جستجوی مقالات مرتبط با کلیدواژه « Photocatalyst » در نشریات گروه « علوم پایه »

In this research, a simple and modified hydrothermal method has been used to synthesize two-dimensional zinc oxide nanostructures. Then, the effect of hydrothermal growth time as one of the main post-treatment parameters on the grown structures was investigated. For this purpose, X-ray diffractometry (XRD) and Field emission scanning electron microscopy (FESEM) were utilized to analyze the morphology and crystalline structure of the samples. It was observed that the grown structures have the sheet-like morphology which their thickness decreases with increasing dying time at 80 °C from 9 to 15 h. The XRD results showed that the structures have been crystalized into the hexagonal phase with (101) as the preferred growth orientation. In addition, decrease in the size of the crystallites (calculated from XRD) was concluded with increasing heating time. In the end, the photocatalytic activity of the samples was investigated, and as a result of this investigation, the sample that was heated for 15 h had a better performance in the degradation of methylene blue.

Desulfurization of petroleum derivatives is a topic of interest to researchers because compounds containing sulfur are harmful in the oil refining process and cause problems such as deactivation of catalysts and corrosion in pipelines and refining equipment. In order to improve the efficiency of desulfurization of dibenzothiophene, copper bismuth oxide/reduced graphene oxide (Bi7.38Cu0.62O11.69/rGO) nanocomposite was synthesized by a simple sonochemical method for the first time. The synthesized nanocomposite was identified by FESEM, FT-IR, XRD, DRS, and EDS analyses. Based on XRD analysis, pure copper bismuth oxide is formed using hydrazine, while using sodium hydroxide does not lead to the desired product. FESEM images showed that the size of Bi7.38Cu0.62O11.69 particles decreases in the presence of rGO. The desulfurization results showed that the presence of rGO causes a significant increase in efficiency due to increased light absorption and reduced recombination rate, so that Bi7.38Cu0.62O11.69/rGO nanocomposite has an efficiency of 87%, while pure Bi7.38Cu0.62O11.69 has an efficiency of 68%. Also, it was found that the purity of the copper bismuth oxide has a great effect on the photocatalytic efficiency, so that by calcining the product and removing the impurities, the efficiency increases from 55% to 68%.

2-Naphthol has undergone a specific oxidation process, leading to the formation of 2-hydroxy-1,4-naphthoquinone, a compound also recognized as Lawsone. In this research, NH2-MIL-125(Ti) was employed as a potent catalyst for photocatalytic reactions in conjunction with H2O2. The impact of NH2-MIL-125(Ti) on the reaction efficiency was prominently observed, leading to noticeable enhancements in the reaction yield.

In this work, the ZnS/montmorillonite/graphitic carbon nitride (ZnS/MMT/g-C3N4) as a novel composite was synthesized through simple strategy. The addition of MMT showed positive impact for increasing the specific surface area of g-C3N4, and the photocatalytic activity of g-C3N4 was achieved higher by using ZnS as a semiconductor. Several techniques were applied to evidence the formation of the as-synthesized composite such as X-ray powder diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Ultraviolet-visible light diffuse reflectance spectroscopy, Brunauer-Emmett-Teller analysis, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The adsorption and photocatalytic activities of ZnS/MMT/g-C3N4 were evaluated for the removal of Rhodamine B (Rh. B). Response surface methodology was used to study the important parameters and their interaction in the adsorption process. The pH, adsorbent dose, and dye concentration were shown the effect on the adsorption process, and the adsorption process was corresponded to Freundlich isotherm and pseudo-second-order kinetic models. The photocatalytic activity of ZnS/MMT/g-C3N4 was studied under several condition, which the best results were obtained 93% yield under ultra violet irradiation. This study presents a novel adsorbent and photocatalyst composite with high yield for the removal of Rh. B dye.

Ceftriaxone is a pharmaceutical compound that causes the pollution of water. In this research, g-C3N4 photocatalyst was synthesized and its efficiency in removal of ceftriaxone was studied. The synthesized g-C3N4 was analyzed using XRD, FTIR, FESEM, EDS, and dot mapping. The effect of the initial concentration of ceftriaxone, dosage of photocatalyst, irradiation time, and pH was studied, and based on these results, the highest removal efficiency of ceftriaxone from the water was obtained at about 83.4% at the concentration of 20 mg/L, pH=2, 0.25 g/500 mL of g-C3N4 photocatalyst at 50 min of irradiation time. This study confirmed that the g-C3N4 photocatalyst can be efficiently removed ceftriaxone from water.