Double Z-scheme Co3O4/Bi4O7/Bi2O3 composite activated peroxymonosulfate to efficiently degrade tetracycline under visible light

Abstract

Co3O4/Bi4O7/Bi2O3 (CBB) composites were prepared, in which Co3O4 was synthesized from Co-MOF as precursor. The peroxymonosulfate (PMS) activated by CBB catalyst under visible light was used to degrade tetracycline (TC). Owing to the synergistic effect of photocatalysis and PMS activation, 98.4% of TC was removed within 60 min. The optimal loading of Co3O4 was determined, and the influence of PMS dosage, initial pH, and disturbing anions on the degradation effect were investigated. The “CBB + Vis + PMS” system showed good reusability, and the degradation was only reduced by 1.7% after 5 cycles. This system also had a good degradation of other five pollutants. The quenching experiment showed that holes (h⁺), superoxide radicals (·O2⁻), and singlet oxygen (¹O2) were the main active species. The degradation products of TC were determined by liquid chromatography-mass spectrometry, and the degradation pathway was proposed. Finally, a double Z-scheme degradation mechanism was proposed in the “CBB + Vis + PMS” system. The peroxymonosulfate activated by CBB under visible light to degrade organic pollutants has widespread application prospects in environmental remediation.

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https://doi.org/10.1007/s11356-022-21359-8
RESEARCH ARTICLE
Double Z‑scheme Co3O4/Bi4O7/Bi2O3 composite activated
peroxymonosulfate toefficiently degrade tetracycline undervisible
light
YajuanZhao1· PuDang1· YaqianGao1· YanLi2· HuidongXie1,3 · ChangYang4
Received: 14 December 2021 / Accepted: 4 June 2022
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022
Abstract
Co3O4/Bi4O7/Bi2O3 (CBB) composites were prepared, in which Co3O4 was synthesized from Co-MOF as precursor. The
peroxymonosulfate (PMS) activated by CBB catalyst under visible light was used to degrade tetracycline (TC). Owing to
the synergistic effect of photocatalysis and PMS activation, 98.4% of TC was removed within 60min. The optimal loading
of Co3O4 was determined, and the influence of PMS dosage, initial pH, and disturbing anions on the degradation effect were
investigated. The “CBB + Vis + PMS” system showed good reusability, and the degradation was only reduced by 1.7% after
5 cycles. This system also had a good degradation of other five pollutants. The quenching experiment showed that holes
(h+), superoxide radicals (·O2
−), and singlet oxygen (1O2) were the main active species. The degradation products of TC
were determined by liquid chromatography-mass spectrometry, and the degradation pathway was proposed. Finally, a double
Z-scheme degradation mechanism was proposed in the “CBB + Vis + PMS” system. The peroxymonosulfate activated by
CBB under visible light to degrade organic pollutants has widespread application prospects in environmental remediation.
Keywords Co3O4/Bi4O7/Bi2O3· Double Z-scheme· Photocatalysis· Peroxymonosulfate· Advanced oxidation process
Introduction
With the rapid economic development, water pollution is
becoming more and more serious (Wang etal. 2020). A large
number of residual antibiotics have been widely detected
in wastewater, which has seriously endangered human
health and the environment. Tetracycline ranks second in
production among all medicinal antibiotics, and it has strong
chemical stability and is difficult to biodegrade (Chen etal.
2019). It exists widely in surface water, groundwater, and
drinking water, seriously endangering ecological balance
and human health (Song etal. 2021). Many researchers
have devoted themselves to the removal of antibiotics in the
water environment using biodegradation, adsorption, chemi-
cal oxidation, and other methods (Dong etal. 2018). Among
these methods, advanced oxidation processes (AOPs) have
attracted much attention because they can generate highly
active species and directly oxidize refractory pollutants into
nontoxic small molecule compounds (Hu and Long, 2016;
Ribeiro etal. 2015). Particularly, advanced oxidation tech-
nology based on sulfate radical (SO4
−·) has been successfully
applied to the removal of organic pollutants in wastewater.
Sulfate radicals have high redox potential (2.5–3.1eV), long
free radical lifetime (20–40μs), wide pH range (2–8), and
unique selectivity to aromatic organics (Ding etal. 2020; Oh
etal. 2016). In the traditional peroxymonosulfate activation
technology, thermal activation requires more energy, which
is not suitable for large-scale use. The water penetration
capacity of radiation activation is limited, and the equipment
cost is high. The treatment efficiency of alkali activation is
Responsible editor: Ricardo A. Torres-Palma
* Huidong Xie
xiehuidong@tsinghua.org.cn
1 School ofChemistry andChemical Engineering, Xi’an
University ofArchitecture andTechnology, Xi’an710055,
Shaanxi, China
2 Library, Xi’an University ofArchitecture andTechnology,
Xi’an710055, Shaanxi, China
3 Xi’an Key Laboratory ofClean Energy, Xi’an University
ofArchitecture andTechnology, Xi’an710055, Shaanxi,
China
4 Division ofLaboratory andEquipment Management, Xi’an
University ofArchitecture andTechnology, Xi’an710055,
Shaanxi, China
/ Published online: 16 June 2022
Environmental Science and Pollution Research (2022) 29:79184–79198
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