Decomposition of gas-phase diphenylether at 473 K by electron beam generated plasma

Abstract

Decomposition of gas-phase diphenylether (DPE) in the order of several parts per million by volume (ppmv) was studied as a model compound of dioxin using a flow-type electron-beam reactor at an elevated temperature of 473 K. The ground state oxygen ( 3 P) atoms played an important role in the decomposition of DPE resulting in the formation of 1,4-hydroquinone (HQ) as a major ring retaining product. The high yield of hydroquinone indicated that the breakage of ether bond (C-O) is important in the initial step of DPE decomposition. Ring cleavage products were CO and CO 2 , and NO 2 was also produced from background N 2 -O 2 . The sum of the yields of HQ, CO 2 and CO accounts for over 90% of the removed DPE. Hydroxyl radicals (OH) were less important in the dilute DPE decomposition at a high water content, and were mostly consumed by recombination reactions to form hydrogen peroxide. The smaller the initial DPE concentrations, the higher the decomposition efficiency and the lower the yields of primary products. NO scavenges oxygen atoms and decreases the DPE decomposition, while the addition of n-butane causes positive effect on the decomposition of DPE due to the several secondary radicals (HO 2 , alkyl and alkoxy radicals) produced during the decomposition of n-butane.

Correlation‐free reflection diagnostics of graphene‐like surface layers in the infrared region

“…More precisely, we use the differential reflectivity Δ R / R = ( R − R 0 )/ R 0 (where R is the reflectance of a tri‐layer (ambient–film–substrate) slab structure, and R 0 is the reflectance of the bare substrate ( d f = 0), respectively) at normal incidence. In this case the analytical expression for Δ R / R has a simple form: …”

Naphthalene and Acenaphthene Decomposition by Electron Beam Generated Plasma Application

“…Facility The irradiation flow system described previously by Kim et al [5] has been slightly modified as shown in Fig. 2.…”

“…Dose calculation was based on the number of nitrogen molecules produced when 100 eV of electron beam energy is absorbed by N 2 O. This experimentally established value of 10 mol/100 eV is available in the literature [5]. The dosimeter gas was irradiated by electron beam at the voltage of 1.5 MV and current ranged up to 5.0 mA .…”

“…benzene and toluene [1], xylene [2], chlorobenzene [3], styrene [4] and diphenylether [5]. The pilot plant tests carried out for waste-incineration flue gas have shown 80% of decomposition ratio for dioxins (with initial concentration of 1 ng m -3 ) for 10 kGy dose applied and over 90% for 14 kGy [6].…”

Polycyclic aromatic hydrocarbons in coal combustion flue gas under electron beam irradiation

“…When ammonia is added to the gas stream these acids are transformed into mixture of NH 4 NO 3 and (NH 4 ) 2 SO 4 which is used as a fertilizer . EB technology for volatile organic compounds removal from flue gases has been investigated since the late 1980s in order to apply this technology in industry (Paur et al, 1991;Hakoda et al, 1998;Han et al, 2003;Kim et al, 2003). Pilot plant tests have been carried out in Japan with the purpose of decomposing/detoxifying a dioxin stream in wasteincineration flue gas (Hirota et al, 2003).…”