Abstract
The removal of soluble cyclic ether contaminants, such as dioxane and THF, produced in industrial chemical processes from water is of great importance for environmental protection and human health. Here we report that nonporous adaptive crystals of perethylated pillar[5]arene (EtP5) and pillar[6]arene (EtP6) work as adsorbents for cyclic ether contaminant removal via host-guest complexation at the solid-solution interface. Nonporous EtP6 crystals have the ability to adsorb dioxane from water with the formation of 1:2 host-guest complex crystals, while EtP5 crystals cannot. However, both guest-free EtP5 and EtP6 crystals remove THF from water with EtP5 having a better capacity. This is because EtP5 forms a 1:2 host-guest complex with THF via host-guest complexation at the solid-solution interface while EtP6 forms a 1:1 host-guest complex with THF. EtP6 also shows the ability to selectively remove dioxane from water even in the presence of THF. Moreover, the reversible transitions between nonporous guest-free EtP5 and EtP6 structures and guest-loaded structures make them highly recyclable.
Highlights
1,4-Dioxane, a cyclic ether often called dioxane, is primarily used as a solvent in industry as well as in the laboratory and a stabilizer for the transport of halogenated hydrocarbons [1]
The search for new and easy strategies or adsorbents for adsorption and subsequent removal of dioxane from water is of great importance
Our group pioneered research on nonporous adaptive crystals (NACs) of pillararenes [27,28,29,30,31,32]. These nonporous crystals with “intrinsic porosity” can capture specific vaporized guests that have noncovalent interactions with them to form new guest-loaded crystal structures, that is, host-guest chemistry at the solid-gas interface. Based on these unique properties, NACs of pillararenes have been successfully applied in the adsorptive separations of hydrocarbons such as styrene purification and xylene isomer separation [28, 30]
Summary
1,4-Dioxane, a cyclic ether often called dioxane, is primarily used as a solvent in industry as well as in the laboratory and a stabilizer for the transport of halogenated hydrocarbons [1]. Our group pioneered research on nonporous adaptive crystals (NACs) of pillararenes [27,28,29,30,31,32] These nonporous crystals with “intrinsic porosity” can capture specific vaporized guests that have noncovalent interactions with them to form new guest-loaded crystal structures, that is, host-guest chemistry at the solid-gas interface. Based on these unique properties, NACs of pillararenes have been successfully applied in the adsorptive separations of hydrocarbons such as styrene purification and xylene isomer separation [28, 30]. The development of such properties for pillararene NACs may broaden their applications in more areas such as liquid-phase separation and water treatment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
