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.

Tunable thermo-reversible bicontinuous nanoparticle gel driven by the binary solvent segregation

“…Gel formation, a non-equilibrium approach, shows tremendous usefulness to form novel structures not achievable with traditional equilibrium approach [1][2][3][4] . In particular, the formation of bicontinuous structures through gelation processes has attracted extensive research interests due to their important applications in energy storage 5 , membrane science 6 , flow-through reaction 7 , and cell delivery 8 . One of the widely studied bicontinuous structure systems is the bicontinuous interfacially jammed emulsion gel (Bijel), which can form porous materials with tortuous channels by arresting the solvent spinodal decomposition with colloidal particles trapped at the interface of two phase-separating solvents 2,[9][10][11][12] .…”

Bicontinuous Interfacially Jammed Emulsion Gels (bijels) as Media for Enabling Enzymatic Reactive Separation of a Highly Water Insoluble Substrate

“…One potential approach to overcome such a challenge is to induce convection in one or both liquid phases. A recent development has shown that bijels can be reinforced to withstand shear and flow 43 . By combining these recent advances in the preparation and application of bijels, we believe our current work brings us one step closer to realizing the vision of bijel-based continuous reactive separations.…”

Multiphase Microreactors Based on Liquid–Liquid and Gas–Liquid Dispersions Stabilized by Colloidal Catalytic Particles

“…AG TL conversion and LA yield of 46 %a nd 34 %, respectively,c an be achieved with productivities of 18 and 40 mmol (mol H + ) À1 As an alternative to emulsions,b ijels reinforced with silica can afford full conversion and high robustness in the base hydrolysis of ethyl acetate using NaOH (Figure 2d). [66] [63] b) Deacetalization; [64] c) Etherification; [65] D) hydrolysis; [66,67] e) Transesterification; [68][69][70][71] f) Alkylation/acylation; [72,73] g) Pechmannr earrangement. [74] Surface-active catalysts have been developed for biodiesel synthesis by transesterification of vegetable oils with methanol (MeOH) (Figure 2e).…”