جستجوی مقالات مرتبط با کلیدواژه « desorption » در نشریات گروه « فیزیک »

Fluorine adsorption on graphene adjusts its band gaps, therefore fluorinated graphene is one of the functional compounds in the electronics industry. In this paper, we investigate the process of melting, fluorine desorption and structural changes due to increasing temperature in single-sided and both-sided fluorinated graphene within molecular dynamics theory and compare the results with the same configuration of hydrogenated graphene structures. Our results reveal that the transition phase from solid-state to the molten state in both-sided fluorinated graphene is accompanied by the formation of polymer chains of carbon and fluorine atoms if the concentration of fluorine atoms extend beyond 50%. In contrast, the results show that in single-sided fluorinated graphene the fluorine atoms are desorbed from the graphene surface, before the beginning of the transition phase. Our calculations also indicate that, unlike two-sided fluorinated graphene structures, the structural changes caused by the increase in temperature in single-sided and both-sided hydrogenated graphene are similar to that of single-sided fluorinated graphene, but at a lower temperature.

One of the most important application of rhenium is its use in nuclear medicine.The recovery of rhenium via biosorption by micro-organisms, in contrast to other methods, has not been investigated yet. In the present study the biosorption of rhenium on Bacillus sp. MGG-83 in a batch of stirred system is reported, and its optimum condition has been determined. The optimum pH-value of the medium was found to be 2 for rhenium. The maximum biosorption of rhenium was obtained at a temperature between 35–40 0C. The rhenium take up increases by increasing the rhenium concentration, and for 250 mg/l the take up was 146.3 mg/g dry wt. The uptake of rhenium within 5 min of incubation is relatively rapid and the continuation of absorption behaves slowly thereafter. The reduction in the V/X0value causes an increase of the adsorbed rhenium and that is due to the increase of the adsorption surface area. The desorption of rhenium which has been carried out with 0.1 M sodium hydroxide at 25 0C was 55%.