Batch Adsorption of Fluoride from Aqueous Solution onto Zr-loaded Garlic Peel (Zr-GP) Particles

摘要

In China, huge amount of garlic is consumed every year, and massive amount of peels are disposed, causing a sever problem in the community. So for the environmental interest, we try to prepare this biowaste to be a low-cost adsorbent to remove fluoride from water. Garlic peel, after pretreatment and activation, was loaded with zirconium(Ⅳ), and used to adsorb the fluoride anion from the aqueous solution. Adsorption kinetics of fluoride are well described in term of pseudo-second-order rate equation, and the adsorption process is strongly dependent on the pH, in the range of pH 2～4, the adsorption of fluoride was quite effective, and the adsorption process fits Langmuir model well, and maximum adsorption capacity at equilibrium pH 2 and 6 was evaluated as 1.10 and 0.89 mol fluoride per kg of Zr-loaded garlic peel gel, respectively. The other coexisting anions such as nitrate, sulfate and phosphate were tested and found that nitrate and sulfate had no negative effect on the adsorption of fluoride, while phosphate a little. So it is quite feasible to utilize garlic waste to prepare the adsorbents for fluoride removal from aqueous solution, showing very good development potential for the groundwater treatment in many countryside areas, e.g., in China.