Yamabe Yoshio, Takahashi Naotake, Sawai Jun, Minami Tamotsu, Kikuchi Mikio, Ishii Toshimitsu
Department of Applied Chemistry, Faculty of Engineering, Kanagawa Institute of Technology, 1030 Shimo-Ogino, Atsugi 243-0292, Japan.
Department of Nutrition and Life Science, Faculty of Health and Medical Sciences, Kanagawa Institute of Technology, 1030 Shimo-Ogino, Atsugi 243-0292, Japan.
Membranes (Basel). 2025 Jan 13;15(1):27. doi: 10.3390/membranes15010027.
Iodine, being an important resource, must be recovered and reused. Iodine is not only attracted to the hydrophobic silicone membrane but also easily vaporized. In this study, we explored the use of five types of silicone hollow fiber membrane modules (SFMMs) for separating iodine in the gaseous phase. In the SFMM, iodine gas and the recovery solution (sodium sulfite and sodium carbonate at a concentration of 10 mM each) were flowed outside and inside the silicone hollow fiber, respectively, in a co-current-flow manner. At an iodine gas flow rate of 0.2 L/min (8.4 × 10 mmol-I/L), the capture efficiency of iodine into the SFMM was approximately 100% for all five SFMMs. With increasing feed gas flow rates, the capture efficiency of iodine decreased, reducing to approximately 50% at 0.8 L/min. However, the recovery efficiency of iodine in the recovery solution was 60-30% at 0.2-0.8 L/min. This decrease in capture efficiency with increasing flow rates was because iodine could not spread and diffuse successfully in the SFMM, resulting in a low recovery efficiency of iodine. Thus, we next improved the structure of the SFMM by placing a perforated pipe in the center of the module. The perforated pipe effectively directs the iodine feed gas from the holes in the pipe to the hollow fiber membrane bundle wrapped around the pipe. With the improved SFMM, the capture efficiency markedly increased to approximately 100% in the range of the flow rates tested in our experiments. The recovery efficiency also increased to ≥70%. These data illustrate the potential application of the improved SFMM for recovering iodine in the gaseous phase.
碘作为一种重要资源，必须进行回收再利用。碘不仅会吸附在疏水性硅膜上，而且易于汽化。在本研究中，我们探索了使用五种类型的硅中空纤维膜组件（SFMMs）来分离气相中的碘。在SFMM中，碘气和回收溶液（亚硫酸钠和碳酸钠，浓度均为10 mM）分别以并流方式在硅中空纤维的外侧和内侧流动。在碘气流速为0.2 L/min（8.4×10 mmol-I/L）时，所有五种SFMMs对碘的捕获效率约为100%。随着进料气体流速的增加，碘的捕获效率降低，在0.8 L/min时降至约50%。然而，在0.2 - 0.8 L/min范围内，回收溶液中碘的回收效率为60 - 30%。捕获效率随流速增加而降低的原因是碘无法在SFMM中成功扩散，导致碘的回收效率较低。因此，我们接下来通过在组件中心放置一根穿孔管来改进SFMM的结构。穿孔管有效地将碘进料气体从管中的孔引导至包裹在管周围的中空纤维膜束。使用改进后的SFMM，在我们实验测试的流速范围内，捕获效率显著提高至约100%。回收效率也提高到≥70%。这些数据说明了改进后的SFMM在回收气相中碘方面潜在的应用价值。
