Experimental study on fluoride removal from mine water by complexing-induction fluoride removal agent

Abstract

In ecologically fragile areas of western and northwestern China, where coal mine water is reused as domestic water or discharged into surface water systems after treatment (the discharge concentration of fluoride (F^-) is less than 1.0 mg/L). In order to solve the disadvantages of adsorption technology such as complicated process, difficult operation and management and unstable effluent quality, an experiment was carried out to remove fluoride by complexing-induction fluoride removal agent. The effects of dosage, reaction time, pH value and turbidity on fluoride removal were investigated, and the defluorination mechanism was analyzed. The results showed that the complexing-induction fluoride removal agent could capture ionic fluoride in mine water through the complex adsorption and chemical induction, and finally form blended precipitates to remove fluoride. When the dosage of the fluoride removal agent was 45 mg/L, reaction time was 12 min, pH value was 8~9 and the turbidity of raw water was less than 100 NTU, the concentration of fluoride ions in the simulateds mine water could be reduced from 5 mg/L to less than 1.0 mg/L. Carbonate ions affected fluoride removal significantly, followed by sulfate ions, while chloride ions had no obvious influence. In the continuous experiment of fluoride removal from mine water, the concentration of fluoride in the effluent was 0.75~0.90 mg/L, and the turbidity was 8.2~10.0 NTU.

Keywords

• complexing-induction fluoride removal agent
• mine water with fluoride
• mine water treatment
• fluoride removal mechanism