Supramolecular Coordination Compounds as Recyclable Templates for Mesoporous Silica
Date
2024-09-03
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Abstract
Porous solid sorbents have emerged as a promising class of materials for capture and storage of guests. One of the most common sorbents is porous silica, which is used in capture and separations, biomedical and research purposes. Porous silica is templated with organic surfactant groups which yield high porosity materials and a specific pore size. However, the templated organics are usually removed by calcination, which generates emissions and does not allow the template to be recycled. Additionally, inducing pores in the size regime of 1-3 nm is often challenging due to the lack of suitable templates. This thesis proposes an alternative strategy that yields pores in this range and a template that can be regenerated. This thesis involves the development of two supramolecular coordination compounds that were used as templates in the synthesis of mesoporous silica. The lanthanum-based coordination compounds (La(CSA)3 and La(TBSA)3) exhibited reversible shifting of peaks in their PXRD patterns with the addition or removal of different solvents. Porous silicas were synthesized upon crosslinking within a silica network, and the template was removed by washing the samples. Changing concentrations and solvents were found to affect the packing of the templates, which affected the porosity of the templated silica. Pore size distribution models applied to the samples calculated that the smallest micropore size was approximately the same size as the width of a single template molecule, showing the ability of these templates to act as porogens for the 1-3nm size range. However, much larger pores were induced by aggregation of the templates and more work is needed to enhance the consistency of the pore size distributions.
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Keywords
supramolecular chemistry, nanoscience, porous materials
Citation
Lin, G. (2024). Supramolecular coordination compounds as recyclable templates for mesoporous silica (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.