The high-enriched cyanogen in pyrethrin wastewater was precipitated in the form of ferrous ferrocyanide ( Fe 2) by ferrous sulfate, then the ferric ferrocyanide ( Fe 4 3), iron blue precipitation with less solubility was formed by means of aeration. 用硫酸亚铁将菊酯生产废水中的高浓度CN-沉淀为Fe2[Fe(CN)6],经曝气后转化为溶解度更小的Fe4[Fe(CN)6]3铁蓝沉淀。