Facile synthesis of nitrogen-doped porous graphene for efficient adsorption of tetracycline: Behavior and mechanism

Abstract

Developing economic and efficient adsorbents is critically important for antibiotic residual removal from contaminated water. Here, Nitrogen-doped porous graphene-like carbon (NPGC) adsorbents were successfully synthesized by self-blowing and doping method, where glucose was used as the carbon source, zinc nitrate was acted as the nitrogen source and the derived ZnO was as the porogen. The obtained NPGC possessed a graphene-like porous structure with moderate nitrogen doping. The removal capacity of NPGC was as high as 451.2 mg g−1 in 50 mg L−1 TC solution, which is much higher than graphene, carbon nanotubes, and activated carbon, due to the larger specific surface area and micro/mesopores on graphene sheets. The adsorption isotherms and kinetics for TC onto NPGC were well-fitted with Langmuir model and pseudo-second-order model. The adsorptive ability of NPGC increased linearly with the increasing graphitic N content due to the enhanced π-π interaction and hydrophobic effect between TC and NPGC. The NPGC also showed potential environmental application as revealed by anti-interference capacity in the interference (coexisting ions and humic acid) and reusability. This work not only provides a facile strategy to develop economic and scalable N-doped graphene, but also systematically studies the adsorption mechanism of TC onto N-doped carbon adsorbents.