Hook-and-Destroy Strategy for Efficient Activation of Persulfate by B-Doped Pyrochar for the Removal of Contaminants of Emerging Concern from Wastewater

This study presents a sustainable and efficient strategy for removing contaminants of emerging concern (CECs) from wastewater using non-metal-doped pyrochar catalysts synthesized via a green, one-step pyrolytic process from pinewood sawdust, urea, and boric acid. The resulting N- and B-doped pyrochars were evaluated for their ability to activate peroxydisulfate (PDS) and degrade a mixture of 25 CECs (15 pesticides and 10 pharmaceuticals). B-doped pyrochar exhibited superior bifunctional performance, combining high adsorption capacity with efficient catalytic PDS activation. Structural characterization confirmed the incorporation of boron into the carbon matrix, generating electron-deficient Lewis acid sites and enhancing the affinity toward PDS and CECs. Quenching and adsorption-degradation analyses revealed a synergistic combination of radical and non-radical pathways, supported by π-π interactions, hydrogen bonding, and Lewis acid-base interactions. Reusability tests confirmed long-term stability and high degradation efficiency over four cycles. These findings demonstrate the potential of B-doped pyrochar as a cost-effective, stable, and environmentally friendly catalyst for practical wastewater treatment.