A critical review on hydrophobic modification strategies of zeolites for volatile organic compounds adsorption

Abstract

Volatile organic compounds (VOCs) are major air pollutants that seriously threaten both the ecological environment and human health. Zeolites are widely utilized for VOCs adsorption and purification owing to their high specific surface area and tunable pore structure. However, in practical humid environments, water molecules significantly hinder the adsorption of VOCs by competing for active sites on the surface of zeolites. This review offers a comprehensive analysis of how water and VOCs compete for adsorption sites, both on the external surfaces and within the internal pore networks of zeolites. Based on this, key strategies for improving zeolite hydrophobicity are systematically summarized, such as increasing the silicon-to-aluminum (Si/Al) ratio to enhance intrinsic hydrophobicity, surface silanization grafting to create hydrophobic barriers, heteroatom doping to regulate surface electronic properties, and core–shell composite design for synergistic performance enhancement. The principles, advantages, and limitations of each approach are discussed. Finally, potential future research directions are proposed, providing theoretical insights and technical support for developing highly efficient and water-resistant zeolites for VOCs adsorption applications.