The design of core–shell ZSM-5@NiAl-LDH composites for efficient adsorption of VOCs under high humidity

Zeolites have been widely utilized in the adsorption of volatile organic compounds (VOCs) due to their high specific surface area and robust stability. However, the adsorption capacity of zeolites for VOCs is considerably reduced under humid conditions due to the competitive adsorption between water and VOCs, thereby limiting their industrial applicability. Herein, we report a core–shell ZSM-5@NiAl-LDH (Z-L) composites designed specifically for efficient adsorption of VOCs under high humidity conditions. The core–shell architecture is achieved by introducing active sites onto the ZSM-5 framework pretreated with high-alkalinity agents, followed by the growth of NiAl-LDH on its surface, creating a regular, vertically staggered structure. Compared with ZSM-5 zeolite, Z-L composites show a larger specific surface area, wider pore size, and larger mesopore volume, allowing a high adsorption capacity of the VOCs. Contact angle and static adsorption tests of water molecules reveal that the LDH shell effectively increases the hydrophobicity of Z-L composites. The dynamic adsorption behavior for m-xylene demonstrates that Z-L composites exhibit significantly enhanced adsorption capacity, 3.79 times that of ZSM-5 zeolite. Furthermore, Z-L composites exhibit a higher selectivity for m-xylene at 60 % relative humidity, achieving a Q wet /Q dry ratio of 86.7 %, outperforming most porous adsorption materials. Kinetic model analysis reveals that the augmentation of mesopores in Z-L composites enhances the effective diffusion space for synthesized samples, resulting in exceptional adsorption performance. This novel synthetic material is anticipated to be a promising candidate for VOCs pollution control in high-humidity environments.