Decomposition of Chlorobenzene by Thermal Plasma Processing

Abstract

Decomposition of chlorobenzene as a model molecule of aromatic chlorinated compounds was studied in radiofrequency (RF) thermal plasma both in neutral and oxidative conditions. Optical emission spectroscopy (OES) was applied for the evaluation of the plasma excitation and molecular rotational-vibrational temperature. Atomic (C, H, O) and molecular (CH, OH, C 2 ) radicals were identified, while the morphology of the formed soot was characterized by electron microscopy. Organic compounds adsorbed on the surface of the soot after plasma processing were comprised of various polycyclic aromatic hydrocarbons (PAH) and chlorinated PAH molecules. Their amount was greatly affected by experimental conditions, especially the oxygen content and plate power. The higher input power reduced the ring number of the PAH molecules. Addition of oxygen significantly reduced the amount of both PAHs chlorinated PAH molecules but enhanced the formation of polychlorinated benzene compounds.

Thermal Plasma Decomposition of Tetrachloroethylene

“…atmosphere (Figure 7-b-c). These values are very similar to the size of carbon particles produced in our previous works [4,6].…”

“…The presence of oxygen did not change the excitation temperature. A similar phenomenon was observed in one of our previous works on the decomposition of chlorobenzene in thermal plasma [4]. In reductive conditions, the excitation temperature increased to 11500 K due to the heating effect of hydrogen ( Table 2).…”

“…Quite surprisingly, Cl 5 N), as well. Although in our recent studies on thermal plasma decomposition of chlorinated compounds OES investigations verified the existence of CN radicals, which referred to the cleavage of the strong N≡N bonds, we could not detect any nitrogen containing species[4,36]. In this work, however, nitrogen has been incorporated into the extracted products in the ligands and even within the aromatic rings.…”

“…Therefore, thermal plasma processing is usually applied in cases when incineration or high-temperature pyrolysis would yield stable, undesired by-products, like soot, dioxins or polycyclic aromatic hydrocarbons (PAHs). Decomposition in thermal plasma has been tested on a large array of compounds, such as (1) small aromatic molecules, like benzene [2], toluene [3] and chlorobenzene [4], (2) linear polymers, like polyethylene [5] and poly(vinyl chloride) [6], (3) halogenated methane derivatives, like chloroform [7], carbon tetrachloride [8], carbon tetrafluoride [9] and Freon-11 [10] and (4) hydrogen containing C 2 molecules, like dichloroethylene [11]. To best of our knowledge, there have not been reports on the RF thermal plasma decomposition of any hydrogen-free C 2 compounds.…”

Continuous and catalyst free synthesis of graphene sheets in thermal plasma jet

“…The decomposition of aliphatic n-alcohols was carried out in an RF thermal plasma system, which consisted of an RF inductively coupled plasma torch (TEKNA PL- 35) connected to a high frequency (4-5 MHz) LEPEL generator, a reactor, a cyclone, a filter unit and a vacuum pump (see Supplementary Data, Figure S1 and papers [44][45]). The doublewall, water cooled cylindrical reactor was made of stainless steel with the inner diameter of 19.7 cm and length of 121.6 cm.…”