Obtención de biocarbón magnético impregnado con nanopartículas de hierro a partir de residuos orgánicos de tocte (Juglans neotropica) y aguacate (Persea americana)

Abstract

Mercury contamination, inadequate organic waste management and the need for an effective adsorbent posed important challenges for environmental conservation and public health protection. In this context, the study focused on obtaining magnetic biochar impregnated with iron nanoparticles from organic wastes of tocte (Juglans neotropica) and avocado (Persea americana), with the purpose of using it in the adsorption of mercury in aqueous solutions. To achieve this, several methods were applied, including impregnation, pyrolysis and conditioning of the biochar, followed by a detailed physical and chemical characterization. The results obtained by atomic absorption spectrometry indicated that a maximum mercury removal rate of 99.993% was achieved for the BCT-NFe treatment and 99.989% for BCANFe, using an initial Hg concentration of 10 ppm and an absorption time of 120 minutes. In addition, characterization revealed significant differences between BCT-NFe and BCA-NFe in terms of moisture content, pH, bulk and true density, as well as porosity, suggesting different biosorption capacities between the two. Analysis by infrared spectroscopy and scanning electron microscopy confirmed the presence of iron nanoparticles and their interaction with biochar. In addition, it was observed that factors such as the type of biochar, the initial mercury concentration and the adsorption time influenced the pH and conductivity of the system. In conclusion, after obtaining biochar and impregnating it with iron nanoparticles, both materials were able to remove more than 99% of mercury, with BCT-NFe being the most effective in the 10 ppm treatment during 120 minutes of adsorption. In addition, it was evidenced that the pH and conductivity varied as the modified factors interacted, significantly influencing the removal.