Recovery of dimethyl sulfoxide from aqueous solutions by highly selective adsorption in hydrophobic metal-organic frameworks.
Metal-organic frameworks (MOFs) have emerged as a new family of nanoporous materials. While gas separation in MOFs has been extensively investigated, liquid separation is scarcely examined and lacks a microscopic understanding. A molecular simulation study is reported here for the recovery of dimethyl sulfoxide (DMSO) from aqueous solutions in three hydrophobic MOFs, namely, Zn(4)O(bdc)(bpz)(2), Zn(bdc)(ted)(0.5), and ZIF-71. Type I adsorption isotherms are observed for DMSO, while H(2)O exhibits type V adsorption isotherms with hysteresis. The saturation capacities of both DMSO and H(2)O decrease following the order of Zn(4)O(bdc)(bpz)(2) > Zn(bdc)(ted)(0.5) > ZIF-71, in accordance with the variation of free volume and porosity in the three MOFs. As attributed to hydrophobic frameworks, the three MOFs are highly selective toward DMSO adsorption from DMSO/H(2)O mixtures. The highest selectivity is predicted up to 1700 in ZIF-71. This simulation study provides molecular insight into the separation mechanism of DMSO/H(2)O liquid mixtures and suggests that hydrophobic MOFs are superior candidates for DMSO recovery.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore.
Anjaiah
A
Nalaparaju
Jianwen
J
Jiang