Reclamation of phosphorus (P) from wastewater using metal-engineered biochar and its reuses as phosphate fertilizers could be an eco-friendly and effective technology for the sustainability of environmental and agricultural systems. Herein, we studied the P removal capacity of filter cake-engineered biochar loaded with Al and Fe and examined their available P release capability into the sand sample. The Al-biochar (63.7 mg/g) had a higher P retention capacity than the Fe-biochar (33.2 mg/g). Over 45 days of the incubation, Al-and Fe-biochar incorporation steadily or increasingly released adequate concentrations of available P to the sand sample. Furthermore, a considerable P fraction (99.4-99.8% of the total P) remained in all metal-biochar samples, suggesting that the metal biochar could be a long-term source of the available P pool. This study highlighted the potential use of Al-and Fe-biochar for providing available P availability in sandy soils.

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