Abstract:

Supported liquid membrane separation processes have recently received considerable attention due to characteristics such as fast mass transfer, high selectivity and separation efficiency, lower operation costs and no secondary pollution. They are particularly suitable for the separation and enrichment of heavy metal ions. However, supported liquid membrane separation processes are limited in largescale industrial applications due to membrane instability and short membrane life. The transportation and separation of Pb(Ⅱ) through a PC-88A-kerosene-HCl dispersion supported liquid membrane(DSLM)， based on the theoretical study of the existing supported liquid membrane(SLM) separation technology， is reported. The effects of pH value in the feed phase, volume ratio of liquid membrane phase and hydrochloric acid, concentrations of HCl in the strip phase and initial concentration of Pb(Ⅱ) in the feed phase are also studied. The results show that lead ion can be transported effectively when pH=5.25 in the feed phase, the volume ratio is 160∶40, concentrations of HCl in the strip phase is 5.00 mol/L. The transport rate of Pb(Ⅱ) can reach to 88.9% through DSLM, and 72.3% through traditional SLM, respectively, under the optimum condition, and the transport time is 190 min for initial concentration of 3.00×10-4 mol/L Pb(Ⅱ). It shows that DSLM has a high transmission efficiency in comparison with conventional SLM. At the same time, the system can improve the stability of the membrane and extend the life of the membrane.

Key words: liquid membrane, dispersion supported liquid membrane, organic phosphonic acid, lead(Ⅱ)