New insights in photocatalytic removal of Alizarin Yellow using reduced Ce3+/TiO2 catalyst

Enhanced visible light photocatalytic performance of a novel FeIn2S4 microsphere/BiOBr nanoplate heterojunction with a Z-scheme configuration

The rational design of heterojunction photocatalysts is an effective way to improve semiconductor photocatalytic activity. The simple solvothermal method was used to successfully prepare visible light-driven FeIn₂S₄ microsphere/BiOBr nanoplate binary heterojunction photocatalysts with varying FeIn₂S₄ contents. The crystal structure, morphology, surface composition, specific surface area, charge separation, and optical properties of the as-prepared photocatalysts were investigated using a variety of analytical methods. In the photocatalytic degradation of rhodamine B, the FeIn₂S₄/BiOBr photocatalysts obtained a degradation efficiency of 96% within 60 min, which was approximately 5.33 and 2.59 times higher than pure FeIn₂S₄ and BiOBr, respectively. Radical trapping experiments and ESR measurements revealed the main active species (·OH, ·O₂^-, and h⁺) produced during photocatalytic degradation. The increased photocatalytic activity was due to the formation of Z-scheme heterojunctions between FeIn₂S₄ and BiOBr, which contributed to the improved effective charge separation of photogenerated charge carriers, augmented specific surface area, and enhanced redox capacity. It is expected that our current study will provide a hopeful way for future environmental remediation research.

Serratula coronata L. Mediated Synthesis of ZnO Nanoparticles and Their Application for the Removal of Alizarin Yellow R by Photocatalytic Degradation and Adsorption

In this study, the potential of biogenic zinc oxide nanoparticles (ZnO NPs) in the removal of alizarin yellow R (AY) from aqueous solutions by photocatalytic degradation, as well as adsorption, was investigated. The synthesized ZnO NPs were prepared by the simple wet-combustion method using the plant extract of Serratula coronata L. as a reducing and stabilizing agent and characterized by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and X-ray photoelectron spectroscopy. Photocatalytic degradation of AY was monitored by UV-visible spectroscopy and the effects of parameters, such as light source type (UV-, visible- and sunlight), incubation time, pH, catalyst dosage and temperature on degradation were investigated. It was demonstrated that the source of light plays an important role in the efficiency of the reaction and the UV-assisted degradation of AY was the most effective, compared to the others. The degradation reaction of AY was found to follow the Langmuir-Hinshelwood mechanism and a pseudo-first-order kinetic model. The degradation kinetics of AY accelerated with increasing temperature, and the lowest activation energy (E_a) was calculated as 3.4 kJ/mol for the UV-light irradiation system, while the E_a values were 4.18 and 7.37 kJ/mol for visible light and sunlight, respectively. The dye removal by the adsorption process was also affected by several parameters, such as pH, sorbent amount and contact time. The data obtained in the kinetics study fit the pseudo-second-order equation best model and the rate constant was calculated as 0.001 g/mg·min. The isotherm analysis indicated that the equilibrium data fit well with the Freundlich isotherm model. The maximum adsorption capacity of AY on biogenic ZnO NPs was 5.34 mg/g.

Photocatalytic degradation of amoxicillin and tetracycline by template synthesized nano-structured Ce3+@TiO2 thin film catalyst

Contamination of the aquatic environment with pharmaceutical compounds is a serious environmental concern. The present investigation aims to utilize the Ce³⁺/TiO₂ thin film catalyst to remove of potential antibiotics (amoxicillin and tetracycline) using the less harmful UV-A radiations. Reduced cerium ion-doped TiO₂ is obtained by a simple one-step facile template method using polyethylene glycol as the templating agent. The synthesized catalysts Ce³⁺@TiO₂ (non-template) and Ce³⁺@TiO₂(T) (template) were characterized by spectroscopic methods. The XPS reaffirms the reduced Ce³⁺ dispersed within the titania network, and the AFM showed the surface roughness of the thin films. Detailed physicochemical analyses were conducted to deduce the degradation mechanism, and repeated use of the thin film photocatalyst showed enhanced stability. Significant mineralization of the antibiotics indicates the potential applicability of the photocatalytic catalyst. Furthermore, the presence of Ce³⁺ significantly restricted the recombination of electron/hole pairs in the photo-excited TiO₂ semiconductor and showed enhanced photocatalytic degradation of the antibiotics proceeded predominantly through the •OH.