A γ-Fe2O3 Embedded In Situ Nitrogen-Doped Carbon Composites for Efficient Bisphenol A Removal: Adsorption Behavior and Property Study

Bisphenol A (BPA), an emerging wastewater contaminant, poses significant ecological risks even in trace concentrations, necessitating advanced removal strategies. In this study, a novel γ-Fe2O3-embedded nitrogen-doped polydopamine-derived carbon composite adsorbent (Fe-PC) was synthesized using polydopamine as a self-nitrogen-doped carbon precursor rather than a conventional shell material. The Fe-PC adsorbent exhibited a high BPA adsorption capacity of 423.86 mg g–1 and rapid equilibrium within 120 min. Adsorption kinetics followed a pseudo-second-order model (R2 = 0.999), while equilibrium data aligned with the Langmuir isotherm, indicating monolayer chemisorption is the dominant mechanism. Thermodynamic analysis confirmed that the process is spontaneous and endothermic. Mechanistic investigations revealed that γ-Fe2O3 introduces abundant active sites, enabling synergistic adsorption via chemical bonding, π–π interactions, hydrophobic interactions, and Fe3+ coordination with BPA hydroxyl groups. Combining high adsorption capacity, rapid kinetics, and stability, Fe-PC offers a promising strategy for efficiently removal of emerging contaminants from water.