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

Abstract

Pickering emulsions, foams, bubbles, and marbles are dispersions of two immiscible liquids or of a liquid and a gas stabilized by surface‐active colloidal particles. These systems can be used for engineering liquid–liquid–solid and gas–liquid–solid microreactors for multiphase reactions. They constitute original platforms for reengineering multiphase reactors towards a higher degree of sustainability. This Review provides a systematic overview on the recent progress of liquid–liquid and gas–liquid dispersions stabilized by solid particles as microreactors for engineering eco‐efficient reactions, with emphasis on biobased reagents. Physicochemical driving parameters, challenges, and strategies to (de)stabilize dispersions for product recovery/catalyst recycling are discussed. Advanced concepts such as cascade and continuous flow reactions, compartmentalization of incompatible reagents, and multiscale computational methods for accelerating particle discovery are also addressed.

Micro- and Nanofluidic pH Sensors Based on Electrodiffusioosmosis

“…Three-dimensional views of the Type A, B, and C structures are depicted in Figure 2d-f, respectively. For each type of channel, the test section, which connects the sample and reference solutions, was designed with the same cross section of 500 × 500 nm 2 and the length of 20 µm for the Type A and C and 475 µm for the Type B structures, although the microchannels for introducing liquids varied depending on the channel types, as shown in the focused view in Figure 2g-i, respectively.…”

“…Micro-and nanofluidic channel devices have attracted much attention for applications such as micromixers [1], microreactors [2,3], and biosensors [4,5] because sufficient sensitivity can be achieved for small samples. Furthermore, nanoscale test sections have a large surface-to-volume ratio that can modify the properties of liquids, causing counterions of surface charges to be dominant.…”

Immobilization: the promising technique to protect and increase the efficiency of microorganisms to remove contaminants

“…10 Small granular biocatalyst particles are used for fluidization, offering high stability even under significant shear forces, so FBRs are favored in applications demanding efficient liquid mixing and high cell density. 204,205 They have been utilized for scaling up hybridoma culture, bioartificial organs, mammalian cell culture and by-product production. 206 Modified FBRs, such as the diversion-type microcapsule-suspension FBR (DMFBR), have been developed to address issues with damage to cell-containing microcapsules and large void volumes.…”

“…The carrier material has sufficient specific gravity to remain suspended during the flow 10 . Small granular biocatalyst particles are used for fluidization, offering high stability even under significant shear forces, so FBRs are favored in applications demanding efficient liquid mixing and high cell density 204,205 . They have been utilized for scaling up hybridoma culture, bioartificial organs, mammalian cell culture and by‐product production 206 .…”