Fluoride in Groundwaters of Southeastern Algeria Region and Their Removal by Cattle Bone Particles

This study focused on fluoride (F − ) concentrations, its distributions in groundwater of Southeastern Algeria region, and its removal using locally produced cattle bone (adsorbent). The contents of F − ions, before and after treatment, were measured by UV–visible spectrometer (Hach DR 6000) at 580 nm. The adsorbent was characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and the phases were identified using the “X'PertHighscore plus” software. The F − water wells concentrations ranged from 0.83 to 2.14 mg/L, with 1.45 mg/L average, where 38% of 21 water sources showed F − values > 1.5 mg/L. The experiment showed that the removal rate of F − reached 100% after a contact time of 60 min using 2 g/50 mL of adsorbent dosage with a diameter of 0.2 mm and F − initial concentration of 2.14 mg/L. The adsorption capacity is considerably dependent upon the particle size, dosage adsorbent, and contact time. However, whatever the particle size, all the residual concentration values obtained were lower than recommended concentration (1.5 mg/L). The experimental data fitted well with Pseudo-second-order model, which suggest the F − adsorbs on cattle bone by chemisorptions (ions exchanges) mechanism. The regeneration study also showed that more than 87% of the adsorption capacity of the spent bone could be recovered.