Research On Process Of Integrated Treatment Of Synthetic Leather Wastewater Containing DMF

The integrated approach of extraction, distillation and adsoroption of DMF wastewater has been proprosed in the paper, for the problem of high energy consumption of traditional distillation in dealing with the DMF wastewater. Firstly DMF in the wastewater is extracted with low boiling chloroform, and then the extractant and DMF are separated by the process of distillation, and lastly the content of DMF in the raffinate is dealt to meet the national emission standard through the process of adsorption.In the condition of the volume’s ratio of chloroform and wastewater to be2:1, the concentration of DMF in the raffinate reaches4.458g/L after the synthetic leather wastewater disposed by six countercurrent extractions, and the overall extraction rate of DMF reaches97.62%. The rectification process of DMF-chloroform system is simulated by the software of Aspen Plus, the result shows that the number of trays of the atmospheric rectification column is10, and the feed position is the6th tray, and the reflux ratio is2; the number of trays of the vacuum rectification column is8, and the feed position is the4th tray, the reflux ratio is3. The mass fraction of chloroform obtained by the distillation is0.9999, and the mass fraction of DMF is0.9984. According to the study of the dynamic adsorption of activated carbon on the raffinate, the dynamic adsorption performance is better when the flow rate is2mL/min, and the diameter of activated carbon particle is1～2mm. In this case, the breakthrough point of dynamic adsorption is180min, the saturated adsorption capacity of the activated carbon on DMF is53.50mg/g. The concentration of DMF can be reduced to less than9.6mg/L after the raffinate disposed by dynamic adsorption which achieves the first level of the national standard. The activated carbon disposed by adsorption treatment is regenerated by hot air, and the adsorption capacity of regenerated activated carbon is87.01%of the new activated carbon. The capacity reaches82.95%after the activated carbon dealt with4times of adsorption regeneration cycles.