Radical-based degradation of sulfamethoxazole via UVA/PMS-assisted photocatalysis, driven by magnetically separable Fe3O4@CeO2@BiOI nanospheres

• Published in: Separation and purification technology 2021-07, Vol.267, p.118665, Article 118665
• Main Authors: Kohantorabi, Mona, Moussavi, Gholamreza, Oulego, Paula, Giannakis, Stefanos
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes (AOPs); Antibiotic degradation; Magnetic photocatalyst; Nanoparticles; Peroxymonosulfate activation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2021.118665

[Display omitted] •Fe3O4@CeO2@BiOI nanospheres were synthesized by a simple hydrothermal method.•The addition of PMS produced a synergetic effect in Fe3O4@CeO2@BiOI photocatalytic system under UVA.•97% of sulfamethoxazole (SMX) was removed from the bulk within 15 min with a rate constant value of 0.221 min−1.•HO∙, SO4∙-, and O2∙- were the dominant reactive species involved in SMX degradation pathway. In this work, novel magnetic Fe3O4@CeO2@BiOI nanospheres were synthesized for the heterogeneous photocatalytic activation of peroxymonosulfate (PMS) towards sulfamethoxazole (SMX) degradation. The phase purity, morphology, and surface properties of the nanocomposite were fully characterized and confirmed the formation of a heterojunction between the magnetic Fe3O4@CeO2 and BiOI. Low catalyst (0.1 g/L) and PMS addition (0.2 mM) under UVA-LED light irradiation led to high catalytic activity in SMX degradation (97%, kapp = 0.221 min−1) within 15 min. The highest quantum yield (QY) value (5.02 × 10−4 molecules photon−1) was measured for the ternary Fe3O4@CeO2@BiOI nanocomposite, which is 3.54, 3.76, and 4.04 times higher than Fe3O4@CeO2, BiOI, and CeO2 coupled with PMS/UVA, respectively. Furthermore, different experimental conditions, including initial solution pH, catalyst:PMS ratio, water matrix ions on the Fe3O4@CeO2@BiOI/PMS/UVA system, were investigated under the optimum reaction conditions. As deduced from the LC/MS analysis, the possible SMX degradation pathways were proposed. Based on radicals scavenging experiments, SO4∙-, HO∙, and O2∙- are mainly involved in SMX degradation. Finally, recycling and leaching experiments confirmed a stable material with coherent catalytic performance for the activation of PMS by Fe3O4@CeO2@BiOI catalyst under UVA, with excellent magnetic recovery capabilities. As such, this material has high potential for degradation of organic contaminants and in extension for water treatment processes.