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Signalling Colour Smoke Compositions
Published in Ajoy K. Bose, Military Pyrotechnics, 2021
Lactose, sucrose, dextrose, starch, etc., are used as fuel since these produce copious quantity of gases due to presence of C, H and O atoms in the molecule forming gaseous products CO, CO2 and H2O and do not produce high heat. Potassium chlorate is chiefly used as an oxidiser.
Components of Energetic Compositions
Published in John A. Conkling, Christopher J. Mocella, Chemistry of Pyrotechnics, 2019
John A. Conkling, Christopher J. Mocella
Potassium chlorate was used in the first successful colored-flame compositions in the mid-1800s and it remains in use today in colored-smoke compositions, firecrackers, toy pistol caps, matches, and some color-producing fireworks.
Revisiting the Early History of Synthetic Polymers: Critiques and New Insights
Published in Ambix, 2018
In a similar manner, Fritzsche found that under the right circumstances treatment of aniline with nitric acid caused the production of a blue or green material. He initially thought that this coloured product might be indigo, but he was not able to generate enough of the product to adequately characterise it.61 Continuing these efforts, he found that the addition of aniline salts to chromic acid produced a dark green precipitate, which ultimately became blue–black in colour. Combustion analysis of the coloured precipitate revealed significant amounts of chromium. He returned to study these transformations of aniline again in 1843.62 In this study, he mixed an alcohol solution of aniline salt with potassium chlorate in hydrochloric acid, resulting in a blue precipitate. This solid turned green upon washing with alcohol, and finally became a dark green upon drying. Combustion analysis of this solid indicated a formula of C24H20N4Cl2O.
Bio-monitoring of DNA damage in matchstick industry workers from Peshawar Khyber Pakhtunkhwa, Pakistan
Published in International Journal of Occupational and Environmental Health, 2018
Muhammad Khisroon, Ajmal Khan, Ubaid Ullah, Farrah Zaidi
Matchstick manufacturing involves exposures to a variety of chemicals, including red phosphorus, neutralizers, carbon black and potassium chlorate. We show in this study that working in these environments in the absence of exposure controls may cause genotoxic effects and increase DNA damage in matchstick workers during occupational exposure, as compared to control subjects as assessed by comet assay. It would be practical to educate the workers who are exposed to matchstick chemicals about the potential hazards of occupational exposure and the importance of using protective measures. Since DNA damage is an important step in events leading from carcinogen exposure to cancer, our study represents an important contribution in evaluating the potential health risk associated with matchstick chemicals exposure. An important outcome of our study is that the management of the matchstick factories where we conducted this work has started implementing safety measures to prevent chemicals exposure to their workers.
Nanotechnology in water and wastewater treatment. Graphene – the nanomaterial for next generation of semipermeable membranes
Published in Critical Reviews in Environmental Science and Technology, 2020
Michał Bodzek, Krystyna Konieczny, Anna Kwiecińska-Mydlak
Brodie, Hummers and Staudenmaier (Hegab & Zou, 2015; Mahmoud et al., 2015) have developed methods of GO preparation, which comprise of oxidation with strong acids and oxidants followed by surface exfoliation. Brodie’s method relies on mixing of graphite with nitric acid and potassium chlorate, whereas Staudenmaier has modified it by using concentrated sulfuric acid, nitric acid and potassium chlorate (Songa et al., 2018). However, these methods had been found to be time-consuming and dangerous and were replaced by Hummers’ method (Perreault, Tousley, & Elimelech, 2014), which required less process steps and was based on mixing of graphite with sodium nitrite, sulfuric acid and potassium permanganate (Hegab & Zou, 2015; Mahmoud et al., 2015). After oxidation, brown oxidized graphite is extracted by ultrasonically induced stripping or by intensive mixing stripping. Firstly, due to the action of a strong acid, i.e. sulfuric, nitric or chloric one, graphite salts are formed, next they are oxidized and finally flaking of GO in water in the form of nanosheets is reached (Li et al., 2008). In Figure 6, the scheme of Hummers’ method for GO nanosheets preparation is shown (Hegab & Zou, 2015; Mahmoud et al., 2015). This method has become the most common one, as it is safe, effective and allows for formation of sheets of different sizes in dependence of oxidant type and oxidation duration (Marcano et al., 2010). In all cases, the rate of oxidation of GO basal plane directly depends on reaction conditions, i.e., temperature, pressure, raw materials properties and oxidation method (Dreyer, Park, Bielawski, & Ruoff, 2010).