| IV The spent electroless nickel plating baths contain a lot of residual nickel (2~7g/L) and organic matter (10~20 g/L), which is difficult to treat with. The traditional methods to treat spent electroless nickel plating baths contain: chemical precipitation method, electrolysis, ion exchange, reverse osmose and ultrafiltration process et al., but the methods have many disadvantages, such as complicated operation, high cost, and can not recover useful matters from effluent. So the technology which can treat and recover the spent electroless nickel plating baths has become the urgent problem to sustainable developmental electroless nickel plating industry.This thesis targeted on the separation typical synthetic wastewater which containing citrate nickel to recover recourses through supported liquid membrane. The main contents of the research contain: (1) The optimum organic solvent, carrier, and stripping extraction agent were selected, the effects of pH and concentration of the synthetic wastewater, carrier concentration in the membrane phase, extraction time, hydrochloric acid concentration in the strip solution phase, ionic strength in the feed solution phase and ratio of water to oil on extraction rate of citrate nickel were discussed. The optimum experimental conditions and membrane composition were obtained. (2) From the perspective of diffusion mass transfer, the effects of stir speed, carrier concentration in the membrane phase, concentration of the feed solution phase and experiment temperature on the transport kinetics have been discussed. (3) The average reside time of tracer in the reactor in the different condition has been evaluated respectively and the type of reactor has been determined. (4) The nickel-containing synthetic wastewater was treated through supported liquid membrane system which has been established by experiments. (5) The effects regulation of ultrasonic wave on extraction and the sapatation of supported liquid membrane have been discussed.The conclusions of the study were as follows:(1) The optimum system to extract citrate nickel were: tri-n-octylmethylammonium chloride and benzene were employed as extraction agent and organic solvent, respectively, hydrochloric acid is strip extraction agent.The optimum operating conditions were: initial citrate nickel concentration in the synthetic wastewater was 0.03 mol/L, carrier TOMAC concentration in the membrane phase was 0.024 mol/L, pH value was equal to 10, extraction time was 30 min, the ratio of water to oil was 1:1. The extraction percentage attained to more than 99%.(2) The effects of stir speed and experiment temperature on speed of extraction indicated: the extraction process of tri-n-octylmethylammonium to citrate nickel was diffusion control.(3) The flow state experiment indicated: with the increasing of the flow speed of liquid or the increasing of ultrasonic efficiency, the average reside time of tracer in the reactor reduced. According to the variance which obtained from the experimental result computation, we may judge that the type of reactor was not ideal one and the deviation to ideal reactor was very big.(4) The optimum transport conditions of citrate nickel in supported membrane system were: pH value was equal to 10, the aperture of supported polypropylene membrane was 0.22μm, the volume ratio of organic phase to strip extraction phase in the stripe dispersion hybrid liquid membrane was 1:1, the flow speed of the feed phase was 10 ml/min. Basised on the above mentioned conditions, the transport percentage of nickel was very high.(5) The effect of ultrasonic wave on extraction result was very obvious. The extraction percentage of citrate nickel was bigger with ultrasonic wave than without the one, to the high point more than 4 times, the transport percentage increased gradually with ultrasonic efficiency increasing.Based on the optimum membrane composition, the separation of citrate nickel through supported liquid membrane has been studied systematically in the paper. It is valuable that provide data for treating practical industry wastewater and doing furthering theoretical research.
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