Photocatalytic performance of titanium dioxide and zinc oxide binary system on degradation of humic matter

Application of photocatalysis using TiO2 or ZnO for the removal of natural organic matter (NOM) dates back more than two decades. Aiming to overcome the drawbacks of sole photocatalysts, use of multiphasic systems has received recent interest. ZnO/TiO2 binary oxide specimens were synthesized by a simple solid state dispersion method in different weight ratios of 1:1; 1:3; and 3:1 (ZT11, ZT13 and ZT31 respectively) and characterized by XRD, SEM, XPS, Raman, UV-DRS, PL and BET techniques. As a surrogate of NOM, humic acid (HA) was subjected to solar photocatalysis and degradation was followed by UV–vis and fluorescence spectroscopic tools along with dissolved organic carbon (DOC) contents. Photocatalytic degradation of HA was approximated to first order kinetic model. Referring to UV–vis parameters, ZT11 binary oxide expressed slightly higher photocatalytic performance with regard to TiO2, ZnO, ZT13 and ZT31 contrary to the mineralization extents as TiO2>ZT13 > ZT31 > ZT11 > ZnO. Excitation-emission matrix fluorescence (EEM) contour plots of the organic matrix displayed almost complete removal of humic-like and fulvic-like fluorophores upon use of sole TiO2 and ZnO. Regional distribution of the fluorophores were still evident with emergence of the new fluorophoric regions upon use of binary oxides. ZnO/TiO2 could be considered as an efficient photocatalyst for the degradation of humic acids under solar irradiation. © 202

Doped TiO2 Photocatalysts for the Photocatalytic Degradation Efficiency of Methylene Blue and Humic Acid under Solar Light

I n various advanced oxidation processes, photocatalysis is a promising and efficient way? to remove natural organic matter consisting of humic acids and fulvic acids. The principle of this method involves both usage of a semiconductor photocatalyst and O2 for the generation of radicals. Among them, TiO2 photocatalysis is the most popular and studied one since TiO has unique properties such as being chemically inert, photocatalytically stable, Phone: +90 386 280 3104cheap, non-toxic, environmentally benign and exhibiting high oxidative power. However, despite all the advantages of using TiO2 as a photocatalyst, there is a major disadvantage. Since TiO2 has a broad band gap, its usage widely under solar light is limited and only allows to be active under UV light. Doping is one of the most popular methods to enhance the photocatalytic activity of TiO2 via using metal or non-metal species as dopants. In this respect, solar light sensitive TiO2 photocatalyst, C, N, S, Se doped and S/N codoped TiO2 photocatalysts were synthesized by using wet-impregnation method. These doped photocatalysts were characterized by Raman spectroscopy to determine the crystal surface morphology. Moreover, methylene blue was used to investigate the photocatalytic performance of prepared doped TiO2 photocatalysts in the presence or absence of organic matrix. Photocatalytic experiments were performed using a solar light simulating photoreactor. Humic acid characterization was monitored by UV-vis and fluorescence spectroscop

Effect of partial oxidation by ozonation on the photocatalytic degradation of humic acids

In this study humic acids, which are known to be a heterogeneous group of organic macromolecules found in natural waters, were oxidized using ozonation and photocatalysis in a sequential system. Ozonation was employed for achieving partial oxidation of humic acids prior to photocatalytic oxidation. Degradation of humic acid was explained by using pseudo first order reaction rate model based on UV-vis measurements. An improvement was achieved in the photocatalytic degradation rates with respect to the degree of pre-oxidation by ozonation. Due to the surface oriented nature of photocatalysis, adsorption characteristics of partially oxidized humic acid samples on TiO2 photocatalyst were evaluated by the application of the Freundlich adsorption model. The photocatalytic degradation rates did not correlate well with the dark adsorption characteristics of the pre-ozonated as well as untreated humic acid samples

More about Persulfate-Assisted Ferrilanthanide-Mediated Photocatalysis of Textile Industry Dye Reactive Black 5: Surface Properties and Structural Assessment

Color and organic matter removal from dyehouse effluent remains a challenging issue for the environmentalist and textile dyer. Until now, various treatment processes have been proposed with limited success. In this study, the textile dye and model industrial pollutant Reactive Black 5 (RB5; 20 mg/L) could be rapidly degraded by persulfate (PS)-enhanced photocatalytic treatment using a novel, home-made lanthanum iron oxide (LF; 0.5 g/L). LF-mediated heterogeneous photocatalysis was effective when the solution pH was kept below 4. The photocatalytic degradation of RB5 solution was enhanced in the presence of 0.6 and 1.2 mM PS. The dissolved organic carbon (DOC) content of the aqueous, hydrolyzed RB5 solution (initial DOC = 5.15 mg/L) was effectively reduced by LF/UV-A (LF = 0.5 g/L; 52–54% DOC removal after 150–180 min) and LF/PS/UV-A (LF = 0.5 g/L; 60–66% DOC removal after 120 min) treatments. LF photocatalyst could be reused in four consecutive cycles for complete color and partial DOC removals without significant deterioration of the treatment performance with the LF/PS/UV-A/pH 3 process. Instrumental analyses of LF’s surface morphology/chemical composition and structural features via EDAX/SEM/Raman/FTIR/UV-vis/fluorescence spectroscopy indicated that LF remained practically intact throughout photocatalytic treatment, though slight changes/decreases in particle size/partial surface deformation and agglomeration coverage were observed, particularly during LF/PS/UV-A treatment. The presence of RB5 and its degradation products on the LF surface revealed that surface adsorption played a major role in LF-mediated photocatalysis. The Fe-content did not deviate appreciably from its original value after photocatalytic treatment. © 2023 by the authors

Photocatalytic and photoelectrocatalytic humic acid removal and selectivity of TiO2 coated photoanode

In this study, photocatalytic (PC) and photoelectrocatalytic (PEC) treatment methods were comparatively investigated as a possible means of removing humic acid (HA) following absorbance at 254 nm (UV254) and total organic carbon (TOC) analysis. The enhanced HA degradation rates were obtained in the PEC system over the conventional PC process under acidic, neutral and alkaline conditions. Preliminary and binary experiments were performed to determine the selectivity of the photoanode in terms of HA and chloride oxidation. TOC, chlorine and photocurrent parameters proved that HA was selectively removed before chlorine generation. The inhibitory effect of carbonate ions on the performance of photoanode was also studied under different pH values. (c) 2008 Elsevier B.V. All rights reserved

Erratum to “Photocatalytic performance of titanium dioxide and zinc oxide binary system on degradation of humic matter” [J. Photochem. Photobiol., A 401 (2020) 112748] (Journal of Photochemistry & Photobiology, A: Chemistry (2020) 401, (S1010603020305475), (10.1016/j.jphotochem.2020.112748))

The publisher regrets that the below mistakes were found in the published paper. 1) In Page 3, "Scherrer equation", the denominator part of the equation was missing.The corrected equation is: Crystallite size (D, nm) was calculated using the Scherrer equation as: [Formula presented] 2) In Page 3, two equations stated after this sentence “The lattice constants “a” and “c” for TiO2 and ZnO were determined from two appropriate reflections (h k l) using the following equations respectively” was written in a combined style. However, the equations should be written separately.[Formula presented] [Formula presented] 3) In Page 3, “Braggs Law using the following equation” was written without a denominator.The corrected equation was: [Formula presented] The publisher would like to apologise for any inconvenience caused. © 202

New Perspectives in Photocatalytic Water Treatment

This Special Issue, entitled “New Perspectives in Photocatalytic Water Treatment”, was planned to cover all relevant topics related to photo-initiated oxidative processes in water treatment, with a special emphasis on pollutant abatement and microorganism inactivation, which were required for improving their practical uses [...