Porous Sorbents for Environmental Applications and Selective Laser Sintering 3D Printing of Dosage Forms

Sammanfattning: The rising levels of greenhouse gas emissions from vehicular and industrial pollution constitute a serious concern not only for the environment but for our entire society. Traditional gas capture and separation techniques, such as amine scrubbing for CO2 gas separation, have been commonly used at a commercial scale, however issues relating to high costs and high energy requirements for sorbent regeneration have limited the efficiency of many of these techniques. The use of porous sorbents, such as metal-organic frameworks (MOFs), has garnered significant attention as an alternative method for the capture and separation of greenhouse gases in recent years, particularly due to their structural and functional tunability. Thus, part of this thesis explores the selective capture of CO2 and SF6 in five new MOFs and mixed-linker zeolitic imidazolate frameworks (ZIFs). The CO2 and SF6 adsorption in microporous bismuth-based MOFs containing narrow ultramicro-pores (e.g. UU-200) was not found to be correlated to the N2-accessible surface area of the framework but was related to pore size effects and possibly framework flexibility. Similar mechanisms for SF6 capture were observed in vanadium- and gallium-based MOFs (UU-201-4) in which an enhanced van der Waals interaction between the gas molecules and the pore surface was obtained due to the pore size of the materials coinciding with the kinetic diameter of SF6 (5.5 Å). This further resulted in good uptake capacities as well as SF6-over-N2 selectivites above 2.75 mmol g-1 and 43, respectively. Furthermore, the selective uptake of CO2 and SF6 could be modified in mixed-linker ZIF-7-8s by tuning of the pore aperture size through a controlled incorporation of the bulkier benzimidazolate linker in the frameworks.The removal of other environmental pollutants (e.g. phosphates) in porous materials such as amorphous mesoporous magnesium carbonate (MMC) was also investigated and showed that the material had superior sorption capacities as compared to its crystalline, non-porous counterpart. MMC was also found to be a capable functional support for other materials such as semiconducting TiO2 and ZnO nanoparticles. The TiO2/ZnO-composite was observed to retain the porosity as well as UV-blocking properties of the respective pristine materials.A part of this thesis was also devoted to the fabrication of personalized solid dosage forms for pharmaceutical applications. To achieve this, 3-dimensional selective laser sintering (SLS) printing was utilized to print both purely polymeric and drug-loaded tablets (containing 10 wt.% naproxen). The subsequent weight and mechanical strength of the obtained tablets could be tuned by either modifying the NIR-active pigment concentration in the powder formulation or by changing the laser energy input that is used during the printing process. Amorphization of the crystalline drug was also achieved in-situ during printing thus showing that the SLS 3D printing may be a promising technique for the manufacturing of solid amorphous dispersions with tailorable properties.