Adsorptive removal of aqueous bezafibrate by magnetic ferrite modified carbon nanotubes

Abstract

In this work, magnetic ferrite modified carbon nanotubes (MFe₂O₄/CNTs, M: Mn or Co) were synthesized and employed as adsorbents to remove emerging pollutant bezafibrate (BZF) from aqueous solution. The structural and surface properties of the prepared adsorbents were characterized, and the performances of the MFe₂O₄/CNTs were systematically investigated from adsorption kinetics and mechanistic points of view. Results showed that the fabricated MFe₂O₄/CNTs could integrate the advantages of CNTs and ferrite, thereby exhibiting an excellent adsorption performance and recyclability. The MnFe₂O₄/CNTs were more effective than CoFe₂O₄/CNTs for BZF adsorption. When the initial concentration of BZF was varied from 5 to 40 mg L⁻¹, the maximum adsorption capacity of MnFe₂O₄/CNTs and CoFe₂O₄/CNTs increased from 14.8 to 33.4 mg g⁻¹ and 8.1 to 27.8 mg g⁻¹, respectively. Moreover, the Langmuir isotherm model and pseudo-second-order equation could elaborate well the adsorption of BZF on MFe₂O₄/CNTs. The thermodynamic analysis further revealed that the adsorptions were spontaneous processes. Based on measurements of surface and pore diffusion and the results of adsorption reactions, possible mechanisms were proposed to explain the adsorption process. This research indicates that the MFe₂O₄/CNTs are potentially applicable for the removal of BZF from aqueous solution.