Production and characterization of geopolymers from diatomaceous earth

The world has been facing an increase in the average surface temperature of the earth due to the high release of carbon dioxide into the atmosphere. One of the main responsible for this release of CO2 is the manufacture of Portland Cement, associated with an emission of carbon dioxide of around 7% of the world's total emissions. In this way, there is a need to find alternatives to Portland cement. This work aims to contribute to this endeavor, proposing the application of a solid waste used as a wine filtration agent in the wine industry, diatomaceous earth, containing high amounts of silicon, to produce geopolymers. A geopolymer is an inorganic polymer produced with an aluminosilicate precursor reacted with an alkaline solution that has been studied as an alternative to cement. Diatomaceous earth and alumina were employed in this work as aluminosilicate sources for the geopolymer precursor, while sodium hydroxide and sodium silicate were used as the alkaline solution. The production process involved mixing all these raw materials of the geopolymers to create a fresh geopolymer. Following production, the geopolymers were characterized using XRD, FTIR, SEM-EDS, and pore property analysis. The results revealed that the most favorable geopolymer was produced considering a NaOH concentration of 10 M and a Si/Al ratio of 3,5. This combination resulted in a higher proportion of geopolymer phase, consequently improving mechanical properties.