Fluoride Removal from Aqueous Solution Using Thermally Treated Dolomite Powder as Adsorbent in the Fixed Bed Column

Aim: 
The objective of this paper was to investigate the ability of thermally treated dolomite powder (TTDP) to remove fluoride ions from wastewater in a fixed bed column system, and to understand how different operating parameters such as bed height, initial fluoride concentration, and flow rate of influent affected the performance of the system.
Materials and Methods: 
The researchers used several different models to analyze the data collected from the column experiments, and they also characterized the TDP adsorbent using field emission scanning electron microscopy and X-ray diffraction in order to understand its surface morphology.
Results: 
Adsorption capacity increased with the initial fluoride concentration and decreased with bed height. Saturation concentration increases with an initial concentration of fluoride and decreases with bed height and flow rate of influent. Error analysis between experimental results and model results has been done using different predefined error functions. Regeneration of TDP adsorbent is done using a 1N NaOH solution.
Conclusions: 
The breakthrough time increases with a low flow rate of 15 ml/min, low influent concentration of 5 ppm, and higher bed depth of 20 cm. The experimental data from the fixed bed column for fluoride removal are well fitted with all classic models, and the coefficient of regression is close to unity. Regeneration studies have shown that the adsorbent (TTDP) can undergo three cycles of regeneration.