Bi5O7I/g-C3N4 Heterostructures With Enhanced Visible-Light Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

Yang Yang,Ruijie Gao,Jinze Li,Jixiang He,Jialei Huang,Huatang Song,Yan Ma,Ziming Zhao,Min Lai

doi:10.3389/fchem.2021.781991

Yang Yang, Ruijie Gao + Show 7 more

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https://doi.org/10.3389/fchem.2021.781991

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Abstract

Bi5O7I/g-C3N4 p-n junctioned photocatalysts were synthesized by alcohol-heating and calcination in air. The structures, morphologies and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS). Photocatalytic activity of the heterojunctioned composites were evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TCH) under visible light illumination. The results indicated that the composites exhibited superior efficiencies for photodegradation of RhB and TCH in comparison with pure BiOI, Bi5O7I and g-C3N4. An effective built-in electric field was formed by the interface between p-type Bi5O7I and n-type g-C3N4, which promoted the efficient separation of photoinduced electron-hole pairs. In addition, 8% Bi5O7I/g-C3N4 composite showed excellent photostability in a five-cycle photocatalytic experiment. Experiments on scavenging active intermediates revealed the roles of active species.

Highlights

Tetracycline antibiotics have a wide range of applications as broad-spectrum antibiotics
Observed on pure Bi5O7I are indexed to crystal planes (312), (004), (204) and (020) of orthorhombic Bi5O7I, respectively, according to the X-ray diffraction (XRD) standard card (JCPDS No.40-0548), which suggested the formation of Bi5O7I after calcination for twice at 500°C
These results revealed that all the reactive species of h+, ·OH, and O2− participated in the photocatalytic degradation processes and all of them played important roles in the photocatalytic degradation reaction of Rhodamine B (RhB)

Summary

Introduction

Tetracycline antibiotics have a wide range of applications as broad-spectrum antibiotics. TCH with a high water solubility is formed by combining tetracycline with hydrochloric acid, which is widely used for treatment of human and animal diseases owing to its low cost, broad antibacterial spectrum, high chemical stability and low side effects (Wang and Wang, 2015). Among various treatment methods of TCH, photocatalytic oxidation technology exhibits advantage of environmental-friendly process, low-energy cost and easy operation (Chen and Liu, 2016). Semiconductor-based photocatalysts have been developed intensively due to their potential applications in water splitting (Kudo and Miseki, 2003), degradation of organic pollutants (Carey et al, 1976), photocatalytic reduction of carbon dioxide (Roy et al, 2010), photocatalytic organic synthesis (Xiao et al, 2015), etc.

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