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    New dye sensitized photocatalysts: Copper(II)-phthalocyanine/TiO2 nanocomposite for water remediation
    (Elsevier Science Sa, 2016) Albay, Cansu; Koc Kesir, Melek; Altin, Ilknur; Bayrak, Riza; Degirmencioglu, Ismail; Sokmen, Munevver
    In this study, a group of novel copper azomethyn-bridged phenolic phtalocyanines (CuPc) were synthesized. These derivatives are completely new, synthesis and characterization studies are first time reported. Four derivatives which have peripheral or non-peripheral substitution on macrocyclic ring were produced and characterized employing various spectroscopic methods. CuPc were immobilized on TiO2 nanoparticles to obtain dye sensitized photoactive nanocomposites (1% of the mass of TiO2). Prepared composites were characterized by SEM, EDX, UV-vis, DRS and XRD analysis. Results revealed that the composites possess anatase structure and phthalocyanine loading on TiO2 exposes strong visible light absorption. Photocatalytic activities of the produced composite materials were tested for reduction of Cr(VI) as a model pollutant and its disinfection properties were investigated using Escherichia coli as a model microorganism employing a near visible UV-A light (365 nm) source. All composite materials exhibited much more photocatalytic activity than bare TiO2 for both pollutants. (C) 2016 Elsevier B.V. All rights reserved.
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    Preparation of phthalocyanine/TiO2 nanocomposites for photocatalytic removal of toxic Cr(VI) ions
    (Elsevier, 2016) Bayrak, Riza; Albay, Cansu; Koc Kesir, Melek; Altin, Ilknur; Degirmencioglu, Ismail; Sokmen, Munevver
    In this study, a group of novel metal free azomethine-bridged phenolic phthalocyanines (H2Pc) was synthesized. These derivatives are completely new and first time reported. Four derivatives at peripheral or non-peripheral substitution on macro cyclic ring were synthesized and characterized employing various spectroscopic methods. H2Pc derivatives (defined as H2Pc-1, H2Pc-2, H2Pc-3, H2Pc-4) were immobilized on TiO2 nanoparticles to obtain photoactive nanocomposites (H2Pc/TiO2, 1% of the mass of TiO2). H2Pc derivatives were used as photosensitizer to improve the near visible-light photocatalytic efficiency of TiO2 catalyst in wastewater treatment. Photocatalytic abilities nanocomposites were tested for photocatalytic reduction of chromium (VI) ions (10 mg/L) and compared with neat TiO2. A near UV light source (365 nm) was used for illumination in a batch reactor and Cr(VI) concentration was monitored during 150 min treatment period. It is clear that H2Pc sensitized photocatalyst is effective for the reduction of chromium ions. Removal percentages were between 83.70 and 99.75% indicating almost total reduction of toxic Cr(VI) ions. Neat TiO2 was able to reduce only 55.43% of initial Cr(VI) ions. All phthalocyanine containing TiO2 composites are significantly more effective and reduce more Cr(VI) ions than TiO2 itself. Photocatalytic action of the catalysts is decreased in the following order H2Pc-4/TiO2 > H2Pc-2/TiO2 > H2Pc-1/TiO2 > H2Pc-3/TiO2. (C) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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    Öğe
    Use of azomethine-bridged phenolic metallophthalocyanines for sensitization of TiO2
    (Desalination Publ, 2017) Koc Kesir, Melek; Albay, Cansu; Altin, Ilknur; Bayrak, Riza; Gokce, Halil; Degirmencioglu, Ismail; Sokmen, Munevver
    A group of novel azomethine-bridged phenolic metallophtalocyanines (substituted at -nonperipheral position, MPc) were synthesized, characterized and used as sensitizer. Phthalocyanine derivatives (containing TiO(II), Fe(II), Co(II), Ni(II) and Zn(II) ions in the center of phtalocyanine) were immobilized on TiO2 photocatalyst using a wet deposition method. MPc/TiO2 nanocomposites have been tested for their photocatalytic reduction ability of Cr(VI) ions in aqueous solution under near visible light irradiation. The results demonstrated that the presence of the sensitizer is certainly beneficial for the photocatalytic activity of TiO2, confirming the significant role of substitution and metal-co-ordination in the center of the phthalocyanine ring. Photoreduction results show that the all composite materials exposed significantly higher Cr(VI) removal performance than bare TiO2-Consequently, MPc sensitized TiO2 nanocomposites may be good alternatives for efficient photocatalysis that can be used for wastewater treatment processes.