Synthesis and Application of Sulfonated Polystyrene as an Efficient Desiccant for Finned Tube Heat Exchangers

Abstract

This paper describes the preparation of microporous, small particle-sized sulfonated polystyrene via emulsion polymerization, using concentrated sulfuric acid as the sulfonating agent, and its application as a dehumidifying desiccant in air conditioning fresh air systems. The polystyrene synthesized through emulsion polymerization has an average particle size of 30 μm, and the degree of sulfonation reaches 37.5% under optimal conditions. Structural and physicochemical characterization results indicate that the sulfonated polystyrene exhibits strong hydrophilicity, high mechanical strength, excellent thermal stability, and acid–base resistance. Adsorption tests show that the sulfonated polystyrene has 50% higher adsorption capacity compared to commercial silica gel and nearly three times that of 3A zeolite. A thick, uniform 150 μm desiccant coating was successfully prepared on a finned tube heat exchanger using an impregnation method, maintaining stable adsorption performance after 50 regeneration cycles. This study provides an energy-efficient, high-performance, and stable water-adsorbing material for air conditioning fresh air systems.