Composite hydrogel derived iron/nitrogen co-doped carbon for bisphenol A removal

Abstract

Conventional carbon-based adsorbents encounter insufficient active sites, low adsorption efficiency and poor anti-interference ability for bisphenol A (BPA) removal. Herein, we developed a cellulose nanocrystal/polyacrylic acid hydrogel derived strategy for the preparation of a novel iron/nitrogen co-doped carbon (FeN@CP800) via simple immersion of iron (III) acetylacetonate and melamine in hydrogel precursors and further carbonization at 800 °C. The precursor scaffold interacted with active species source by swelling behavior to form hydrogen bonds and Fe coordination, thereby facilitating subsequent growth of multiple active conformations without aggregation. The hierarchical porous surface morphology, abundant N doping, multi-active site structure and large specific surface area significantly improved the accessible BPA adsorption of FeN@CP800. The maximum adsorption capacity calculated by Langmuir model was 309.17 mg·g−1, 4.5 times higher than that of bare CP. Benefited from pore filling, hydrogen bonds, π-π stacking and hydrophobic interactions, the excellent adsorption performance of FeN@CP800 was retained under varied coexisting ions species, ionic strength and solution pH with 84 % capacity retention after 5 cycles. DFT calculations disclosed the Fe4N component was the predominant active sites to improve the adsorption and interfacial transfer process. Thus, these findings provide a new strategy to design high-performance adsorbent for phenolic pollutants removal in water.