Adsorptive Behavior of Phosphate onto Activated Carbons Varying Surface Physicochemical Properties

Abstract

This study demonstrated the modification of commercially available activated carbons (CS and R1) by de-ashing (DA), oxidation (Ox) and outgassing (OG) treatment to possess different surface area, pore volume, and the amount of surface functional groups, and these parameters were related to the efficiency of phosphate removal. The results showed that positively charged carbon surface due to the adsorption of protons to the basic sites resulted in the promotion of phosphate adsorption, that is, the extent of the surface area with the basic sites such as Cπ electrons and/or basic oxygen groups would enable to enhance the efficiency of phosphate adsorption.

Keywords:

• activated carbon
• coexistent anion
• phosphate adsorption
• solution pH
• surface functional group

ACKNOWLEDGEMENTS

This study was funded in part by the Japan Society for the Promotion of Science (JSPS) under Grants-in-aid for Scientific Research (C) (No. 23510091). The authors wish to express gratitude to Prof. Dr. Masami Aikawa of Kisarazu National College of Technology for his fruitful discussion. Gratitude is also extended to Prof. Dr. Keiichi Nagao, Head of Safety and Health Organization, Chiba University, for his encouragement and support on this work. We also thank anonymous reviewers for providing their useful comments and suggestions on the manuscript.

Notes

*Total acidic.