SiC foam with a hollow skeleton and microporous strut wall used as a membrane contactor for the liquid-liquid extraction of Ce3+ and Pr3+

Membrane contactors have received considerable attention for extraction due to non-dispersive mass transfer through porous membranes. The past decades have seen the rapid development of organic hollow fiber membrane contactors, but very few studies have explored the applications of inorganic membranes in extraction, possibly due to their high costs. In this work, a novel SiC foam material with a hollow skeleton and microporous strut wall was used as a ceramic membrane contactor (HS-FCMC) for rare earths extraction. The foam's structure was characterized by scanning electron microscopy (SEM), X-ray micro-computed tomography (micro-CT), and mercury intrusion porosimetry (MIP). The flow and concentration fields inside and outside the foam cell were simulated by computational fluid dynamics (CFD), and the mass transfer through the ceramic membrane was analyzed. Based on the nitric acid–Ce 3+ /Pr 3+ –P507–kerosene chemical system, the extraction efficiency of Pr 3+ and Ce 3+ using the HS-FCMC reached 96.13% and 92.86%, respectively. A comparison study with poly tetra fluoroethylene (PTFE) hollow fibers was also conducted. The results indicate that the HS-FCMC is suitable for rare earths extraction due to the multiscale porous structure and chemical stability of the hollow-skeleton SiC foam. This research advances the knowledge of inorganic membrane extraction methods.