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Scope of the Problem
Published in Jason W. Birkett, John N. Lester, Endocrine Disrupters in Wastewater and Sludge Treatment Processes, 2002
This group of chemicals includes seven of the polychlorinated dibenzodioxins (PCDDs) and 10 of the polychlorinated dibenzofurans (PCDFs). Structural examples of these compounds are given in Figure 1.4. Tetrachlorodibenzo-p-dioxin (TCDD) is the most biologically active and toxic member of this group. Animal studies have shown that TCDD has a deleterious effect on reproductive functions, and this compound can produce both antiandrogenic and antiestrogenic effects.110 Dioxins are persistent in the environment and have the potential for bioaccumulation, which is cause for concern because the EPA has characterized dioxins as likely human carcinogens as well as having the capacity for endocrine disruption. Structures of organic oxygen compounds.
Polymers and Their Composites for Water-Splitting Applications
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Polymers in Energy Conversion and Storage, 2022
Zahra Pezeshki, Zahra Heidari, Mashallah Rezakazemi, Mohammad Younas
Radiolysis can be used as a process to break down water into H2 and O2 gases with the help of fuel or nuclear waste. This process is divided into three stages: physical, physico-chemical, and chemical. During this process, water goes through a breakdown sequence into hydrogen peroxide, hydrogen radicals, and assorted oxygen compounds, such as ozone, which when converted back into oxygen releases great amounts of energy (Figure 17.28) [143,144]. Some of these releases are explosive. This decomposition is generated mostly by the α particles, which can be thoroughly absorbed by very thin layers of water. The radiolysis reaction can be written as: H2O→HO•.H•.HO2•.eaq−.H3O+.OH−.H2O2.H2
Gas Generation and Composition
Published in T. H. Christensen, R. Cossu, R. Stegmann, Landfilling of Waste: Biogas, 2020
T. H. Christensen, R. Cossu, R. Stegmann
Three main groups of biologically generated trace components can be differentiated: oxygen compounds;sulphur compounds;hydrocarbons.Oxygen compounds. Compounds containing oxygen are generated mainly during the degradation of the organic waste components. They appear in the gas only in the early phase of gas generation.
An exhaustive experimental evaluation on the effects of using Jatropha biodiesel as an admixture in a DI diesel engine powered by waste plastic fuel
Published in International Journal of Sustainable Energy, 2023
Rajan Kumar, Manoj Kumar Mishra, Manish Kumar Roy
Figure 21 presents the variations in NOx emissions as a function of load. Nitrogen oxides, comprising predominantly nitrogen monoxide (NO) and a minor proportion of nitrogen dioxide (NO2), are discharged in significant quantities by combustion engines, with concentrations reaching up to two thousand parts per million. The NOx family encompasses an array of nitrogen-oxygen compounds. NOx emissions are particularly undesirable due to their propensity to react and generate ozone within the atmosphere, thereby contributing significantly to photochemical smog. This harmful gas, resulting from the interaction between ambient air and automobile exhaust, raises considerable environmental concerns. As NOx decomposes, it releases both nitrogen oxide and elemental oxygen, which subsequently forms ozone. This ground-level ozone proliferation leads to annual crop losses, further emphasising the need for effective mitigation strategies.
Effect of pentanol-biodiesel blends on performance and emission characteristics of the diesel engine
Published in International Journal of Ambient Energy, 2021
Nagarajan Jeyakumar, Bose Narayanasamy
Smoke emission arises out of unburnt hydrocarbons and it depends on the nature of fuel used. It is a representation of soot concentration in exhaust gases (Ramakrishnan et al. 2018).The variation of smoke emissions with various load conditions is depicted in Figure 7. Maximum smoke emission observed at a higher engine load is due to the injection of more quantity of fuel (Babu and Anand 2017). The smoke values of diesel fuel range from 0.4 BSU at low load to 5.4 BSU at full load conditions, whereas for K100 smoke opacity value ranges from 0.9 BSU at low load to 7.2 BSU at full load. The smoke opacity values of K90Pn10 vary from 0.7 BSU at low load to 6.7 BSU at full load conditions, whereas for K80Pn20, smoke opacity values from 0.5 BSU at low load to 6 BSU at full load. The smoke emission values of K90Pn10 and K80Pn20 were 7.3% and 17.5% lower than that of K100, respectively. The presence of oxygen compounds in the test fuel samples with the addition of pentanol can be attributed to the reduced smoke opacity. Soot nuclei formation is reduced with the presence of oxygen molecules which promotes post oxidation of soot (Hulwan and Joshi 2011). Better air mixing due to improved air-entrainment due to increased ignition delay promotes soot reduction for pentanol fuel blends (Li, Wang, Wang, and Xiao 2015). Pentanol addition results in the reduction of smoke emission with the increased availability of O2 promoting better combustion (Babu and Anand 2017; Ramakrishnan et al. 2018).
Hydrothermal liquefaction of Glycyrrhiza glabra L. (Liquorice): Effects of catalyst on variety compounds and chromatographic characterization
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
According to the results of the GC-MS analysis of light bio-oil and heavy bio-oil at 300°C and 350°C, the compounds they contain are classified as monoaromatics, aliphatics, polyaromatics, heterocyclics, and oxygen compounds, these ratios are seen in Figure 7. In the light bio-oil obtained at 300°C, it was found that the catalysts (H3BO3, ZnO) increased the ratio of monoaromatics and heretocyclics compounds and also polyaromatic compounds were obtained with the catalyst ZnO in a small proportion. According to the results of the heavy bio-oil analysis, while the ratio of oxygen compounds increased with the use of a catalyst, the ratio of heterocyclic compounds decreased. Although similar behaviors were observed in the experiments carried out at 350°C, different rates of compounds were obtained with the effect of temperature. According to the results of the light bio-oil analysis, the rate of monoaromatics compounds increased with the use of a catalyst. When the results of the heavy bio-oil analysis are investigated, an increase in the ratio of oxygen compounds is observed.