Visual study and simulation of interfacial liquid layer mass transfer in membrane-assisted antisolvent crystallization

Abstract

Herein, an interfacial mass transfer process based on hollow fiber membrane assisted antisolvent crystallization (MAAC) was studied via real-time microscopic and computational fluid dynamic (CFD) method. The micro-scale antisolvent liquid layer was clearly detected on the antisolvent/solution interface. The antisolvent concentration and layer thickness were determined by different refractive index of the mixing fluid. CFD simulation results also confirmed the formation of uniform supersaturation gradient, indicating the approximate two-dimensional liquid layer mass transfer on the membrane surface. The competition effect between the feed solution shear force and antisolvent permeation flow rendered the high adjustability of the liquid layer features. Experimental comparison between MAAC and conventional AC indicated that crystal production obtained by MAAC possessed narrower size distribution and great morphology without defects. This novel interfacial liquid layer mass transfer mechanism opens a new approach for novel antisolvent crystallization with intensified interfacial mass transfer.