Decomposition of CH 3 SH in a RF Plasma Reactor: Reaction Products and Mechanisms

Journal of the Air & Waste Management Association

Huang

Chen

et al. 2003

Self Cite

The traditional technologies for odor removal of thiol usually create either secondary pollution for scrubbing, adsorption, and absorption processes, or sulfur (S) poisoning for catalytic incineration. This study applied a laboratory-scale radio-frequency plasma reactor to destructive percentage-grade concentrations of odorous dimethyl sulfide (CH 3 SCH 3 , or DMS). Odor was diminished effectively via reforming DMS into mainly carbon disulfide (CS 2 ) or sulfur dioxide (SO 2 ). The removal efficiencies of DMS elevated significantly with a lower feeding concentration of DMS or a higher applied rf power. A greater inlet oxygen (O 2 )/DMS molar ratio slightly improved the removal efficiency. In an O 2 -free environment, DMS was converted primarily to CS 2 , methane (CH 4 ), acetylene (C 2 H 2 ), ethylene (C 2 H 4 ), and hydrogen (H 2 ), with traces of hydrogen sulfide (H 2 S), methyl mercaptan (CH 3 SH), and dimethyl disulfide. In an O 2 -containing environment, the species detected were SO 2 , CS 2 , carbonyl sulfide, carbon dioxide (CO 2 ), CH 4 , C 2 H 4 , C 2 H 2 , H 2 , formaldehyde, and methanol. Differences in yield of products were functions of the amounts of added O 2 and the applied power. This study provided useful information for gaining insight into the reaction pathways for the DMS dissociation and the formation of products in the plasmolysis and conversion processes. INTRODUCTIONDimethyl sulfide (CH 3 SCH 3 , or DMS) is an odorous organosulfur pollutant subject to strong public criticism. Natural sources of DMS include oceanic emissions, marine biogenic sources, and terrestrial biogenic sources. 1 In industry, DMS is emitted to the atmosphere from the incomplete combustion of coal and oil, synthetic fibers and resins, petroleum refining process, Kraft paper mills, synthetic polymer spinning, tannery process, and so on. 2,3 The olfactory detection threshold of DMS is ϳ0.001 ppm, fairly close to that of methyl mercaptan (CH 3 SH) (0.002 ppm), ethyl mercaptan (C 2 H 5 SH) (0.001 ppm),

Section: Discussionmentioning

confidence: 99%

Deodorization of Dimethyl Sulfide Using a Discharge Approach at Room Temperature

Journal of the Air & Waste Management Association

Huang

Chen

et al. 2003

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“…The mole fraction of the product species was determined by comparing with the response of the peak height of standard gas at the same wavenumber. 13,14 However, the concentrations of SF 4 and S 2 F 10 were estimated from data of Heise et al 15 and Wilmshurst and Bernstern. 16 All unreacted F atoms were assumed to be converted into F 2 , 17 and the mole fraction of F 2 was determined using a mass balance.…”

Section: Discussionmentioning

confidence: 99%

Decomposition of SF₆in an RF Plasma Environment

Shih

Lee

Journal of the Air & Waste Management Association

et al. 2002

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Sulfur hexafluoride (SF 6 )-contained gas is a common pollutant emitted during the etching process used in the semiconductor industry. This study demonstrated the application of radio-frequency (RF) plasma in the decomposition of SF 6 . The decomposition fraction of SF 6 [η SF6, (C in -C out )/C in × 100%] and the mole fraction profile of the products were investigated as functions of input power and feed O 2 /SF 6 ratio in an SiO 2 reactor. The species detected in both SF 6 /Ar and SF 6 /O 2 /

“…(1) Decomposition of CH 3 SH in a RF Plasma Reactor: Reaction Products and Mechanisms Tsai et al (2001) studied the application of the RF cold plasma method to the decomposition of methanethiol (methyl mercaptan, CH 3 SH) at different O2/CH3SH ratios (0−4.5), with various input powers (20−90 W), and at constant operating pressure (30 Torr). The species detected in the CH 3 SH/O 2/ Ar RF plasma were SO 2 , CS 2, OCS, CO, CO 2, CH 4 , C 2 H 4 , C 2 H2, H 2 , H 2 O, HCOH, and CH 3 OH.…”

Section: (4) Decomposition Of Boron Trifluoride In the Rf Plasma Envimentioning

confidence: 99%

“…An advantage of using the RF plasma reactor is that a conventional reaction therein can be completed at a lower temperature elsewhere (Hsieh et al, 1998a). Many studies have demonstrated that the destruction or treatment of hazardous gases by applying RF plasma technology is very practical Li et al, 1996;Hsieh et al, 1998a, b, c;Wang et al, 1999a, b;Liao et al, 2000;Wang et al, 2000;Hsieh et al, 2001;Liao et al, 2001;Tsai et al, 2001;Shih et al, 2002;Tsai et al, 2002;Shih et al, 2003;Tsai et al, 2003;Wang et al, 2003;Tsai et al, 2004;Liao et al,2005;Wang et al, 2005a, b;Hsieh et al, 2007;Tsai et al, 2007). The above mentioned cited articles (from 1996 to 2007) show that RF power is delivered through the power meter and the matching unit to an outer copper electrode that is wrapped around the reactor, the other electrode is earthed.…”

Section: Introduction and A Brief Review Of Decomposition Of Air Toximentioning

confidence: 99%

Decomposition of Methyl Tert-Butyl Ether by Adding Hydrogen in a Cold Plasma Reactor

Hsieh

Chang

et al. 2011

Aerosol Air Qual. Res.

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Methyl tert-butyl ether (MTBE) is extensively used as an oxygenate and octane enhancer in gasoline. Its release to the environment has generated great public and governmental concern. In this study, we give a brief review of the decomposition of air toxics by the application of radio frequency (RF) plasma reactors and then present our study on decomposition of methyl tert-butyl ether by adding hydrogen in a cold plasma reactor. Based on our references, there are four types of the application in the RF plasma reactors are discussed, including: (i) Application I.: Converting methane, decomposing carbon dioxide, ethoxyethane, and ethylene oxide; (ii) Application II.: Decomposing methyl chloride, 1,1-C 2 H 2 Cl 2 , and CH 2 Cl 2 ; (iii) Application III.: Decomposing dichlorodifluoromethane, CHF 3 , CH 2 F 2 , CCl 2 F 2 , and BF 3 ; (iv) Application IV.: Decomposing dichlorodifluoromethane, CH 3 SH, CS 2 , SF 6 , and SF 6 + H 2 S mixture. Moreover, this study demonstrates the feasibility of applying a radio frequency (RF) plasma reactor for decomposing and converting MTBE. Experimental results indicate that the decomposition efficiency (η MTBE ) and the fraction of total input carbon converted into CH 4 , C 2 H 2 and C 2 H 4 (F CH4+C2H2+ C2H4 ) increased with the input power and decreased as both the H 2 /MTBE ratio and the MTBE influent concentration in the MTBE/H 2 /Ar plasma environment increased. Interestingly, applying radio frequency plasma to the decomposition of MTBE while adding hydrogen constitutes alternative method of decomposing and converting MTBE into CH 4 , C 2 H 4 , C 2 H 2, iso-butane and iso-butene.