A new strategy for enhanced phosphate removal from waters using ferric oxide impregnated biochar

[Display omitted] •Fe@N-BC was fabricated using a positively charged biochar as the host.•Fe@N-BC can preferably and rapidly sequester phosphate from waters.•N-BC promoted the dispersion of ferric oxide and pre-enrichment of phosphate.•Fe@N-BC can effectively treat the synthetic phosphate-polluted in column settings. To overcome application limitation of the available biochar-based metallic oxide composites for the removal of anionic pollutants like phosphate, a new strategy was proposed that metallic oxide was anchored in the positively charged biochar, acquired by introducing high-density quaternary ammonium groups. The resultant nanocomposite adsorbent Fe@N-BC exhibited high adsorption speed, capacity and preference to phosphate. In the existence of competing anion Cl- at higher levels, Fe@N-BC possessed 3–5 times greater working adsorption capacity of phosphate than a commercial phosphate adsorbent D201 and the mixture of ferric oxide and N-BC with the same proportion as the composite. Fixed-bed adsorption runs of Fe@N-BC could treat ∼ 194 bed volumes (BV) of a synthetic phosphate-polluted wastewater before breakthrough achieving (