Study Of Liquid-Liquid Extraction Of Cr (Ⅵ) In Micro-Impinging Stream Reactors

Equipment miniaturization is an important way of chemical process intensification. As a new process strengthening equipment, micro-impinging stream reactor (MISR), which combines the advantages of micro reactor and impinging stream technology, has a superior micro-mixing performance and good application prospect. With the development of chemical production and emphasis on environmental issues, high efficiency, energy saving and thorough treatment methods of the environmental problems have been proposed and used widely. The application of MISR on environmental and wastewater treatment not only can promote the environmental protection development, but also provides new directions of reactor improvement. In this thesis, research on the extraction of harmful ion Cr (Ⅵ) from wastewater has been conducted in MISR and the strengthening effect of MISR on extraction process was confirmed.(1) The effects of operating conditions and structural parameters on extraction of Cr (Ⅵ) from aqueous phase has been studied with TBP as extractant and kerosene as diluent. Results demonstrated that:the extraction efficiency was improved with increase of flow rates, but emulsification would happen when flow rate was too high. The extraction was the best when the two impinging phases were with equal momentum and extraction rate was increased along with the extension of standing time. Inlet capillary length did not affect the extraction result, while the smaller the inlet capillary diameter was, the larger impinging momentum could be provided, which led to higher extraction rate. The best outlet structure was without outlet pipe. Compared with traditional stirring method, MISR demonstrated great strengthening effect on extraction process in terms of higher extraction rate, shorter reaction time and less energy consumption.(2) By changing diluent and the separation methods of the raffinate, the MISR extraction effect got optimized. The results showed that:the best result for development of demulsification time and extraction rate could be obtained with cyclohexane as diluent; salting-out centrifugation could not only shorten the time of demulsification, but also improve the extraction results.