Hollow Fibers with Encapsulated Green Amino Acid-Based Ionic Liquids for Dehydration

Dehydration technologies with low energy consumption using non-toxic materials are important in industrial, residential, and transport applications. Herein, nanocomposite polymeric hollow fibers with high dehydration capability were demonstrated with the incorporation of green amino acid-based ionic liquids. The ionic liquid was encapsulated in designed sub-micrometer carbon capsules (ENILs) and dispersed in thin polydimethylsiloxane (PDMS) coating layers. The effect of different coating compositions and operation conditions on the water vapor permeance and selectivity of water vapor over nitrogen was investigated using vacuum and sweep gas. Both sorption and permeation results suggested strong interactions between the water vapor and the encapsulated ionic liquid. The selectivity greatly depends on the PDMS coating and the amount of loaded ENIL. A linear increase of the water vapor over nitrogen selectivity was observed up to 50% ENIL loading in PDMS. The membrane systems had water vapor permeance up to 10,600 GPU and selectivity of 4500, which are promising characteristics for application in membrane air dehumidification and other dehydration processes.