蛇纹石-粘土复合颗粒吸附地下水中氟离子实验研究

Experimental Study on Adsorption of Fluoride Ion in Groundwater by Serpentine-clay Composite Particles

为高效解决含氟地下水污染问题,采用室内静态实验方法,利用粘结挤压法制备的新型吸附剂蛇纹石-粘土复合颗粒对含氟地下水进行吸附实验研究,分析了在不同投加量、反应时间、振荡速度、p H值、温度、初始氟离子浓度条件下蛇纹石-粘土复合颗粒的除氟性能,并探究了除氟机理。实验结果表明,处理200 m L、5 mg/L的含氟地下水,蛇纹石-粘土复合颗粒投加量500 mg、反应时间120 min、振荡速度120 r/min、p H值6. 5～7. 0、温度30℃时效果最佳,氟离子去除率达94. 32%;去除率随原水氟离子浓度的增大而逐渐减小。吸附动力学拟合结果表明,蛇纹石-粘土复合颗粒吸附剂对氟离子的吸附作用符合准二级动力学方程,吸附等温线符合Freundlich等温吸附模型;应用2. 0 mol/L的明矾对蛇纹石-粘土复合颗粒浸渍12 h进行再生效果较好,再生率为78. 93%。

In order to solve the problem of fluorine-containing groundwater pollution efficiently,using the indoor static test method,the adsorption experiment on fluorine-containing groundwater was carried out by serpentine-clay composite particle,which is a new adsorbent prepared by bonding extrusion method.The defluorination performance of serpentine-clay composite particles with different dosage,reaction time,oscillating velocity,pH value,temperature and initial concentration of fluorine ion was analyzed,and the mechanism of defluorination was investigated.The experimental results show that the best results of fluorine-containing groundwater removal are as follows:total dosage of 500 mg,reaction time of 120 min,oscillating velocity of 120 r/min,pH value of 6.5-7.0,temperature of 30℃for 200 mL groundwater with fluorine of 5 mg/L,and the removal rates for fluorine ion reach 94.32%.The removal rate decreases with the increase of fluoride ion concentration in raw water.The results of adsorption kinetics fitting show that the adsorption of fluorine ion by serpentine-clay composite particles is in accordance with the quasi second order kinetic equation and the adsorption isotherm is in accordance with the Freundlich isotherm model.The regeneration of serpentine-clay composite particles by 2.0 mol/L alum for 12 h is better,and the regeneration rate can reach 78.93%.