The Removal of Acid Violet 7 from Aqueous Solutions by Photocatalytic-Poly(Ethylene Glycol Dimethacrylate-co-4-Vinylpyridine)-Titanium Dioxide Nanocomposite Beads: Kinetic, Isotherm, Thermodynamic Studies

The photocatalytic-poly(ethylene glycol dimethacrylate-co-4-vinylpyridine)-titanium dioxide (pho-poly(EGDMA-co-4-VP)-TiO2) nanocomposite beads prepared from copolymerizing of ethylene glycol dimethacrylate (EGDMA) with 4-vinylpyridine (4-VP). The synthesized nanocomposite beads were investigated as a novel photocatalytic adsorbent for the adsorption of Acid Violet 7 (AV7) dye molecules from aqueous solutions in this study. The pho-poly(EGDMA-co-4-VP)-TiO2 nanocomposite beads were characterized by N2 adsorption/desorption isotherms, elemental analysis, X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), and swelling studies. The influence of initial solution pH, initial solution concentration, temperature, contact time to adsorption-desorption of the removal process was comprehensibly studied. The adsorption process was found to be optimal in the wide pH range of 2-9. The equilibrium adsorption data obtained was well described by the Langmuir isotherm model and adsorption kinetics followed a pseudo-second-order kinetic model, indicating that adsorption was the rate-limiting step. The nanocomposite beads could be regenerated by a treatment with 0.1M NaOH (up to ca. 92%). These features make the pho-poly(EGDMA-co-4-VP)-TiO2 nanocomposite beads potential supports for AV7 removal from aqueous solution.