Facile one-pot synthesis of magnetic nitrogen-doped porous carbon for high-performance bilirubin removal from BSA-rich solution

Abstract

The development of high-performance adsorbents for efficient removal of bilirubin from albumin-rich solution is still a considerable challenge. In this study, a magnetic nitrogen-doped porous carbon (m-NpC) was facilely synthesized through a simple one-pot route using the biomass chitosan and the iron salt Fe(NO₃)₃·9H₂O as precursors, and NaCl as template agent, respectively. Intriguingly, the resulting m-NpC material showed a hierarchically micro–meso–macroporous structure, high surface area (289 m² g⁻¹), large pore volume (0.33 cm³ g⁻¹), and good magnetic response. In particular, the basic site-rich surface of m-NpC obtained as a result of nitrogen doping could compete effectively with albumin for bilirubin binding. As such, the m-NpC was used as a magnetically separable bilirubin adsorbent and showed superior adsorption properties for bilirubin removal from a bovine serum albumin (BSA)-rich solution. Under optimized conditions, the maximum adsorption capacity of m-NpC was up to 72.4 mg g⁻¹, which is significantly higher than the value achieved by magnetic non-nitrogen doped porous carbon (24.7 mg g⁻¹), but also superior to those of many previously reported adsorbents for BSA-boned bilirubin removal. Moreover, as evidenced by hemolysis assay, this material exhibited only a negligible hemolysis effect. These results suggest that the composite developed in this work can be used as a promising adsorbent in blood purification application to mitigate the risk of excess bilirubin.