N, N-dimethylacetamide (DMAC) is widely used as chemical raw materials and organic solvents in petroleum, chemical, pharmaceutical, pesticide and other industries. It has strong polarity, chemical stability and biological toxicity.
1. The wide use of dimethylacetamide causes a large amount of DMAC wastewater pollution
Dimethylacetamide (DMAC) is an important pharmaceutical raw material and is widely used in the production of antibiotic drugs such as cephalosporins and amoxicillin. In addition, the strong solubility of dimethylacetamide makes it widely used in coatings, medicines, plastic films, heat-resistant synthetic fibers, acrylonitrile spinning and other fields. At present, the production of foreign polyimide films, soluble polyimide, polyimide-polyperfluoroethylene-propylene composite films, polyimide (aluminum) films, soluble polyimide molding powder and other materials Dimethylacetamide is often used as a solvent, and it is also used as an excellent polar solvent in the domestic polymer synthetic fiber spinning field.
Due to the excellent performance and wide range of uses of dimethylacetamide (DMAC), a large amount of DMAC-containing wastewater is dumped into the environment during the production process every year. The toxic substances in these wastewater can cause huge damage to the water environment.
2. Solvent extraction process for treating DMAC wastewater
At present, extraction methods, biochemical methods, supercritical water oxidation methods, photocatalytic oxidation, physical and chemical methods, chemical methods, etc. are mostly used to treat DMAC-containing wastewater at home and abroad. The solvent extraction method is undoubtedly a more economical and feasible treatment method. It can not only pretreat DMAC wastewater, but also recover the DMAC solvent in the wastewater and return it to production.
Liquid-liquid solvent extraction is an operation method that uses the principle of different solubilities of solutes in mutually immiscible solvents to transfer solutes from one solvent to another. Chloroform can be used as the extraction agent to treat DMAC wastewater, and the concentration of DMAC in the final discharged wastewater can be reduced to 180mg/kg.
The liquid-liquid solvent extraction method has low energy consumption and high recovery rate for low-concentration DMAC.