烷基硅烷化Silicalite-1分子筛膜的醇水分离性能  

Ethanol Aqueous Solution Separation Performance of Alkylsilane Modified Silicalite-1 Zeolite Membrane

作　　者：赵业昊 吴红丹[1] 周志辉[1] 赵尧 ZHAO Yehao;WU Hongdan;ZHOU Zhihui;ZHAO Yao(College of resources and environmental engineering,Wuhan University of science and technology,Hubei Key Laboratory of Efficient Utilization and Agglomeration of Metallurgical Mineral Resources,Wuhan 430081,China)

机构地区：[1]武汉科技大学资源与环境工程学院,冶金矿产资源高效利用与造块湖北省重点实验室,武汉430081

出　　处：《硅酸盐学报》2024年第7期2275-2285,共11页Journal of The Chinese Ceramic Society

基　　金：湖北省教育厅科学研究计划指导性项目(B2020019)。

摘　　要：Silicalite-1分子筛膜因其疏水特性在低浓度有机物/水分离中得到广泛应用。但膜面硅羟基(Si—OH)的存在会严重影响其分离效果。以Silicalite-1分子筛膜为基膜,表面接枝正辛基三乙氧基硅烷(OTES)来消除Si—OH,进一步改善疏水性,提高其分离能力。系统考察OTES浓度、反应温度和修饰时间对于膜改性效果的影响,分析改性机理,并对比改性前后Silicalite-1分子筛膜的渗透汽化稳定性。结果表明,烷基硅烷的接枝能有效提高膜疏水性、分离性能与长期稳定性。当OTES的质量分数为3%、温度为60℃、时间为10 h时,所制备的膜在70℃分离3.5%±0.1%(质量分数)的乙醇水溶液,膜通量为0.92 kg·m^(–2)·h^(–1),分离因子达到30.4,且能够在连续120 h的渗透汽化过程中,保持良好的稳定性。烷基硅烷接枝优化了Silicalite-1分子筛膜的表面结构,在渗透汽化法回收有机组分领域具有广阔的应用前景。Introduction Silicalite-1 zeolite membrane has a high separation performance due to its hydrophobic properties,which can preferentially permeate organic molecules and effectively block water molecules in aqueous-organic phase mixtures.However,the hydrophilic Si—OH on the surface of Silicalite-1 zeolite membrane is one of the most important reasons for the low hydrophobicity and selectivity of membrane,which preferentially adsorbs water molecules,and easily reacts with ethanol in the solution and generates Si—OC_(2)H_(5) to block the zeolite pores.To solve the problems above,the n-octyltriethoxysilane (OTES) was grafted onto the surface of Silicalite-1 zeolite membrane to eliminate Si—OH,further improving hydrophobicity and separation ability of the membrane.The effects of mass fraction of OTES,reaction temperature and modification time on the membrane modification were investigated.The modification mechanism was analyzed,and the pervaporation stability of Silicalite-1 zeolite membrane before and after modification was compared.Methods A molar ratio of precursor solution was n(TEOS):n(TPAOH):n(H_(2)O):n(Na OH) of 1.00:0.05:75.00:0.03.Silicalite-1 zeolite with a particle size of 400 nm was used as seeds to prepare Silicalite-1 zeolite membranes by a secondary growth method.The membranes were hydrothermally crystallized at 175℃for 8 h.After washing,the membranes were calcined at 550℃for 4 h to remove the template,obtaining silicalite-1 zeolite membranes.Silicalite-1 zeolite membranes were placed in a solution with OTES as a solute and toluene as a solvent at different mass fractions of 1%–5%,and modified at 20–100℃for 5–20 h.The membranes were washed with anhydrous ethanol to remove the residual solvent,and finally dried at 80℃for 12 h to obtain the OTES@Silicalite-1 zeolite membranes.The separation performance of OTES@Silicalite-1 zeolite membranes was tested by a laboratory homemade pervaporation device.The membrane flux was calculated via a weighing method,the separation factor was analyzed wi

关 键 词：Silicalite-1分子筛膜 烷基硅烷 接枝改性 醇水分离 渗透汽化 

分 类 号：TQ028[化学工程]