Magnetic mining waste based-geopolymers applied to catalytic reactions with ozone

• Published in: Heliyon 2023-06, Vol.9 (6), p.e17097-e17097, Article e17097
• Main Authors: Gier Della Rocca, Daniela, Santos e Sousa, Flávio Augusto, Domingos Ardisson, José, Peralta, Rosely Aparecida, Rodríguez-Castellón, Enrique, Peralta Muniz Moreira, Regina de Fátima
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes; Alkali-activated aluminosilicates; Heterogeneous catalysis; Iron oxides; Mining waste
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2023.e17097

The demand for sustainable and low-cost materials for wastewater treatment is increasing considerably. In this scenario, geopolymers have gained great interest, due to their good mechanical properties, their ability to be produced from industrial waste and their adsorbent or catalytic properties. In this study, novel magnetic mining waste based-geopolymers were produced by incorporating a residue from phosphate waste rocks, which were extensively characterized (XRD, TGA/DTA, SEM, BET, XRF, FTIR, Mössbauer, ss-NMR and XPS). The materials produced showed formation of a dense framework, even with 75% incorporation of the residue. The iron oxides and their magnetic properties remained unchanged, and their application in advanced oxidation reactions were evaluated, in particular, as catalysts in ozonation reactions. All of the geopolymers presented catalytic activity in the ozonation reaction, with catalytic ozone decomposition values of up to 2.98 min−1, which is 99 times greater than non-catalyzed reactions. Moreover, the reuse (performed in three cycles) and hot filtration-like experiments demonstrated, respectively, the regenerability and heterogeneous catalytic properties of the produced materials, showcasing the potential of these waste materials for catalytic geopolymer production. demonstrating the potential of this waste to produce catalytic geopolymers. [Display omitted] •Up to 75% of magnetic waste from phosphate mining was incorporated into geopolymers.•The waste addition produced solids with dense frameworks and magnetic properties.•The materials catalyze ozone decomposition in acid aqueous suspension media.•Positive synergic effect between geopolymer and magnetite to catalytic ozonation.