Photocatalytic Purification of Orange-II-Dye-Polluted Wastewater Using TiO<sub>2</sub>-Modified g-C<sub>3</sub>N<sub>4</sub> Composite

Textile dyes are considered to be one of the major sources of water pollution due to their complex chemical structures. Photocatalytic dye degradation is an eco-friendly method that uses light-activated catalysts to break down complex dye molecules in wastewater into harmless byproducts. In the pres...

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Bibliographic Details
Main Authors: Bin Guo, Monir Uzzaman, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata, Satoshi Kaneco
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:C
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Online Access:https://www.mdpi.com/2311-5629/10/4/103
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Summary:Textile dyes are considered to be one of the major sources of water pollution due to their complex chemical structures. Photocatalytic dye degradation is an eco-friendly method that uses light-activated catalysts to break down complex dye molecules in wastewater into harmless byproducts. In the present study, pure and N-doped g-C<sub>3</sub>N<sub>4</sub> were synthesized using one-pot calcination. The fabrication of g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> and TC-g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> was accomplished by physical mixing. The prepared photocatalysts were used to treat the Orange-II-polluted wastewater. The structural properties, surface morphology, light-harvesting capability, and electrochemical properties were assessed using XRD, XPS, SEM, TEM, BET, DRS, PL, EIS, Mott–Schottky, and transient photocurrent response (TPCR) analyses. The improved charge separation and migration properties of g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> were confirmed by the PL, EIS, and TPCR results. TEM and XPS data confirmed the formation of a g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composite. Enhanced photocatalytic decolorization was achieved for g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> compared with pure g-C<sub>3</sub>N<sub>4</sub> or TiO<sub>2</sub>. The 1 wt% g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composite exhibited the highest (92.1%) decolorization efficiency during 60 min of UV irradiation. Furthermore, the pseudo-first-order reaction rate constant (k) of 1 wt% g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> was calculated to be 0.0213 min<sup>−1</sup>, which was 2.5 times better than that obtained with bare TiO<sub>2</sub>. Finally, for a better understanding of the g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> decolorization process, a possible reaction mechanism was proposed.
ISSN:2311-5629