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Degradation Pathways of Various Plastics
Published in Hyunjung Kim, Microplastics, 2023
Hyunjung Kim, Sadia Ilyas, Gukhwa Hwang
The most significant damage occurs from highly reactive ozone in the atmosphere, which can attack the double bonds of some plastics and elastomers by ozonolysis. The ozonolysis leads to the interaction of ozone molecule reacts with the double bond to produce an unstable, reactive ozonide (polyatomic anion). The rapid decomposition of the ozonide results in double bond cleavage and ultimately polymer chain breaking. The chain breaking by ozonolysis leads to a decrease in molecular weight and a reduction in material strength that can further cause brittlement and material cracking. For example, in elastomers, ozone can induce cracking on surfaces exposed to the atmosphere, and this ozone-cracking effect is often seen in old car tires. However, elastomers like Neoprene have good ozone resistance because the double bonds in the polymer chain are protected from attack by ozone due to the presence of chlorine in polymer backbone which decreases the electron density in the double bonds, thereby reducing the tendency to react with ozone (Davis et al., 2010).
Inorganic Chemical Pollutants
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Also, ozone can generate new antigenic species and might react with susceptible subgroups in proteins and other cellular components, to modify their structural and antigenic characteristics. Autoimmune reactions after ozone may explain some of the high incidences of autoantibodies in a subgroup of chemically sensitive. Ozone attacks polyunsaturated fatty acids such as in lipid membranes and sulfhydryl groups of proteins (especially enzymes), free amino acids (e.g., cysteines), and GSH.99 It depletes the sulfhydryl content of the lung and cross-links the bases in DNA. It oxidized aromatic amino acids, especially tyrosine and phenylalanine, via their unsaturated rings.99 Ozone breaks down products into toxic ozonides, which also causes tissue damage, especially to the phospholipids of the cell membranes.100 Ozone can damage cytochrome enzymes of the pulmonary mixed-function oxidase (MFO) systems, resulting in increased chemical sensitivity.
Symbols, Terminology, and Nomenclature
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Osmotic coefficient () - Defined by = ln aA/(MAmB), where MA is the molar mass of substance A (normally the solvent), aA is its activity, and the mB are molalities of the solutes. [1] Osmotic pressure () - The excess pressure necessary to maintain osmotic equilibrium between a solution and the pure solvent separated by a membrane permeable only to the solvent. In an ideal dilute solution = cBRT , where cB is the amountof-substance concentration of the solute, R is the molar gas constant, and T the temperature. [1,2] Ostwald dilution law - A relation for the concentration dependence of the molar conductivity of an electrolyte solution, viz., 1 1 c = + ° K ( ° )2 where c is the solute concentration, K is the equilibrium constant for dissociation of the solute, and ° is the conductivity at c = 0. Ounce (oz) - A non-SI unit of mass. The avoirdupois ounce equals 28.34952 g, while the troy ounce equals 31.10348 g. Overpotential () - In an electrochemical cell, the difference between the potential of an electrode and its zero-current value. Oximes - Compounds of structure R2C=NOH derived from condensation of aldehydes or ketones with hydroxylamine. Oximes from aldehydes may be called aldoximes; those from ketones may be called ketoximes. [5] Oxo compounds - Compounds containing an oxygen atom, =O, doubly bonded to carbon or another element. The term thus embraces aldehydes, carboxylic acids, ketones, sulfonic acids, amides and esters. [5] Ozonides - The 1,2,4-trioxolanes formed by the reaction of ozone at a carbon-carbon double bond, or the analogous compounds derived from acetylenic compounds. [5] Pair production - A process in which a photon is converted into a particle and its antiparticle (e.g., an electron and positron) in the electromagnetic field of a nucleus. Paraffins - Obsolescent term for saturated hydrocarbons, commonly but not necessarily acyclic. Still widely used in the petrochemical industry, where the term designates acyclic saturated hydrocarbons, and stands in contradistinction to naphthenes. [5] Paramagnetism* - A type of magnetism characterized by a positive magnetic susceptibility, so that the material becomes weakly magnetized in the direction of an external field. The magnetization disappears when the field in removed. In the simplest approximation (Curie's law) the susceptibility is inversely proportional to temperature. Parity - The property of a quantum-mechanical wave function that describes its behavior under the symmetry operation of coordinate inversion. A parity of +1 (or even) is assigned if the wave function does not change sign when the signs of all the coordinates are changed; the parity is -1 (or odd) if the wave function changes sign under this operation. Parsec (pc) - A unit of distance defined as the distance at which 1 astronomical unit (AU) subtends an angle of 1 second of arc. It is equal to 206264.806 AU or 3.085678 × 1016 m. Particle induced x-ray emission (PIXE) - See Techniques for Materials Characterization, page 12-1.
Nanometric Systems Containing Ozonated Oil with Potential Activity against Skin Pathogens
Published in Ozone: Science & Engineering, 2023
Kiany de Oliveira Firmino, Francielli Lima Dos Santos, Morgana Souza Marques, Bárbara Souza da Costa, Gabriela da Silva Collar, Juliana Caierão, Alexandre Meneghello Fuentefria, Irene Clemes Külkamp Guerreiro, Renata Vidor Contri
Ozone can be more easily and more safely applied topically by ozonated vegetable oils. Through the ozonization process, ozone interacts with double bonds of the monounsaturated fatty acid and produces ozonated compounds such as ozonides, peroxides and aldehydes (Skalska, Ledakowicz, Perkowski, Sencio 2009; Rizzo et al. 2021). An ozone reservoir in the skin is achieved due to ozonides (Ugazio, Tullio, Binello, Tagliapietra, Dosio 2020). Several vegetable oils can be used, such as sunflower seed and olive oil (Oğuzkan et al. 2018). The possibility of applying mineral ozonated oil has also been described (Iorio, Liberatore, Koh, Otani, Camilo 2016). Several investigations have proved the antimicrobial activity of ozonated oils (Sechi et al. 2001; Skalska, Ledakowicz, Perkowski, Sencio 2009; Moureu, Violleau, Haimoud-Lekhal, Calmon 2015; Ouf, Moussa, Abd-Elmegeed, Eltahlawy 2016; Iorio, Liberatore, Koh, Otani, Camilo 2016; Serio et al. 2017). In addition, a dermatological gel containing 30% of ozonated sunflower seed oil has shown good compatibility with keratinocytes and fibroblasts, demonstrating potential for being considered safe for human use (Serio et al. 2017).
Iodine and Peroxide Index Rapid Determination by Mid- and Near-infrared Spectroscopy in Ozonated Sunflower Oil and Ozonated Fats
Published in Ozone: Science & Engineering, 2022
Julien Vinet, S. Tréguier, C. Levasseur-Garcia, A. Calmon, F. Violleau
Given that the antibacterial activity of ozonated oil is related to its chemical composition (Moureu et al. 2015a), it is vital to develop easy and rapid methods to characterize vegetable oils after reaction with ozone. The reaction mechanism (Criegee 1975) describes the reaction of ozone with the carbon-carbon double bonds (unsaturation) of the fatty acid chains of oils to form a primary ozonide, which will rearrange and form an aldehyde and a zwitterion. In a second step, different species form depending on the nature of the solvent. The peroxidic family is of interest for its antibacterial activity. In fact, it has been shown that the antibacterial activity increases with the number of peroxidic species (Moureu et al. 2015b; Ugazio, Tullio, and Dosio 2020). The degree of unsaturation and the number of oxidized species are therefore two interesting characteristics to monitor to determine the antibacterial activity of an ozonated fat.
Effects of ozonized rapeseed oil on bioremediation of diesel oil contaminated soil by Bacillus mycoides NS1020
Published in Bioremediation Journal, 2020
Arkadiusz Polewczyk, Olga Marchut-Mikołajczyk, Piotr Drożdżyński, Jarosław Domański, Krzysztof Śmigielski
Similar phenomenon was observed in samples inoculated with B. mycoides NS1020 strain. The addition of 50 g or 100 g of vegetable oil resulted in considerable diesel oil degradation (80% and 63%, respectively). In the case of trials with the indigenous microorganisms in the presence of the same doses of vegetable oil, a similar correlation was observed. However, in these tests, 68%, and 55%, reduction was detected. The addition of 10 g of vegetable oil resulted in a significant leakage of petroleum compounds. Almost 100% loss of hydrocarbons in samples with ozonized vegetable oil indicated that this agent can enhance the degradation of diesel oil. One of the most important components of rapeseed oil is triglycerides. The reaction of ozone with these unsaturated molecules generates the formation of a mixture of oxygenated compounds such as ozonides, peroxides and aldehydes (Chen et al. 2016). This indicates that the ozonized vegetable oil has proven itself as the extractant which oxidizes the hydrocarbons while causing their higher susceptibility to degradation.