膜科学与技术

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

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.

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

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