Robust Bijels for Reactive Separation via Silica-Reinforced Nanoparticle Layers.

Abstract

Pickering emulsions have been successfully used as media for catalysis and separation. However, simultaneous reaction and separation cannot be performed in a continuous mode in these systems, because reagents cannot be readily loaded into or recovered from the dispersed phase. Bicontinuous interfacially jammed emulsion gels (bijels), in which the oil and water phases are continuous throughout the structure, have potential as media for simultaneous reaction and separation in a continuous mode. In this work, we take a major step toward realizing this vision by demonstrating the ability of bijels to be used in reactive separation performed in a batch fashion. To perform effectively, bijels must maintain their morphology and interfacial mass transfer properties during reaction. To strengthen the bijels, we modify the solvent transfer-induced phase separation (STRIPS) method to make bijels resistant to mechanical stresses and prevent detachment of nanoparticles from the oil/water interface due to pH changes by chemically fusing the interfacial nanoparticles. The reinforced bijel is successfully tested in base-catalyzed hydrolysis of esters and remains robust under these challenging conditions.