关键词: 静电纺丝, 光热材料, 聚苯胺, 膜蒸馏, 印染废水

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