Phosphorus elimination from aqueous solution using ‘zirconium loaded okara’ as a biosorbent

• ZLO exhibited reasonably high phosphorus adsorption capacity (44.13 mg/g).
• Except pH 12, pH 2–11 had a minor effect on phosphorus retention by ZLO.
• Phosphorus removal by ZLO was rapid with the efficiency reached 95% in 30 min.
• The adsorption process had feasible, spontaneous, and endothermic nature.
• Phosphorus was captured by ZLO predominantly as chemisorption.

This work deals with the capture of phosphorus from aqueous solutions by biosorption onto zirconium loaded okara (ZLO). The batch-mode experiments were conducted to examine the effect of pH, biosorbent dose, initial phosphorus concentration, contact time, and temperature on the process. It was found that, the adsorption was most favored in the pH range of 2–6. The optimal doses for the adsorption, at initial phosphorus concentrations of 5, 10, 25, 50 mg/L were 2, 3, 7, 10 g/L, respectively. The maximum adsorption capacity of ZLO was approximately 44.13 mg PO4/g at 298 K. The phosphate removal was rapid, reaching 95% in 30 min. Freundlich model best fitted the equilibrium data, while Pseudo-second order model satisfactorily described the kinetic results. Thermodynamic analysis revealed feasible, spontaneous, and endothermic nature of the process. The research would be beneficial for developing a promising, eco-friendly phosphorus biosorbent from a plentiful AWB – okara.