The Fluoride Removal in Water by Egg Shell, Activated Carbon, and Rice Husk Ash

Abstract

This research objective was to examine the efficiency of fluoride removal from the water by egg shell,
activated carbon, and rice husk ash by using adsorption process. The continuous adsorption columns were
used in this experiment. The heights of adsorbents were 60 cm. and the primary concentration of fluoride in
synthetic water was 10 mg/l. The experiments were divided into 3 phases. The first phase was the comparison
of the efficiency of fluoride removal from the water by 3 adsorbents. The second phase was the comparison of
the efficiency of fluoride removal from a sequence different of adsorbents. The third phase was the
examination of mixed adsorbents for fluoride removal. The water samples were collected after tested and
composite samples were taken to analyze the residues fluoride concentration by using Electrode method
(3 replications).
The results found that the 3 adsorbents had the efficiency of fluoride removal exceeded 40 %. The
egg shell had the highest fluoride removal efficiency at 61.8 %, following by activated carbon (53.4 %) and rice
husk ash (42.5 %), respectively. The comparison of the efficiency of fluoride removal from a sequence different
of adsorbents were not significantly different at 0.05 (p-value = 0.960). And the mixed adsorbents showed the
reductions in fluoride up to 62%.