Mesoporous carbon/cobalt ferrite nanocomposite: A charge and pH independent magnetic adsorbent for dye pollutant treatment

Abstract

Mesoporous carbon/cobalt ferrite (C/CFO) nanocomposite, as a novel charge and pH independent adsorbent with easy magnetic separation performance, was developed. The adsorption characteristics are examined by batch adsorption tests, which indicate that the C/CFO nanocomposite can be used for the removal of both cationic dye (e.g. Methylene Blue, MB) and anionic dye (e.g. Congo Red, CR) within a wide solution pH range (from 3 to 11). The Langmuir isotherm and the pseudo-second-order kinetic model can be used to describe the adsorption of both dyes onto nanocomposite. The maximum adsorption capacities for MB and CR calculated from Langmuir isotherm model are 43.05 and 270.64 mg/g, respectively. The ion-π interaction between microcrystal graphite in the nanocomposite and dye molecules is postulated to be the adsorption mechanism, evidenced by Raman spectra. Adsorption thermodynamics show that both MB and CR adsorptions are spontaneous and exothermic. The nanocomposite with adsorbed dyes can be easily detached from solution within 3 min upon the application of magnetic field. Recycling experiments show that 97.6% and 75.3% of initial adsorption capacity for CR and MB can be retained in the third cycle.