Magnetic vinylphenyl boronic acid microparticles for Cr(VI) adsorption: Kinetic, isotherm and thermodynamic studies


KARA A. , Demirbel E., TEKİN N., OSMAN B. , Besirli N.

JOURNAL OF HAZARDOUS MATERIALS, vol.286, pp.612-623, 2015 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 286
  • Publication Date: 2015
  • Doi Number: 10.1016/j.jhazmat.2014.12.011
  • Title of Journal : JOURNAL OF HAZARDOUS MATERIALS
  • Page Numbers: pp.612-623
  • Keywords: Magnetic polymers, Adsorption isotherm, Adsorption kinetic, Adsorption thermodynamic, Cr(VI) ions, AQUEOUS-SOLUTION, AFFINITY-CHROMATOGRAPHY, HEXAVALENT CHROMIUM, WASTE-WATER, REMOVAL, IONS, EQUILIBRIUM, TEMPERATURE, SORPTION, BEADS

Abstract

Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate(EG)-vinylphenyl boronic acid(VPBA)) [m-poly(EG-VPBA)], produced by suspension polymerization and characterized, was found to be an efficient solid polymer for Cr(VI) adsorption. The m-poly(EG-VPBA) microparticles were prepared by copolymerizing of ethylene glycol dimethylacrylate (EG) with 4-vinyl phenyl boronic acid (VPBA). The m-poly(EG-VPBA) microparticles were characterized by N-2 adsorption/desorption isotherms, electron spin resonance (ESR), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), elemental analysis, scanning electron microscope (SEM) and swelling studies. The m-poly(EG-VPBA) microparticles were used at adsorbent/Cr(VI) ion ratios. The influence of pH, Cr(VI) initial concentration, temperature of the removal process was investigated. The maximum removal of Cr(VI) was observed at pH 2. Langmuir isotherm and Dubinin-Radushkvich isotherm were found to better fit the experiment data rather than Fruendlich isotherm. The kinetics of the adsorption process of Cr(VI) on the m-poly(EG-VPBA) microparticles were investigated using the pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models, results showed that the pseudo-second order equation model provided the best correlation with the experimental results. The thermodynamic parameters (free energy change, Delta G(0) enthalpy change, Delta H-0; and entropy change, Delta S-0) for the adsorption have been evaluated. (C) 2015 Elsevier B.V. All rights reserved.