Evaluation of Removal Efficiency of Fluoride from Aqueous Solutions Using Modified Carbon of Oak Fruit: Isotherm and Kinetic Studies

Abstract

Fluoride is one of the developed compounds that can enter water resources in different ways. The World Health Organization has recommended its maximum permissible concentration in drinking water of 1.5 mg/l so that its concentration exceeding the permissible limit can be harmful to the health of living organisms and ecosystems. The aim of this study was to determine the efficiency of activated carbon modified by the thermo-chemical method from oak fruit in fluoride removal. This research was conducted in a discontinuous system on a laboratory scale, and for this purpose, the effect of effective parameters such as time, pH, concentration, adsorbent dose, and other factors was investigated. The results of the experiments showed that the maximum amount of removal takes place during 90 min, pH=3, adsorbent dose of 0.1 g/l, and pollutant concentration of 50 mg/l. The results of the synthetic models showed that the Freundlich model with the coefficient of determination (R2=0.863) is a better model than the Langmuir model with the coefficient of determination (R2=0.736) to describe the synthetic behavior of the absorber. Until now, most absorption methods have been performed to remove the pollutant concentration of 30 mg/l. In the current study, with the input pollutant concentration of 50 mg/l, it can be stated that the activated carbon modified from the oak fruit is a cheap, efficient, and effective adsorbent. It is considered available to remove fluoride from aqueous solutions.