预分散溶剂萃取法处理Cr(Ⅲ)废水

摘要

The extraction experiments of chromium(Ⅲ) from aqueous waste solution by predispersed solvent extraction (PDSE) process with extractant (HEHPEHE) and its mixture, including acidic extractant (D2EHPA),alkaline extractant (TOA) and neutral extractant (TBP) were carried out respectively.It is found that the extractant HEHPEHE exhibited high extraction selectivity to chromium(Ⅲ) from aqueous waste solution.The colloidal liquid aphrons (CLAs) were successfully generated using kerosene as a solvent,HEHPEHE as an extractant,sodium dodecyl benzene sulphate (SDBS) as a surfactant in aqueous phase and polyoxyethylene sorbitol anhydride monolaurate (Tween-20) in oil phase.To study the extraction efficiency and advantages of the PDSE process in the removal of chromium(Ⅲ),the effects of major factors,such as initial chromium(Ⅲ) concentration,volume of colloidal gas aphrons (CGAs),HEHPEHE volume fraction,phase ratio (solvent phase to water phase),mass fraction of dodecyl trimethylammonium bromide (HTAB),mass fraction of SDBS,mass fraction of Tween-20 and initial pH of aqueous waste solution were also investigated and the appropriate process conditions were obtained.Under the appropriate conditions,the extraction efficiency of chromium(Ⅲ) above 99.9 ％ can be achieved and the treated aqueous waste solution can be discharged directly without polluting the environment.%以2-乙基己基膦酸单2-乙基己基酯(HEHPEHE)为萃取剂,以及与其它萃取剂形成酸加酸、酸加碱、酸加中性混合萃取剂,通过考察萃取剂对废液中的Cr3+萃取分配比的影响,筛选出萃取Cr3+的适宜萃取剂HEHPEHE；采用预分散溶剂萃取技术对含Cr3+废液进行分离研究,以煤油为稀释剂,HEHPEHE为萃取剂,十二烷基苯磺酸钠(SDBS)为水性表面活性剂,吐温20(Tween-20)为油性表面活性剂,制备胶质液体泡沫CLAs.同时,为了研究预分散溶剂萃取技术萃取Cr3+废液的效果,考察了废液中的Cr3+浓度、胶质气体泡沫CGAs体积、萃取剂浓度、相比、阳离子表面活性剂十六烷基三甲基溴化铵(HTAB)浓度、阴离子表面活性剂SDBS浓度、表面活性剂Tween20浓度以及Cr3+废液的pH值等影响因素对Cr3+的萃取率影响,得到了萃取Cr3+的适宜条件；并用实际的含Cr3+废液进行检验,结果表明,在获得的适宜工艺条件下,经过二级萃取后,废水可以直接排放,Cr3+的萃取率超过99.9％.