电促灰岩离解动态除氟实验研究

高氟地下水的除氟是保证居民远离氟地方病的有效手段之一。本研究利用新型封闭除氟装置探究电促灰岩动态除氟的化学驱动力、主控因素及稳定除氟能力。结果表明,在电场强化条件下,与灰岩接触的高氟水会形成局部萤石过饱和,可有效去除水中过量的氟。整个反应过程可分为启动阶段与稳定阶段。电压梯度是除氟反应主控因素,当电压梯度大于4. 8V·cm~(-1)时,除氟效果较好。反应过程中阳极附近F-富集高于初始浓度,而阴极附近更易生成CaF_2沉淀,表明阴极除氟效果更优。灰岩固体颗粒表面形态变化巨大,存在明显的腐蚀现象。当两极电压差为24V、极板间距3cm时,阴极附近氟浓度能迅速地由10mg·L~(-1)降低至国家饮用水标准以下。

The Experimental Study on dynamic De-fluorination with Limestone in Electric Field

High fluoride groundwater de-fluorination is the one of the most effective methods to ensure local residents away from endemically fluorine diseases. A new type of sealing de-fluorination device was used to find out the driving force, influence factors and de-fluorination ability of dynamic de-fluorination with limestone in electric field. The research presented that the fluorine could be degraded and the fluorite would be over formed as the reacting between limestone and high fluoride water in electric field. And the whole process could be divided into initialization phase and stabilization phase. Furthermore the voltage gradient is the main factor of the de-fluorination. The ability of de-fluorination would increase if the voltage gradient is over 4.8V/cm. During the process, the concentration of F_- would enrich at anode and CaF₂ would be formatted at cathode, which indicate de-fluorination will be better at cathode. Also the configuration of limestone surface varied much and corrosion could be observed clearly. When the voltage was 24V and distance between electrodes was 3cm, the concentration of fluoride at cathode decreased to the Nation Sanitary standard for drinking water quickly.