POTENCIAL USO DE BIOMASSA DE CASCAS DE ABÓBORA (Cucurbita spp.) COMO BIOSSORVENTE NA REMOÇÃO DO HERBICIDA DIURON® EM MATRIZES AQUOSAS

Abstract

Brazil is one of the countries that most use agrochemicals due to its high agricultural production, which is responsible for supplying a large part of the world's demand for food. The uncontrolled application of agrochemicals, even if necessary for pest control, represents a great danger to all living beings, given that compounds used often have a high degree of toxicity and can persist for a long time in the environment, causing soil contamination and waters. In 2018, the mass of agrochemicals applied on Brazilian soil reached 530,000 tons. Therefore, simple and low-cost methods for water decontamination are increasingly needed. The adsorption process is one of the most used treatment methods for water decontamination and can be applied to remove organic and inorganic components. The adsorption when compared to others treatment methods has advantages such as, for example, high efficiency, easy implementation, spontaneous process and the possibility of reconstituting the adsorbent material. Due to the high cost of conventional adsorbents, studies for the development of adsorbents from biomass (biosorbents) have grown increasingly. The present work studied the potential of pumpkin peels biomass (Cucurbita spp.) as biosorbent for the removal of the agrochemical Diuron® from aqueous matrices. The developed material was characterized by Fourier transform mid-infrared spectroscopy (mid-FTIR), thermogravimetry (TG-DTG), Area Surface and Porosity Analyser (ASAP) and point of zero charge (PZC). The tests showed that the highest values for adsorption capacity were obtained at alkaline pHs. The kinetic study revealed that the equilibrium was established in the first 30 min, being the pseudo-second order model that better fit the data obtained, with R2 of 0.9956, indicating a chemical adsorption process. The sorption tests presented experimental values of 10.5 mg.g-1 and the better fit for the data obtained was the Langmuir isothermal model (R2 = 0.9634). The efficiency of pumpkin peels biomass was shown by the results obtained, indicating a favorable use for the removal of Diuron® in aqueous matrices, contributing to future studies using complex matrices.