我国电子、光伏、无机氟化工、煤矿开采、煤基化工等行业产生的废水普遍存在氟化物超标问题,除氟药剂法作为废水除氟的新方法,存在投药量及污泥产生量较大等问题。采用响应曲面BBD法对该除氟药剂的制备条件进行试验设计和优化,并与常用混凝剂除氟性能进行对比。通过扫描电子显微镜分析(SEM)、X射线粉末衍射(XRD)分析手段对不同制备阶段除氟药剂进行表征分析,结合处理后上清液残留元素水平和各元素利用率对除氟机理进行探究。结果表明:除氟药剂最优制备条件为n(M)/n(Si)(M为金属总量)为44.91、n(Al)/n(Mg)为40.64、n(Al)/n(Fe)为34.92,在该条件下所制备的除氟药剂在投药量1.35g/L时,氟离子质量浓度由20mg/L降至0.71mg/L,达到GB3838—2002《地表水环境质量标准》Ⅲ类标准限值1.0mg/L以下,氟离子去除率达96.45%,响应曲面法建立的模型相关系数R2为0.9690;对于初始氟质量浓度10~200mg/L的含氟水样,除氟药剂按比例投加,上清液剩余氟质量浓度均小于1.0mg/L;与常用混凝剂的除氟性能顺序为:除氟药剂>PAC>PAFC>PFS;SEM和XRD表征分析发现除氟药剂形态和结构均发生改变,通过反应聚合形成多种多羟基聚合物,这些多羟基聚合物与氟离子间发生离子交换,从而去除氟离子;通过对上清液残留进行元素分析,结合所投加除氟药剂中各金属元素浓度,分析得出铝、硅、铁、镁的元素利用率分别为99.98%、97.16%、92.22%和18.39%;除氟药剂对多种实际含氟工业废水均高效且适用。

In China, the wastewater produced by electronics, photovoltaic, inorganic fluorine chemical industry, coal mining, coal based chemical industry generally has the problem of exceeding fluoride. As a new method of wastewater fluoride removal, there are problems such as large dosage and sludge production. Preparation conditions of the defluoridation agent were designed and optimized by response surface BBD method, and the defluoridation performance was compared with that of common coagulants. Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) were used to characterize and analyze the defluorination agents at different preparationstages. The mechanism of defluorination was explored in combination with the residual element level and the utilization rate of each elementin the supernatant after treatment. The results show that the optimal preparation conditions for defluorination agents are n(M) / n(Si) (Mrefers to the total amount of metal) is 44.91, n(Al) / n(Mg) is 40.64, and n(Al) / n(Fe) is 34.92. Under these conditions, when thedosage of defluorination agents prepared is 1.35 g/ L, the fluoride concentration can be reduced from 20 mg/ L to 0.71 mg/ L, which is below the limit of 1.0 mg/ L of GB 3838—2022 Water Environmental Quality Standard Class III standard of Surface. The fluoride removalrate reaches 96. 45%, and the correlation coefficient R2 of the model established by response surface method is 0. 969 0. For thefluorine-containing water samples with initial fluorine concentration of 10-200 mg/ L, the fluoride removal agent is added proportioned,and the residual fluorine concentration in the supernatant is all less than 1.0 mg/ L. The order of defluorination performance with common coagulants is: defluorination agent >PAC>PAFC>PFS. SEM and XRD analysis show that the morphology and structure of the defluoridation agents are changed, and a variety of polyhydroxyl polymers are formed through reactive polymerization. The ion exchange occurrebetween these polyhydroxyl polymers and fluoride ions, and the fluoride ions are removed. Based on the analysis of the residual elements inthe supernatant and the concentration of metal elements in the defluorination reagent, the element utilization rates of aluminum, silicon,iron and magnesium are 99. 98%, 97. 16%, 92. 22% and 18. 39%, respectively. The defluorination reagent is effective and suitablefor many kinds of industrial wastewater containing fluorine.

0 引言

1 试验

   1.1 除氟药剂的制备

   1.2 响应面法优化除氟药剂组分

   1.3 废水除氟试验   

2 结果与讨论

   2.1 BBD试验设计及结果

   2.2 除氟药剂效果

   2.3 除氟药剂除氟机理

   2.4 除氟药剂在实际含氟废水处理中的应用

3 结论