title: Magnetic vinylphenyl boronic acid microparticles for Cr(VI) adsorption: kinetic, isotherm and thermodynamic studies.
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 N2 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, ΔG(0) enthalpy change, ΔH(0); and entropy change, ΔS(0)) for the adsorption have been evaluated.
authors: Uludag University, Faculty of Arts and Science, Department of Chemistry, 16059 Bursa, Turkey. Electronic address: akara@uludag.edu.tr.
authors: Ali
authors: A
authors: Kara
authors: Uludag University, Faculty of Arts and Science, Department of Chemistry, 16059 Bursa, Turkey.
authors: Emel
authors: E
authors: Demirbel
authors: Kocaeli University, Faculty of Arts and Science, Department of Chemistry, 41380 Kocaeli, Turkey.
authors: Nalan
authors: N
authors: Tekin
authors: Uludag University, Faculty of Arts and Science, Department of Chemistry, 16059 Bursa, Turkey.
authors: Bilgen
authors: B
authors: Osman
authors: Uludag University, Faculty of Arts and Science, Department of Chemistry, 16059 Bursa, Turkey.
authors: Necati
authors: N
authors: Beşirli
mesh_terms: D000327:Adsorption; D001897:Boronic Acids / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D007700:Kinetics; D060328:Magnetic Phenomena; D008689:Methacrylates / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013816:Thermodynamics; D014753:Vinyl Compounds / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: C427523:4-vinylphenyl boronic acid; D001897:Boronic Acids; D008689:Methacrylates; D014753:Vinyl Compounds; D014874:Water Pollutants, Chemical; C421283:poly(ethylene glycol)-dimethacrylate; D002857:Chromium; C074702:chromium hexavalent ion; D011092:Polyethylene Glycols
keywords: Adsorption isotherm; Adsorption kinetic; Adsorption thermodynamic; Cr(VI) ions; Magnetic polymers