FeCl3和AlCl3协同絮凝去除焦化废水中氟和有机物

Simultaneous removal of fluoride and organic matters from coking wastewater by coagulation

氟是焦化废水中的待去除的主要污染物。采用FeCl3和AlCl3作为絮凝剂,研究了絮凝对焦化废水中氟和有机物的去除效果,并考查了不同剂量和pH条件下氟和有机物的去除率。结果表明:AlCl3和FeCl3对F-的最高去除率分别为94.4%和27.3%;在投量为20 mmol·L^-1时,FeCl3和AlCl3的TOC去除率分别达到27.6%和23.9%。因此,AlCl3对氟的去除率比FeCl3的更高,但FeCl3对有机物的去除率相对更高。加入Ca^2+可以促进氟的去除,但有机物的去除率会下降。另外,通过考察不同pH和铁铝配比对去除率的影响,探讨了同时加入FeCl3和AlCl3的去除效果。结果表明,最适合去除有机物和氟的工作条件是pH为6.5,AlCl3和FeCl3的比值为8∶2。本研究探索了FeCl3和AlCl3对焦化废水中氟和有机物的去除机理,实验结果可为焦化废水的深度处理提供参考。

Fluoride is a predominant contaminant to be removed from coking wastewater.Here,we used AlCl3 and FeCl3 as coagulants,investigating the removal of fluoride and organic matters from coking wastewater,accompanied by exploring the effect of pH and coagulant dosage on the removal efficiency.The results suggested that the best fluoride removal efficiency for AlCl3 and FeCl3 were 94.4%and 27.3%,respectively.At dosage of 20 mmol·L^-1,the removal efficiency of total organic carbon(TOC)for FeCl3 and AlCl3 were 27.6%and 23.9%,respectively.Therefore,AlCl3 has greater potential to remove fluoride,while FeCl3 exhibited higher removal efficiency of organic matters.The addition of Ca^2+had some positive effects on fluoride removal,even though decreased the removal efficiency for organic matters.Besides,the performance of Al-Fe combined coagulant was also studied by investigating the effects of pH and Al/Fe ratio on the removal efficiency of fluoride and organic substances.It is suggested that the optimal working condition for the removal of these matters was achieved with the pH of 6.5 and the Al/Fe ratio at 8∶2.In this study,the mechanism of FeCl3 and AlCl3 for the removal of fluorine and organic matters in coking wastewater was explored,and the results can provide reference for the advanced treatment of coking wastewater.