Investigation of the Kinetics and Reaction Mechanism for Photodegradation Tetracycline Antibiotics over Sulfur-Doped Bi2WO6-x/ZnIn2S4 Direct Z-Scheme Heterojunction

Abstract

The rational design of direct Z-scheme heterostructural photocatalysts using solar energy is promising for energy conversion and environmental remediation, which depends on the precise regulation of redox active sites, rapid spatial separation and transport of photoexcited charge and a broad visible light response. The Bi2WO6 materials have been paid more and more attention because of their unique photochemical properties. In this study, S2− doped Bi2WO6-x coupled with twin crystal ZnIn2S4 nanosheets (Sov−BWO/T−ZIS) were prepared as an efficient photocatalyst by a simple hydrothermal method for the removal of tetracycline hydrochloride (TCH). Multiple methods (XRD, TEM, XPS, EPR, UV vis DRS, PL etc.) were employed to systematically investigate the morphology, structure, composition and photochemical properties of the as-prepared samples. The XRD spectrum indicated that the S2− ions were successfully doped into the Sov−BWO component. XPS spectra and photoelectrochemical analysis proved that S2− served as electronic bridge and promoted captured electrons of surface oxygen vacancies transfer to the valence band of T−ZIS. Through both experimental and in situ electron paramagnetic resonance (in situ EPR) characterizations, a defined direct Z-scheme heterojunction in S-BWO/T−ZIS was confirmed. The improved photocatalytic capability of S-BWO/T−ZIS results ascribed that broadened wavelength range of light absorption, rapid separation and interfacial transport of photoexcited charge, precisely regulated redox centers by optimizing the interfacial transport mode. Particularly, the Sov−50BWO/T−ZIS Z-scheme heterojunction exhibited the highest photodegradation rate was 95% under visible light irradiation. Moreover, this heterojunction exhibited a robust adsorption and degradation capacity, providing a promising photocatalyst for an organic pollutant synergistic removal strategy.

Enhanced Visible-Light-Responsive Photocatalytic Degradation of Ciprofloxacin by the CuxO/Metal-Organic Framework Hybrid Nanocomposite

“…The EPR spectra show that no signal is detected under the dark condition ( Figure 6 a). In contrast, strong signals with a peak intensity of 1:2:2:1, which belong to the OH radicals, are detected when Cu x O/MOF is irradiated with the visible light for 1–10 min [ 55 ]. Additionally, the DMPO-O 2 − signals in the methanol solution are shown in Figure 6 b.…”

Modulation of Z-scheme photocatalysts for pharmaceuticals remediation and pathogen inactivation: Design devotion, concept examination, and developments

“…The negative slopes indicated that the semiconductors are n-type and it was further employed to determine band edge positions of the semiconductors to compare with radical experiments to substantiate the interfacial charge transfer to follow indirect Z-scheme with Bi as the electron mediator between BiOCl and Bi 2 O 3 . There are numerous photodegradation experiments that have been conducted with different photocatalytic Z-scheme heterojunctions towards degradation of single [10] , [78] , [79] and multiple [80] tetracycline antibiotics in water. Dual direct Z-scheme MoS 2 /g-C 3 N 4 /Bi 24 O 31 Cl 10 ternary heterojunction was evaluated towards degradation of TC with 97.5% degradation efficiency in 50 minutes of visible-light irradiation by Kang and co-workers [62] .…”

“…Diverse tactics investigated for possible improvement of the general efficiency of semiconductors for removal of pharmaceuticals include metal doping [9] , non-metal doping [10] , multi-elemental doping with metals and/or non-metals [11] , use of supports [12] , and formation of heterojunctions [13] , [14] . The contribution of heterojunctions towards abatement of different classes of pharmaceuticals such as β- blockers, hormones, antibiotics, cholesterol-lowering drugs, oestrogens, anti-psychotics, non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics has been studied recently [15] , [16] , [17] , [18] , [19] , [20] .…”

The Growth of Extended Melem Units on g-C3N4 by Hydrothermal Treatment and Its Effect on Photocatalytic Activity of g-C3N4 for Photodegradation of Tetracycline Hydrochloride under Visible Light Irradiation

“…Tetracycline hydrochloride (TC) is one of the most common pharmaceutical residues, which is in wide usage on a global scale [ 5 ]. Therefore, a variety of methods have been developed to remove TC from an aqueous environment, including membrane separation, biodegradation, adsorption, Fenton oxidation, and photocatalyst degradation [ 6 , 7 , 8 , 9 , 10 ]. Among them, the photodegradation process is considered as a superior strategy for elimination of TC based on its low cost, sustainable technology, and high removal efficiency [ 11 , 12 ].…”