Study of Cu NPs reactivity for compounds with different chemical structures: Black reactive dye 5, picric acid and 2,4-D herbicide.

In this study, the copper nanoparticles (Cu NPs) reactivity for degradation of the reactive dye black 5 (RP5), picric acid (PA) and 2,4-D herbicide was evaluated. The RP5 degradation occurred by oxidative via, through hydroxyl radicals generated in situ, with active participation of Cu(I) and H2O2. The use of catalase confirmed the hydrogen peroxide formation in situ. Reduction degradation via electron transfer was also possible. On the other hand, PA had low degradation efficiency (less than 20%) under any conditions studied (similar to those used for RP5). High degradation efficiency for 2,4-D was achieved by the association of the Cu NPs/H2O2. Thus, the behavioral model of Cu NPs has been proven. This behavioral difference of the chemical species to be degraded in relation to the behavior of the Cu NPs was studied, evaluating its redox behavior by voltammetric analyzes. This study aided in the understanding and selection of the chemical species that can be degraded by these NPs.