Fabrication of magnetic zinc-cobalt bimetallic ZIF derived carbon nanotubes for adsorptive removal of polycyclic aromatic hydrocarbons

Developing efficient and recyclable adsorbent materials is crucial for the environmental remediation of polycyclic aromatic hydrocarbons (PAHs). In this study, magnetic bimetallic carbon nanotube materials (BM-CNTs) derived from zinc-cobalt bimetallic ZIFs (BMZIFs) were fabricated and employed for the adsorptive removal of PAHs. Characterization results of BM-CNTs revealed a porous network structure formed by intertwined carbon nanotubes with uniform dispersion of Co and Zn metal particles. The adsorptive removal efficiency of the magnetic BM-CNTs was more than 84.5 % for all four PAHs (C 0  = 10 mg/L), and the adsorption experimental data are well described by the Langmuir model and the pseudo-second-order kinetic model. Additionally, the maximum adsorption capacities of BM-CNTs for Phenanthrene (PHE), Pyrene (PYR), Benzo[k]fluoranthene (BKF), and Benzo[a]anthracene (BAP) are 71.3 mg/g, 74.4 mg/g, 157.7 mg/g, and 179.7 mg/g, respectively, and the thermodynamic analysis revealed that the PAHs adsorption was an exothermic (ΔH˚<0), spontaneous (ΔG˚<0), and entropically unfavorable (ΔS˚<0) process. Moreover, the influence of different anions, cations, and sample pH on adsorption efficiency was not obvious. This research constructed a magnetic bimetallic ZIF derived carbon nanotubes for PAHs adsorption and offers a promising removal methods for environmental remediation.