Recovery of Dimethyl Sulfoxide from Aqueous Solutions by Highly Selective Adsorption in Hydrophobic Metal−Organic Frameworks

摘要

Metal−organic frameworks (MOFs) have emerged as a new family ofnnanoporous materials. While gas separation in MOFs has been extensivelyninvestigated, liquid separation is scarcely examined and lacks a microscopicnunderstanding. A molecular simulation study is reported here for the recovery ofndimethyl sulfoxide (DMSO) from aqueous solutions in three hydrophobic MOFs,nnamely, Zn4O(bdc)(bpz)2, Zn(bdc)(ted)0.5, and ZIF-71. Type I adsorptionnisotherms are observed for DMSO, while H2O exhibits type V adsorption isothermsnwith hysteresis. The saturation capacities of both DMSO and H2O decrease followingnthe order of Zn4O(bdc)(bpz)2 > Zn(bdc)(ted)0.5 > ZIF-71, in accordance with thenvariation of free volume and porosity in the three MOFs. As attributed tonhydrophobic frameworks, the three MOFs are highly selective toward DMSOnadsorption from DMSO/H2O mixtures. The highest selectivity is predicted up ton1700 in ZIF-71. This simulation study provides molecular insight into the separationnmechanism of DMSO/H2O liquid mixtures and suggests that hydrophobic MOFs are superior candidates for DMSO recovery.