Abstract: Membrane distillation technology is currently a hot research topic in the field of water treatment. To enhance the effectiveness of membrane distillation in the concentration treatment of dyeing wastewater, this paper designed a dual-loaded polyaniline nanofiber membrane to increase the proportion of photothermal conversion materials and the surface area of the nanofiber membrane, so as to achieve efficient concentration.
First, nanoscale polyaniline particles were synthesized. Subsequently, a controlled amount of nano-sized polyaniline was incorporated into the polyacrylonitrile spinning solution, and polyaniline-doped nanofiber membranes were obtained through electrospinning. These polyaniline-doped nanofiber membranes were then immersed in an aniline solution, followed by the addition of ammonium persulfate to facilitate in-situ polymerization on the nanofiber surface, and the grafting and growth of polyaniline. This resulted in the formation of dual-loaded polyaniline nanofiber membranes. This dual-loading approach increases the polyaniline content in the photothermal material, thereby enhancing the photothermal effect and ultimately boosting the efficiency of membrane distillation.
The results showed that the prepared dual-loaded polyaniline nanofiber membrane exhibited excellent morphology, with the surface-loaded polyaniline evenly distributed. The dual loading significantly increased the polyaniline content in the nanofiber membrane matrix and enhanced the membrane surface area, leading to a substantial improvement in light absorption intensity and photothermal conversion efficiency. Under one solar intensity, the membrane surface temperature could rapidly rise to over 70 ℃ within 5 minutes, demonstrating excellent photothermal conversion performance. Further water evaporation tests revealed that under the dual polyaniline photothermal effect, the highest water evaporation rate reached 1.66 kg/(m2·h), higher than that of similar membrane distillation materials. Finally, a solar membrane distillation concentration experiment was conducted on the dye wastewater. The continuous 14-day experiment showed that the total water evaporation reached 51.8%, and the residual dye concentration increased to 453 mg/L. Meanwhile, the membrane exhibited good stability during use, with a decrease in water evaporation rate of only 5.6 % before and after use, and the water evaporation rate of the regenerated membrane still reached 1.60 kg/(m2·h), demonstrating good antipollution and recycling performance.
The above research results indicate that the dual-loaded polyaniline nanofiber membrane exhibits superior water evaporation efficiency, maintaining continuous and stable evaporation during the prolonged concentration process of dye wastewater, and retains a high evaporation rate even after cleaning. This study provides valuable insights for membrane distillation technology and contributes to the development of innovative membrane materials for distillation applications.

Key words: electrospinning, photothermal materials, polyaniline, membrane distillation, dye wastewater

摘要： 为了增强膜蒸馏对印染废水浓缩处理的效果，设计了双重负载聚苯胺纳米纤维膜，以提高废水蒸发浓缩的效率。首先在聚丙烯腈纺丝液中混合一定量纳米聚苯胺，利用静电纺丝制得聚苯胺掺杂纳米纤维膜，再通过表面接枝生长聚苯胺，形成双重负载聚苯胺纳米纤维膜。结果表明：通过双重负载提高了纳米纤维膜载体中聚苯胺含量且增加了膜的比表面积，其光热转换效应显著提高。一个太阳光强度下膜表面温度可在5 min内迅速升温至70 ℃以上，显示出极好的光热转换性能。水蒸发测试发现，在双重聚苯胺光热转换作用下，该膜最高水蒸发速率达到1.66 kg/(m2·h)。最后针对染料废水进行了浓缩实验，连续14 d的实验表明该膜具有良好的使用稳定性，使用前后水蒸发速率仅降低5.6%。经测试，使用过的膜经过再生处理后水蒸发速率仍达到1.60 kg/(m2·h)，表现出良好的抗污染和循环使用性能。上述研究结果为膜蒸馏技术的发展提供了有意义的参考，有助于新型蒸馏膜材料的开发。

关键词: 静电纺丝, 光热材料, 聚苯胺, 膜蒸馏, 印染废水