| The sebacic acid is a kind of important organic chemical material which can be widely used to produce the polyamide plastics, high temperature lubricant, cold plasticizer, resin and so on. About 30 tons wastewater will be discharged for each ton production of sebacic acid in the present industrial process. What the wastewater contain are sodium sulphate, phenol, sebacic acid and other fatty acids. The emission of this kind of wastewater not only pollutes the environment, but also loses the valuable resources which are contained in the wastewater. Therefore, evaporation and adsorption processes were used to treat the wastewater in order to recover sodium sulphate in the wastewater. The research result can provide the basic data for the industrial process in the future.Preliminary wastewater treatment process was determined through experiments. After 800 mL water was evaporated from per 1000 mL wastewater, sulfuric acid was added to adjust the pH of the concentrated solution to 2. Then the concentrated solution was cooled to around 35℃, and filtered to remove the precipitates of crude sebacic acid impurities. The filtrate has 4800 mg/L COD and yellow color. The anhydrous sodium sulfhate obtained from this filtrate has purity of 98.1%, but it is not qualified because of its yellow color and odour. Therefore, it is necessary to have further treatment.The results of Fenton reagent oxidation, the activated carbon adsorption and NKA-2 resin adsorption were compared in the follow-up handling of the filtrate. The optimum operating conditions were obtained after detecting the effect of reaction temperature, reaction time, H2O2:FeSO4·7H2O mol ratio and 30%H2O2 consumption on the COD removal in the Fenton oxidation process. In the adsorption experiment, the effect of the adsorption time, temperature, pH and the amount of adsorbent on the COD removal was detected by static adsorption experiment. The optimum static adsorption conditions were determined through single factor experiments. Activated carbon adsoption shows the best result. The optimum conditions are as follows: adsorption time: 2 h; temperature: 40℃; pH value: 2; activated carbon dosage: 10g/150mL filtrate. After activated carbon adsorption treatment, the COD of the filtrate was decreased to 830 mg/L, and the removal rate of COD is 83%. The purity of the anhydrous sodium sulphate recovered from this filtrate can reach 99.3%. The product has no smell, white color, and the yield is 90.0%. In the dynamic adsorption process, the effect of flow rate on the COD removal was studied, the conclusion shows that low flow rate is conducive to dynamic adsorption.The equilibrium concentration and equalibrium adsorption capacity was determined through static adsorption experiments. The models of BET, Freundlich and LangmuirFreundlich are applied to regress parameters of models, and the BET model shows the best result.
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