Tuning the adsorption behaviors of water, methanol, and ethanol in a porous material by varying the flexibility of substituted groups

Abstract

Exploring the adsorption and separation of water, methanol, and ethanol is important concerning the use of a sustainable energy source from biofuel. In this paper, the effects of the flexibility of substituted groups have been studied based on three iso-reticular metal–organic frameworks (MOFs), in which the pore surface is decorated with propargyl (–CH₂–CCH), allyl (–CH₂–CHCH₂), and propyl (–CH₂–CH₂–CH₃) groups respectively. These substituted groups stretch into the channel, acting as gates, and the gate-opening for guests is controlled by the flexibility as well as host–guest interactions. Our study results indicate that (i) the adsorption capacity of water, methanol and ethanol enhances accordingly with the increase of the flexibility of substituted groups; (ii) the adsorptive discrimination of water, methanol, and ethanol on this porous sorbent could be tuned by varying the substituted groups.