TY - JOUR
T1 - Synergistic ternary porous CN-PPy-MMt nanocomposite for efficient photocatalytic metronidazole mineralization
T2 - Performance, mechanism, and pathways
AU - Balakumar, Vellaichamy
AU - Sekar, Karthikeyan
AU - Chuaicham, Chitiphon
AU - Manivannan, Ramalingam
AU - Sasaki, Keiko
N1 - Funding Information:
V. B. and K. S. would like to thank the Japan Society for the Promotion of Science (JSPS) for providing a postdoctoral fellowship for foreign researchers (P19393) and a research grant (JP19F19393). HR(S)TEM was performed at the Ultra-Microscopy Research Centre (URC) at Kyushu University. This work was partially supported by the Nanotechnology Platform Program (Molecule and Material Synthesis) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2021/8
Y1 - 2021/8
N2 - Carbon nitride based photocatalysts are widely used to decontaminate aqueous solutions by eliminating toxic and non-biodegradable compounds. It is desirable to develop a photocatalyst with high charge separation and migration efficiency. In this study, synergistic ternary porous carbon nitride-polypyrrole-montmorillonite (CN-PPy-MMt) was successfully synthesized via an in situ oxidative polymerization method. The photocatalytic performance towards mineralization of metronidazole (MZ) under visible light was studied, where the CN-PPy-MMt (10%) nanocomposite exhibited the best performance compared to CN-PPy-MMt (5%, 15%, 20%), CN-PPy, pure CN and other nanocomposites reported. This superior photocatalytic mineralization performance was attributed to synergistic inter-constituent interactions within the CN-PPy-MMt nanocomposite, which effectively enhanced the light absorption capacity and charge transfer, and reduced the recombination of electron-hole pairs. The results were confirmed by UV-DRS, photocurrent, impedance, and photoluminescence measurements. The effect of interfering anions was examined and the results indicated that the MZ mineralization efficiency was significantly inhibited by the addition of HCO3- and PO43-. The reusability and stability of the photocatalyst were excellent even after five repeated photocatalytic reactions. Analysis of the radical scavenger properties indicated that superoxide radicals (O2-) and holes (h+) played a major role in the mineralization of MZ. The intermediate products were confirmed using liquid chromatography-mass spectrometry, which provided an insight into the MZ mineralization mechanism. This work suggested that the design of a ternary nanocomposite based on CN with conducting polymers could be an effective strategy to improve the photocatalytic mineralization of antibiotics and energy related applications.
AB - Carbon nitride based photocatalysts are widely used to decontaminate aqueous solutions by eliminating toxic and non-biodegradable compounds. It is desirable to develop a photocatalyst with high charge separation and migration efficiency. In this study, synergistic ternary porous carbon nitride-polypyrrole-montmorillonite (CN-PPy-MMt) was successfully synthesized via an in situ oxidative polymerization method. The photocatalytic performance towards mineralization of metronidazole (MZ) under visible light was studied, where the CN-PPy-MMt (10%) nanocomposite exhibited the best performance compared to CN-PPy-MMt (5%, 15%, 20%), CN-PPy, pure CN and other nanocomposites reported. This superior photocatalytic mineralization performance was attributed to synergistic inter-constituent interactions within the CN-PPy-MMt nanocomposite, which effectively enhanced the light absorption capacity and charge transfer, and reduced the recombination of electron-hole pairs. The results were confirmed by UV-DRS, photocurrent, impedance, and photoluminescence measurements. The effect of interfering anions was examined and the results indicated that the MZ mineralization efficiency was significantly inhibited by the addition of HCO3- and PO43-. The reusability and stability of the photocatalyst were excellent even after five repeated photocatalytic reactions. Analysis of the radical scavenger properties indicated that superoxide radicals (O2-) and holes (h+) played a major role in the mineralization of MZ. The intermediate products were confirmed using liquid chromatography-mass spectrometry, which provided an insight into the MZ mineralization mechanism. This work suggested that the design of a ternary nanocomposite based on CN with conducting polymers could be an effective strategy to improve the photocatalytic mineralization of antibiotics and energy related applications.
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U2 - 10.1039/d1en00254f
DO - 10.1039/d1en00254f
M3 - Article
AN - SCOPUS:85112864849
VL - 8
SP - 2261
EP - 2276
JO - Environmental Science: Nano
JF - Environmental Science: Nano
SN - 2051-8153
IS - 8
ER -