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DOI : 10.17640/KSWST.2015.23.6.13 ,    Vol.23, No.6, 13 ~ 23, 2015
Title
Removal of Fluoride Using Crushed Concrete and Characterization of Its Adsorption
구본운 Bon Wun Gu , 강구 Ku Kang , 박성직 Seong Jik Park
Abstract
Crushed concrete was used for the removal of fluoride from aqueous solution and its adsorption characteristics were investigated. Adsorption experiments have been conducted in batch conditions. From the experiments using crushed concrete thermally treated at different temperatures, it was found that thermal treatment on crushed concrete had a deleterious effect on the fluoride removal. Kinetic sorption test and model analysis showed that fluoride adsorption to crushed concrete was dependent on chemisorption. Equilibrium adsorption results followed the Langmuir adsorption isotherm model with adsorption capacity of 28.50 mg/g. The estimated thermodynamic parameters (ΔH°, ΔS° and ΔG°) indicated that the adsorption was spontaneous and endothermic. Additional batch experiments indicated that fluoride adsorption to crushed concrete was the highest at pH 3 and decreased with increasing pH. The effect of other anion on fluoride removal by crushed concrete followed the order of PO4^3- > HCO3- > SO4^2- □ NO3-. This study demonstrated that crushed concrete was proven to be an effective adsorbent with high adsorption capacity of fluoride and its use for the fluoride removal is economical and environmentally sustainable.
Key Words
Fluoride, Adsorption, Crushed concrete, Thermodynamic Parameters, Thermal Treatment, Batch Experiment
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