Preparation of multi-walled carbon nanotubes coated with CoFe2O4 nanoparticles and their adsorption performance for Bisphenol A compound

In this study, the adsorption performance and characterization properties of the multi-walled carbon nanotubes were improved by coating this material with CoFe2O4 nanoparticles. The resultant adsorbent (MWCNTs/CoFe2O4) was first synthesized using solvothermal co-precipitation and Electrophoretic precipitation methods, characterized, then used in the adsorption system of Bisphenol A (BPA) wastewater. The influence of pH (3-11), initial BPA concentration (25-100 mg/L), MWCNTs/CoFe2O4 dosage (0.1-1.5 g/L), contact time (0-240 min), and temperature (283-328 K) on BPA removal adsorption onto MWCNTs/CoFe2O4 was investigated. Better results for BPA removal ( 99%) were achieved in acidic conditions (pH = 3), and the equilibrium state was reached at 150 min of contact time. The Langmuir and pseudo-second order models were suitable to describe the adsorption isotherm and kinetics, as verified by goodness-of-fit analysis. The adsorption of BPA molecules onto MWCNTs/CoFe2O4 active groups was occurred via chemisorption interaction, based on the analyses of Dubinin-Radushkevitch and Freundlich isotherms. Moreover, the endothermic, favorable, and spontaneous nature of BPA adsorption onto MWCNTs/CoFe2O4 was proved by thermodynamic studies. Reusing MWCNTs/CoFe2O4 after 6 cycles showed a ten percent reduction in adsorption capacity, which indicates the good stability and reusability. The maximum adsorption capacity of MWCNTs/CoFe2O4 for BPA adsorption from Langmuir model was 416.6 mg/g, which is much higher than that of reported other adsorbents used for the same purpose. This study revealed that MWCNTs/CoFe2O4 is a promising adsorbent for BPA adsorption with high removal efficiency, easy separation, and good reusability properties. (C) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.