Hydrochars from pinewood for adsorption and nonradical catalysis of bisphenols

In the present study, hydrochars (HCs) were prepared from pinewood biomass by high-temperature pyrolysis and applied as environmental-friendly adsorbents and catalysts in the removal of bisphenol F (BPF) and bisphenol S (BPS) from water. It was found that the structural oxygen defects on hydrochars not only enhance the specific surface area for adsorption of the bisphenols, but also function as an electron conductor for molecular oxygen activation in nonradical pathways. The hydrochar pyrolyzed at 800 °C (HC-800) showed the superior adsorption and catalytic performances toward BPS and BPF removals in a wide pH range, and the removal efficiencies were hardly inhibited by the coexistent inorganic anions and humic acid. Particularly, the nonradical reaction is the dominated catalytic oxidation process in a H₂O₂-HC-800 system, different from the traditional radical-based process with persistent free radicals on hydrochars derived from low-temperature pyrolysis. This study provides a novel route toward the efficient removal of endocrine disrupting compounds via the synergistic adsorption and nonradical catalysis.