PVA-PAA/PTFE复合膜的制备及其在MD中浓缩垃圾渗滤液的研究 |
作者:李志霞,谢松辰,晋墩尚,宋旭峰,彭跃莲 |
单位: 北京工业大学 环境与生命学部,北京 100124 |
关键词: Janus复合膜;DCMD;耐污染;垃圾渗滤液 |
DOI号: |
分类号: TQ 028 |
出版年,卷(期):页码: 2022,42(4):96-104 |
摘要: |
膜蒸馏(MD)由于受浓差极化影响小,有望在浓盐水的深度浓缩中发挥作用,但它在实际运行过程中面临膜污染和润湿的问题。本研究采用旋涂法在商用疏水性聚四氟乙烯(PTFE)膜上涂覆一层亲水性皮层,制备了一种Janus复合膜。该皮层由聚乙烯醇(PVA)和聚丙烯酸(PAA)通过高温脱水缩合而成,在热水中性质稳定,具有较强的耐污染能力。Janus复合膜具有不对称的润湿性,PTFE膜表面呈疏水性,空气中水接触角为144.3°;涂层在空气中亲水,水接触角为59.1°,水下憎油。用含500 mg/L腐殖酸(HA)、14.7 mM硫酸钙(CaSO4)以及各自添加氯化钠(NaCl)的溶液作为进料液在直接接触式膜蒸馏(DCMD)中研究有机污染和无机结垢过程。在浓缩实际垃圾渗滤液3倍时,复合膜通量在17.6 kg/m2·h,较PTFE基膜更加稳定;冷凝液电导率低于3 μS/cm,表明制得的Janus复合膜在处理垃圾渗滤液方面具有一定的应用潜力。 |
Membrane distillation (MD) is expected to play a role in the concentration of brine due to little influence by concentration polarization, but it faces the problems of membrane fouling and wetting in actual operation. In this study, a Janus composite membrane was prepared by spin coating a hydrophilic skin layer on a commercial hydrophobic polytetrafluoroethylene (PTFE) membrane. The skin layer was made of polyvinyl alcohol (PVA) and polyacrylic acid (PAA) through high-temperature dehydration condensation. It was stable in hot water and had good anti-fouling ability. The Janus composite membrane had asymmetric wettability. The coating was hydrophilic in the air, water contact angle was 59.1° and oil repellent underwater. The organic fouling and inorganic scaling processes were investigated using 500 mg/L humic acid (HA), 14.7 mM calcium sulfate (CaSO4), and sodium chloride (NaCl) as feed solutions. The Janus membrane was used in concentrating actual landfill. When the concentration factor was three, a stable flux of 17.6 kg/m2·h, and the permeate conductivity of 3 μS/cm could be got, indicating that the prepared Janus composite membrane had application potential in the process of landfill leachate treatment. |
基金项目: |
国家自然科学基金项目(21878005) |
作者简介: |
李志霞(1995-),女,内蒙古乌兰察布人,硕士研究生,主要从事膜材料改性和膜制备研究 |
参考文献: |
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