Adsorptive removal of phosphate from aqueous solutions using iron-lanthanum-doped foam glass adsorbent

The purpose of this study was to develop an adsorbent for phosphate using iron-lanthanum-loaded foamed glass recycled from colored glass bottles. The optimal preparation conditions for the adsorbent were 0.1% iron and 1% lanthanum loaded onto the foam glass and calcined at 350°C for 2 h. Adsorption kinetics for phosphate onto the adsorbent were fitted to pseudo-second-order model. The phosphate adsorption was identified as chemisorption, which occurred due to ligand exchange. The adsorption isotherm for phosphate on the adsorbent was expressed as a Langmuir model. The maximum adsorption capacity was calculated to be 1.3 mg-P g^-1. The equilibrium constant (3.1 L mg^-1) of the adsorbent was significantly higher than that of previous studies. Hence, the adsorbent developed in this study demonstrated favorable adsorption at low phosphate concentrations, indicating that it can remove phosphate from domestic wastewater and natural water. The adsorbent is a promising and cost-effective phosphate adsorbent that promotes waste glass recycling. PRACTITIONER POINTS: Adsorbent for phosphate using iron-lanthanum-loaded foamed glass recycled from colored glass bottles was developed. The adsorbent demonstrated favorable adsorption at low concentrations of phosphate. The adsorbent is effective in removing phosphate from domestic and natural waters.