Superoleophilic conjugated microporous polymer nano-surfactants for realizing unprecedented fast recovery of volatile organic compounds

Abstract

A pervaporation membrane with fast and selective permeation is key to improving the recovery efficiency of volatile organic compounds from water. Here, we synthesize a new type of nanofiller-conjugated microporous polymer (CMP) to fabricate polydimethylsiloxane (PDMS)-based mixed matrix membranes (MMMs) and explore their application in the recovery of organic solvents from water via pervaporation. Due to their good dispersibility in the dope solvent and compatibility with PDMS, uniform MMMs without discrete particle phases or aggregates are prepared. Interestingly, CMP nanosheets play a unique role as a nano-surfactant in enhancing both the sorption and diffusion coefficients, realizing unprecedented fast recovery of organic solvents from water. The total flux of the as-fabricated membranes can be enhanced from 74.8 to 406.2 kg μm⁻² h⁻¹ and the separation factor α_{ethyl acetate/water} is increased from 118.7 to 526.6 when using 5 wt% ethyl acetate aqueous solution as the feed at 50 °C. In addition, the CMP-incorporated PDMS membranes are also effective in recovering a wide range of organic compounds from water, including ethanol, acetone, tetrahydrofuran and acetonitrile.