Obtenção de pontos quânticos de carbono a partir dos resíduos de misturas de agroquímicos

Abstract

The expansion of agriculture by the state of Mato Grosso demonstrates a significant demand for agricultural production for food supply, attributed to the current growth of the world population. At the same time, productivity improvement is intrinsically linked to innovations in agricultural practices, requiring the concomitant use of different agrochemicals, such as herbicides, fungicides, and fertilizers, which are crucial for the control of pests, insects, weeds, and diseases, as well as for the excellent development of cultivated plants. The simultaneous application of mixtures of agrochemicals is carried out in systems called tank mixes. However, managing these agrochemical residues has taken place in crucial concerns to its destination without impacting the environment and human health. For this, a viable alternative to an ecologically correct destination in favor of the Principles of Green Chemistry is proposed to use these residues in synthesizing carbon quantum dots (CQDs). The CQDs are highlighted as carbon nanoparticles with different properties, especially luminescence. The preparation efficiency of the CQDs from residues of agrochemical mixtures by conventional hydrotermal treatment, was evaluated by the characterization by spectroscopic techniques of UV-vis, photoluminescence, FTIR, and ICP-OES. These techniques made it possible to evaluate the quantum yield of their luminescence, around 6.68%, as well as to evaluate the presence of existing functional groups containing oxygen and nitrogen in the chemical structure of the CQDs, in addition to making it possible to assess whether the presence of the metallic ions present could suppress the luminescence of the CQDs produced. The addition of ethylenediaminetetraacetic acid (EDTA) sodium salt indicated that the presence of metal ions did not interfere with the luminescence of the CQDs when exposed to the UV lamp. Given the above, it can be said that it is possible to use the residues of agrochemical mixtures as raw material for the production of CQDs, in addition to being a promising and sustainable destination from the socio-economic and environmental point of view.