Enhancement mechanism of an improved liquid membrane using selective permeation retardant for heavy metal ions separation

摘要: Abstract Liquid membrane (LM) separation is a kinetic process that can be enhanced by increasing the difference between permeation rates of components. The addition H3Cit/Na3Cit as selective retardant enlarge Cu(II) and Cd(II) ions when P507 was used extractant. This analogous to masking agent employed in liquid–liquid extraction (LLE). However, mainly affects LM’s kinetics, while impacts LLE's equilibrium. It found coefficient LM system could much greater than LLE owing LM's effect. Following H3Cit/Na3Cit, ion rate selectively retarded, selectivity Cd(II)/Cu(II) significantly comparison with control system. To reveal this enhancement mechanism, new model established which interfacial chemical reactions mass transfer resistance middle connection zone H-type device were considered. model's predictions agreed well experimental data. According model' quantitative analysis, affected apparent reaction constants differently, key mechanism. Aside from concentration, also predicted variations coefficient, purity, yield time. An optimal time defined obtain high purity simultaneously. Finally, further verified applied on preliminary basis supported liquid strip dispersion, technology potential for industrial application.