Eco-nano solutions for rapid phosphorus recovery: Closing the loop for sustainable agriculture

Efficient phosphorus (P) removal from agricultural drainage is crucial for making its removal and recovery economically viable and operationally feasible. This study evaluated cost-effective, green-synthesized nanoparticles (using grass extract) for rapid and efficient P adsorption. Batch experiments were conducted to assess the effect of pH, P concentration, adsorbent dosage, contact time, and temperature on P adsorption. The nanoparticles removed 20 mg/L of P in 5 min, demonstrating their significant potential for effective adsorption in short retention time. They achieved a maximum adsorption capacity of 77.5 mg g^-1, outperforming their chemically synthesized counterparts. Moreover, smaller particles exhibited faster initial adsorption, while larger ones contributed more to overall adsorption over time. Modeling results revealed that rapid initial P adsorption was driven by physisorption, while chemisorption controlled the rate of adsorption in the later stages. After five regeneration cycles, the nanoparticles retained over 50 % of their adsorption capacity, demonstrating strong reusability potential. Further research is needed to optimize these nanoparticles for P removal from dynamic agricultural drainage, offering a cost-effective and sustainable solution for P management.