Energy-efficient separation of organic liquids using organosilica membranes via a reverse osmosis route

We developed a procedure that saves significant amounts of energy during the separation of organic liquids via organic solvent reverse osmosis (OSRO). The proof-of-concept was confirmed using theoretical calculation to demonstrate energy-consumption at less than 1/100th and 1/10th that of conventional distillation and pervaporation (PV), respectively. Bis(triethoxysilyl)acetylene (BTESA)-derived organosilica membranes consisting of a SiO₂–ZrO₂ intermediate layer and an α-Al₂O₃ support were evaluated by challenging a series of azeotropic mixtures of methanol/toluene, methanol/methyl acetate, methanol/dimethyl carbonate (DMC), and methanol/methyl tert-butyl ether (MTBE). BTESA membranes showed excellent size- and/or shape-sieving properties and remarkable levels of organic-tolerance with an ultrahigh methanol flux that outperforms state-of-the-art polymeric membranes. In particular, the robust ceramic support and rigid organosilica networks endowed the resultant membranes with the ability to withstand transmembrane pressures as high as 18 MPa.