Adsorptive removal of fluoride in groundwater

This study focused on the removal of fluoride from groundwater by selecting the highest performing fluoride removal adsorbent among locally available adsorbents using laboratory scale batch adsorption studies. The adsorbents tested were high aluminium content bauxite ore (HABO), high iron content bauxite ore (HFBO), locally fabricated zeolite and pulverised activated neem seeds. The model water used was prepared by simulating the prevailing groundwater quality in Northern Ghana. After screening the adsorbents, the HABO was the best fluoride removal adsorbent. The removal of fluoride using the HABO decreased with increasing pH. Averagely, sulphate, chloride and nitrate in the model water reduced the removal capacity of the HABO by 57, 24 and 38% respectively. The combined effect of these anions showed a 60% reduction in the removal capacity of the HABO. The adsorption data fitted Freundlich and Langmuir isotherms and the adsorption capacity (K) was 0.90 mg/g. The kinetic studies indicated the type of adsorption to be chemisorption.The HABO was characterised by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Energy Dispersive X-ray (EDX) and Thermogravimetric analysis (TGA).