3D Printed Adsorbent Materials – A tool for climate change mitigation?

• Autor(a) principal: Melo, Pedro Jorge Cortesão Vieira de
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/24748
• topic: Adsorption; 3D printing; Metal Organic Framework; MIL-53(Al); Binders; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

In recent decades, an increase of research has been carried out on adsorbents for the adsorption of gases that contribute to the increase of the greenhouse effect and damaging of the ozone layer, as well as on the structuring of these adsorbents for pressure swing adsorption (PSA), using traditional techniques such as mold extrusion, tape casting and freeze casting. A modern 3D printing technique was applied in the formulation of a metal organic framework (MOF) adsorbent in monolithic and cylindrical geometries to reduce the pressure drop in adsorption columns related to the use of the adsorbents in powder form. All the stages are described for the selection of a final paste containing 90% mass percentage of MIL-53(Al) adsorbent, 4% of polyvinyl alcohol, 3% of hydropropyl methyl cellulose and 3% of bentonite clay. The formulated paste was printed on a fused deposition modelling (FDM) type 3D printer, where multiple parameters such as the print speed, heating plate temperature, wall thickness and extruder screw rotation were studied. The optimized parameters in the 3D printing of cylindrical structured adsorbent are as follows; printing speed – 3mm/s and temperature of printing – 60ºC. Additionally, the optimized parameters in the 3D printing of monolith structured adsorbents are as follows; printing speed – 5mm/s, temperature of printing – 40ºC and height of print layer – 0,4mm. After the structuring, the paste sample was subjected to several characterization tests in order to compare the sample prepared paste to the adsorbent powder. The performed tests consisted on equilibrium tests of carbone dioxide and methane, thermogravimetric analysis (TGA), 77K nitrogen adsorption, FTIR, SEM and helium pycnometry. Some changes were noted in the microporous structure when comparing the results of the printed sample with the adsorbent powder, as well as losses of adsorption capacity of 38,75 % and 47,53% at 15,5 and 1,6 bar respectively in carbon dioxide, and 60,86% and 71,68% at 16 and 2,13 bar respectively in methane. Through the obtained results, it is concluded that, despite the vast potential and the successful printing of cylindrical pieces, the 3D printing technique proved not to be completely effective in the production of printed pieces in monolithic form using a paste with adsorbent and binders.