以核孔膜为基底疏/亲水复合膜的制备及其DCMD性能研究
作者:唐 娜12,陈乃麟12,项 军12,田桂英12
单位: 1.天津科技大学化工与材料学院,天津300457 2.天津市卤水化工与资源生态化利用重点实验室,天津300457
关键词: 核孔膜;非溶剂致相法;疏水/亲水膜;直接接触式膜蒸馏
分类号: TQ028.8
出版年,卷(期):页码: 2021,41(4):25-34

摘要:
 核孔膜具有孔道可控,耐热,机械强度高,耐酸碱性等优点,相比传统无纺布有更低的传质阻力。因此本文创新性地将核孔膜作为基膜,使用聚偏氟乙烯(PVDF)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂,采用非溶剂致相法制备了PVDF/PET核孔膜复合的疏水/亲水膜,并对复合膜的微观结构,机械性能,亲疏水性,孔隙结构进行深入表征,研究了添加剂浓度和核孔膜孔径对膜微观形态和性能的影响。结果表明:提高LiCl添加剂含量使得铸膜液的黏度增大,膜指状孔结构变小且海绵状结构变紧密,PVDF/PET核孔复合膜的平均剥离力从4.48N下降为1.19 N,孔径从0.1327 μm减少到0.0804 μm,孔隙率从44.65%减少至37.60%;核孔膜孔径增大导致复合膜的机械强度减小。直接接触式膜蒸馏(DCMD)分离性能测试表明PVDF/PET核孔复合膜通量比相同厚度单层PVDF疏水膜通量提升约30%;可稳定运行超过39 h。本文为高通量膜蒸馏用膜制备提供了新思路,具有重要的应用前景。
 Nuclear track membrane generally possesses controllable pores, low heat resistance, high mechanical strength, and high acid/alkali resistance. In contrast to the non-woven fabrics-based membrane, nuclear track membrane displays much lower mass transfer resistance. In this paper, the nuclear track membrane is innovatively used as the base membrane, polyvinylidene fluoride (PVDF) is used as the bulk membrane material using N, N-dimethylacetamide (DMAc) solvent. The PVDF composite membrane is prepared by the non-solvent phase method. The microstructure, mechanical properties, hydrophobic property, and porosity of the composite membrane are discussed in terms of additive LiCl concentration and different nuclear track membranes. The results show that the high concentration of the LiCl additive increases the viscosity of the casting solution, resulting in a finger-like pore structure becomes smaller and the compact sponge structure in the composite membrane. The maximum peel strength of the PVDF/PET nuclear track composite membrane decreases from 4.48 N to 1.19 N, and the pore size decreases from 0.1327 μm to 0.0804 μm, the porosity decreased from 44.65% to 37.60%; the large pore size of the nuclear track membrane reduces the mechanical strength of the composite membrane. DCMD separation test exhibits that the flux of the PVDF composite membrane is about 30% higher than that of a single PVDF hydrophobic membrane at the same thickness; it stably runs 39 h in the stability test. Therefore, this work provides a new idea for high-flux membrane of distillation and shows a great potential to be utilized in the DCMD process.

基金项目:
天津市自然科学基金(18JCZDJC37200)

作者简介:
唐娜(1972-),女,辽宁海城人,博士,教授,博士研究生导师。主要研究方向:膜分离,海卤水资源综合利用。

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