Evaluation of Active Bauxite Mine (Tash) in the Removal of Fluoride From Drinking Water: A Case Study on Kuhbonan Water

Background Intake of high concentration of fluoride causes health problems in human. Therefore, finding a way for removing excessive fluoride from water is among the most important tasks in water supply projects. How to remove excess fluoride from water is the objective of this project, and as a case study, it was carried out with the aim of investigating the efficiency of bauxite ore in Tash mine in removing fluoride.
Materials & Methods The study was performed in a laboratory scale on a synthetic sample collected from the water of Kuhbonan region in the Environmental Health Research Center of Kerman. The adsorbent was prepared from bauxite of Tash mine in Semnan Province. Bauxite analysis was carried out by X-ray fluorescence and diffraction spectrometry methods. The effects of such parameters such as pH, contact time, the adsorbent amount, and different fluoride concentrations on the removal process were investigated. The experiments were performed on real water sample under optimal conditions. To better understand the adsorption process, kinetics and isotherm of the adsorption were investigated, too. The level of fluoride was determined by SPADNS method. For data analysis, Excel software was used.
Results The maximum obtained fluoride removal efficiency was 68.20% in a synthetic sample, at pH=7, contact time of 120 minutes, by using 25 g/L bauxite. This level was obtained 45.84% in the real sample under optimal conditions. Adsorption of fluoride followed Langmuir adsorption isotherm equation with a correlation coefficient of 0.991 and second-order model with a correlation coefficient of 0.985.
Conclusion Without preliminary preparation, the bauxite of Tash mine can be used as an inexpensive and effective absorbent for removing fluoride from groundwater with low concentrations of fluoride.