Nonthermal Plasma Chemical Processing of Bromomethane.

Nonthermal plasma chemical decomposition of bromomethane (CHBr) was investigated with a coaxial type packed-bed plasma reactor. It has been demonstrated that plasma chemical processing is an effective approach to decompose CHBr in a wide concentration range. It has been shown that CHBr decomposition reactivity depends on reactor operating factors such as background gas, O concentration, and humidification. Higher decomposition efficiencies can be obtained in dry N. However, organic byproducts such as BrCN are concurrently produced under deaerated conditions. Water suppresses CHBr decomposition and also affects the yields of CO (CO and CO) and organic byproducts due to the involvement of some active species generated from water. The presence of O retards CHBr decomposition by quenching high-energy electrons, while it suppresses organic byproducts and improves CO yield. The reacted carbons in CHBr are recovered as CO almost quantitatively in air. Higher CO selectivities cannot be achieved by increasing O concentration. NO formation, which is accompanied by CHBr decomposition, can be effectively suppressed by decreasing O concentration down to 2%. Furthermore, reaction mechanisms are discussed by comparing the reactivities of CHBr and its congeners.