Study On Recycling Process Of DMF From Wastwater

Dimethylformamide (DMF) is an excellent industrial solvent and organic synthetic material with wide range of applications. However, DMF must be recycled for its toxic and biodegradable. In the current recovery process of DMF, the decomposition of formic acid has a great influence on recovering rate of DMF and lead to increase energy consumption. Thereby, facilitating decomposition of formic acid to reduce acid concentration and increasing recovering rate of DMF became a exigent problem in the recycling process of DMF. In addition, the industrial domestic recovery process of DMF focuses on distillation technology for its high recovering rate of DMF. But for its long process, large investment and high energy consumption, Study on new technology with low investment and energy consumption has an important theoretical and practical significance.In this paper, catalytic characteristic of different catalysts such as sulfuric acid, H-ZSM-5 catalyst, nickel oxide, Pd/AC to decomposition of formic acid have been studied. It is shown that sulfuric acid, ZSM-5 zeolite, SBA-15, nickel oxide/mesoporous alumina have less effect. The decomposition rate of formic acid is 3% -5% with no practical value. By contrast, Palladium carbon catalyst shows good catalytic characteristic selected as the supported metal catalyst decomposition of formic acid was catalytic amount of catalyst was 1.7%, the decomposition rate of formic acid can reach 87% as 1.7% catalyst. The study focus on the effect of different reaction temperature, amount of catalyst and recycled. The results show the catalytic and repeated characteristic is good. After further research, the catalyst can be applied to the industrial production of DMF recovery with important practical significance.A new extraction-distillation recovery technology of DMF from waste water has been set forth. A suitable extraction solvent (CHCl3) has been select. The influence of ratio of phase, extraction time and standing time on extraction have been discussed effect. The experimental results show that the appropriate operating conditions is that (chloroform /DMF) is 3, the extraction time as10min and standing time was 10min. Under these conditions, five cross-flow extraction recycling rate of DMF reach 91%. A draft technical design of the industrial extraction-distillation recovery of DMF has been provided in this paper.