Abstract: The membranes of polyvinylidene fluoride, which were synthesized by our laboratory, were used to study the transfer and extraction performances of Nd(Ⅲ) and Sm(Ⅲ) with the extraction system of HEH/EHP-kerosene. The results show that the membrane material was suitable to the study on membrane extraction, and could offer a good transfer performance in the membrane construction parameters selected. The extraction reaction in the membrane module was the same as that in liquid liquid process. HEH/EHPammoniated for increasing the mass transfer coefficient was almost the same with increasing the concentration of HEH/EHP, and H⁺ was still transferred first at higher pHrange of feed solution when HEH/EHP was ammoniated. The controlling model of the membrane extraction process was the diffusion model accompanied by interfacial reaction. The controlling function of interfacial reaction would increase gradually with the increasing of the membrane pore size. The mass transfer coefficient increased when extraction and stripping were carried out simultaneously.

Key words: Membrane module, Membrane extraction, 2-Ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEH/EHP), Mass transfer