Enhancement removal of crystal violet dye using magnetic calcium ferrite nanoparticle: Study in single- and binary-solute systems

A novel adsorbent of CaFe2O4 magnetic nanoparticles (MNPs) was synthesized as an efficient adsorbent to removal dye pollutants, cationic dye (crystal violet, CV) and acid dye (congo red, CR) were investigated in single and binary systems. Adsorption tests showed that CaFe2O4 MNPs presented an excellent high affinity to CR (efficiency of CR removal, 96.1%), while CV was hardly adsorbed in single system. The remarkably high adsorption efficiency of CR dyes on CaFe2O4 is rationalized on the basis of H-bonding interactions as well as dipole-dipole between adsorbent and acid dye molecules. In a binary dye system, CaFe2O4 showed enhanced adsorption for CV, and the adsorption percentage for CV increased from 5.0% to 30.4%. The enhanced adsorption was attributed to the synergistic effect due to the electronic attraction between CV and CR, which promoted CV co-adsorption on CaFe2O4. Because of the excellent regeneration capacity the CaFe2O4 MNPs are considered to be interesting materials for the uptake of, for instance, toxic dyes from wastewater. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.