Appraisal of Fluoride Removal Capability of Al-Fe Oxide-Infused Diatomaceous Earth in a Continuous Flow Fixed-Bed Column

This study was carried out to appraise the groundwater fluoride removal effectiveness of Al-Fe oxide-infused diatomaceous earth (DE) in a continuous flow fixed-bed column. The adsorbent was optimally synthesized and then characterized. A glass column designed for the experiment was packed with the test adsorbent at specific doses. The effects of flow rate, influent fluoride concentration and bed height (adsorbent dose) on fluoride removal were evaluated by fixing the value of a parameter while varying the other. The breakthrough volume was the volume of treated water obtained until the concentration of fluoride in treated was 1.5 mg/L, being the World Health Organization (WHO, 2017) maximum limit of fluoride in drinking water. The maximum breakthrough volume obtained in the study was 118.2 mL at the optimum conditions of influent F- concentration = 5 mg/L, 1–g adsorbent giving an initial bed height = 7.5 cm, and flow rate = 1.97 mL/min. Channeling and co-existing anions were limiting factors for the attainment of breakthrough volume for groundwater defluoridation. Further work using granulated adsorbent may probably improve the rigidity of adsorbent and reduce channeling effect.