Abstract—The adsorption of phosphate onto zirconium-loaded activated carbon (Zr-AC) was studied, and phosphate was recovered from deep seawater using the Zr-AC. The Zr-AC complex was prepared by mixing activated carbon with a zirconyl nitrate solution. The amount of phosphate that adsorbed onto the Zr-AC depended on the pH of the solution. Phosphate was adsorbed quantitatively at below pH 8.0, and the amount adsorbed decreased as the pH increased. Zr-AC was found to adsorb phosphate from seawater almost as efficiently as from an aqueous solution made with distilled water. The equilibrium adsorption capacity of the Zr-AC for phosphate in seawater was measured and extrapolated using the Langmuir and Freundlich isotherm models. The Langmuir model fitted the experimental data better than did the Freundlich model, and the calculated maximum adsorption capacity for phosphate was 0.64 mmol/g. Phosphate was recovered from deep seawater using a chromatographic selective recovery process using a packed-bed column. The results showed that phosphate was selectively adsorbed in the adsorption step, and the phosphate could be recovered and concentrated into a NaOH solution in the desorption step. The adsorbent in the column was able to be repeatedly used to recover phosphate from seawater.
Index Terms—lumn test, deep seawater, phosphate recovery, Zirconium-loaded activated carbon.
Takaaki Wajima is with the Department of Urban Environment Systems, Graduate School of Engineering, Chiba University, Japan (e-mail: wajima@tu.chiba-u.ac.jp).
[PDF]
Cite: Takaaki Wajima, "Phosphate Adsorption on Zirconium-Loaded Activated Carbon, and its Application for Phosphate Recovery from Deep Seawater," International Journal of Chemical Engineering and Applications vol. 7, no. 6, pp. 388-393, 2016.
