Reactivity of Fe-amended biochar for phosphorus removal and recycling from wastewater

Using biochar to remove phosphorus (P) from wastewater has the potential improve surface water quality and recycle recovered P as a fertilizer. In this research, effects of iron modification on sorption behavior molecular characterization two different biochars an activated carbon were studied. A produced cow manure anaerobic digest fibers (AD) pyrolyzed under NH 3 gas had greatest phosphate capacity (2300 mg/kg), followed by (AC) (1500 then coniferous forest biomass (BN) (300 mg/kg). Modifying AC with 2% mass increased capacities BN 2000 mg/kg 2300 mg/kg, but decreased AD 1700 mg/kg. Molecular analysis using K-edge X-ray absorption near edge structure (XANES) spectroscopy indicated that calcium minerals predominant species in unmodified biochar. However, Fe-modified biochars, XANES data suggest was sorbed P-Fe-biochar ternary complexes. Phosphorus more available for release (greater than 35% total released) (less 1%). Iron 3% its content, biochar, 1% after Fe modification. Results provide fundamental information needed advance use treatment processes recover it recycling slow-release soil