Green Synthesis of Iron Oxide Nanoparticles by RS Lichen Extract and its Application in Removing Heavy Metals of Lead and Cadmium.

The present study was carried out with the aim of green synthesis of iron oxide nanoparticles by a distilled extract of SR (Ramalina sinensis), a local species of Fandoghlu forest in Ardabil. Among effective compounds in the extract of this local plant to remove lead and cadmium toxic metals are carbohydrates and phenolic compounds and the green synthesis of Fe3O4 nanoparticles was accomplished in a 1 h period at 70 degrees Celsius, with gradual addition of ammonia to the distiled extract obtained from plant. Synthesized iron oxide nanoparticles have been confirmed by various techniques such as ultra-violet spectrophotometry, XRD, FT-IR, SEM, and EDAX elemental analysis. In the spectrum obtained from the UV-spectrophotometer, the peak appearing at 310 ± 5 nm indicates the electron transfer of oxygen to the synthesized iron from the SR lichen. The XRD spectrum also showed the characteristics of Ɵ2 Theta=30.55, 36, and 43.35, which confirmed with iron oxide nanoparticles. The uniform spherical nature of iron oxide nanoparticles (III) in size from 20 to 40 nm were visible using SEM images. The obtained peak at 514 cm-1 in the infrared spectrum showed the formation of a new bond between iron and oxygen. The thermodynamic studies and adsorption investigation showed that lead was followed by the Langmuir adsorption model (R2 = 0.999) and cadmium was followed by Freundlich absorption model (R2 = 0.986) and the process of removing is spontaneous and exothermic. The data obtained from kinetic studies of removing lead and cadmium from aqueous solutions were fitted in a second-order kinetic model with an appropriate correlation coefficient of 0.99. The ability to remove lead and cadmium by magnetic nanoparticles of iron oxide was respectively 82% and 77% for initial concentration of 50 mg/l and pH in the range of 5-4.

Theoretical investigation of the use of nanocages with an adsorbed halogen atom as anode materials in metal-ion batteries.

The applicability of C44, B22N22, Ge44, and Al22P22 nanocages, as well as variants of those nanocages with an adsorbed halogen atom, as high-performance anode materials in Li-ion, Na-ion, and K-ion batteries was investigated theoretically via density functional theory. The results obtained indicate that, among the nanocages with no adsorbed halogen atom, Al22P22 would be the best candidate for a novel anode material for use in metal-ion batteries. Calculations also suggest that K-ion batteries which utilize these nanocages as anode materials would give better performance and would yield higher cell voltages than the corresponding Li-ion and Na-ion batteries with nanocage-based anodes. Also, the results for the nanocages with an adsorbed halogen atom imply that employing them as anode materials would lead to higher cell voltages and better metal-ion battery performance than if the nanocages with no adsorbed halogen atom were to be used as anode materials instead. Results further implied that nanocages with an adsorbed F atom would give higher cell voltages and better battery performance than nanocages with an adsorbed Cl or Br atom. We were ultimately able to conclude that a K-ion battery that utilized Al21P22 with an adsorbed F atom as its anode material would afford the best metal-ion battery performance; we therefore propose this as a novel highly efficient metal-ion battery. Graphical abstract The results of a theoretical investigation indicated that Al22P22 is a better candidate for a high-performance anode material in metal-ion batteries than Ge44 is. Calculations also showed that K-ion batteries with nanocage-based anodes would produce higher cell voltages and perform better than the equivalent Li-ion and Na-ion batteries with nanocage-based anodes, and that anodes based on nanocages with an adsorbed F atom would perform better than anodes based on nanocages with an adsorbed Cl or Br atom.