Removal of Fluoride from Drinking Water Using Egg Shells

Fluoride is one of the ions that naturally occurring and often found in ground or river water both in high and low concentration where its origin might come naturally or anthropogenic. Fluoride in concentration above 1.5 ppm is having a bad side effect to human health since it causes fluorosis that increases the hardness of bones and teeth while reducing their elasticity, thus making the bones brittle.
Removal of fluoride or defluridation is often required in order to reduce the concentration of fluoride in drinking water below its safe level before being consumed. There are many techniques that can be used in order to reduce the concentration of fluoride in water such as adsorption, reverse osmosis, precipitation, and electrodialysis. Adsorption is one of the defluoridation methods that offer low cost and acceptable efficiency without removing other important ions from the water. However its cost and efficiency is highly dependent on its type of adsorbent.
Egg shells, a cheap waste product from food industry, are the chosen adsorbent in this study, where it potential of being an adsorbent of fluoride is being tested by varying the pH and the adsorbent amount. From the study, it is seen that the optimum pH of the adsorption lies at pH around pH5 with highest efficiency of 0.1334942 mgfluoride/gegg shell. Its capability of regeneration is also being tested and NaOH proven to be the effective reagents for its regeneration process. A further study is suggested on looking at the effect of time od the adsorption amount and also further study regarding which is more feasible between regenerating the used eggshell or replace it with a new one.