Assisting the carbonization of biowaste with potassium formate to fabricate oxygen-doped porous biochar sorbents for removing organic pollutant from aqueous solution.

[Display omitted] • OPBs were synthesized by the assisted-pyrolysis of biowaste with potassium formate. • O content (26%) and surface functional groups were abundant in OPBs. • Pore structure with high specific surface area (1386 m2 g−1) was formed in OPBs. • OPBs showed enhanced sorption capacity for DEP (453 mg g−1). • Pore filling, π-π stacking and H bonding dominated the DEP sorption by OPBs. In contrast to the efforts dedicated to applying porous biochars in environmental remediation, the search for green synthesis methods, which are crucial for industrialized production, is often neglected. Herein, oxygen-doped porous biochars were prepared for the first time by the assisted carbonization of hydrochar with a novel noncorrosive activator, potassium formate, and these biochars displayed a porous structure with large amounts of micropores (surface area: 1242 ∼ 1386 m2 g−1). Interestingly, the biochars contained an abundance of oxygen element (20 ∼ 26%), which formed many functional groups. Through sorption experiments, it was demonstrated that the oxygen-doped porous biochars were excellent sorbents for diethyl phthalate, and maximum sorption quantity reached 453 mg g−1. Monolayer sorption by pore filling, hydrogen bonding, electrostatic interaction and π-π stacking was the potential mechanism. This finding indicated that potassium formate was promising as an activator to greenly convert biowaste into advanced biochars for removing organic pollutants from aqueous solutions. [ABSTRACT FROM AUTHOR]