Nitrogen-doped porous hydrochar for enhanced chromium(VI) and bisphenol A scavenging: Synergistic effect of chemical activation and hydrothermal doping.

Nitrogen-doped porous hydrochar (NPHC) was successfully synthesized by hydrothermal carbonization and activation with KHCO ₃ , which was employed for scavenging hexavalent chromium (Cr(VI)) and bisphenol A (BPA) in contaminated water. N doping increased the unique active sites such as amino and molecular N in NPHC for adsorbing contaminants, and enhanced the activation effect. Compared to original (HC) and N-doped hydrochar (NHC), the S _BET of material improved from 3.99 m ² /g and 4.71 m ² /g to 1176.77 m ² /g. Meanwhile, NPHC exhibited more superior adsorption capacity for Cr(VI) (323.25 mg/g) and BPA (545.34 mg/g) than that of porous hydrochar (213.17 and 343.67 mg/g). Moreover, NPHC possessed pH-dependence and presented more excellent tolerance for interfering ions and regeneration performance. Notably, the Cr(VI) capture by NPHC was dominated via pore filling, electrostatic interaction, reduction, and complexation, while π-π stacking, H-bond interaction, and hydrophobic action were relevant to the binding mechanism of BPA. Overall, the proposed functionalization strategy for biochar was conducive to enhance the remediation of water bodies.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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