新型除氟载铁(Fe^3+)螯合絮凝剂的制备研究

Study on preparation of novel defluorinated ironloaded(Fe^3+)chelating flocculanty

以聚丙烯酰胺絮凝剂为原料,利用铁盐对氟离子的还原作用,将絮凝剂载铁改性得到载铁螯合絮凝剂,该改性絮凝剂能达到从水中除去F-的目的。通过改变改性实验中絮凝剂的用量、铁离子的浓度、pH值、反应温度、反应时间来确定除氟剂的最佳制备参数,用等温吸附模型描述对其除氟过程进行拟合,并探究干扰离子对载铁絮凝剂除氟效果的影响。实验表明,改性实验的最佳反应条件为4 mL亚氨基二乙酸接枝聚丙烯酰胺絮凝剂,0.013 mol/L三氯化铁溶液,pH值为2.1,在35℃下反应50 min,除氟率可达97%,除氟过程可用Freundlich等温吸附模型描述。Na2SO4对除氟效果影响严重,KCl和CaCl2次之,用改性载铁絮凝剂除氟时,要先除去干扰离子,避免减弱除氟效果。方法不会在水中引入其他离子、成本低、操作易、除氟效果好、可用于大规模含氟水处理。

Polyacrylamide flocculant was used as the raw material,using iron salts to reducte fluoride ion,modification of flocculant-loaded iron to obtain iron-bearing chelating flocculant and achieving the aim of removing the content of F-from the water.Determine the optimal preparation parameters of the defluorinating agent by changing the amount of flocculant,the concentration of iron ions,the pH value,the reaction temperature and the reaction time in the modification experiment,fitting the defluorination process by an isothermal adsorption model description,and explore the effect of interfering ions on the defluoridation effect of iron-loaded flocculants.The experiments indicate that the best reaction conditions for modification experiment is that 4 mL iminodiacetic acid grafted polyacrylamide flocculant,the iron content in Fe^3+soln is 0.013 mol/L,the pH value is 2.1,reaction temperature is 35℃,react 50 min,the removal rate of F-in the water is 97%and the defluorination process can be described by Freundlich isotherm adsorption model.Na2SO4 has a serious effect on the fluoride removal effect,followed by KCl and CaCl2,so when using modified iron-loaded flocculants to remove fluoride,first remove interference ions to avoid weakening the effect of fluoride removal.The method does not introduce other ions into water,has low cost,easy operation,good defluorination effect,and can be used for large-scale fluorine-containing water treatment.