One-step fabrication of porous carbon microspheres with in situ self-doped N, P, and O for the removal of anionic and cationic dyes

Abstract

Porous carbon microspheres (NPO-PCSs) with a high specific surface area (1769 m2 g−1) and in situ self-doped multiple heteroatoms (N, P, and O) were skillfully fabricated via one-step direct pyrolysis of cross-linked poly(cyclotriphosphazene-co-phloroglucinol) microspheres. The doping carbon structure of NPO-PCSs with intrinsic microporosity promises the potential for the adsorption of cationic and anionic dyes (Methyl Blue and Methyl Orange). Moreover, there is a π-π interaction between the ordered graphite units of NPO-PCSs and the aromatic rings of dye molecules, which promotes the dye adsorption capacity of NPO-PCSs. Meanwhile, these in situ self-doped heteroatoms (N, P, and O) can play as Lewis base and the formed Lewis acid-base interaction improves the adsorption performance of the NPO-PCSs. Additionally, for the large containing oxygen groups of the NPO-PCSs adsorbent, there could be the electrostatic attraction between the NPO-PCSs adsorbent and the dye molecules. As results, the absorptivity of the NPO-PCSs for MB and MO could reach 356 and 281 mg g−1 at 25 °C and pH = 7, respectively. Thus, the high-performance NPO-PCSs versatile adsorbent might have a great potential for practical application in wastewater purification.