There is a need for the purification of indoor air owing to a high rate of pollution in today’s world. For this, cabin air filters (CAFs) are widely used, which requires the addition of certain adsorbents to increase the volatile organic compound (VOC) removal efficiency. However, this addition causes high-pressure resistance, which may hamper commercial applications by requiring more energy and negatively affecting fresh air delivery rate. Hence, in this study, a high-performance combined CAF (CCAF) with excellent dust and chemical filtration performance and low differential pressure was prepared using granular activated carbon (GAC)/activated carbon fiber (ACF) mixed medium. The GAC/ACF mixed medium had higher air permeability than the ACF medium of the same weight, and it exhibited similar ultrafine dust filtration performance to the ACF medium without an increase in differential pressure. In addition, the GAC/ACF mixed medium showed excellent gas removal performance without increasing differential pressure by combining the VOC removal characteristics of the GAC and ACF filter media. The improved VOC removal performance of the GAC/ACF mixed medium was due to the hybrid effect of the hierarchical pore structures of the GAC and the nearly uniform pore structures of the ACF, which resulted in a slow and increased gas adsorption by the GAC and rapid gas adsorption of the ACF.

Fabric fibrous filter has been used in various industrial applications owing to the low cost and wide generality. However, the basic properties of fabric materials often limit the practical utilization including hot gas cleaning. This study attempts to find new coatings of porous fibrous filter media in order to overcome its insufficient thermal resistance and durability. Teflon was one of the plausible chemicals to supplement the vulnerability against frequent external thermal impacts. A foaming agent composed of Teflon and some organic additives was tentatively coated on the glass fiber mat. The present test Teflon foam coated filter was fount to be useful for hot gas cleaning, up to 250℃-300℃. Close examination using XPS(X-ray Photoelectron Spectroscopy) and Contact angle proved the binding interactions between carbon and fluorine, which implies coating stability. The PTFE/Glass foam coated filter consisted of more than 95% (C-F)n bond, and showed super-hydrophobic with good-oleophobic characteristics. The contact angle of liquid droplets on the filter surface enabled to find the filter wet-ability against liquid water or oil.

The PP-g-Vim-CH3I adsorbent, which possesses antibacterial and ion-exchange functions, was synthesized by photoinduced grafting of 1-vinyl imidazole (Vim) onto polypropylene, non-woven fabric and subsequent quaternization using methyl iodide (CH3I). The adsorption properties of PP-g-Vim-CH3I for nitrate ion were studied in batch mode and fixed-bed columns. The adsorption equilibria of NO3-N on PP-g-Vim-CH3I were well described by the Langmuir isotherm model, and the adsorption energy was 9.03 kJ/mol, which indicates an ion-exchange process. Adsorption-kinetic data were fitted with a pseudo-second-order kinetic model. The Bohart-Adams model was found to be suitable for simulating the breakthrough curves obtained from the fixed-bed columns. The fixed-bed sorption capacity of nitrate ion from the model was in the range 100.8 ~ 108.6 mg/g without the presence of competing anions but decreased to the range 55.7 ~ 96.2 mg/ g in groundwater due to adsorption competition with the coexisting anions, especially SO4 2− ion. The PP-g-Vim-CH3I adsorbent could be regenerated by washing with 1.0 N NaCl without serious lowering the adsorption capacity.

In recent years, the demand for advanced treatments in the water-treatment industry has increased, and physicochemicalseparation technologies have come into wide use. However, biofouling is a major problem for the separation processes in water and wastewater treatment. One anti-biofouling strategy is to construct antibacterial surfaces. In this work, polypropylene (PP) fiber was endowed with antibacterial/adsorption property by photoinduced graft polymerization of 1- vinyl imidazole (Vim) followed by quaternization with alkyl iodides. A concentration of Vim equal to 5 vol.% in 10-20 vol.% methanol, a photoirradiation time of 5 h and a reaction temperature of 80oC proved to be optimal for the grafting of Vim onto PP. The modified PP fibers were characterized by means of FT-IR, SEM, antibacterial and adsorption tests. We found that the quaternized PP-g-Vim fiber with methyl iodide exhibited high adsorption capacity for NO3-N and excellent antibacterial activities against both E. coli and S. aureus.