Author: | Ma, Kaikai |
Title: | Facile fabrication of metal-organic framework/fiber composite for hazardous chemical removal |
Advisors: | Xin, H. John (ITC) |
Degree: | Ph.D. |
Year: | 2020 |
Subject: | Fibrous composites Organometallic polymers Hong Kong Polytechnic University -- Dissertations |
Department: | Institute of Textiles and Clothing |
Pages: | xiii, 166 pages : color illustrations |
Language: | English |
Abstract: | Porous metal-organic framework (MOFs) with high chemical and structural complexities are gaining great interests from academia and industry for their versatility in a multitude of areas, however their poor processability hinders their potential in practical application. Design and fabrication of MOF-based composites, with intact functionality of MOFs and good processability, has attracted widespread attention in both industrial and academic areas for its importance in boosting the practical values of MOFs. Highly accessible textile fiber with high flexibility is a promising substrate to support the functional MOF coating layer for various application such as heterogeneous catalysis, chemical sensing, pollutant removal, and drug release. Although reported MOF coating fabrication methods are encouraging, coating of MOFs on fiber surface remains challenging in many aspects, including the need for expensive coating materials and equipment, low mass loading and coverage on the fiber surface, and poor method generalizability to thermo-sensitive fiber. In this thesis, the author arms to design facile fabrication methods of MOF/fiber composites, which could combine the processability of fiber substrate and functionality of MOF coating. In this thesis, previously reported MOF/fiber fabrication methods and mechanisms was reviewed to understand the underlying techniques and target certain areas for further development. Following the literature review, this study demonstrated the development of three facile MOF/fiber composite synthesis methods, including coordination replication method, hydrothermal growth method, and dip-coating method, with the generalizability to different MOFs and fiber substrates. Importantly, the designed fabrication methods only need the use of common equipment widely available in materials industries, making these methods highly desirable for their scalability. Moreover, in methods, surface chemical modification and atomic layer deposition (ALD) were not needed to improve the MOF nucleation and growth on fiber surface. The prepared flexible MOF/textile composites maintained the flexibility of fiber substrates and the functional properties of MOFs. Furthermore, these composites could be cut or tailored into different shapes, increasing their potential for mounting these materials into industrial equipment, such as adsorption devices and protective gears. Following fabrication, the application of MOF/fiber composites in important relevant fields such as pollutant control and human protection against ultra-toxic warfare agents was explored. Firstly, the HKUST-1/cotton composite, prepared using a coordination replication method, was used as a filter for removal of organosulfur compound from simulated gasoline and toxic ammonia adsorption. The MOF coating had excellent accessibility for capture these harmful chemicals. Secondly, the Zr-MOF/polyester composite prepared via an eco-friendly aqueous synthesis approach was employed as a heterogeneous catalyst for nerve agent hydrolysis in an alkaline buffer solution. The prepared composite showed the fastest degradation efficiency against nerve agent and related simulant. Thirdly, a ternary MOF-808/polymeric buffer/cotton composite was developed using a simple dipping-coating method and showed excellent solid-phase catalytic performance in nerve agent degradation under ambient conditions, which is a significant step forward for the destruction of these harmful chemicals in practical environments. The MOF/fiber composites integrating the advantages of functionality and processability could dramatically enhance their potential industrial applications. |
Rights: | All rights reserved |
Access: | open access |
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