Investigation on Amino Distribution in Porous Resins for Low Concentration SO2 Purification

Abstract Effective purification of low concentration SO2 at cathode air stream side is essential for Proton exchange membrane fuel cells performance in the real-world application. Amino modification porous material is the effective purification media. The modifier distribution along the pore channels is one of the most influencing parameters that determine the purification performance. Amino-modified porous resins are synthesized to assess the mechanism of modifier distribution along the pore channel. Modifier concentration, modification time, modification temperature, and intersolubility between solvent and modifier are found to significantly affect the modifier distribution. Increased modifier concentration within a relatively low range (0-200 g/L) is favorable to grafting modifier in external pore channel. However, no more significant modifier grafting was found for higher modifier concentration due to the higher solvent viscosity and lower modifier diffusion. Increased modification time leads to more amino groups grafted in deep pore channel. However, after the modification time is longer than 6 hours, the modifier no longer diffuses into deeper pore channel due to the diffusion limitation. Solvent property significantly affects the modifier solubility and the swelling degree of porous resin. Larger intersolubility between solvent and modifier enhances the modifier diffusion into pore channel.