Utilization of coal gangue for preparing high-silica porous materials with excellent ad/desorption performance on VOCs

BACKGROUND Coal gangue causes a series of environmental problems due to its low utilization rate and high amount of hoarding. However, the preparation of porous materials with coal gangue is an effective method of resource utilization. Mesoporous silica and meso-microporous ZSM-5 were prepared with alkali melting activation-acid leaching and hydrothermal synthesis, respectively. The orthogonal experiment was used to explore the optimal preparation conditions for mesoporous silica. Meso-microporous ZSM-5 were characterized with instruments. The adsorption and desorption performance of the porous material was explored by dynamic adsorption/desorption on volatile organic compounds (VOCs). RESULTS The optimal preparation conditions for mesoporous silica are a roasting temperature of 800 degrees C, mass ratio of coal gangue to sodium carbonate of 1:0.6, and sulfuric acid leaching of 4 mol L-1. The characterization results show that the molecular sieve has a superior specific surface and a certain amount of mesoporous pores due to the addition of the appropriate mesoporous template. The results of toluene dynamic adsorption experiments show that the meso-microporous ZSM-5 (ZSM-5-0.025PAC) has excellent adsorption and desorption performance (the adsorption capacity is up to 47.02 mg g(-1)), water resistance (the adsorption capacity decreased only 4.64%), and renewability (the adsorption and desorption efficiency is up to 95% and 97%). CONCLUSION The porous materials prepared presented excellent VOCs ad/desorption performance, which has good industrial application prospects. The research provides a novel approach for the utilization of coal gangue. (c) 2022 Society of Chemical Industry (SCI).