| With the development of industry and the improvement of people’s living standard, the demand of dye products and pesticide carbaryl is also increasing. However, wastewater containing raw material is highly harmful to water environment, and even endangers the aquatic organisms, and also can bring immeasurable harm to human beings if discharging directly. Since 1968, the invention of the emulsion liquid membrane technology by professor Li, it was widely used in sewage treatment and enrichment of metal ions and recycling, etc, because of its advantages of high efficiency, economy, easy operation.In this paper, the emulsion liquid membrane separation technology dealing with 1-naphthol simulated wastewater was investigated. The main content of the thesis research and the results were as follows:(1) Emulsion was prepared by a magnetic stirring apparatus with different stirring speed to make the pre-emulsion and then assisted by the ultra-sonication devices for minutes. The effect of kinds of oil phase (cyclohexane, kerosene, n-heptane, methylbenzene, p-xylene), the internal phase (Na2CO3, Na3PO4, NaOH), on 1-naphthol removal rate and leakage rate were investigated. The results showed that:the lowest magnetic stirring speed was 720 rpm, ultrasonic time for 5 min, cyclohexane as the oil phase, NaOH solution as the internal phase, stable emulsion was obtained. The maximum 1-naphthol removal rate 97.99% and the minimum leakage rate of 1.43% at 35 min were obtained.(2) The emulsion droplets was studied by the hot and cold polarizing microscopy, and it was found that almost all of emulsion droplets diameter was lower than 10 μm, reached the standard of a stable emulsion.(3) Cyclohexane was employed as oil phase, NaOH as the internal phase, Span 80 as surfactant and liquid paraffin as membrane, to prepare a stable emulsion. The effect of single factors, such as, the ratio of oil to inner phase, the concentration of NaOH, pH of web phase, mixing time, and external to emulsion phase ratio (treat ratio), on 1-naphthol removal rate and the leakage rate were studied. The results showed that:the ratio of oil to inner phase 0.5, NaOH concentration 2%, the original pH of web phase, the mixing time 15 min, the treat ratio 5, and the removal rate of 1-naphthol and the leakage rate can reach 97.99% and the minimum leakage rate of 1.43% at 35 min respectively.(4) Demulsification experiments were carried out by various methods:centrifugal emulsion breaking, heating emulsion breaking, ultrasonic emulsion breaking, and introduction of n-butyl alcohol. After the mass transfer, the emulsion was separated, collected the oil phase after demulsification, and then re-prepared the emulsion and applied in 1-naphthol removal, to examine whether the oil phase can be reused. The experimental results showed that:the centrifugal emulsion breaking method was the best,67.36% breaking rate was obtained at 15 min. And the recovety of oil phase was reused in emulsification, the extraction efficiency of 1-naphthol was still up to 91.45%, while the leakage rate was higher at 35 min than the first oil phase.(5) In order to improve the phenomenon of swelling that Span 80 as surfactant, various hydrophilic surfactants coupling with Span 80, such as Tween 20, sodium dodecyl sulfate, sodium dodecyl benzene sulfonic acid and Tween 80, were investigated. It was found that sodium dodecyl benzene sulfonic acid was the optimal, based on the removal rate of 1-naphthol and the emulsion leakage rate.(6) Single factor optimization experiment and the orthogonal experiment were used to study the effect of HLB value of Span 80 and dodecyl benzene sulfonic acid sodium compound, the internal phase concentration of NaOH, the ratio of oil to inner phase and treat ratio, on the removal rate of 1-naphthol and optimization of experimental conditions. Single factor optimization experiment results:combination of dodecyl benzene sulfonic acid sodium and Span80 with the HLB value of 5.5, the concentration of NaOH 2%, the ratio of oil to inner phase 1, treat ratio 5,1-naphthol removal rate reached 96.75%. The optimal experimental results based on orthogonal experiment are:the HLB value of 5.5, the concentration of NaOH was 3%, the ratio of oil to inner phase was 0.5, treat ration was 3,1-naphthol removal rate reached 98.05%. |
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