Adsorptive Removal of Phosphorus using Metal-Loaded Biosorbents from Aquatic Environment

Abstract

Adsorption gel for metal ions was prepared from orange juice residue in a simple manner by interacting with calcium hydroxide. Heavy metal ions such as lead(II), iron(III) and copper(II) were selectively adsorbed over other metal ions such as zinc(II), cadmium(II) and manganese(II) at low pH. Loading this gel with high valent metal ions such as lanthanum(III), cerium(III) and zirconium(IV) resulted in effective and selective adsorption of phosphate from water containing excess concentrations of other anionic species such as sulfate, carbonate and chloride. Zirconium(IV) was the most effective among the metal ions. Among the phosphorus compounds, phosphate was more strongly adsorbed on zirconium(IV)-loaded gel than phosphite and hypophosphite. The adsorption capacity for phosphate on the zirconium(IV)-loaded gel was the highest among adsorbents that have been reported in literature, including other zirconium(IV)-containing adsorbents. The effectiveness of this gel was verified by applying it to actual wastewater samples containing trace concentrations of phosphorus.