Efeito da temperatura e voltagem aplicada na cinética de formação do íon amônio produzido por plasma frio de ar atmosférico em meio aquoso

Abstract

Among the advanced oxidative processes (AOP’s), cold plasma is one of the most efficient in the generation of reactive species and a treatment of aqueous residues. As a "green" technology, that is, with the capacity not to generate other wastes or toxic polluters, plasma are a source of scientific knowledge, in order to identify reactive species and their kinetic mechanism’s. Two types of reactive species can be formed from plasma, and they are reactive oxygen species (ROS) and reactive nitrogen species (RNS). Among the ROS’s, we can mention the hydroxyl radical (•OH), main species of AOP’s, ozone (O3), and others. Among the RNS’s we can mention nitrite (NO2), nitrate (NO3), and others. In this work, the formation mechanism of an RNS, the ammonium ion (NH4+), from plasma ultrapure water activated, and the effect of the electric potencial applied on the kinetic constant value (kobs). The kinetic model of formation for this specie is suitable for a zero order reaction, with the value of kobs decreasing with the increasemnt of temperature and applied voltage. Thermodynamic values of activation elucidate an associative reaction.