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<p>The presence of volatile organic compounds (VOCs) poses significant health and environmental risks. This study investigates the catalytic oxidation of ethylbenzene (EB) vapor using a silver-impregnated zeolitic imidazolate framework-67 (Ag@ZIF-67). The effectiveness of the catalyst in converting EB was evaluated in a continuous-flow fixed-bed reactor. The Ag@ZIF-67 catalyst was synthesized and characterized using X-ray diffraction (XRD), energy dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR). The XRD patterns of the synthesized ZIF-67 and Ag@ZIF-67 showed distinct peaks, confirming the successful formation of the sodalite framework. The results indicate that relative humidity (RH) significantly influences performance: at low RH (30%), removal efficiency improved at lower temperatures due to enhanced pollutant transport to active sites. In contrast, high RH (70%) reduced efficiency at temperatures above ≈ 250&#xa0;°C as water molecules blocked EB access to active sites. Space velocity (SV) was also critical: lower SVs resulted in higher removal efficiency for both 50% (T<sub>50</sub>) and 90% (T<sub>90</sub>) conversions of EB. As SV increased, T<sub>50</sub> shifted from 97&#xa0;°C to 111&#xa0;°C and T<sub>90</sub> from 211&#xa0;°C to 223&#xa0;°C, indicating decreased efficiency. Higher EB concentrations initially increased removal efficiency at low temperatures, but at higher concentrations active-site saturation occurred, reducing efficiency. For example, increasing the EB concentration raised T<sub>50</sub> from 87&#xa0;°C to 127&#xa0;°C and T<sub>90</sub> from 198&#xa0;°C to 231&#xa0;°C, demonstrating a decline in catalyst performance. These findings advance the understanding of metal-organic framework (MOF) based catalysts for VOC control and provide insights for developing air pollution mitigation technologies.</p>

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Synthesis and optimization nanocomposite catalyst based on silver@Zeolite imidazolite frameworks − 67 (Ag@ZIF-67) and catalytic application for ethyl benzene vapor removal in air matrices

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年11月26日

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  • Reza Pourbabaki,
  • Parvin Seirafi,
  • Zabiholah Damiri

摘要

The presence of volatile organic compounds (VOCs) poses significant health and environmental risks. This study investigates the catalytic oxidation of ethylbenzene (EB) vapor using a silver-impregnated zeolitic imidazolate framework-67 (Ag@ZIF-67). The effectiveness of the catalyst in converting EB was evaluated in a continuous-flow fixed-bed reactor. The Ag@ZIF-67 catalyst was synthesized and characterized using X-ray diffraction (XRD), energy dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR). The XRD patterns of the synthesized ZIF-67 and Ag@ZIF-67 showed distinct peaks, confirming the successful formation of the sodalite framework. The results indicate that relative humidity (RH) significantly influences performance: at low RH (30%), removal efficiency improved at lower temperatures due to enhanced pollutant transport to active sites. In contrast, high RH (70%) reduced efficiency at temperatures above ≈ 250 °C as water molecules blocked EB access to active sites. Space velocity (SV) was also critical: lower SVs resulted in higher removal efficiency for both 50% (T50) and 90% (T90) conversions of EB. As SV increased, T50 shifted from 97 °C to 111 °C and T90 from 211 °C to 223 °C, indicating decreased efficiency. Higher EB concentrations initially increased removal efficiency at low temperatures, but at higher concentrations active-site saturation occurred, reducing efficiency. For example, increasing the EB concentration raised T50 from 87 °C to 127 °C and T90 from 198 °C to 231 °C, demonstrating a decline in catalyst performance. These findings advance the understanding of metal-organic framework (MOF) based catalysts for VOC control and provide insights for developing air pollution mitigation technologies.