The effect of pore structure of zeolite on the adsorption of VOCs and their desorption properties by microwave heating

Mordenite and X- or Y-type faujasite were used to remove volatile organic compounds (VOCs) by adsorption at 25 °C. A microwave heating desorption system was applied for pollutant adsorbent regeneration. Studies were focused on the relationship between the adsorption and/or desorption behavior of selected VOCs (benzene, toluene, o-, m-, p-xylene, methanol, ethanol, iso-propanol, and methylethylketone: MEK) and the physicochemical properties of the zeolites (i.e. acidity, Si/Al ratio, crystal structure, pore structure, surface area, and pore volume) in this work. It was shown that the adsorption behavior of mordenite zeolites with low surface area depended on its crystal structure, while the faujasite zeolites with large surface area depended on the mesopore volume. Faujasite zeolites showed the greatest adsorption capacity for the selected VOCs. It was also shown that the mesopore volume with ink-bottle pores was advantageous for adsorption and, contrarily, the mesopore volume with cylindrical mesopores was advantageous for VOC desorption and zeolite regeneration. High efficiency desorption of VOCs was obtained using microwave heating. The highest microwave heating desorption efficiency was obtained with molecular sieve 13X due to the cylindrical pore structure.

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► Adsorption/desorption of VOCs and physicochemical properties of zeolites.
► Mesopore volumes of zeolites is one of the most influential on VOCs adsorption.
► Cylindrical pore structure leads to highly efficiency desorption by microwave heating.