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Item Robust Co(II)-Based Metal-Organic Framework for the Efficient Uptake and Selective Detection of SO2(ACS Publications (American Chemical Society), 2024-03-26) López-Cervantes VB; López-Olvera A; Obeso JL; Torres IK; Martínez-Ahumada E; Carmona-Monroy P; Sánchez-González E; Solís-Ibarra D; Lima E; Jangodaz E; Babarao R; Ibarra LA; Telfer SGMUF-16 is a porous metal-organic framework comprising cobalt(II) ions and 5-aminoisophthalate ligands. Here, we measured its reversible SO2 adsorption-desorption isotherm around room temperature and up to 1 bar and observed a high capacity for SO2 (2.2 mmol g-1 at 298 K and 1 bar). The uptake of SO2 was characterized by Fourier transform infrared (FT-IR) spectroscopy, which indicated hydrogen bonding between the SO2 guest molecules and amino functional groups of the framework. The location and packing of the SO2 molecules were confirmed by computational studies, namely, density functional theory (DFT) calculations of the strongest adsorption site and grand canonical Monte Carlo (GCMC) simulations of the adsorption isotherm. Furthermore, MUF-16 showed a remarkable selective fluorescence response to SO2 compared to other gases (CO2, NO2, N2, O2, CH4, and water vapor). The possible fluorescence mechanism was determined by using time-resolved photoluminescence. Also, the limit of detection (LOD) was calculated to be 1.26 mM (∼80.72 ppm) in a tetrahydrofuran (THF) solution of SO2Item Metal-organic framework (MOF) membranes for gas separations : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Chemistry at Massey University, Manawatu, New Zealand(Massey University, 2024-04-29) Zhang, YimingThe study presented in this thesis involves the design, preparation and evaluation of metal-organic frameworks (MOFs) for gas separation applications, with a focus on the development of MOF membranes with both high gas permeability and good selectivity. Here, two types of membranes, including crystal glass composite membranes (CGCMs) and mixed matrix membranes (MMMs), were prepared and characterized, followed by a comprehensive evaluation of their performance for CO₂ separation. Separating gases using membranes is appealing due to their efficiency and low energy requirements. Recently, glasses have been discovered that are produced by the melt-quenching of ZIFs. In chapter 2, we propose that useful membranes can be prepared by combining ZIF glasses with MOFs. We prepared these crystal-glass composite membranes by ball milling ZIF-62 with various crystalline MOFs followed by pressing into a tablet, heating to melt the ZIF-62 into a glass, and subsequent cooling. This fabrication process delivers membranes with homogenous dispersion of crystalline MOF particles in a ZIF glass matrix. As an alternative, we show how pre-forming ZIF-62 glass allows membranes to be formed with MOFs with relatively low stability. The resulting crystal-glass composite membranes show ultrahigh CO₂ permeance. MMMs offer great potential for gas separation through the integration of nanofillers into polymers with excellent processability. Among these, MOF-based MMMs have emerged as promising candidates for advanced gas separation applications. However, a major obstacle hindering their performance is the inherent interfacial incompatibility between MOFs particles and the polymer matrix. In this thesis, we present a viable solution utilizing a scalable ball milling approach to address this challenge, specifically targeting the interfacial incompatibility between MUF-16 and the polymer matrix. Significantly, our approach involves the production of MUF-16 with varying crystal sizes through ball milling prior to MMM fabrication. In chapter 3 and 4, we illustrate that the nanosizing of MUF-16 (nsMUF-16) enhances its dispersion within three different polymer matrices (Pebax, 6FDA-DAM and 6FDA-Durene), effectively minimizing non-selective voids around the particles. Importantly, MMMs incorporating nsMUF-16 consistently exhibit superior CO₂ separation performance compared to those utilizing micro-sized MUF-16. Overall, this study highlights a versatile methodology employing engineered approaches to develop high-performance membranes with enhanced interfacial compatibility for gas separation. Furthermore, this approach holds promise for extending the processability of other MOF adsorbents into matrix materials, thereby broadening the scope of potential applications in gas separation technologies. Due to the distinctive structural arrangement of MUF-15, where the phenyl rings of the ipa ligands protrude into the void space, there exists a potential for substituting the ipa ligand with various functional groups. This opens avenues for obtaining analogues of MUF-15. These functionalized variants, denoted as MUF-15-X (with X representing substituents such as F, Br, CH₃, and NO₂), offer the prospect of imbuing MUF-15 with diverse gas sorption properties. Consequently, our interest is piqued to explore the structural characteristics and gas separation capabilities of these analogues across different functional groups. In chapter 5, we present a comprehensive investigation into 6FDA-DAM-based MMMs incorporating MUF-15 and its analogues for CO₂ separation from CH₄. Notably, this study constitutes the pioneering utilization of MUF-15 analogues as fillers in MMMs specifically designed for CO₂/CH₄ separation. It introduces a spectrum of emerging MUF-15 derivatives as potential filler materials for MMM development and underscores the efficacy of pore structure functionalization in augmenting the separation performance of MMMs.Item Niobium K-Edge X-ray Absorption Spectroscopy of Doped TiO2 Produced from Ilmenite Digested in Hydrochloric Acid(American Chemical Society, 2022-08-16) Haverkamp RG; Kappen P; Sizeland KH; Wallwork KSNiobium doping of TiO2 creates a conductive material with many new energy applications. When TiO2 is precipitated from HCl solutions containing minor Nb, the Nb in solution is quantitatively deposited with the TiO2. Here, we investigate the structure of Nb doped in anatase and rutile produced from ilmenite digested in hydrochloric acid. Nb K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) are used to characterize the environment of 0.08 atom % Nb doped in TiO2. XANES shows clear structural differences between Nb-doped anatase and rutile. EXAFS for Nb demonstrates that Nb occupies a Ti site in TiO2 with no near neighbors of Nb. Hydrolysis of Ti and Nb from acid solution, followed by calcination, leads to a well dispersed doped material, with no segregation of Nb. Production of Nb-doped TiO2 by this method may be able to supply future demand for large quantities of the material and in energy applications where a low cost of production, from readily available natural resources, would be highly desirable.Item 3D printing materials for large-scale insulation and support matrices : thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering, Massey University, Albany, New Zealand(Massey University, 2019) Harris, MuhammadAdditive manufacturing (AM) techniques have promising applications in daily life due to their superiority over conventional manufacturing techniques in terms of complexity and ease of use. However, current applications of polymer-based 3D printing (3DP) are limited to small scale only due to the high cost of materials, print times, and physical sizes of the available machines. In addition, the applications of 3DP are yet to be explored for insulation of different large-scale mechanical structures. For example, milk vats are large structures with complex assemblies (like pipes, joints, couplings, valves, ladders, vessel doors) that requires insulation to store the milk at a low temperature of 6 °C as per the NZCP1 regulations in New Zealand. Generally, milk vats lack any kind of proper insulation around them and require additional cooling systems to keep the milk at a prescribed temperature. Any variations in the temperature can lead to deterioration in the quality of milk. Therefore, there exists a research gap that can not only help to solve an industrial issue but also can be a first step towards real large-scale 3DP applications that can potentially lead to many others in future. For example, pipe insulation, food storage tanks, chemical storage tanks, water treatment. This research explores new and inexpensive materials for large-scale 3DP. For this purpose, the current state of the 3DP materials is analyzed and based upon this analysis two distinct approaches are devised: 1) in-process approach to improve the mechanical properties of the existing materials like polylactic acid (PLA), and 2) modification of inexpensive materials (like materials used in injection, rotational, and blow moulding) to make them printable. In the first approach, by controlling the process parameters, mechanical properties are studied. While in the second approach, blends of high density polyethylene (HDPE) and polypropylene (PP) with different thermoplastics (acrylonitrile butadiene styrene, ABS and polylactic acid, PLA) are investigated to achieve printability. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) are used to analyze the proposed materials. The overall objective of this research is to devise low-cost materials comparable to the conventional processes that are capable of providing good mechanical properties (tensile, compressive and flexural) along with high resistance to thermal, moisture, and soil degradation. The results present significant enhancement, up to 30%, in tensile strength of PLA through in-process heat treatment. However, the softness induced during printing above 70 °C directs to the second approach of developing the novel blends of HDPE and PP. In this regard, the research develops three novel blend materials: 1) PLA/HDPE, 2) ABS/HDPE, and 3) ABS/PP. These materials are compatibilized by a common compatibilizer, polyethylene graft maleic anhydride (PE-g-MAH). PLA/HDPE/PE-g-MAH provides highest tensile strength among all existing FDM blends (73.0 MPa) with superior resistance to thermal, moisture and soil degradation. ABS/HDPE and ABS/PP provide one of the highest mechanical properties (tensile, compressive, and flexural) in ABS based FDM blends with superior thermal resistance to six days aging. ii The chemical characterization of aforementioned novel FDM blends shows partial miscibility with sufficient signs of chemical grafting. The significant intermolecular interactions are noted in FTIR that shows the grafting through compatibilizer (PE-g-MAH). The DSC analysis shows visible enhancement in different thermal parameters like glass transition, melt crystallization and degradation along with signs of partial miscibility. Furthermore, TGA analysis confirms the partial miscibility along with the enhanced onset of degradation temperature. The increase in onset temperatures of each of the three blends proves the thermal stability to high temperatures. Hence, each of the developed blends is capable of resisting any material deterioration during routine cleaning operation at 70 °C of milk vats. This research has resulted in 5 journal publication (four published and one submitted), two conference proceedings and a number of posters presented at local conferences. This research is the part of food industry and enabling technologies (FIET) research program funded by the ministry of business, innovation and employment (MBIE), New Zealand in collaboration with Massey University, Auckland.Item Hybrid organic-inorganic layered electronic materials : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Physics at Massey University, Manawatu campus, New Zealand(Massey University, 2012) Islah-u-dinHybrid organic-inorganic materials combine distinct features of organic and inorganic components into single molecular frameworks that exhibit tunable electronic, optical and magnetic properties. An extending layered network is formed by covalently bound layers of inorganic materials that are electronically coupled by organic components. A control on the stacking orientation of these layers can help tailor the structural, physical and chemical properties of resulting compounds. This thesis presents an investigation of the synthesis, characterization and effects of doping, primarily by ion-implantation, on structural, chemical and physical properties of transition-metal oxide based organic-inorganic hybrid materials. These materials were synthesized and characterized by a variety of experimental techniques. The crystal structures of these compounds were probed by powder and single-crystal X-ray diffraction while various other techniques such as Raman spectroscopy, X-ray photoelectron spectroscopy, magnetic and resistivity measurements were applied to examine the chemical and physical properties of these materials. The crystal structure of these materials consists of infinite layers of transition metal oxides interlinked by organic ligands. The organic-ligands are aligned so as to define small cages within these structures, potentially, to accommodate metal ions. Intercalation of alkali-metal atoms within these cages brings about important altercations in the structural, chemical and physical properties of these materials. The presence of intercalated species was confirmed by single-crystal X-ray diffraction and X-ray photoelectron spectroscopy while spectral changes observed from Raman measurements and a significant reduction in electrical resistance of implanted materials refer to charge carrierinjection into the conduction band. Significant changes in structure and physical properties of these materials were observed by increasing the number of atoms in ligand tethers while introduction of additional metal atoms, by in-situ doping, in the inorganic oxide layers, leads to strong antiferromagnetic interactions in otherwise diamagnetic materials. These results demonstrate the possibilities of exploiting the self-assembly of organic and inorganic precursors to realize the potential applications these materials have to offer.