Thermal stability of polymeric carbon nitride (PCN)-Al2O3–ZrO2 nanocomposites used in photocatalysis

Polymeric carbon nitride (PCN) was recently found to have extensive applications in the field of photocatalysis. Knowledge about thermal stability of PCN nanocomposites is crucial for this application and designing the final product. In this work, the thermal stability of PCN-Al2O3–ZrO2 nanocomposites was investigated. PCN nanocomposites were obtained in two steps: (1) microwave hydrothermal synthesis of co-precipitated AlOOH and ZrO2 precursors, followed by drying; (2) mixing the nanopowders with melamine powder and annealing in air in a tube furnace at 400, and 450 °C. The PCN nanocomposites were examined by attenuated total reflection technique of Fourier transformed infrared spectroscopy. Also, the evolved gas analysis was performed combining differential scanning calorimetry and thermogravimetry coupled with mass spectroscopy and FTIR. The results show that only PCN-Al2O3–ZrO2 nanocomposite obtained at 400 °C is stable from room temperature up to 490 °C and during thermal decomposition, in one step releases ammonia (NH3), cyanic acid (HNCO), water (H2O), and carbon dioxide (CO2). The limitation of the PCN-Al2O3–ZrO2 thermal stability and performance is AlOOH–ZrO2 used as a nanocomposite component.

GC-MS Analysis, Antioxidant and Antimicrobial Screening of Volatile Oil of Lepidium vesicarium

Background: Lepidium vesicarium (Cruciferae), one of the important medicinal plants with a long history of medicinal use. The current study was designed to evaluate the free radical scavenging and antimicrobial activities of the L. vesicarium EO as one of the Iranian plant species. Methods: The compositions of the EO from the aerial parts of L. vesicarium were analyzed by GC-MS and GC-FID. Furthermore, anti-oxidant and anti-microbial potentials were investigated via DPPH reagent and disk diffusion procedure, respectively. Results: A total of 18 compounds amounting 97.70% of the oil have been identified, while Benzyl cyanide (43.94%), Isothio cyanic acid (22.69%) and Benzyl isothio cyanate (20.69%) were the main constituents. The EO showed no activity against the free radicals and studied microbial strains (gram positive and gram negative and also fungi species). Conclusion: On the whole, the presence of cyanide derivatives in studied EO revealed the rational use of this plant in medicine. Comparing with other genesis of Lepidium, anti-oxidant and anti -microbial properties of L. vesicarium essential oil were not noticeable.