Preparation of Iron Salt-Modified Sludge Biochar and Its Uptake Behavior for Phosphate

Residual sludge is a significant waste resource, and the preparation of biochar achieves disposal. Biochar has high uptake capacity for phosphate. To prepare adsorbent phosphate, was chemically anaerobically treated in presence iron salts pyrolyzed. We investigated effects pyrolysis temperature salt on phosphate capacity, finding that pretreatment with removed intrinsic thus improving ability. The optimal adsorbent, denoted SB-B-Fe, prepared by at 700 °C subsequently modified 20 g/L iron-containing solution, yielding 0.5 mg/g. Further, performance SB-B-Fe remains pH 5–9 less affected interfering anions. sorption kinetics are consistent pseudo-second-order kinetic model, suggesting chemisorption, Langmuir model saturation 0.85 mg/g prefers monolayer molecular uptake. characterization showed surface provided many sites specific area. hope these findings will encourage development other value-added waste-based materials environmental remediation.