Phosphate ion removal from a solution by soda-lime borosilicate glass

The excessive phosphate ion content in industrial wastewater causes water eutrophication. The objective of this study is to develop a new method of phosphate ion removal from wastewater using soda-lime borosilicate glass. Soda-lime borosilicate glass with high content of modifiers is reacted in a solution containing phosphate ions. Ca²⁺ ions that are leached out of the glass combine with P⁵⁺ ions in a solution to form hydroxyapatite crystals on the glass surface. The phosphate ions can thereby be removed from the solution. The phosphate ion removal rate was highest when glass containing 20–30 mol% of CaO was reacted in a solution with pH of 3.0. The phosphate ion removal rate was faster when the glass was reacted with the solution under a dynamic condition than under a static condition. The elimination rate also strongly depended on the surface area of the glass.