Activity For Degradation Of Tetracycline Research Articles

Visible-light-driven Ag/Bi3O4Cl nanocomposite photocatalyst with enhanced photocatalytic activity for degradation of tetracycline

In this study, a novel Ag/Bi3O4Cl photocatalyst has been synthesized by a facile photodeposition process. Its photocatalytic performance was evaluated from the degradation of tetracycline (TC) under visible light irradiation (λ > 420 nm). The 1.0 wt% Ag/Bi3O4Cl photocatalyst could significantly enhance the degradation of TC compared with pure Bi3O4Cl, with the degradation level reaching 94.2% in 120 minutes. The enhancement of photocatalytic activity could be attributed to the synergetic effect of the photogenerated electrons (e−) of Bi3O4Cl and the surface plasmon resonance (SPR) caused by Ag nanoparticles, which could improve the absorption capacity of visible light and facilitate the separation of photogenerated electron–hole pairs. In addition, electron spin resonance (ESR) analysis and trapping experiments demonstrated that the superoxide radicals (˙O2−), hydroxyl radicals (˙OH) and holes (h+) played crucial roles in the photocatalytic process of TC degradation. The present work provides a promising approach for the development of highly efficient photocatalysts to address current environmental pollution, energy issues and other related areas.

Carbon dots decorated the exposing high-reactive (111) facets CoO octahedrons with enhanced photocatalytic activity and stability for tetracycline degradation under visible light irradiation

Octahedral CoO with exposed high-reactive (111) facets holds a promising noble-metal-free material in the photocatalysis. However, the (111) facet is usually unstable and easily deactivated during the photocatalytic process as the result of its poloar catastrophe. In this work, carbon dots (CDs) as co-catalyst modified and stabilized the (111) facets of CoO octahedrons (CDs-CoO) were prepared by one-step solvothermal method. The desired CDs-CoO shows the excellent photocatalytic activity and well stability. Meanwhile, the CDs-CoO (5wt.%) composite exhibits the highest photocatalytic activity for degradation of tetracycline (87%, 60min), and presents remarkable photostability after five successive cycles (5h). This enhanced photocatalytic activity and outstanding stability in CDs-CoO composites could be ascribed to several merits of CDs that not only improve charge separation efficiency but also strengthen the interaction between CDs and high-reactive (111) facets of CoO octahedrons.

Construction of SrTiO3/Bi2O3 heterojunction towards to improved separation efficiency of charge carriers and photocatalytic activity under visible light

In this paper, the novel SrTiO3/Bi2O3 heterostructures photocatalysts were fabricated by a facile microwave process, and the visible-light-driven photocatalytic activity has been investigated for tetracycline (TC) degradation. The as-synthesized of SrTiO3/Bi2O3 photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffuse reflection spectroscopy (DRS). The photocatalytic performance was evaluated by the degradation TC under visible light irradiation (λ > 420 nm). Compared to pristine SrTiO3 and Bi2O3, the as-prepared SrTiO3/Bi2O3 samples exhibited remarkably enhancing photocatalytic activity for degradation of TC. It was found that the 50% SrTiO3/Bi2O3 heterojunction showed the highest photocatalytic efficiency for TC degradation, and the degradation rate could reach 85% in 140 min. The enhanced photocatalytic activity was attributed to the formation of a heterojunction between SrTiO3 and Bi2O3, which could greatly improve the transfer and separation of charge carriers in the two-phase interface. Meanwhile trapping experiments indicated that the h+ and OH were the main active species.

Fabrication of a Ag/Bi3TaO7 Plasmonic Photocatalyst with Enhanced Photocatalytic Activity for Degradation of Tetracycline.

A novel Ag/Bi3TaO7 plasmonic photocatalyst has been prepared by a simple photoreduction process. The as-prepared Ag/Bi3TaO7 photocatalyst exhibited an enhanced photocatalytic activity for the degradation of tetracycline (TC) compared to that of a bare Bi3TaO7 catalyst. The 1 wt % Ag-loaded Bi3TaO7 sample showed the highest photocatalytic efficiency for TC degradation (85.42%) compared with those of the other samples. The enhanced photocatalytic activity could be ascribed to the synergistic effect of the surface plasmon resonance caused by Ag nanoparticles. Electrochemical impedance spectroscopy demonstrated that the incorporation of silver nanoparticles onto the Bi3TaO7 surface promoted the separation of photogenerated carriers. In addition, an electron spin resonance (ESR) and trapping experiment revealed that the photoinduced active species hydroxyl radical and superoxide radical were the main active species in the photocatalytic process of TC degradation. The photocatalytic reaction mechanism was discussed by active species trapping and ESR analysis.

Ag-decorated K2Ta2O6 nanocomposite photocatalysts with enhanced visible-light-driven degradation activities of tetracycline (TC)

In this paper, octahedral K2Ta2O6 nanocrystals have been synthesized by a single-step hydrothermal method. Then the visible-light-driven plasmonic Ag–K2Ta2O6 nanocomposite photocatalysts are prepared by a photochemical reduction process. The product was characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV–visible diffuse-reflectance spectroscopy (DRS). The results show that the Ag nanoparticles are uniformly loaded on the surface of the K2Ta2O6. The prepared Ag–K2Ta2O6 exhibits an efficient photocatalytic activity for degradation of tetracycline (TC) under visible-light irradiation and shows good repeatability and stability. In particular, the highest photocatalytic activity at the nominal atomic ratio of silver to tantalum as 3%, which is more than 3 times that of pure K2Ta2O6.

Single-crystalline AgIn(MoO4)2 nanosheets grafted Ag/AgBr composites with enhanced plasmonic photocatalytic activity for degradation of tetracycline under visible light

Single-crystalline AgIn(MoO4)2 nanosheets have been successfully fabricated by facile hydrothermal method without any surfactants. Subsequently, Ag/AgBr-grafted AgIn(MoO4)2 nanosheets were synthesized by the in situ photoreduction of AgBr/AgIn(MoO4)2 composites prepared by a deposition–precipitation method. Under visible light irradiation. The Ag/AgBr/AgIn(MoO4)2 composites exhibit a strong absorbance in the visible region because of the surface plasmon resonance absorption of Ag nanocrystals. Compared with bare AgIn(MoO4)2 nanosheets, Ag/AgBr nanoparticles and Ag/AgIn(MoO4)2 composites, a dramatic enhancement in the degradation rate of tetracycline (TC) is observed over the Ag/AgBr/AgIn(MoO4)2 composites. The immense enhancement of the photocatalytic activity is attributed to the extended absorption in the visible-light region, effective charge separation, and synergistic enhancement induced by surface plasmon resonance (SPR) in the heterostructured Ag/AgBr/AgIn(MoO4)2. This study provides new insight into the fabrication of highly efficient and stable ternary metal molybdate based plasmonic photocatalysts and facilitates their practical application to solve environmental issues. The mechanism for the photodegradation of TC over Ag/AgBr/AgIn(MoO4)2 is discussed in detail.

HYDROTHERMAL SYNTHESIS AND ENHANCED VISIBLE-LIGHT PHOTOCATALYTIC ACTIVITY OF CdS QUANTUM DOTS SENSITIZED CARBON NANOTUBES (CNTs) NANOCOMPOSITE

A new-type photocatalyst of cadmium sulfide carbon nanotubes ( CdS /CNTs) was prepared by the hydrothermal method. This as-prepared CdS /CNTs composite photocatalyst was proved to exhibit an excellent photocatalytic activity for degradation of tetracycline (TC). Specially, the 95%- CdS –5%-CNTs composite photocatalyst played the best degradation rate (81.2%) in 60 min under the visible light irradiation. Moreover, this 95%- CdS –5%-CNTs composite photocatalyst possessed great stability and could be used at least four cycles with almost no loss of photocatalytic efficiency. Furthermore, the as-synthesized CdS /CNTs composite photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffused reflectance spectra (UV-Vis), Raman and thermal gravimetry (TG). In addition, the possible mechanism and kinetics of photodegradation of TC with CdS /CNTs photocatalyst was also discussed.