Influence of applied plasma power on degradation of L-proline in an inductively coupled RF plasma reactor

Abstract

Surface treatments such as heat treatments, paints, plasma treatments and galvanizing are important in metal working industry. In those treatments, the required adhesion characteristics can be limited if contaminants are present, so there is a need to clean these surfaces. Conventional processes can be costly, some generated waste may be environmentally hazardous and, in some cases, due to part geometry, they are not effective. Alternatively, plasma treatments which are considered to be environmentally clean, more efficient and with lower operating costs can overcome those difficulties. Due to the reactional complexity of these treatments, there are many fields to be researched, such as which reactions are due to impacts of (neutral) chemical species and which are due to excited species and radiation. The present work aims to verify the interactions between Ar-10%O2 plasma using amino acid L-proline in an inductively coupled radiofrequency plasma. This study showed that oxidative plasma promotes high degradation of the sample. A gas analyzer (quadrupole mass spectrometer) coupled to the gas outlet was used and many gaseous products are detected during treatment, such: H2, H2O, CO, NO (Nitric Oxide) and CO2 while L-proline undergoes intense degradation. The conclusions allow to state that the interaction between the Ar/O2 plasma and L-proline promotes intense degradation through the breakdown of the heterocyclic ring of the molecule.