Phosphorus capture first begins via contact by initial surface diffusion followed by intraparticle diffusion into the porous structure. Functionalized surface groups then attract P-ions from the wastewater stream. 

Electrostatic interactions attract p-ions below the point of zero charge via outer sphere complexion. P-ions replace existing ions already on the sorbent surface, while inner sphere complexion via Ligand exchange begins to form stable complexes. New precipitates on surface may also appear.

Once the biochar becomes fully saturated with phosphorus, it is ready for agricultural soils as a phosphorus fertilizer alternative. This application improves soil health while preventing further nutrient loss.