萃取-吸附法处理二甲基甲酰胺(DMF)废水的实验研究

采用溶剂萃取-活性炭吸附处理某制革厂的高浓度二甲基甲酰胺(DMF)废水(ρ(DMF)为93 4g L),研究了CHCl3对DMF的萃取效果、活性炭对萃余液的动态吸附性能、用溶剂CH2Cl2再生的效果和反复再生后活性炭的吸附性能。结果表明,用CHCl35级逆流萃取后,萃余液ρ(DMF)降到1 33g L,萃取率达98 6%。萃取液拟用精馏分离回收CHCl3和DMF。萃余液经活性炭吸附后COD可降到100mg L以下,达到了国家一级排放标准。饱和活性炭经CH2Cl2洗脱、160℃空气活化再生后,其吸附性能和数量基本不变,可反复使用。 

Study on Treating DMF Containing Wastewater by Solvent Extraction-Activated Carbon Adsorption

Solvent extraction-activated carbon adsorption method was used to treat the N,N-dimethylformamide(DMF)containing wastewater,with DMF concentration of 93.4 g/L,produced from a tannery.The capability of CHCl3 extracting DMF,the capability of activated carbon dynamic adsorption,the regeneration effect of loaded activated carbon and the adsorption effect after regenerated repeatedly were researched by experiment.The experimental results showed that after 5 stages of countercurrent extracting,the DMF content of extraction raffinate decreased to 1.33 g/L,the DMF extraction rate came to 98.6%.CHCl3 and DMF could be recovered by distillation from the extracted solution. After the extraction raffinate was treated by activated carbon adsorption,chemical oxygen demand(COD) of effluent reduced to below 100 mg/L,conforming to Class 1 criterion of the national standard.The loaded activated carbon was washed with CH2Cl2 and regenerated under 160 ℃,and its quantity and adsorption capability almost did not decrease after regenerated repeatedly.