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Acetic acid-assisted fabrication of hierarchical flower-like Bi2O3 for photocatalytic degradation of sulfamethoxazole and rhodamine B under solar irradiation
- Bao, Yueping, Lim, Teik-Thye, Zhong, Ziyi, Wang, Rong, Hu, Xiao
- Journal of colloid and interface science 2017 v.505 pp. 489-499
- acetic acid, adsorption, catalysts, irradiation, lighting, oxidation, pH, photocatalysis, rhodamines, solar radiation, sulfamethoxazole, superoxide anion
- With the assistance of acetic acid (CH3COOH), a novel 3D flower-like Bi2O3 was synthesized via hydrothermal process followed by calcination. For the first time, the role of CH3COOH as a capping agent in the formation of flower-like structure was investigated. The as-prepared flower-like Bi2O3 had a high activity on the degradation of sulfamethoxazole (SMX) under simulated solar light irradiation due to the narrow band gap of 2.69eV, high percentage of β-Bi2O3 as well as high intensity of polar facets (120) and (200). Meanwhile, the photocatalytic degradation followed apparent pseudo-first-order kinetics. The rate constant (k) increased from 0.7×10⁻² to 3.0×10⁻²min⁻¹ with the catalyst loading varying from 0.5 to 2.0gL⁻¹. Increasing pH values from 3 to 11 led to the decrease of k from 2.2×10⁻² to 0.2×10⁻²min⁻¹, which could be attributed to the electrostatic adsorption between SMX molecules and Bi2O3. The radical quenching experiments showed both direct (h⁺) and indirect oxidation (OH and O2-) happened in this process.