Background: Fluoride is an essential element for human health body, since in standard levels, it prevents the tooth decay. If fluoride concentration in drinking water exceeds from standard levels, it can leads to some diseases such as alzeimer syndrome, sterility, brittle bones, and thyroid disorder. So, removal of excess amounts of fluoride seems to be essential in order to health protection and prevention of the environment.

Methods: In this work, modified pumice with HCl and NaOH were used for removal of fluoride from aqueous solution. Several experimental parameters including pH (2-10), temperature (20-60^°C), adsorbent dosage (2-10 g/L), initial fluoride concentration (5-20 mg/L), and contact time were studied. All experiment were conducted in batch system by keeping constant one parameter and changing others.

Results: Results showed that removal efficiency was increased with increase in contact time, initial fluoride concentration and adsorbent dosage. The maximum removal efficiency was observed at pH 6, 10 g/L adsorbent dosage, 20^°C solution temperature, 90 min reaction time and 20 mg/L of fluoride concentration. Moreover, the maximum removal efficiency was observed by adsorbents modified with HCl. In general, results revealed that modified Pumice with HCL could remove 96% of fluoride at 90 min contact time, pH=6, 20^°C and 20 mg/L of fluoride concentration.

Conclusion: Results showed that pumice modified with HCl and NaOH had high capacity in removal of fluoride which the capacity was higher for pumice  modified with HCl.