Search

Adsorption and photocatalytic decolorization methods were used to remove Reactive Orange 16 dye from textile wastewater by using ethyleneglycoldimethacrylate and 1-vinyl-1,2,4-triazole, m-poly(EGDMA-VTA)-TiO2 polymer composite particles with magnetic synthesized by suspension polymerization. The characterization of the synthesized m-poly(EGDMA-VTA)-TiO2 particules were carried out by using XRD, FTIR, SEM–EDS-elemental mapping, ESR, and BET analyses. Both adsorption and photocatalytic decolorization processes of RO16 dye were applied to the polymer particles. The effects of solution pH, amount of adsorbent, initial dye concentration, temperature, and time on the adsorption capacity were investigated. The removal of R016 dye reached a maximum at pH 3. Dye substance removal decreased due to increasing temperature and adsorbent amount. As a result of experimental studies, the adsorption of RO16 dye was explained by the Langmuir isotherm, while its kinetics was stated by a pseudo-second-order mechanism. Additionally, thermodynamic functions (ΔHo, ΔGo, and ΔSo) have been determined. At the end of adsorption, the decolorization kinetics were elucidated by examining the adsorbent amount, time, and dye concentration parameters for the photocatalytic decolorization of non-adsorbed dyes. It was determined that the photocatalytic activity was highest at low dye concentration and high photocatalyst content. Additionally, it was determined that decolorization kinetics studies were compatible with the Langmuir–Hinshelwood model. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol dimethacrylate-2-vinyl pyridine)-TiO2 [poly (EGDMA-2-VP)] - TiO2 microbeads were synthesized by suspension polymerization method for photocatalytic decolorization of textile dyes from aqueous solution. The synthesized cross-linked [poly (EGDMA-2-VP)] - TiO2 microbeads were characterized by scanning electron microscopy (SEM), X-ray Diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). To investigate the usability of the obtained microbeads in dye decolorization, the paramreters such as pH, polymer amount, time, and dye concentration were examined both under sunlight and 366 nm UV light. Optimum conditions under which maximum photocatalytic decolorization of the dye were pH 3, polymer amount 0.05 g, dye concentration 30 mg /L and time 5 hours. [ABSTRACT FROM AUTHOR]

This study is aimed at the synthesis and characterization of the mesoporous magnetic-poly(divinylbenzene-1-vinylimidazole)[m-poly(DVB-VIM))microbeads(average diameter = 53–212 µm); their application as adsorbent in the removal of Cu(II) ions from aqueous solutions was investigated. The mesoporous m-poly(DVB-VIM) microbeads were prepared by copolymerizing of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The mesoporous m-poly(DVB-VIM) microbeads were characterized by N2 adsorption/desorption isotherms, ESR, elemental analysis, scanning electron microscope (SEM), and swelling studies. At fixed solid/solution ratio the various factors affecting adsorption of Cu(II) ions from aqueous solutions such as pH, initial concentration, amount of mesoporousm-poly(DVB-VIM)) microbeads, contact time, and temperature were analyzed. Langmuir, Freundlich, and Dubinin-Radushkvich isotherms were used the model adsorption equilibrium data. The Langmuir isotherm model was the most adequate. The pseudo first-order, pseudo-second-order, Ritch-second-order, and intraparticle diffusion models were used to describe the adsorption kinetics. The experimental data fitted to pseudo second-order kinetic. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy changes. Morever, after the use in adsorption, the mesoporous m-poly(DVB-VIM) microbeads with paramagnetic property was separated via the applied magnetic force. These features make the mesoporous m-poly(DVB-VIM) microbeads a potential candidate for support of Cu(II) ions removal under magnetic field. [ABSTRACT FROM PUBLISHER]

Abstract: Sulfonic acid functionalized poly(ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole), poly(EGDMA-VTAZ-SO3H), is evaluated in the esterification of lactic acid with methanol. From nitrogen physisorption data, high surface area (220m2/g) and type IV isotherm are obtained. Conversion measurements indicate a stronger interaction of poly(EGDMA-VTAZ-20%SO3H) with water molecules than that occurring in poly(EGDMA-VTAZ-10%SO3H). Hence, the higher catalytic activity of poly(EGDMA-VTAZ-10%SO3H) is related to the more hydrophobic microenvironment of –SO3H sites, which reduces the acid site deactivation associated with adsorption of water generated during the reaction. Moreover, apparent activation energy is found to be 48.02kJmol−1, which can be comparable with the literature values. [Copyright &y& Elsevier]

Abstract: The magnetic-poly(divinylbenzene-4-vinylpyridine) [m-poly(DVB-4VP)] microbeads (average diameter: 180–212μm) were synthesized by copolymerizing of divinylbenzene (DVB) with 4-vinylpyridine (4VP) and by mixing this copolymer with Fe3O4 nanoparticles. The resultant material was characterized by N2 adsorption/desorption, ESR, elemental analysis, scanning electron microscope (SEM) and swelling studies. After functionalized with sulfonic acid, m-poly(DVB-4VP-SO3H) was characterized by FT-IR and TGA analysis. The results showed that both of Fe3O4 and –SO3H are bonded to the polymer successfully. N2 adsorption/desorption isotherms of synthesized samples had the hysteresis behaviour associated with mesoporous materials (pore diameter: 3.73nm). Sulfonic acid functionalized mesoporous m-poly(DVB-4VP-SO3H) has been demonstrated to have higher reactivity than commercially available solid acid catalysts for the conversion of propionic acid to methyl ester. The apparent activation energy was found to be 38.5kJmol−1 for m-poly(DVB-4VP-20%SO3H). The catalyst showed negligible loss of activity after four repetitive cycles. [Copyright &y& Elsevier]

Abstract: Sulfonic acid functionalized poly (ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole), poly (EGDMA–VTAZ–SO3H) (average diameter 1.0–1.5mm), was found to be efficient solid acid catalyst for the esterification of methanol and propionic acid under heterogeneous reaction conditions. The pristine polymer, poly (EGDMA–VTAZ), was produced by suspension polymerization and then proton-conducting polymer was obtained by blending of poly (EGDMA–VTAZ) with different percentage of H2SO4 solutions. The protonation of aromatic heterocyclic rings was proved with Fourier-transform infrared spectroscopy (FT-IR). Thermo gravimetric (TG) analysis showed that the catalyst is thermally stable up to 573K. The surface morphology of the catalyst was characterized by scanning electron microscopy (SEM). Poly (EGDMA–VTAZ–SO3H) beads can be regenerated and reused, so this provides a potential application. It has a rate constant which exceeds that of Amberlyst-15 by a factor of about four at 333K. As for the reaction equilibrium constant (Ke ), which is independent of temperature ranging from 318 to 343K, was determined to be 3.16. The apparent activation energy was found to be 41.6kJmol−1 for poly (EGDMA–VTAZ–SO3H). [ABSTRACT FROM AUTHOR]

Abstract: Water soluble poly(1-vinyl-1,2,4-triazole) (PVT) as a novel dielectric layer for organic field effect transistor is studied. Dielectric spectroscopy characterization reveals it has low leakage current and rather high breakdown voltage. Both n-channel and p-channel organic field effect transistors are fabricated using pentacene and fullerene as active layers. Both devices show device performances with lack of hysteresis, very low threshold voltages and high on/off ratios. Excellent film formation property is utilized to make AlO x and thin PVT bilayer in order to decrease the operating voltage of the devices. All solution processed ambipolar device is fabricated with simple spin coating steps using poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH–PPV) end capped with polyhedral oligomeric silsesquioxanes (POSS) as active layer. Our investigations show that PVT can be a very promising dielectric for organic field effect transistors. [Copyright &y& Elsevier]