Three birds with one stone: Designing a novel binder-free monolithic zeolite pellet for wet VOC gas adsorption

Zeolites are promising materials for the adsorption of volatile organic compounds (VOCs), thanks to their unique pore structure, large specific surface area, and excellent stability. However, the synthesis of monolithic zeolites with a well-defined macroscopic shape, significant mechanical strength, and high VOCs adsorption capacity in humid conditions remains challenging. Here, the synthesis of binder-free monolithic zeolite pellets, possessing robust mechanical strength, high adsorption capacity, and excellent water tolerance, is reported through a citric acid sacrifice strategy. By in situ dealuminization, Y zeolite pellets have greatly improved the specific surface area and mesopore volume, leading to superior acetone and toluene adsorption performance. Moreover, the extracted aluminum species produced during the dealuminization act as a “bridge” to promote the zeolite particles into pelletization with a sufficiently high mechanical strength. Under 90% relative humidity, the acetone and toluene adsorption capacity of the synthesized zeolite pellets reach above 90% of the adsorption capacity under dry conditions, showing potential in practical industrial application. It is anticipated that this synthetic strategy will benefit the forming and development of monolithic zeolite.