Bone Char from an Invasive Aquatic Specie as a Green Adsorbent for Fluoride Removal in Drinking Water

In this study, bone chars were obtained from an alien aquatic species "devilfish" bones by pyrolysis of 500-800 degrees C. Bone chars were evaluated as a sustainable adsorbent of fluoride, and it was found pyrolyzed bone char at 500 degrees C adsorbed the most amount of fluoride. Thermodynamic parameters of fluoride adsorption on devilfish bone chars were estimated as Delta H degrees = 7.213 kJ mol(-1), Delta G degrees = 23.61 kJ mol(-1), and Delta S degrees = 103.4 J mol(-1) K-1 indicating that adsorption is endothermic, spontaneous, and with a great affinity of fluoride on bone char. The fluoride desorption study showed that fluoride is desorbed from the material of 0.24 to 20.06%, so the adsorption is considered to be partly reversible. The regeneration of the bone char at 400, 500, and 600 degrees C was studied, and it was noted that its adsorption capacity decreases slightly, so it could be considered appropriate for the use in water treatment technologies. Adsorption of fluorides from drinking well water of a rural community with dental fluorosis problems and high levels of fluoride in water revealed that by increasing the amount of the bone char of 0.05 to 0.8 g, the disposal of fluoride increases from 69.1 to 98.7%. Lastly, it was established that the bone char synthesized from devilfish is a low-cost, viable, sustainable material to remove fluorides from water and represents an environmental management strategy of this alien species.