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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Inorganic peroxides are salts that contain a metal and two oxygen molecules. These oxidizers are water reactive and when in contact with water produce free oxygen and heat. The heat produced is sufficient to ignite nearby combustibles. Some acids at higher concentrations can be strong oxidizers and cause combustion in contact with organic materials. Nitric acid is a very dangerous oxidizing acid, it is corrosive and the vapors are poisonous.
Chemicals from Non-hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Nitric acid is commercially produced by oxidizing ammonia with air over a platinum-rhodium wire gauze. The following sequence represents the reactions occurring over the heterogeneous catalyst: 4NH3+5O2→4NO+6H2O2NO+O2→2NO23NO2+H2O→2HNO3+NO
Water Management
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Safety. Citric acid, 75% phosphoric acid (H3PO4), and 35% sulfuric acid (H2SO4) are relatively safe to work with as compared to the 67% nitric acid (Table 8.21). Nitric acid is very caustic and can cause serious injury to exposed tissue, especially eyes and lungs. Avoid skin and eye exposure when handling any acid. Acid-resistant eyewear, gloves, and apron should be worn. Acids are corrosive and can damage clothing that is not immediately rinsed. Also, when mixing acid stock solutions, always add acid to a larger volume of water to create the stock. Never add water to concentrated acid.
Distribution and Statistical Analysis of Chemical Elements in Soil from the Territory of the Republic of Kosovo
Published in Soil and Sediment Contamination: An International Journal, 2023
Granit Kastrati, Ramë Vataj, Flamur Sopaj, Krste Tašev, Trajče Stafilov, Robert Šajn, Musaj Paçarizi
Samples from each individual soil depth in amounts of about 1 to 3 kg (0–5 cm and 20–30 cm) were stored in plastic bags, then cleaned of foreign matter, dried at room temperature, crushed, sieved through a 2 mm sieve, and grinded in an agate mill (Retsch PM 100 CM) and sieved onto a sieve of W = 125 microns, type Analysensieb DIN ISO 3310–1, stainless steel, to obtain particles below 0.125 mm. Then, samples were digested with acid mixture of HNO3, HClO4, HF and HCl in accordance with the international standards ISO 14,869–1:2001(E) (Stafilov et al. 2018). The digestion was performed in the following order: the accurately measured mass of dust samples (0.25 g) was placed in Teflon vessels. Then, 5 ml of concentrated HNO3 65% was added until brown vapors left the vessels. Nitric acid is a very suitable oxidizing agent for the digestion of organics in samples. For complete digestion of the inorganic components, 5–10 ml of HF (≥40%) was added. When the digestion became a clear solution, 1.5 ml of HClO4 70% was added for complete digestion of the organic matter. After cooling the vessels for 15 min, 2 ml of HCl 37% and 5 ml of water were added for the total dissolution of the metal ions. The obtained solution was filtered through Munktell filter paper No. 2, and the filtrate was leveled with redistilled water in a 25 ml volumetric plastic flask. The final sample was stored in plastic bottles labeled with the sample number and sent for analysis.
Humid air plasma-assisted surface treatment as a green functionalization technique to enhance the multi-walled carbon nanotubes dispersion and stability in aqueous solutions
Published in Journal of Dispersion Science and Technology, 2022
Masoud Tabarsa, Bahman ZareNezhad
Plasma technique, on the other hand, produces an ionized gaseous medium that has milder conditions than chemical techniques and does not cause serious damage to the nanoparticles in this medium.[16] The plasma process can be used for surface modification of various materials by altering surface properties and functions while maintaining the bulk properties of the material, which is an important advantage over the usual wet chemical method. Furthermore, it is well known that, environmental issues has been attracted more and more attentions in the recent years. In this way, employment of eco-friendly techniques have replaced traditional methods, especially in developed countries. Nitric acid is one of the most widely used materials as a strong oxidizing agent for oxidation of carbon-based materials.[17,18] However, environmental pollutions and health impacts due to the production of toxic by-products such as N2O and NOx gases, as well as the destruction of carbon structures treated by this strong oxidizing agent has led researchers to look for eco-friendly and nondestructive techniques for oxidizing these materials.[19] Low temperature plasma methods are green and nondestructive techniques which can be considered as good candidate for this purpose.[20]
An investigation of changes in structural parameters and organic functional groups of inertinite rich lignite during acid treatment processes
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Yash Jaiswal, Sunder Lal Pal, Harsh Jaiswal, Anusha Jain, Lav Kush, Devendra Rai, Dhiraj Tatar
The variations in carbon %, oxygen %, calorific value, degree of demineralization, and BET surface area with the percentage of ash remaining in coal after demineralization are presented in supplementary figure S1. It can be observed from Table 1 and supplementary figure S1 that the reduction in ash % in coal sample is accompanied by an increase in the degree of demineralization and BET surface area. However, the calorific value shows negligible change upon demineralization. Supplementary figure S1 also shows that the reduction in ash% does not follow any particular pattern for changes in the amount of oxygen and carbon present. From Table 1, it can be inferred that the amount of nitrogen present remains intact after a three-step HF/HCl/HF demineralization process while more than twofold increase can be observed in case of HF/HNO3 demineralization process. The increase in nitrogen content can be attributed to the nitration and oxidation of nitric acid in the organic system. It was also observed that more than half of the sulfur was removed using HF/HNO3 process while limited sulfur removal was achieved by HF/HCl/HF process. Nevertheless, the highest removal (90.82%) of ash from raw coal was achieved by a three-step HF/HCl/HF process.