The combustion of fossil fuels has increased the level of atmospheric carbon dioxide (CO2), leading to global warming. To mitigate the problem of global warming, many technologies have been developed to reduce CO2 emissions, such as the capture and storage of CO2 on porous materials. Carbon-free energy sources such as hydrogen gas and solar power are a promise technology to replace fossil fuels. In this work, the MIL-100(Fe) has been synthesised by an HF-free method. Furthermore, the study investigates the adsorption performance of MIL-100(Fe) towards a variety of gases, such as Hydrogen gas, carbon dioxide gas, and water vapor. The maximum hydrogen uptake of MIL-100(Fe) is 0.25 wt.% at 5 °C and 40 bar, while the maximum CO2 uptake is 32.6 wt.% at 5 °C and 10 bar. The high water adsorption capacity of 57.62 wt.%, combined with the stepwise adsorption at relatively low humidity, makes MIL-100(Fe) a very suitable candidate for Adsorption heat transfer (AHT) applications. The market of heating and cooling applications is dominated by the vapor compression heat pumps (VCHP). However, the VCHP are environmentally unfriendly, operated by electric energy, and contribute to greenhouse gas emissions. The low environmental impact makes AHP an ideal alternative to the vapor compression heat pumps. The AHP uses an eco-friendly refrigerants, such as water and ammonia, and is driven by low-grade heat sources, such as waste heat and solar thermal energy. Nevertheless, the AHP suffers from a long adsorption-desorption cycle. The long cycle time is caused by low heat and mass transfer efficiencies in the adsorbent bed. To tackle this problem, the composite coatings approach has been proposed to increase heat transfer efficiency in the adsorbent bed. MIL-100(Fe) composite coatings have been prepared by binder-based Drop coating method. Specifically, Four types of matrices have been used for the synthesis of different MOF coatings: the organosilane (Npropyltrimethoxysilane and 3-Aminopropyl- triethoxysilane), polyvinylpyrrolidone (PVP), and sulfonated copolymer NEXAR. The morphological and structural features of the MOF coating were characterised by SEM analysis and a wettability test. Subsequently, a pull-off test, scratch test, and impact test were carried out to evaluate the mechanical stability of the synthesised coatings. Finally, the water sorption isobars of the samples were evaluated by a DVS thermogravimetric system. The MOF PVP coatings exhibit superior performance in both mechanical and pull-off adhesion tests, even at high MOF percentage. Furthermore, the MOF PVP coatings exhibited significantly higher water adsorption uptake and step-like adsorption isobars, thereby making them a promising candidate for adsorption cooling applications. In contrast, the MOF Nexar coatings showed a clear reduction in the maximum water vapor relative to the pure MOF (27.2 wt.%). For instance, SU-M75 showed water uptake of 12.71 wt.%, while SU-M90, with 90% MOF, reached water uptake of 21.1 wt.%.
Development of MIL-100(Fe) Based Composite Coatings for Adsorption Heat Pump Applications
IDREES MOHAMEDAHMED ABDALLAH, MUHTADI
2025-12-12
Abstract
The combustion of fossil fuels has increased the level of atmospheric carbon dioxide (CO2), leading to global warming. To mitigate the problem of global warming, many technologies have been developed to reduce CO2 emissions, such as the capture and storage of CO2 on porous materials. Carbon-free energy sources such as hydrogen gas and solar power are a promise technology to replace fossil fuels. In this work, the MIL-100(Fe) has been synthesised by an HF-free method. Furthermore, the study investigates the adsorption performance of MIL-100(Fe) towards a variety of gases, such as Hydrogen gas, carbon dioxide gas, and water vapor. The maximum hydrogen uptake of MIL-100(Fe) is 0.25 wt.% at 5 °C and 40 bar, while the maximum CO2 uptake is 32.6 wt.% at 5 °C and 10 bar. The high water adsorption capacity of 57.62 wt.%, combined with the stepwise adsorption at relatively low humidity, makes MIL-100(Fe) a very suitable candidate for Adsorption heat transfer (AHT) applications. The market of heating and cooling applications is dominated by the vapor compression heat pumps (VCHP). However, the VCHP are environmentally unfriendly, operated by electric energy, and contribute to greenhouse gas emissions. The low environmental impact makes AHP an ideal alternative to the vapor compression heat pumps. The AHP uses an eco-friendly refrigerants, such as water and ammonia, and is driven by low-grade heat sources, such as waste heat and solar thermal energy. Nevertheless, the AHP suffers from a long adsorption-desorption cycle. The long cycle time is caused by low heat and mass transfer efficiencies in the adsorbent bed. To tackle this problem, the composite coatings approach has been proposed to increase heat transfer efficiency in the adsorbent bed. MIL-100(Fe) composite coatings have been prepared by binder-based Drop coating method. Specifically, Four types of matrices have been used for the synthesis of different MOF coatings: the organosilane (Npropyltrimethoxysilane and 3-Aminopropyl- triethoxysilane), polyvinylpyrrolidone (PVP), and sulfonated copolymer NEXAR. The morphological and structural features of the MOF coating were characterised by SEM analysis and a wettability test. Subsequently, a pull-off test, scratch test, and impact test were carried out to evaluate the mechanical stability of the synthesised coatings. Finally, the water sorption isobars of the samples were evaluated by a DVS thermogravimetric system. The MOF PVP coatings exhibit superior performance in both mechanical and pull-off adhesion tests, even at high MOF percentage. Furthermore, the MOF PVP coatings exhibited significantly higher water adsorption uptake and step-like adsorption isobars, thereby making them a promising candidate for adsorption cooling applications. In contrast, the MOF Nexar coatings showed a clear reduction in the maximum water vapor relative to the pure MOF (27.2 wt.%). For instance, SU-M75 showed water uptake of 12.71 wt.%, while SU-M90, with 90% MOF, reached water uptake of 21.1 wt.%.Pubblicazioni consigliate
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