TMCS修饰MFI分子筛膜的制备及乙醇/水分离稳定性的研究

doi:10.11949/0438-1157.20201083

摘要/Abstract

摘要：

采用三甲基氯硅烷（TMCS）作为修饰源对MFI分子筛膜进行表面改性，系统考察了TMCS浓度以及修饰时间对于MFI分子筛膜在分离乙醇/水混合物时的性能影响。SEM、XRD、²⁹Si NMR、FT-IR、接触角实验及分离实验结果表明，TMCS可以与硅羟基反应，嫁接分子筛膜表面，在消除膜表面硅缺陷的同时提高膜的疏水性及膜分离性能的稳定性。随着TMCS浓度以及反应时间的增加，修饰后MFI分子筛膜的通量及分离因子略有下降，但稳定性增强。在TMCS的浓度为0.4%（质量），修饰时间为2 h时，所得到的膜具有最佳渗透汽化分离性能，并可在60℃下分离5%（质量）乙醇/水混合物时保持良好的稳定性。在连续90 h渗透汽化分离过程中，其渗透通量稳定在1.61 kg·m^-2·h^-1 左右，分离因子保持在20以上。

关键词: 沸石, 膜, 渗透蒸发, TMCS, 表面改性, 稳定性

Abstract:

Trimethylchlorosilane (TMCS) was used as the modification source to modify the surface of MFI zeolite membranes. The effect of TMCS concentration and modification time on the performance of MFI zeolite membranes in the separation of ethanol/water mixtures was systematically investigated. Biofuel ethanol is a kind of renewable fuel resource with the characteristics of low carbon and sulfur-free. Pervaporation is considered as a most promising energy-efficient process for ethanol extraction from the fermentation broth containing dilute alcohol. Pure-silica MFI zeolite membrane, also called silicalite-1 membrane, possesses uniform pore size of 0.55 nm and desirable hydrophobicity with the potential to achieve large flux and high separation factor for ethanol over water. However, the significant performance degradation of MFI zeolite membranes in ethanol/water mixture separation is an obstacle to industrial their application. Based on the literature investigation and our previous work, we found that the stability of membrane during pervaporation was affected by the silicon defects in MFI zeolite membranes formed under alkaline synthetic conditions. Herein, we present the Si—OH eliminated MFI membranes by a simple Trimethylchlorosilane (TMCS) modification, which can effectively prevent the chemical reaction between Si—OH groups and components, endowing the long-term pervaporation stability for the ethanol/water mixture. The effects of TMCS content and modification time on the separation performances of membranes were studied, and the obtained membranes were characterized by SEM, XRD,²⁹Si NMR, FT-IR and contact angle measurement. The results show that the surface Si—OH groups can be effectively reduced after the modification, and obtained membranes showed improved hydrophobicity and separation stability. With the increase of silane content and modification time, the obtained MFI zeolite membranes showed decreased initial pervaporation performance but better stability. The zeolite membrane prepared with TMCS content of 0.4%(mass) and the reaction time of 2 h had the best separation performance and also showed a long-term stability for the separation of 5%(mass) ethanol/water mixture at 60℃. During the 90 h pervaporation process, the permeation flux slightly decreased from 1.83 kg·m^-2·h^-1 to 1.61 kg·m^-2·h^-1, and the separation factor decreased from 27 to 20. For the unmodified MFI zeolite membrane, however, the permeation flux dramatically decreased from 3.46 kg·m^-2·h^-1 to 0.6 kg·m^-2·h^-1, and the separation factor decreased from 30 to 3. This study showed that, the surface organic modification can be an effective method to improve the hydrophobicity and separation stability of MFI zeolite membrane.

Key words: zeolite, membranes, pervaporation, TMCS, surface modified, stability

中图分类号:

O 613.72

彭莉, 吴政奇, 王博轩, 王兴, 顾学红. TMCS修饰MFI分子筛膜的制备及乙醇/水分离稳定性的研究[J]. 化工学报, 2021, 72(1): 569-577.

PENG Li, WU Zhengqi, WANG Boxuan, WANG Xing, GU Xuehong. Preparation and stability study of TMCS modified MFI zeolite for ethanol/water separation[J]. CIESC Journal, 2021, 72(1): 569-577.

图/表 14

图1 MFI分子筛膜渗透汽化装置1—MFI molecular sieve membrane; 2—sampling tube; 3—thermometer; 4—vacuum gauge; 5—cold hydrazine; 6—liquid nitrogen tank; 7—drying tower; 8—rotor; 9—water bath heating stirrer; 10—vacuum pump

Fig.1 Schematic diagram of apparatus for MFI zeolite membrane pervaporation

图2 MFI分子筛膜TMCS修饰消除膜表面硅羟基的示意图

Fig.2 Schematic representation of elimination of surface Si—OH groups of MFI zeolite membrane by TMCS modification

图3 MFI及采用不同TMCS浓度溶液修饰后MFI分子筛膜的SEM图

Fig.3 SEM patterns of MFI zeolite membrane after modified by TMCS solutions with different concentration

图4 MFI及采用不同TMCS浓度溶液修饰后MFI分子筛膜的XRD谱图

Fig.4 XRD patterns of MFI zeolite membrane after modified by TMCS solutions with different concentration

表1 不同TMCS浓度溶液修饰前后MFI分子筛膜的渗透汽化性能

Table 1 Pervaporation performance of MFI zeolite membrane after modification in TMCS solutions with different concentration

TMCS含量/%(质量)	修饰前		修饰后
TMCS含量/%(质量)	渗透通量/ (kg·m^-2·h^-1)	分离因子	渗透通量/ (kg·m^-2·h^-1)	分离因子
0.2	3.47	35	2.91	34
0.4	3.66	37	2.16	28
0.6	3.41	35	1.76	21
0.8	3.59	34	1.05	13
1.0	3.29	39	0.62	7

图5 MFI及采用不同TMCS浓度溶液修饰后MFI分子筛膜的渗透汽化性能

Fig.5 The pervaporation performance of MFI zeolite membrane and those after modified in TMCS solutions with different concentration

图6 经不同修饰时间后TMCS修饰MFI分子筛膜的SEM图

Fig.6 SEM images of MFI zeolite membrane after TMCS modification for different time

图7 MFI及经不同修饰时间后的TMCS修饰MFI分子筛膜的XRD谱图

Fig.7 XRD patterns of MFI zeolite membrane and those after TMCS modification for different time

表2 经TMCS不同修饰时间后的MFI分子筛膜的渗透汽化性能

Table 2 Pervaporation performance of MFI zeolite membrane after TMCS modification for different time

修饰时间/h	修饰前		修饰后
修饰时间/h	渗透通量/ (kg·m^-2·h^-1)	分离因子	渗透通量/ (kg·m^-2·h^-1)	分离因子
1	3.29	36	2.94	34
2	3.40	30	1.83	27
3	3.15	34	1.42	14
4	3.24	34	0.97	9

图8 经TMCS修饰不同时间后的MFI分子筛膜的渗透汽化性能示意图

Fig.8 The pervaporation performance of MFI zeolite membrane and those after TMCS modification for different time

图9 修饰前、后MFI分子筛膜接触角结果

Fig.9 Water contact angle of the membranes before and after TMCS modification

图10 TMCS修饰前、后MFI分子筛颗粒的29Si NMR图谱

Fig.10 29Si NMR spectrum of MFI zeolite particles before and after TMCS modification

图11 TMCS修饰前、后MFI分子筛颗粒的傅里叶红外谱图

Fig.11 FT-IR spectrum of the MFI zeolite particles before and after TMCS modification

图12 TMCS修饰前、后MFI分子筛膜的渗透汽化分离稳定性

Fig.12 The stability of MFI zeolite membrane before and after TMCS modification

参考文献 32

1	Aditiya H B, Mahlia T M I, Chong W T, et al. Second generation bioethanol production: a critical review [J]. Renewable & Sustainable Energy Reviews, 2016, 66: 631-653.
2	Kiuchi T, Yoshida M, Kato Y. Energy saving bioethanol distillation process with self-heat recuperation technology [J]. Journal of the Japan Institute of Metals, 2015, 58(3): 135-140.
3	Cao Z Q, Xia C J, Jia W, et al. Enhancing bioethanol productivity by a yeast-immobilized catalytically active membrane in a fermentation-pervaporation coupling process [J]. Journal of Membrane Science, 2020, 595(9): 117485-117493.
4	Bai F W, Anderson W A, Moo-young M. Ethanol fermentation technologies from sugar and starch feedstocks [J]. Biotechnology Advances, 2008, 26(1): 89-105.
5	姚迅, 彭莉, 徐晓涵, 等. 多级孔道ZSM-5分子筛超滤膜的制备[J]. 化工学报, 2017, 68(11): 4351-4358.
	Yao X, Peng L, Xu X H, et al. Fabrication of hierarchical ZSM-5 zeolite membranes for ultrafiltration[J]. CIESC Journal, 2017, 68(11): 4351-4358.
6	任建新. 膜分离技术及其应用 [M]. 北京: 化学工业出版社, 2003: 513.
	Ren J X. Membrane Separation Technology and Application [M]. Beijing: Chemical Industry Press, 2003: 513.
7	徐南平, 邢卫红, 赵宜江. 无机膜分离技术与应用 [M]. 北京: 化学工业出版社, 2003: 347.
	Xu N P, Xing W H, Zhao Y J. Inorganic Membrane Separation Technology and Application [M]. Beijing: Chemical Industry Press, 2003: 347.
8	Chapman P D, Oliveira T, Livingston A G, et al. Membranes for the dehydration of solvents by pervaporation [J]. Journal of Membrane Science, 2008, 318(1/2): 5-37.
9	Vane L M. Separation technologies for the recovery and dehydration of alcohols from fermentation broths [J]. Biofuels, Bioproducts and Biorefining, 2008, 2(6): 553-588.
10	Zheng P Y, Li C, Wang N X, et al. The potential of pervaporation for biofuel recovery from fermentation: an energy consumption point of view [J]. Chinese Journal of Chemical Engineering, 2019, 27(6): 1296-1306.
11	孔晴晴, 张春, 王学瑞, 等. 含氟体系中MFI型分子筛膜的制备及其乙醇/水分离性能 [J]. 化工学报, 2014, 65(12): 5061-5066.
	Kong Q Q, Zhang C, Wang X R, et al. Preparation of MFI zeolite membranes in fluoride media and separation performance for ethanol/water mixture [J]. CIESC Journal, 2014, 65(12): 5061-5066.
12	Wu Z Q, Zhang C, Peng L, et al. Enhanced stability of MFI zeolite membranes for separation of ethanol/water by eliminating surface Si—OH groups [J]. ACS Applied Materials & Interfaces, 2018, 10(4): 3175-3180.
13	Kuhn J, Sutanto S, Gascon J, et al. Performance and stability of multi-channel MFI zeolite membranes detemplated by calcination and ozonication in ethanol/water pervaporation [J]. Journal of Membrane Science, 2009, 339(1/2): 261-274.
14	Yu L, Korelskiy D, Grahn M. Very high flux MFI membranes for alcohol recovery via pervaporation at high temperature and pressure [J]. Separation and Purification Technology, 2015, 153: 138-145.
15	Charlotte A, Jonas H. Effects of exposure to water and ethanol on silicalite-1 membranes [J]. Journal of Membrane Science, 2008, 313(1/2): 120-126.
16	Zapata P A, Huang Y, Gonzalez-borja M A, et al. Silylated hydrophobic zeolites with enhanced tolerance to hot liquid water [J]. Journal of Catalysis, 2013, 308: 82-97.
17	Prodinger S, Derewinski M A, Vjunov A, et al. Improving stability of zeolites in aqueous phase via selective removal of structural defects [J]. Journal of the American Chemical Society, 2016, 138(13): 4408-4415.
18	Zhou H, Korelskiy D, Sjöberg E, et al. Ultrathin hydrophobic MFI membranes [J]. Microporous and Mesoporous Materials, 2014, 192: 76-81.
19	Han X L, Wang L, Li J D, et al. Tuning the hydrophobicity of ZSM-5 zeolites by surface silanization using alkyltrichlorosilane [J]. Applied Surface Science, 2011, 257(22): 9525-9531.
20	Sano T, Hasegawa M, Ejiri S, et al. Improvement of the pervaporation performance of silicalite membranes by modification with a silane coupling reagent [J]. Microporous Materials, 1995, 5(3): 179-184.
21	Kosinov N, Sripathi V G P, Hensen E J M. Improving separation performance of high-silica zeolite membranes by surface modification with triethoxyfluorosilane [J]. Microporous and Mesoporous Materials, 2014, 194: 24-30.
22	Kuwahara Y, Maki K, Kamegawa T, et al. Simple design of hydrophobic zeolite material by modification using tefs and its application as a support of TiO₂ photocatalyst [J]. Topics in Catalysis, 2010, 52(1/2): 193-196.
23	Kuwahara Y, Kamegawa T, Mori K, et al. Fabrication of hydrophobic zeolites using triethoxyfluorosilane and their application as supports for TiO₂ photocatalysts [J]. Chemical Communications, 2008, 39: 4783-4785.
24	Chaouati N, Soualah A, Chater M. Adsorption of phenol from aqueous solution onto zeolites Y modified by silylation [J]. Comptes Rendus Chimie, 2013, 16(3): 222-228.
25	Mhaisagar Y S, Joshi B N, Mahajan A M. Surface texture modification of spin-coated SiO₂ xerogel thin films by TMCS silylation [J]. Bulletin of Materials Science, 2012, 35(2): 151-155.
26	Negishi H, Okamoto M, Sano T, et al. Surface silylation of silicalite membranes and their pervaporation performance for the separation of ethanol from ethanol-water mixtures [J]. Journal of the Ceramic Society of Japan, 2014, 122(1425): 357-360.
27	解林坤, 杜官本, 代沁伶, 等. TMCS等离子体对西南桦木材表面的修饰[J]. 中南林业科技大学学报, 2016, 36(3): 96-100.
	Xie L K, Du G B, Dai Q L, et al. Surface modification of Betula alnoides wood by trimethylchlorosilane plasma [J]. Journal of Central South University of Forestry & Technology, 2016, 36(3): 96-100.
28	Deng L F, Zuo X R, Lu B, et al. Effection of surface modification of silica aerogels with mixed modifier(TMCS/HMDSO) at ambient pressure [J]. Materials Review, 2013, 27(2B): 75-78.
29	李惠云, 郭金福. 有机氯硅烷修饰的介孔SBA-15及其疏水性[J]. 化学世界, 2011, 52(7): 389-392.
	Li H Y, Guo J F. Study on mesoporous SBA-15 modified by organochlorosilane and its hydrophobicity [J]. Chemical World, 2011, 52(7): 389-392.
30	Shu X J, Wang X R, Kong Q Q. High-flux MFI zeolite membrane supported on ysz hollow fiber for separation of ethanol/water [J]. Industrial & Engineering Chemistry Research, 2012, 51(37): 12073-12080.
31	Yuan J J, Zhu P X, Fukazawa N, et al. Synthesis of nanofiber-based silica networks mediated by organized poly(ethylene imine): structure, properties, and mechanism [J]. Advanced Functional Materials, 2006, 16(17): 2205-2212.
32	Khedkar M V, Somvanshi S B, Humbe A V, et al. Surface modified sodium silicate based superhydrophobic silica aerogels prepared via ambient pressure drying process [J]. Journal of Non-Crystalline Solids, 2019, 511: 140-146.

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