AVALIAÇÃO DA EFICIÊNCIA DOS CARVÕES ATIVADOS PRODUZIDOS A PARTIR DA CASCA DA BANANA NANICA (Musa paradisíaca) NA BIOSSORÇÃO DE ÍONS CHUMBO EM ÁGUA

Abstract

The constant increase in population, population density and climate change contradict the principle that water availability is abundant and unlimited. The efficient water use can help to solve many problems related to scarcity and still guarantee continued agricultural production. This study aimed to verify the banana nanica (Musa paradisíaca) peel efficiency in the lead ions biosorption in water, providing a low cost and effective method for water reuse. There are numerous water and waste treatment techniques available that can be used successfully; however, the acquiring equipment and supplies cost and the high maintenance of these systems makes their implementation in rural areas unfeasible. Thus, this project execution enabled the development of an alternative solution for the water contaminated with heavy metals treatment, in particular, lead, resulting from the ore extractive activities and agriculture, from the banana peels use. For that purpose, atomic adsorption techniques (biosorption) were utilized using coals prepared from banana nanica peels. These were dried in an oven with air recirculation at 60 °C for 96 h, crushed in a commercial blender and sieved to obtain a fraction composed of microparticles up to 500 μm. Then the coals were obtained by calcination 200, 250, 300 and 350 ° C. For the biosorbent preparation, the working pH (pH = 5) was determined from the Zero Charge Point and thermogravimetric analysis (TGA) was performed to identify the best temperatures for obtaining the coals. Scanning electron microscopy and infrared spectroscopy analyzes were performed to characterize the coals and identify the functional groups present. Finally, were performed the kinetic study and the evaluation of the lead content adsorption by flame atomic absorption spectrophotometry and adjustments to the Freundlich and Langmiur biosorption isotherm models. Coals prepared at 250, 300 and 350 °C showed excellent biosorption results with 100% lead removal at pH 5, and the other coals showed removal above 90% for all pHs. The model that best described the experimental data behavior for the biosorption isotherms was the Freundlich model, where R2 values of 0.9920 were obtained; 0.9451; 0.945; 0.9771 for temperatures 200, 250, 300 and 350 ºC, respectively. Thus, it was possible to demonstrate that the use of biosorption with coals prepared from the banana peel presents itself as a low-cost and easy-to-apply process that enables the knowledge expansion about practices in the rural environment and chemical knowledge.