酚类废水的络合萃取预处理研究

Research of complexation extraction in pretreatment of phenolic wastewater

酚类物质不利于废水的生化处理。在废水进入污水站生化处理前,需要对其中的酚类物质进行预处理。采用磷酸三丁酯作为络合剂、正辛醇作为稀释剂处理苯酚和硝基苯酚类废水,研究了温度、pH、萃取剂/废水比对萃取的影响以及萃取剂的再生情况。结果为优化条件下:废水pH=4.0、温度为30℃,萃取剂中磷酸三丁酯与正辛醇质量比为1∶3,萃取剂与废水质量比为0.3∶1,经络合萃取后,废水COD可以从12360 mg/L降至5130 mg/L,BOD5/COD由0.17提高至0.48,废水的可生化性明显改善,可满足生化处理要求。萃取剂可通过NaOH溶液处理再生。络合萃取是一种有效的酚类废水预处理方式。

The phenolic pollutants are harm to the microbes in biochemical treatment of wastewater.Before biochemical treatment of wastewater treatment station,the phenolic pollutants need to be pretreated.In this paper,phenolic wastewater was treated by complexation extraction using tributyl phosphate as complexing agent and n-octanol as diluent.The influences of temperature,pH,extractant ratio to extraction process,and regeneration method of extractant were studied.The results showed that after pretreatment with pH 4.0,temperature 30℃,mass ratio of tributyl phosphate to n-octanol 1∶3,mass ratio of extractant to water 0.3∶1,COD in wastewater was reduced from 12360 mg/L to 5130 mg/L,and BOD5/COD was increased from 0.17 to 0.48.The extractant can be regenerated by NaOH solution.Complexation extraction is an effective pretreatment method for phenolic wastewater.