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Published in J. Russell Boulding, Epa Environmental Engineering Sourcebook, 2019
Jim Rawe, Evelyn Meagher-Hartzell
A 40- by 120-foot test zone in an aquifer that receives leachate from an industrial landfill at the Du Pont Plant near Victoria, Texas was used to demonstrate the in situ biotransformation of tetrachloroethene (PCE), TCE, DCE, chloroethane, and VC to ethane and ethylene using microbial reductive dehalogenation under sulfate-reducing conditions. Ground water from this zone was alternately amended with either benzoate or sulfate and circulated through the aquifer. Initially PCE and TCE concentrations were approximately 10 and 1 micro-mole (μM), respectively. After a year of treatment the halogenated compounds were reduced to concentrations near or below 0.1 μM. PCE and TCE degraded to DCE rapidly following the introduction of benzoate. A decrease in sulfate concentrations led to increases in the vinyl chloride concentrations. Therefore, sulfate concentrations were kept above 10 mg/L until the DCE was further biodegraded. After approximately 6 months of treatment, most of the DCE, chloroethane, and VC biodegraded to produce ethane and ethylene [38].
Chemical and Physical Properties
Published in Leon Golberg, Hazard Assessment of Ethylene Oxide, 2017
Contaminants of concern for estimating biological or toxicological properties are chlorine-containing C2 chemicals including vinyl chloride, ethylidene dichloride, chloroethane, and ethylene chlorohydrin. The extent to which these contaminants may be present depends primarily on the particular process used for the manufacture of the chemical. Such impurities, if present at all, are in the range of 1 to 10 ppm concentration and do not significantly affect biological testing results. All modern U.S. manufacturing processes use direct oxidation and halogen-containing impurities are essentially absent. The extent to which ethylene chlorohydrin and ethylene glycol may form under the conditions of a test would have greater potential for modifying the observed biological effect in various test systems than would any contained impurities.
Analysis and Design of Photoreactors
Published in James J. Carberry, Arvind Varma, Chemical Reaction and Reactor Engineering, 2020
Eliana R. de Bernardez, María A. Clariá, Alberto E. Cassano
The proposed low chlorine concentration in the feed, together with the presence of an inert gas, allow us to safely assume that: The main reaction products will be hydrochloric acid and mono-chloroethane. This assumption can be easily confirmed with experimental results.Under the stated operating conditions thermal effects will be small. Hence isothermal behavior is applicable.
Batch extraction of gossypol from cottonseed meal using mixed solvent system and its kinetic modeling
Published in Chemical Engineering Communications, 2019
Surinder Singh, S. K. Sharma, S. K. Kansal
The commonly utilized commercial solvent for carrying out solvent extraction is hexane. Other solvents utilized for solvent extraction are methanol, acetone, ethanol, propanol, pentane, heptane, octane, dioxane, butanone, isopropanol, butanol, chloroform, 1, 2-di-chloroethane, perchloroethylene, trichloroethylene, ethyl ether, butanone, chloroform, dichlorohexane, methyl pentane, etc. (Harris et al., 1947; Hron et al., 1994; Wan et al., 1995; Kuk and Hron, 1998; Kuk et al., 2005). Hexane now has been listed as a toxic compound (Kuk and Hron, 1998) and its limit in food grade materials is fixed to 5 mg/L. Ethanol as a green solvent has been used by various researchers (Liu et al., 1981; Saxena et al., 2012). Acidic ethanol has also been utilized to extract gossypol from cottonseed meal (Hron et al., 1992; Pelitire et al., 2014).
Differential and mechanism analysis of sulfate influence on the degradation of 1,1,2- trichloroethane by nano- and micron-size zero-valent iron
Published in Environmental Technology, 2023
Yi Li, Naijin Wu, Jiuhao Song, Zhenxia Wang, Peizhong Li, Yun Song
A mass balance analysis of chlorine for mZVI(groups M0, M8, M80) and nZVI(groups N0, N8, N80) was conducted. As shown in Figure 3, we divided the possible chlorine pathways in the reaction into five components: chlorine loss due to volatilisation, chlorine contained in the residual 1,1,2-TCA, chlorine in the gas-phase products (VC, CA, 1,1-DCE), chlorine in the liquid-phase products (VC,1,1-DCE), and chlorine ions in the solution. For the liquid-phase products, the only products monitored were VC and 1,1-DCE, while the gas-phase products were monitored for ethylene, ethane, vinyl chloride, chloroethane, and 1,1-DCE. The molar concentrations of all products are shown in Table S3 and S4.