Synthesis of nanoporous cobalt/carbon materials by a carbonized zeolitic imidazolate framework-9 and adsorption of dyes

Abstract

Herein, four nanoporous cobalt/carbon materials were synthesized by one-step calcination of the zeolitic imidazolate framework-9 (ZIF-9) at 600, 700, 800, and 900 °C. The adsorption performance of the obtained Z9-600, Z9-700, Z9-800, and Z9-900 towards methylene green (MeG) in an aqueous solution was investigated. The results indicate that Z9-600 demonstrates maximum adsorption as compared to other three materials. The adsorption capacity of Z9-600 for another eleven organic dyes (malachite green, rhodamine B, rhodamine 6G, crystal violet, methyl blue, methyl orange, acid red 18, acid orange 7, orange G, congo red, and rosaniline) was studied systematically. Valid analysis based on the data demonstrates that the pseudo-second-order model, the intra-particle diffusion model, and the Langmuir model are suitable for describing the adsorption process of Z9-600. The regeneration efficiency of Z9-600 for MeG is >93% after 4 cycles of reuse. These highly-effective, economical, and recyclable features demonstrate that nanoporous cobalt/carbon ZIFs are promising adsorbents for the treatment of wastewater containing dyes.