Fluoride Removal Research By Adding Metal Oxide And Impregnating Calcined Ceramic Particles

Fluorine is an essential trace element for human beings, the Fluorine is normally contained in the ores in the nature, but it will be dissolved out when washed by the rain, which caused fluorine pollution of surface water and groundwater. China is one of the most serious endemic fluorosis countries in the world. The removal of excessive fluoride from drinking water is of great significance for the protection of lives and health of people. For seeking a novel, new, low cost, high efficiency and easy manufacture craft absorbent. This study could be divided into two parts, we adapted ceramic particles which treated by two different methods as the absorbents to remove the fluoride from aqueous solution. In the first part, adding FeSO4·7H2O and Fe2O3as the ingredients of the ceramics; In the second part, using FeCl3and AICl3salt solutions to impregnate the granular ceramics. The physical characteristics of materials were determined by SEM, XRD, EDS, BET and FTIR. The effect and adsorption characteristic of these ceramic materials were investigated by batch studies, including the effect of dosage, pH, initial fluoride concentration etc., analysis of isotherm parameters and kinetic parameters was taken meanwhile. In the first part, the experiment results indicate that under various pH(2-11), the best adsorption capacity of ceramic materials which contains FeSO4·7H2O is94.23%, the other one which contains Fe2O3is60.48%. Adsorption capacity of these two materials increased with the increase of adsorbent dosage. Adsorption isotherms indicate that both ceramics have surface and intra-particle adsorption during the adsorption process. Adsorption kinetics also indicate that both materials have physical adsorption and chemical adsorption. In the second part, results indicated that under various pH (2-11), the best adsorption capacity89.3%at pH6. Fluoride removal capacity of the coated ceramic materials increased with the increase of initial fluoride concentration. Adsorption isotherms data indicated that adsorption process was fitted to Langmuir isotherm model. The adsorption process was followed pseudo-second-order kinetic models which indicated a physical and chemical adsorption process by this adsorbent.