Soot produced from the combustion of fossil fuels, widely distributed in the atmosphere, is significantly different from most carbons for which the surface structure and/or reactivity have been studied. The composition and surface structure of soot derived from the combustion of n-hexane have been examined by FT-IR, Raman, UC CP/MAS NMR, and EPR spectroscopies as well as through desorption measurements. Carbon-oxygen functionalities on the fresh carbon surface include acid anhydride, a carbonyl conjugated with an aromatic segment, an alkyl-ketone, and aryl ether linkages. Also present, confirmed by isotopic substitution, is a quantity of unsaturated C-H, dependent upon the combustion conditions. The degree of aromaticity and the graphitic nature of this soot have been determined.
Successive extraction of soluble components of hexane soot with a suite of solvents has been followed by CGC/MS, FT-IR, UV/Vis, fluorescence, and NMR spectroscopic analysis of these extracts. From these studies, additional understanding of the structure and reactivity of this material has emerged. A significant portion of the soot is extractable as polynuclear aromatic and aliphatic compounds, while the nonextractable solid structure, with both aromatic and aliphatic portions, contains such carbon-oxygen functionalities as acid anhydride, carbonyl, and ether linkages. A model of hexane soot as formed in flame is proposed on the basis of this work.
In Bangladesh, use of beauty cream is very much popular and a common daily task for the people. The current study is focusing on the assessment of some toxic heavy metals such as lead, cadmium, chromium, and mercury contamination in some beauty creams commonly used by Bangladeshi people. The results indicate that the concentrations of lead, cadmium, and chromium exceed the maximum allowable concentrations, whereas mercury is found below the acceptable limit set by WHO/EU. However, according to Health Canada, the concentrations of cadmium and chromium for all the selected samples (except cadmium in sample coded A) was within the permissible limit. Health risks associated with these metal intakes via dermal exposure route are evaluated in terms of chronic daily intake (CDI) and hazard quotient (HQ). The carcinogenic risk (CR) estimated for chromium indicates that it is within the acceptable range. The cancer and non-cancer risk results indicate that although the chances of cancer risk and non-cancer risk resulting from the use of these cosmetic products were unlikely, buildup of these toxic heavy metals overtime on continuous usage could be detrimental for Bangladeshi people.
Electrochemical capacitors (ECs) are a vital class of electrical energy storage (EES) devices that display the capacity of rapid charging and provide high power density. In the current era, interest in using ionic liquids (ILs) in high‐performance EES devices has grown exponentially, as this novel versatile electrolyte media is associated with high thermal stability, excellent ionic conductivity, and the capability to withstand high voltages without undergoing decomposition. ILs are therefore potentially useful materials for improving the energy/power performances of ECs without compromising on safety, cyclic stability, and power density. The current review article underscores the importance of ILs as sustainable and high‐performance electrolytes for electrochemical capacitors.
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