Scholarlink

<p>Industrial wastewater pollution with synthetic dyes is a severe environmental issue owing to its toxicity and persistence. This study presents the synthesis of a 2D-reduced graphene oxide (rGO)-MnO<sub>2</sub> nanorod composite through an ultrasonic-assisted hydrothermal method, aimed to achieve efficient photocatalytic degradation of Malachite Green (MG) and Congo Red (CR) dyes. The crystal structure, surface morphology, elemental composition, and surface area of the rGO/MnO<sub>2</sub> binary nanocomposite were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis respectively. XRD confirmed the formation of the α-MnO₂ phase. SEM and TEM images showed the uniform deposition of MnO₂ nanorods onto rGO sheets. UV-DRS studies revealed a reduction in the band gap from 3.21&#xa0;eV (pristine MnO₂) to 2.54&#xa0;eV (20% rGO-MnO₂), improving visible-light absorption. The crystallite size of MnO₂ increased from 27&#xa0;nm (pristine) to 47&#xa0;nm (20% rGO-MnO₂), indicating the structural impact of rGO incorporation. The rate constant (<i>k</i>) for MG degradation was 2.2 times higher in the 20% rGO-MnO₂ composite than in pristine MnO₂, demonstrating improved photocatalytic activity. The optimized 20% rGO-MnO₂ composite degraded 94.2% of MG and 96.3% of CR under UV light in 60&#xa0;min. This performance was significantly better than pristine MnO₂, which degraded 69.1% of MG and 55.01% of CR. Kinetic analysis confirmed pseudo-first-order reaction behavior. The rate constant (<i>k</i>) for MG degradation increased from 0.0565&#xa0;min⁻<sup>1</sup> (MnO₂) to 0.1363&#xa0;min⁻<sup>1</sup> (20% rGO-MnO₂). This work demonstrates a highly efficient and scalable MnO₂/rGO hybrid photocatalyst with superior charge carrier separation, suppressed recombination, and enhanced degradation performance, making it a promising candidate for real-world wastewater treatment applications.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Synthesis of MnO2@2DrGO hybrid nanocomposite for efficient removal of hazardous textile dyes from water

  • 期刊论文

  • 发表日期：

    2025年3月25日

查看全文
  • V. Janakiraman,
  • M. Varun,
  • G. S. Uthayakumar,
  • V. Loganathan,
  • G. Kalpanadevi,
  • J. Navarajan

摘要

Industrial wastewater pollution with synthetic dyes is a severe environmental issue owing to its toxicity and persistence. This study presents the synthesis of a 2D-reduced graphene oxide (rGO)-MnO2 nanorod composite through an ultrasonic-assisted hydrothermal method, aimed to achieve efficient photocatalytic degradation of Malachite Green (MG) and Congo Red (CR) dyes. The crystal structure, surface morphology, elemental composition, and surface area of the rGO/MnO2 binary nanocomposite were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis respectively. XRD confirmed the formation of the α-MnO₂ phase. SEM and TEM images showed the uniform deposition of MnO₂ nanorods onto rGO sheets. UV-DRS studies revealed a reduction in the band gap from 3.21 eV (pristine MnO₂) to 2.54 eV (20% rGO-MnO₂), improving visible-light absorption. The crystallite size of MnO₂ increased from 27 nm (pristine) to 47 nm (20% rGO-MnO₂), indicating the structural impact of rGO incorporation. The rate constant (k) for MG degradation was 2.2 times higher in the 20% rGO-MnO₂ composite than in pristine MnO₂, demonstrating improved photocatalytic activity. The optimized 20% rGO-MnO₂ composite degraded 94.2% of MG and 96.3% of CR under UV light in 60 min. This performance was significantly better than pristine MnO₂, which degraded 69.1% of MG and 55.01% of CR. Kinetic analysis confirmed pseudo-first-order reaction behavior. The rate constant (k) for MG degradation increased from 0.0565 min⁻1 (MnO₂) to 0.1363 min⁻1 (20% rGO-MnO₂). This work demonstrates a highly efficient and scalable MnO₂/rGO hybrid photocatalyst with superior charge carrier separation, suppressed recombination, and enhanced degradation performance, making it a promising candidate for real-world wastewater treatment applications.