Fiber-Based Gas Filter Assembled via In Situ Synthesis of ZIF-8 Metal Organic Frameworks for an Optimal Adsorption of SO2: Experimental and Theoretical Approaches

For environmental protection from exposure to airborne toxic gases, metal organic frameworks (MOFs) have drawn great attention as gas adsorbent options, with their advantages in chemical tailorability and large porosity. To develop a fiber-based gas filter that is effective against SO2 gas, zeolite imidazole framework-8 (ZIF-8) was applied to polypropylene nonwoven by various methods. Among the tested methods, the sol-gel impregnation method showed the highest ZIF-8 loading efficiency. There existed an optimal loading of ZIF-8 for the maximum adsorption efficiency, and it was associated with the accessibility of gas molecules to the ZIF-8 pores and active sites. Dominant adsorption processes and mechanisms were investigated by fitting the theoretical sorption models to experimental data. The results demonstrate that the increased ZIF-8 loading to fibers, beyond a certain level, may hinder the diffusivity and increase the barrier effect, eventually decreasing the adsorption efficiency. This study is novel and significant in that a multifaceted approach, including experimental analysis, theoretical investigation, and computational modeling, was made for scrutinizing the intricate phenomena occurring in the gas sorption process. The results of this study provide the fundamental yet practical information on the manufacturing considerations for the optimal design of MOF-loaded fibrous adsorbents.