Protein-derived nitrogen and sulfur co-doped carbon for efficient adsorptive removal of heavy metals

Abstract

Abstract A nitrogen and sulfur co-doped carbon has been synthesized employing egg white as a sustainable protein-rich precursor. According to CHNS elemental analysis, N, S and O heteroatoms accounted for mass fractions of 3.66%, 2.28% and 19.29% respectively, and the types of surface functionalities were further characterized by FT-IR and XPS measurements. Although the carbon possessed a smaller surface area (815 m2·g−1) compared to a commercial activated carbon (1100 m2·g−1), its adsorption capacity towards Co2+ reached 320.3 mg·g−1, which was over 8 times higher compared to the limited 34.0 mg·g−1 over the activate carbon. Furthermore, the carbon was found to be an efficient adsorbent towards a series of metal ions including VO2+, Cr3+, Ni2+, Cu2+ and Cd2+. Combined with its environmental merits, the protein derived carbon may be a promising candidate for heavy metal pollution control.