One-step preparation of magnetic N-doped sodium alginate–based porous carbon and efficient adsorption of bisphenol A

To resourcefully utilize algal biomass and effectively remove bisphenol A (BPA) from water, sodium alginate (SA) was prepared as the nitrogen-doped magnetic porous carbon material (SAC/N/Fe) with well-developed pore structure according to a one-step method using K2CO3, melamine, Fe(NO3)3·9H2O as the activator, nitrogen dopant, and magnetic precursor, respectively, in this study. The best product, SAC/N/Fe-0.2, was obtained by adjusting the mass ratio of raw materials, and its specific surface area and pore volume were 2240.65 m2 g−1 and 1.44 cm3 g−1, respectively, with a maximum adsorption capacity of 1248.23 mg g−1 for BPA at 308 K. SEM, XRD, XPS, VSM, and FT-IR characterization confirmed that the iron was successfully doped, giving the porous carbon a magnetic separation function. The adsorption process of BPA was more consistent with the Langmuir model and the proposed secondary kinetics, and the adsorption effect was stable and efficient in a wide pH range and under the interference of different metal ions. At the same time, the porous carbon was easy to separate and recover with good regeneration performance.