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<p>Arsenic contamination in water, particularly in its toxic form As(III), is a significant environmental issue in Brazil and globally. To address this, simple oxides of Fe<sub>2</sub>O<sub>3</sub> and TiO<sub>2</sub>, along with heterojunction structures TiO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> and Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub>, were synthesized using an adapted Pechini method for the decontamination of As(III) via heterogeneous photocatalysis. TiO<sub>2</sub> exhibited only the anatase phase, while Fe<sub>2</sub>O<sub>3</sub> showed only the hematite phase (α-Fe<sub>2</sub>O<sub>3</sub>). The Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> structure displayed both the hematite and anatase phases, whereas the TiO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> heterojunction exhibited the anatase, rutile, hematite, and maghemite (γ-Fe<sub>2</sub>O<sub>3</sub>) phases. The materials displayed micro/mesoporous characteristics, with surface areas ranging from 20 to 45 m<sup>2</sup>&#xa0;g<sup>−1</sup>, and band gap energies in the range of 2.1 to 3&#xa0;eV. Hematite was the most effective adsorbent for arsenic. Under UV light irradiation, photolysis achieved 87% oxidation of As(III) in 20&#xa0;min. The decontamination efficiencies achieved were 63%, 88%, 88%, and 99% for Fe<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub>, and TiO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub>, respectively. Catalyst reuse tests demonstrated excellent stability, with all catalysts maintaining over 80% decontamination efficiency after four cycles. These results highlight the promising potential of TiO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> heterojunctions for efficient and sustainable As(III) decontamination from contaminated water.</p>

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TiO2/Fe2O3 and Fe2O3/TiO2 heterojunction nanocomposites applied to As(III) decontamination

  • 期刊论文

  • 发表日期：

    2025年2月28日

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  • Michel Zampieri Fidelis,
  • Gabriele Bolzan Baroncello,
  • Eduardo Abreu,
  • Edivaldo dos Santos Filho,
  • Éder Carlos Ferreira de Souza,
  • Giane Gonçalves Lenzi,
  • Rodrigo Brackmann

摘要

Arsenic contamination in water, particularly in its toxic form As(III), is a significant environmental issue in Brazil and globally. To address this, simple oxides of Fe2O3 and TiO2, along with heterojunction structures TiO2/Fe2O3 and Fe2O3/TiO2, were synthesized using an adapted Pechini method for the decontamination of As(III) via heterogeneous photocatalysis. TiO2 exhibited only the anatase phase, while Fe2O3 showed only the hematite phase (α-Fe2O3). The Fe2O3/TiO2 structure displayed both the hematite and anatase phases, whereas the TiO2/Fe2O3 heterojunction exhibited the anatase, rutile, hematite, and maghemite (γ-Fe2O3) phases. The materials displayed micro/mesoporous characteristics, with surface areas ranging from 20 to 45 m2 g−1, and band gap energies in the range of 2.1 to 3 eV. Hematite was the most effective adsorbent for arsenic. Under UV light irradiation, photolysis achieved 87% oxidation of As(III) in 20 min. The decontamination efficiencies achieved were 63%, 88%, 88%, and 99% for Fe2O3, TiO2, Fe2O3/TiO2, and TiO2/Fe2O3, respectively. Catalyst reuse tests demonstrated excellent stability, with all catalysts maintaining over 80% decontamination efficiency after four cycles. These results highlight the promising potential of TiO2/Fe2O3 heterojunctions for efficient and sustainable As(III) decontamination from contaminated water.