A novel Al-based MOF with straight channel and pocket pore structure for trace benzene adsorption and benzene/cyclohexane separation

Benzene (Bz) vapor poses significant health risks to humans, even at trace concentrations. Additionally, the separation and recycling of Bz and cyclohexane (Cy) is challenging due to their similar kinetic diameters and boiling points. Developing an adsorption-separation material with stronger interactions with Bz than with Cy could serve as a viable strategy for trace Bz adsorption and Bz/Cy separation. In this study, we present a novel aluminum-based metal–organic framework, ZJU-521(Al), composed of tetrakis (4-carboxyphenyl)methane and a helical chain [Al 5 (OH) 7 (−COO) 8 ] ∞ , featuring a simple network of one-way rods and tetrahedra. This framework exhibited a uniform micropore size of 7.23 Å and a specific surface area of 1,248 m 2  g −1 , demonstrating excellent trace Bz adsorption (4.18 mmol g −1 ) at P/P 0  = 0.01, attributed to its straight channel and orthogonal-array pocket pore structure. The ideal adsorbed solution theory selectivity and separation factor values of ZJU-521(Al) for Bz/Cy were 22.50 and 6.20, respectively, indicating its potential as a material for Bz/Cy separation. Multicomponent simulations showed that Bz molecules were preferentially adsorbed in the pocket due to stronger interactions, such as Al–π interactions. Thus, ZJU-521(Al) exhibits stronger interactions with Bz than with Cy, facilitating effective Bz/Cy separation.