Activity For Degradation Of Tetracycline Hydrochloride Research Articles

Construction of MoS2/TiO2 Heterojunction for Excellent Photocatalytic Degradation of Tetracycline

AbstractA series of MoS2/TiO2 heterojunction photocatalysts were prepared through the hydrothermal method and were analyzed via many characterizations. The tetracycline hydrochloride (TCH) was used to evaluate the performance of the photocatalysts under visible light. Compared with TiO2, the MoS2/TiO2 heterojunction has increased inhomogeneity and uneven grain size. The MoS2/TiO2 heterojunction exhibited the best activity for TCH degradation with a removal rate of 95.4 % in 120 min with a rate constant of. The reaction rate constants of MoS2/TiO2 heterojunction (0.0236 min−1) were 2.6 times and 18.2 times of the pure TiO2 and MoS2 (0.0090 min−1 and 0.0013 min−1), respectively. The research on the photocatalytic mechanism suggested that the charge transfer path conforms to the II‐scheme model, in which h+ and e− play a crucial role. This research provides strong practical support for the preparation of II‐scheme high‐efficiency photocatalytic materials.

Band gap-controllable N, P co-doped carbon@ZnxCd1−xIn2S4 for photocatalytic reduction of chromium(VI) and degradation of tetracycline hydrochloride

Construction of carbon-based heterostructural photocatalyst materials with high electron transfer rates is a practical and effective strategy for the mineralization of organic pollutants and removal of toxic metal ions under visible-light irradiation. This study developed a facile hydrothermal route to prepare a series of heterojunction photocatalysts, wherein ZnxCd1-xIn2S4 nanosheets were immobilized on nitrogen and phosphorus co-doped hollow carbon spheres (N, P-C) to form N, P-C@ZnxCd1-xIn2S4 nanocomposites. Comprehensive characterization of the nanocomposites revealed that the tuning of the Zn/Cd molar ratio could effectively modulate the ZnxCd1−xIn2S4 energy band structure. Moreover, Zn0.5Cd0.5In2S4 had the most negative conduction band position and loads on non-metal-doped carbon, with superior carrier transport properties and separation efficiency. N, P-C@Zn0.5Cd0.5In2S4 (N, P-C@ZCIS2) exhibited the best photocatalytic activity for tetracycline hydrochloride degradation and Cr(VI) reduction, with rate constants of 0.04822 mg−1 min−1 and 0.14303 min−1, respectively. Notably, the photocatalysts exhibited good activity and stability even after cycle experiment. This study provides new insights into the design of carbon-based heterojunction photocatalysts for the removal of harmful chemicals.

Sulfur tuning oxygen vacancy of Ba2Bi1.4Ta0.6O6 for boosted photocatalytic tetracycline hydrochloride degradation and hydrogen evolution

Photocatalysis, such as solar-driven photodegradation and energy conversion, has attracted great attention, given that it provides a promising solution for alleviating the energy shortage and environmental contamination issues. However, the insufficient light absorption and charge separation/transport efficiency restrict the solar conversion efficiency. It has been proved that oxygen vacancies (Ov) can improve the photocatalytic activity by enhancing the light absorption. But in this study, we show that oxygen vacancies hinder the charge separation/transfer in Ba2Bi1.4Ta0.6O6. The incorporation of S further pushes the light absorption edge up to 1170 nm. Therefore, the S/Ov-Ba2Bi1.4Ta0.6O6 sample can absorb not only the full range of visible light but also part of near-infrared light. More importantly, it mitigates the drawback of oxygen vacancies, improving the charge separation/transport by 1.65 times. As a result, The S/Ov-Ba2Bi1.4Ta0.6O6 nanowires manifest 4.41 times and over 100 times higher photocatalytic activity for tetracycline hydrochloride degradation and hydrogen production, respectively.

Fabrication of double Z-scheme photocatalyst BiOI/g-C3N4/CoFe2O4 with enhanced photocatalytic activity for tetracycline hydrochloride degradation

Double Z-scheme BiOI/g-C3N4/CoFe2O4 was prepared and used for tetracycline hydrochloride degradation under visible light. The degradation rate can reach 85.2% after 240 min. The enhanced photocatalytic performance benefits from the synergistic effect of increased visible light absorption, double Z-scheme charge transfer mechanism and layered structure. Slight photocorrosion of CoFe2O4 causes the degradation process to be divided into a fast stage and a slow stage. BiOI/g-C3N4/CoFe2O4 is still stable during the photocatalytic reaction.

Synthesis of a Novel Photocatalyst MVO4/g-C3N4 (M = La, Gd) with Better Photocatalytic Activity for Tetracycline Hydrochloride Degradation under Visible-Light Irradiation

In this study, novel photocatalysts MVO4/g-C3N4 (M = La, Gd) were prepared by the hydrothermal method, through which different loading amounts of 10–50%MVO4 and g-C3N4 were mixed and ultrasonically oscillated to gain heterojunction catalysts. All the samples were characterized by XRD, SEM, TEM, FT-IR, XPS, Us-vis, and PL to ensure the successful integration of LaVO4 and GdVO4 with g-C3N4. The obtained results showed that MVO4/g-C3N4 could effectually improve the separation efficiency of photogenerated carriers during the photodegradation process, thus improving the photodegradation efficiency, while among them, 40%GdVO4/g-C3N4 showed the best photocatalytic performance and degradation of tetracycline hydrochloride, reaching up to 91% for 3 h, which was 3.64 times higher than pristine g-C3N4. From the discussed results above, the possible mechanism of the photodegradation process was put forward. This study supplies a promising method to gain g-C3N4-based photocatalysts for antibiotics removal.

Biomimetic synthesis of C-doped g-C3N4 spinous hollow microspheres from sunflower pollen with enhanced visible-light photocatalytic performance

The C-doped g-C3N4 hybrids were synthesized by using melamine as the raw material and sunflower pollen as the bio-template. At a fixed amount of melamine (1 g), a series of hybrids (g-C3N4/C-X, where X is the weight of pollen) were obtained by varying the dosage of pollen. The g-C3N4/C-0.4 partially reserved the morphology of pollen, that is, spinous hollow microsphere with particle size of 25–30 μm. In comparison with the bulky g-C3N4 gained from melamine and other g-C3N4/C hybrids, the g-C3N4/C-0.4 exhibited highest visible-light photocatlaytic activity for tetracycline hydrochloride degradation. The introduction of pollen not only improved the morphology of bulky g-C3N4, but also improved its photoelectric property. The high visible-light photocatalaytic performance of g-C3N4/C-0.4 could be due to its large specific surface area, strong light absorption ability and high separation efficiency of photo-generated electron-hole pairs derived from the doped C materials which played the role of electron trappers.

Surface structure tuning of BiOCl nanosheets by the sequential introduction of oxygen vacancies, PO43− and Ag+ for boosting photodegradation of tetracycline hydrochloride

The surface structure significantly impacts the physicochemical properties of semiconductors. Constructing heterojunction is a universal approach to tune surface structure, which can effectively accelerate the charge transfer at the interface. Here, BiOCl nanosheets which occupy high ratio of surface atoms to entire atoms were used as a model photocatalyst, and a strategy was proposed to tune its surface structure by sequential introduction of oxygen vacancies, PO43− and Ag+ on surface of BiOCl nanosheets. In order to inhibit the overgrowth of heterogeneous component, the excess PO43− was timely removed by centrifugation before adding Ag+. As a result, the as-obtained optimal sample which was confirmed to be a composite composed of BiOCl, BiPO4 and AgCl showed superior photocatalytic activity for tetracycline hydrochloride degradation with the rate of 38 times higher than that of pristine BiOCl, which was mainly attributed to the quick migration of photongenerated carrier. The active species h+ and •O2− played a vital role in this degradation process. Our strategy not only greatly saved investment of noble metal Ag, but also provide superior stability. On the basis of experimental results and density functional theory calculation, the visible-light driven catalytic mechanism was revealed.

Fabrication of oxygen defect-rich pencil-like ZnO nanorods with CDots and Ag co-enhanced photocatalytic activity for tetracycline hydrochloride degradation

In this work, oxygen defect-rich pencil-like ZnO nanorods were prepared by a simple hydrothermal method, and Ag and CDots co-catalysts were further introduced for modification. The morphology, structure, UV–vis diffuse reflectance, photoluminescence (PL) and electrochemical properties of the as-prepared photocatalysts were studied by a series of analytical techniques and measurements. The results indicated that pencil-like morphology and the existence of oxygen defects increased the carrier concentration and promoted charge carrier separation of ZnO. The introduction of Ag and CDots co-catalysts further improved the electron-hole pairs separation and visible light utilization of photocatalysts. Gaussian three-peak fitting of the PL spectra proved that the introduction of co-catalysts also affected the relative content of various oxygen defects in the catalyst. As a typical pollutant, tetracycline hydrochloride (TCH) was used to detect the photocatalytic performance of as-prepared catalysts. CDots/Ag/ZnO possessed the strongest TCH removal and mineralization performance, and the possible degradation mechanism and pathways of TCH were proposed. Furthermore, the consequence of the biotoxicity assessment showed that the ternary photocatalyst had good biocompatibility and low biotoxicity.

Fabrication of CdS/titanium-oxo-cluster nanocomposites based on a Ti32 framework with enhanced photocatalytic activity for tetracycline hydrochloride degradation under visible light

In this work, CdS/Ti32-oxo-cluster (CTOC) composites were first synthesized via in situ precipitation and ultrasonic methods. The experimental results demonstrated that CdS nanoparticles uniformly decorated the surface of CTOC with high specific area and microporous to form composite structures. Meanwhile, the CdS/CTOC composites exhibited an excellent high rate of photocatalytic activity for tetracycline hydrochloride (TC) degradation under visible light irradiation, and the activity performance was approximately 4.49 and 16.36-fold higher than that of pure CdS and CTOC, respectively. Moreover, The Ti3+ signal was detected by electron paramagnetic resonance (ESR) technique after irradiation, and the superoxide radical (O2−) and holes (h+) were proven to be the main active species during the degradation of TC. Photocatalytic mechanism and intermediates over CdS/CTOC composites were elucidated and corresponding reaction model and degradation routes of TC were presented. It is anticipated that this work could boost new insight on CdS/ CTOC binary composite systems to effectively degrade organic pollutants, which given a strategy for application on practical industry.

CeO2 /Bi2 WO6 Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

CeO2 /Bi2 WO6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO2 /Bi2 WO6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi2 WO6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO2 /2Bi2 WO6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO2 and Bi2 WO6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO2 could significantly enhance the photocatalytic activity of CeO2 /Bi2 WO6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO2 /Bi2 WO6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory.

Synthesis of surface plasma photocatalyst Ag loaded TiO 2 nanowire arrays/graphene oxide coated carbon fiber composites and enhancement of the photocatalytic activity for tetracycline hydrochloride degradation

Abstract Ag loaded TiO2 nanowire arrays/graphene oxide coated carbon fiber composites (Ag-TiO2NAs@GOCF) with a large surface area, high photocatalytic efficiency and a good visible light response was synthesized use the new method by growing of titania nanowire arrays (TiO2NAs) on the surface of graphene oxide coated carbon fibers (GOCF) prior to loading with Ag. The Ag-TiO2NAs@GOCF was characterized by X-ray Diffraction (XRD), Fourier Transform Infrared spectra (FT-IR) and Scanning Electron Microscopy (SEM), Raman spectra, Brunner–Emmet–Teller measurements (BET), UV–vis diffuse reflectance spectra (DRUVS) and the optimum catalytic conditions of Ag-TiO2NAs@GOCF such as pH, catalyst concentration, initial antibiotic concentration, illumination time, reused times were explored and the photocatalytic degradation mechanism was discussed. The catalytic activity of the new catalyst was improved and the photocatalytic efficiency of the catalyst was increased. The maximum photocatalytic efficiency of the Ag-TiO2NAs@GOCF for tetracycline hydrochloride was 95.73%. This work provided a simple but effective approach to synthesize the novel catalyst and the Ag-TiO2NAs@GOCF has great potential application value for treatment of medicine wastewater.

Graphene oxide supported titanium dioxide & ferroferric oxide hybrid, a magnetically separable photocatalyst with enhanced photocatalytic activity for tetracycline hydrochloride degradation

A facile, robust approach to the synthesis of Fe3O4/rGO/TiO2nanocomposites is described.

Bi4O5Br2 ultrasmall nanosheets in situ strong coupling to MWCNT and improved photocatalytic activity for tetracycline hydrochloride degradation

Multiwalled carbon nanotube (MWCNT)/Bi4O5Br2 materials have been prepared with the Bi4O5Br2 ultrasmall nanosheets in situ strong coupling to MWCNT via the ionic liquid (IL) assisted solvothermal method. The formation mechanism was based on the original formation of strong coupling between the IL and MWCNT, and then the tight junctions between Bi4O5Br2 and MWCNT can be established as the bromine ions in the IL react with bismuth source to in situ produce Bi4O5Br2 during solvothermal process. The structures, morphologies, surface features, optical properties, electronic structures and photocatalytic properties were investigated in detail. The MWCNT/Bi4O5Br2 materials exhibited increased photocatalytic activity than pure Bi4O5Br2 for the degradation of antibiotic agent tetracycline hydrochloride and rhodamine B. Meanwhile, the 0.1wt% MWCNT/Bi4O5Br2 materials displayed the highest activity. The hole and O2− were determined to be the main active species during the photodegradation process under visible light irradiation by the electron spin resonance, X-ray photoelectron spectroscopy valence band spectra and active species trapping experiments. After the introduction of MWCNT, the molecular oxygen activation capacity of Bi4O5Br2 greatly improved, which was believed to be responsible for the increased photocatalytic activity.