Biocarvão de exocarpo de sapucaia (lecythis pisonis) para a adsorção de verde brilhante
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Data
2024-02-23
Autores
Campos, Phelipe Augusto Carvalho
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Universidade Federal do Espírito Santo
Resumo
In contemporary times, the escalating processes of industrialization and urbanization have led to watercourses' contamination by persistent organic pollutants (POPs), such as dyes, pharmaceuticals, pesticides, and aromatic hydrocarbons. Consequently, water quality is significantly compromised. To mitigate these adverse impacts, adsorption emerges as an effective and economically viable technique for treating effluents contaminated with POPs. The choice of adsorbent material is pivotal for the development of an adsorption-based decontamination process. In this context, biocarbons possess suitable characteristics as adsorbents, including high surface area, mechanical stability, and surface functional groups that act as binding sites for various organic species. With the aim of contributing to the development of sustainable technologies, this study primarily focused on the synthesis and performance evaluation of a biocarbon produced from the exocarp of Sapucaia (Lecythis pisonis) for removing the dye Brilliant Green (VB). The biocarbon synthesis, utilizing Sapucaia exocarp as a precursor, occurred at a temperature of 600°C under a nitrogen atmosphere. The synthesized material was characterized through thermogravimetric analysis (TG), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Surface area (BET and BJH) and pH at the point of zero charge (pH_PZC) were also determined. Adsorption kinetic tests for VB were conducted at temperatures of 25, 35, 45, and 55°C, using a dye solution at a concentration of 250 ppm and a pH of 7. Characterization results indicated that the synthesized material exhibited a considerable surface area and the presence of crucial surface functional groups, fundamental for successful adsorption processes. The adsorption tests revealed that the synthesized biocarbon exhibited high efficacy in removing the dye from aqueous solutions. Among the nonlinear kinetic models applied to the experimentally obtained data, the Avrami model more accurately described the VB adsorption process. According to this model, the adsorption kinetics are fractional order. Moreover, the analysis of parameters related to the Weber and Morris diffusion model indicated that the dye adsorption kinetics are controlled by more than one mechanism, supporting the Avrami model. The Sips model proved to be the most suitable for fitting the experimental equilibrium results, and thermodynamic results suggested that the adsorption process is endothermic, spontaneous, and irreversible. This study underscores the potential of biocarbon derived from Sapucaia exocarp as a promising solution for the effective removal of organic pollutants, such as Brilliant Green, from aqueous solutions. Additionally, it emphasizes the need for future research, given the limited knowledge available in the literature on this material, offering opportunities for further studies and enhancements.
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Corantes , Verde brilhante , Biocarvão