| Liquid membrane was made to extract nickel ions in the nickel contained wastewater, with Span85as surfactant, TBP as mobile carrier (Extraction agent), liquid paraffin as a membrane enhancer, kerosene solvent as membrane solvent, NH3·H2O, NaOH, Na2S, as the internal phase solution.The stability of the emulsion liquid membrane and extraction rate of nickel ions were studied by conductivity and polychrome microscopy. The best condition was determined by changing the influence factors, such as surface active agent content, flow carrier the content of the mobile carrier, the concentration of the internal phase reagent, stirring time and stirring speed, etc. The result of experiment indicated that the suitable composition of NH3·H2O liquid membrane was Span85:TBP:Paraffin: Kerosene=5:4:1:90(volume ratio), the concentration of NH3H2O in internal phase was1.0mol/L and Ni(Ⅱ) in external phase was0.5g/L, the extraction rate of Ni(Ⅱ) from Nickel containing solution was up to99.32%. The suitable composition of Sodium hydroxide liquid membrane was Span85:TBP:Paraffin: Kerosene=5:4:1:90(volume ratio), the concentration of Sodium hydroxide in internal phase was0.5mol/L and Ni(Ⅱ) in external phase was0.5g/L, the extraction rate of nickel(Ⅱ) from Nickel containing solution was up to94.64%. The suitable composition of Sodium sulfide liquid membrane was Span85:TBP:Paraffin:Kerosene=5:3:1:91(volume ratio), the concentration of Sodium sulfide in internal phase was0.2mol/L and Ni(Ⅱ) in external phase is0.5g/L, the extraction rate of Ni(Ⅱ) from Nickel containing solution was up to97.23%. The volume ratio of oil phase to the internal phase was1:1,and the volume ratio of emulsion to the water phase was1:3, which were apply to the three kinds of system all.Demulsification experiments were carried out by ways of centrifugal emulsion breaking, ultrasonic emulsion breaking, heating emulsion breaking, and unite emulsion breaking. The experimental results showed that, in the unite emulsion, the effect of heating emulsion breaking was better, followed by centrifugal emulsion breaking, and the ultrasonic emulsion breaking was the worst. Breaking rate of NH3· H2O system, Sodium hydroxide system, and Sodium sulfide system emulsion were98.9%,97.3%, and98.9%, respectly by centrifugal-heating. And the recovery of oil phase was reused in emulsification, the extraction efficiency of Ni(II) were still up to76.23%,64.86%, and60.93%, respectly.The product in the membrane of NH3· H2O system, Sodium hydroxide system and Sodium sulfide system were studied by infrared spectroscopy. The experimental showed that, by comparing the infrared spectra of the carrier and nickel ions with the carrier, the carrier played a role of transmission. Through of comparison the infrared spectra of the emulsion before and after separation, the emulsion internal phase enriched nickel ions. By comparing the infrared spectra of original oil phase and oil phase after emulsion breaking, the oil after the emulsion breaking can be reused. |
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