Search results for "Chemical decomposition"
showing 10 items of 31 documents
Urea as a PCDD/F inhibitor in municipal waste incineration.
2001
Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from municipal waste incineration have been widely studied because of their extensive toxicity, and many efforts have been made to restrict their emissions. Although a number of chemical compounds have been shown in laboratory-scale tests to inhibit the formation of PCDD/Fs, few have been tested in pilot- or full-scale plants. This work evaluates the effect of urea as a PCDD/F inhibitor in a pilot-scale incinerator that uses refuse-derived fuel (RDF). The decomposition of urea under the test conditions was also studied using detailed kinetic modeling. An aqueous solution of urea was injected into the flue gas stream …
Generation of monosubstituted o-benzynes from polymeric reagents via heterolytic fragmentations
1984
Abstract Generation of four 4-substituted o-benzynes by heterolytic — fragmentation reactions is demonstrated.
Modeling of a continuous photocatalytic reactor for isovaleraldehyde oxidation: Effect of different operating parameters and chemical degradation pat…
2013
International audience; An investigation of isovaleraldehyde (ISOV) photocatalytic oxidation was conducted at initial concentrations ranging from 25 to 150 mg/m3 and different relative humidities (5-90% RH) in order to characterize the process performances close to indoor air conditions. Experiments were carried out in two different reactors: cylinder and flat-plate photoreactor (planar reactor) at different air gap (20-60 mm) and gas residence times (0.67-5.0 s). A plug flow reactor system was developed in order to perform kinetic studies of (i) isovaleraldehyde removal, (ii) selectivity of CO2, (iii) byproducts formation and removal. It appears that ISOV removal efficiencies increased wit…
119Sn M�ssbauer studies of bis[cysteinato(1?)-S]- and bis[penicillaminato(1?)-S]-diorganotin(IV) species in the crystalline state and in frozen aqueo…
1988
The bonding and the configuration of the tin environment in the title compounds {R2Sn[SCH2CH(NH3+)COO−]2 and R2Sn[SC(CH3)2CH(NH3+)COO−]2, indicated in the following as R2Sn(cysH)2 and R2Sn(penH)2 respectively} has been investigated through the determination of the Mossbauer-Zeeman spectra of Ph2Sn(cysH)2 and Ph2Sn(penH)2 in the solid state, and through conventional Mossbauer spectroscopy of Me2Sn(penH)2 in the solid state as well as of Me2Sn(cysH)2 and Me2Sn(penH)2 in aqueous solution (frozen). The treatment of the data by the pointcharge model approach suggested the general occurrence of a tetrahedral C2SnS2 core. In aqueous Hepes buffer, a tertiary amino nitrogen atom has been observed to…
Electrochemical processes in macro and microfluidic cells for the abatement of chloroacetic acid from water
2014
Abstract The remediation of solutions contaminated with monochloroacetic acid (CAA), which is one of the most resistant haloacetic acids (HAAs) to chemical degradation, dramatically depends on the adopted electrochemical approach: (i) CAA is only poorly oxidized either by homogeneous hydroxyl radical in electro-Fenton (EF), electrogenerated active chlorine or electro-oxidation on Pt anode; (ii) it is moderately abated by direct reduction on silver or compact graphite cathodes (from 30% in macro cells to 60% in the microfluidic devices); (iii) it is quantitatively removed by direct electro-oxidation on a boron-doped diamond (BDD) anode. The use of a microreactor enables operation in the abse…
Characterization of Chlorolignins in Bleached Kraft Pulp Mill Effluents Using Elemental Analysis and Fingerprinting by CuO Oxidation And Hplc
1994
Abstract Elemental analyses and chemical degradation techniques were applied to characterize lignin compounds in different stages of the chlorine bleaching process and in total mill effluent. Ultrafiltration was used for separation of chlorolignins into three nominal molecular weight fractions. Alkaline CuO oxidation products were analyzed by HPLC with diode array detection. Major compounds were identified by reference to authentic compounds. For comparison, native lignins (MWL), kraft lignins, and humic substances were studied as well. The oxygen, carbon and organic chlorine contents were closely similar in the various mill samples and their fractions. In all mill samples, vanillin and 6-c…
Performance Analysis of Ammonia in Solid Oxide Fuel Cells
2021
The transition of the marine propulsion system towards alternative fuels is mandatory to offset carbon emission. Among the alternative fuels, ammonia is carbon-free and can be produced in sustainable ways. Ammonia has 17.8% hydrogen (wt %) and is easily liquified at 25°C and 8 bar pressure. The two-stroke internal combustion engines currently used in the marine sector reach efficiencies of about 50% but generate substantial polluting emissions. Solid oxide fuel cells generate electricity with efficiencies greater than 50 % and can use ammonia as fuel. In this work, a single-cell SOFC was characterised using in-situ ammonia decomposition reaction (Int-ADR) and compared with ex-situ ammonia …
Improvement of the MgH2 Formation-Decomposition Reaction: Kinetic Study of the CeMg11Ni System
1992
Decarboxylation and alkaline colour fading reactions in presence of humic substances.
2002
Humic substances (HSs) can substantially influence velocity of reactions in the environment as shown on example of decarboxylation and alkaline colour (e.g., malachite green and crystal violet) fading reactions. In colour fading and decarboxylation reactions of 6-nitrobenzisoxazole-3-carboxylic acid HS act as inhibitors, but additions of surfactants change the pattern of reaction. The inhibitory activity of HSs much depends on their origin. The velocity of studied reactions depends also on pH, temperature and concentration of HS used. Possible micellar catalysis mechanism has been suggested.
The Structure and the Stereochemistry of Atractyliretin
1986
The nor-kaurane diterpene Atractyliretin was obtained by acid hydrolysis of Atractyloside, a toxic substance isolated from ATRACTYLIS GUMMIFERA L (Compositae). On the basis of spectral (IR, (1)H-NMR, (13)C-NMR and MS) analysis and chemical degradation its structure and stereochemistry was identified as 4.