,237(1-2):15-24. doi: 10.1016/j.memsci.2004.02.007 [25] WANG T, ZHANG Y L, PAN J H, et al. Hydrothermal reduction of commercial P25 photocatalysts to expand their visible-light response and enhance their performance for photodegrading phenol in high-salinity wastewater[J]. Applied Surface Science,2019,480:896-904. doi: 10.1016/j.apsusc.2019.03.052 [26] VATANPOUR V, MADAENI S S, MORADIAN R, et al. Fabrication and characterization of novel antifouling nanofiltration membrane prepared from oxidized multiwalled carbon nanotube/polyethersulfone nanocomposite[J]. Journal of Membrane Science,2011,375(1-2):284-294. [27] SILVA T L S, MORALES-TORRES S, FIGUEIREDO J L, et al. Multi-walled carbon nanotube/PVDF blended membranes with sponge- and finger-like pores for direct contact membrane distillation[J]. Desalination,2015,357:233-245. doi: 10.1016/j.desal.2014.11.025 -
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