One‐pot synthesis of meso‐microporous ZSM‐5 and its excellent performance in VOCs adsorption/desorption

Abstract

BACKGROUND: The meso-microporous ZSM-5 is used for treating the complicated industrial organic waste gas, owing to its good hydrophobicity, excellent thermal and hydrothermal stability, and lower mass transfer resistance than conventional ZSM-5, resulting in its great adsorption property for volatile organic compounds (VOCs). In this paper, different types of meso-microporous ZSM-5 (NZ5, MZ5) were prepared using the templates and then characterized by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and so on. The adsorption/desorption performance and diffusion mechanism of VOCs on meso-microporous ZSM-5 were further investigated. RESULTS: The meso-microporous ZSM-5 (MZ5), prepared with the cationic surfactant, contained not only large and uniform mesopores but also certain amounts micropores. Moreover, it exhibited excellence adsorption performance for organic molecules due to its relatively reasonable porous structure. The rich porous structure might mean that the cationic surfactant had better effects for producing mesopores in zeolite than the organic additives, such as phenyltriethoxy silane. More importantly, it showed the excellent thermal and hydrothermal stability and great desorption property, which was more than 95% within 20 min at 200°C. Finally, the diffusion mechanism of toluene on the meso-microporous ZSM-5 was investigated, which was suitable for Fick's second law under the low adsorption pressure. CONCLUSION: The meso-microporous ZSM-5 (MZ5, NZ5), prepared by hydrothermal synthesis method with the template, exhibited excellent adsorption/desorption performance, thermal and hydrothermal stability and lower mass transfer resistance than the conventional ZSM-5 (CZ5) for handling the VOCs.

Experimental and DFT investigations on adsorption–regeneration performance and deactivation mechanism over engineered carbon fiber: role of pore structure and functional groups

“…[4][5][6] In particular, the pore distribution in ACMs can be regulated to facilitate OVOCs diffusion and to balance adsorption and desorption processes. 7,8 For instance, Wang et al demonstrated that a well-developed hierarchical pore structure could promote the desorption efficiency of ethyl acetate (EA) on ACMs; the desorption efficiency remained as high as 93% after several cycles of adsorption and desorption. 9 In general, ACMs with a controlled and homogeneous pore structure can provide good porosity for interfacial interactions by maintaining an interlaced carbon-skeleton structure that makes the most of the surface area available for the mass transfer that underpins adsorption.…”