Pervaporation properties of silylated ionic liquid-derived organosilica membrane

Abstract

We previously reported gas/vapor permselectivities, microstructures, and permeation mechanisms of silylated ionic liquid (IL)-derived organosilica membranes (IL organosilica membranes), which are a class of chemically stabilized IL membranes. In this study, an IL organosilica membrane was used for organic liquid separation using pervaporation (PV) for the first time. Unary PV tests were conducted using alcohols, ketones, aromatic hydrocarbons, and alkanes. We investigated the relationship between the permeances of the organic compounds and differences in the Hansen solubility parameters between the membrane and organic compounds to evaluate the selective permeability of the organic compounds through the membrane. Second, binary PV tests were conducted to separate (1) alcohols/alkanes and (2) aromatics/alkanes. In the toluene/n-hexane (toluene 48 mol%) separation tests, a toluene/n-hexane permeance ratio of 11 was obtained with a toluene permeance of 2.6 × 10−6 mol m−2s−1Pa−1. Further, the membrane exhibited high selectivity for 1-hexanol in a binary 1-hexanol/n-hexane mixture. The IL organosilica membrane exhibited excellent potential for affinity-based organic liquid separation.