Insights into the Nature of the Active Sites of Pt-WOx/Al2O3 Catalysts for Glycerol Hydrogenolysis into 1,3-Propanediol

The chemo-selective hydrogenolysis of secondary hydroxyls is an important reaction for the production of biomass-derived α,ω-diols. This is the case for 1,3-propanediol production from glycerol. Supported Pt-WOx materials are effective catalysts for this transformation, and their activity is often related to the tungsten surface density and Brönsted acidity, although there are discrepancies in this regard. In this work, a series of Pt-WOx/γ-Al2O3 catalysts were prepared by modifying the pH of the solutions used in the active metal impregnation step. The activity–structure relationships, together with the results from the addition of in situ titrants, i.e., 2,6-di-tert-butyl-pyridine or pyridine, helped in elucidating the nature of the bifunctional active sites for the selective production of 1,3-propanediol.

Application of Molybdenum ZSM-5 for Catalytic Oxidation of Wastewater Containing Methylene Blue

Background:: A vital section of water pollution mostly comes from the dying industry, which contaminates the water bodies by discharging the effluents into them. Naturally, it is carcinogenic as it contains harmful chemicals and minerals. To prevent this , many researchers have studied the issue and came to an inference that Methylene blue should be removed from wastewater. Many researchers and scientists proposed that Zeolite with little modifications could be one of the feasible options for catalytic oxidation of dyes in wastewater. Our focus is mostly based on Molybdenum impregnated H-ZSM-5 to catalytically oxidize methylene blue present in wastewater. Objective:: This method examined the Catalytic oxidation of wastewater containing Methylene Blue by the application of Mo-ZSM-5. Methods:: Raw H-ZSM-5 was activated and impregnated with previously prepared MoCl5 and allowed to dry and calcine at the required temperature. The product was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and BET Surface Area Analyser methods. Catalytic oxidation reactions were carried out at room temperature using hydrogen peroxide as oxidant. The effect of each parameter was investigated vividly. Results:: From the Energy Dispersive X-ray Spectroscopy method, it was observed that the percentage for Molybdenum over H-ZSM-5 was 9%. Surface area analysis suggested that the value for the surface area of unimpregnated H-ZSM-5 was 511 m2/g for 5% impregnation and 307 m2/g for 10% metal impregnation. A sharp decrease in the surface area was observed. Scanning Electron Microscopy images depict that the crystalline structure of raw H-ZSM-5 would not be damaged due to metal impregnation. Its shape and size were unaltered. In the images, the porous surface was observed. Conclusion:: Zeolites are an important catalyst in active phases for acidic/basic/redox catalysed reactions. Its activity and selectivity affected by the crystalline structure as well as morphological properties. Molybdenum impregnated H-ZSM-5 catalyst is best popularly known for its shape selectivity property. It promotes faster decomposition of H2O2 to non-reactive O2, which shows poor oxidation activity.

Radio-Frequency Thermal Plasma Treated Activated Carbon Impregnated with Mn and Ag for Volatile Organic Compounds Adsorption

In this study, we have prepared a composite adsorbent with highly dispersed Mn and Ag nanocatalyst on the surface of activated carbon (AC) by applying the Radio-Frequency (RF) thermal plasma technique for the efficient removal of VOCs. The ACs before and after metal impregnation with RF plasma treatment were characterized by SEM, TEM, EDS, and nitrogen adsorption analysis. Adsorption behaviors of toluene, acetaldehyde, and formaldehyde on ACs before and after modification were also investigated in fixed-bed systems. The experimental adsorption results for VOCs on parent ACs and metal impregnated ACs (Mn-AC and Mn/Ag-AC) were well explained by modified continuous sigmoidal (MCS) model.

The Recent Advancement in Rapid Golgi Method and Result Interpretation

The foundation knowledge of recent advancements of neuroscience was based on the Golgi staining observations. This is one of the best approaches to visualise the neuronal cytoarchitecture and complete morphology of neurons with incomparable clarity. This technique is based on the principle of heavy metal impregnation. There are many modifications and advancement occurred to improve the visualization. This chapter will provide the recently used protocols to visuals the neuronal architecture, dendritic arborization and spine density in different brain regions. Along with the manual observation, the present chapter also describes the currently used tools and software for the better understanding and visualisation of neurons.

Selective Catalytic Reduction of NOx with NH3 on Cu-, Fe-, and Mn-Zeolites Prepared by Impregnation: Comparison of Activity and Hydrothermal Stability

Cu-, Fe-, and Mn-zeolite (SSZ-13, ZSM-5, and BEA) catalysts have been prepared by incipient wetness impregnation and characterized by N2 physisorption, H2-TPR, NH3-TPD, and XPS methods. Both metal and zeolite support influence the deNOx activity and hydrothermal stability. Cu-zeolites and Mn-zeolites showed medium temperature activity, and Fe zeolites showed high temperature activity. Among all the catalysts, Cu-SSZ-13 and Fe-BEA are the most promising hydrothermally resistant catalysts. Fresh and hydrothermally treated catalysts were further examined to investigate the acidic and redox properties and the zeolite surface composition. Increased total acidity after metal impregnation and loss of acidity due to hydrothermal treatment were observed in all the catalysts. Hydrothermal treatment resulted in migration of metal or in strong metal support interations, whereby changes in reduction patterns are observed.