Associating Physical and Photocatalytic Properties of Recyclable and Reusable Blast Furnace Dust Waste

• Published in: Materials 2024-02, Vol.17 (4), p.818
• Main Authors: Chaves, Nayane O, Lima, Lucas S, Monteiro, Michael D S, Sobrinho, Raimundo A L, Ferreira, Nilson S, Ramos, Glenda Q, da Fonseca Filho, Henrique D, Oliveira, Rosane M P B, Matos, Robert S
• Format: Article
• Language: English
• Subjects: Charge transfer; Decoloring; Dust; Dyes; Electrical resistivity; Electrodes; Ferric oxide; Ferromagnetism; Fourier transforms; Hydroxyl radicals; Investigations; Iron; Iron oxides; Methylene blue; N-type semiconductors; Photocatalysis; Photodegradation; Physical properties; Raw materials; Spectrum analysis; Stability analysis; Structural analysis; Thermal stability; Wastewater treatment; Water treatment
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17040818

Blast furnace dust waste (BFDW) proved efficient as a photocatalyst for the decolorization of methylene blue (MB) dye in water. Structural analysis unequivocally identified α-Fe O as the predominant phase, constituting approximately 92%, with a porous surface showcasing unique 10-30 nm agglomerated nanoparticles. Chemical and thermal analyses indicated surface-bound water and carbonate molecules, with the main phase's thermal stability up to 900 °C. Electrical conductivity analysis revealed charge transfer resistance values of 616.4 Ω and electrode resistance of 47.8 Ω. The Mott-Schottky analysis identified α-Fe O as an n-type semiconductor with a flat band potential of 0.181 V vs. Ag/AgCl and a donor density of 1.45 × 10 cm . The 2.2 eV optical bandgap and luminescence stem from α-Fe O and weak ferromagnetism arises from structural defects and surface effects. With a 74% photocatalytic efficiency, stable through three photodegradation cycles, BFDW outperforms comparable waste materials in MB degradation mediated by visible light. The elemental trapping experiment exposed hydroxyl radicals (OH•) and superoxide anions (O2-•) as the primary species in the photodegradation process. Consequently, iron oxide-based BFDW emerges as an environmentally friendly alternative for wastewater treatment, underscoring the pivotal role of its unique physical properties in the photocatalytic process.