Abstract:The reaction of CCl2F2 (CFC‐12) with methane (in an argon bath gas) in a dielectric barrier discharge (DBD) non‐thermal plasma reactor at atmospheric pressure has been investigated. The reaction (where oxygen and nitrogen are excluded from the feed gas) produced a range of gas phase products, including H2, HCl, HF, CHF3, CF3CH2F, CHClF2, CH3Cl, CH2ClF, CH2Cl2, CHCl2F and CHCl3 as well as solid products which were primarily non‐crosslinked polymers. The conversion of CCl2F2 increased, from 44 to 71%, when the i… Show more
“…The mechanism in the formation of gaseous species has been described in detail in our earlier publication. 14 In this article, mechanistic discussions in the formation of various radicals in the plasma reactor as well as their reaction in the synthesis of polymers are presented.…”
Section: Resultsmentioning
confidence: 99%
“…The detailed procedure for calculating power input to the reactor can be found in our earlier publication, 16 with a slight modification as described in a later publication. 14 The feed gases were argon (99.999%, Coregas), CFC-12 (99.98%, Actrol), and methane (99.95%, Linde), and the feed streams were controlled by mass flow controllers (Brooks). The results presented in this article were generated with a feed condition of 1.25% CCl 2 F 2 and 1.25% CH 4 in argon at 100 cm 3 min −1 .…”
A dielectric
barrier discharge (DBD) nonequilibrium plasma reactor
was employed to polymerize CFC-12 (CCl2F2, dichlorodifluoromethane)
at atmospheric pressure. The plasma polymerization of this saturated
halogenated hydrocarbon was conducted in the presence of methane as
reactant, in an argon bath gas and where the reaction environment
was free from oxygen and nitrogen. The reaction resulted in the formation
of non-cross-linked polymer product and whereby the non-cross-linked
nature of the polymer enabled its characterization by solution state 13C and 19F nuclear magnetic resonance (NMR) spectroscopic
analysis. The generated polymer was also analyzed by Fourier transform
infrared (FTIR) spectrometry, and the spectra thus obtained were consistent
with the analysis by NMR. The analyses of NMR and FTIR spectroscopy
reveal the formation of fluoropolymers from the conversion of CFC-12.
“…The mechanism in the formation of gaseous species has been described in detail in our earlier publication. 14 In this article, mechanistic discussions in the formation of various radicals in the plasma reactor as well as their reaction in the synthesis of polymers are presented.…”
Section: Resultsmentioning
confidence: 99%
“…The detailed procedure for calculating power input to the reactor can be found in our earlier publication, 16 with a slight modification as described in a later publication. 14 The feed gases were argon (99.999%, Coregas), CFC-12 (99.98%, Actrol), and methane (99.95%, Linde), and the feed streams were controlled by mass flow controllers (Brooks). The results presented in this article were generated with a feed condition of 1.25% CCl 2 F 2 and 1.25% CH 4 in argon at 100 cm 3 min −1 .…”
A dielectric
barrier discharge (DBD) nonequilibrium plasma reactor
was employed to polymerize CFC-12 (CCl2F2, dichlorodifluoromethane)
at atmospheric pressure. The plasma polymerization of this saturated
halogenated hydrocarbon was conducted in the presence of methane as
reactant, in an argon bath gas and where the reaction environment
was free from oxygen and nitrogen. The reaction resulted in the formation
of non-cross-linked polymer product and whereby the non-cross-linked
nature of the polymer enabled its characterization by solution state 13C and 19F nuclear magnetic resonance (NMR) spectroscopic
analysis. The generated polymer was also analyzed by Fourier transform
infrared (FTIR) spectrometry, and the spectra thus obtained were consistent
with the analysis by NMR. The analyses of NMR and FTIR spectroscopy
reveal the formation of fluoropolymers from the conversion of CFC-12.
“…A detailed description of our procedure for calculating power input to the reactor can be found in our earlier publication. 29 The input power can then be converted to estimate the input energy density (input energy density = P/F, where P is the average power dissipated by the reactor and F is the total volumetric feed rate). The input energy density range for this investigation was 3−13 kJ L −1 and the corresponding applied voltage range was 14.1−15.2 kV (peak−peak).…”
Section: Methodsmentioning
confidence: 99%
“…The power input to the plasma reactor was determined by the enclosed area of a voltage-charge Lissajous figure. A detailed description of our procedure for calculating power input to the reactor can be found in our earlier publication . The input power can then be converted to estimate the input energy density (input energy density = P / F , where P is the average power dissipated by the reactor and F is the total volumetric feed rate).…”
The
reaction of CCl3F (CFC-11) with CH4 (in
an argon bath gas) in a dielectric barrier discharge nonequilibrium
plasma was examined. Oxygen and nitrogen were excluded from the feed
stream and the reactions resulted in the production of fluorine-containing
polymers, as well as a range of gaseous products including H2, HCl, HF, C2H3F, C2H3Cl, C2H2ClF, CHCl2F, CCl2F2, CH3Cl, CH2Cl2, CHCl3, and C2Cl4. The polymeric material
synthesized during reaction is characterized as being non-cross-linked
and random in nature, containing functional groups including CH3, CH2, CHCl, CHF, CF2, and CF3. The conversion level of CCl3F increased from 37% to
63% as the input energy density increased from 3 to 13 kJ L–1 (the applied voltage range was 14.1 to 15.2 kV, peak–peak).
The electrical discharge was characterized and found to be a slight
modification of filamentary discharge toward a diffuse discharge due
to the presence of the relatively low concentration of CCl3F and CH4 (less than 2% each) in argon. A reaction mechanism
is proposed describing the formation of gas phase, as well as polymeric
products.
“…The Cl-H bonding energy of CH 2 Cl 2 is 4.28 eV and is lower than the energy of metastable Ar (11.55 eV) produced by electron impact, as shown in reaction ( 9) [99]. Therefore, CH 2 Cl 2 is also possibly decomposed by Penning ionization by the energy transfer collision of metastable Ar (Ar*) as shown in the following reactions: [99,100].…”
Section: Decomposition Of Persistent Organic Pollutantsmentioning
Electrical pulsed discharge plasma produces various powerful oxidizing agents, such as hydroxyl radicals and ozone, which have high oxidation potential. These species play an important role in the decomposition of persistent organic compounds in wastewater. Because highly concentrated oxidants are directly produced inside the plasma, plasma realizes high-speed wastewater treatment without pretreatment of samples, such as pH adjustment. The pulsed discharge plasma generated over the water surface and inside bubbles is highlighted as a highly efficient method for plasma generation and radical supply into wastewater. In this paper, the physical and chemical properties of the discharge plasma generated over a water surface are described. The decomposition of persistent organic compounds dissolved in wastewater, such as 1,4-dioxane, formic acid, and dichloromethane, by plasma discharge is demonstrated, and their mechanisms are discussed. These persistent compounds, which have strong toxicity and stability, can be efficiently decomposed and removed quickly from solutions by plasma treatment. Furthermore, the treatment of nutrient solutions used in hydroponic systems for plant cultivation is also introduced as a novel application of plasma, and the effects of bacterial inactivation, decomposition of allelochemicals, and improvement in plant growth by plasma are demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.