Facile synthesis of regenerable NaY zeolite adsorbent relying on alcohol-terminated compounds for efficient trace sulfur dioxide capture

Abstract

The selective removal of sulfur dioxide (SO2) is of importance for the desulfurization and purification of exhaust gases, but it is still challenging to design adsorbents with high capture capacities (particularly at low partial pressures) and great cyclic stability. Herein, a facile strategy is proposed to optimize the adsorption performance of NaY zeolites, where various alcohol-terminated compounds (n-pentanol, ethylene glycol, polyethylene glycol) with different molecular structures are introduced as auxiliaries to facilitate the zeolite nucleation process and the formation of microporous structures. These alcohols promote the crystallization of NaY, increase the specific surface area and expand the microporosity due to the formation of micelles during synthesis. Coupled with the rise of surface basic sites, the chemisorption and physisorption of SO2 on designed zeolites is considerably improved. The PEG-Y sample derived from polyethylene glycol gives the highest dynamic adsorption of SO2 (315 mg/g), high-level SO2 equilibrium adsorption (2.18 mmol/g) under exceptionally low pressure (0.002 bar), preferred separation performance of SO2 from SO2/N2, robust stability and great regenerability. This technique can be further employed to fabricate analogous adsorbents for other gas adsorption and separation processes.