Production and characterization of absorbent heat from the bark of residual Brazil nut bark (Bertholletia Excelsa l.)

Abstract

Background: The increasing efforts to reduce the environmental impact on the Amazon's natural resources are focusing on watercourses that pass through effluents with high concentrations of heavy metals. The adsorption by absorbent is one of the methods used to remove metallic ions. In this assignment, the preparation of activated carbon from Brazil nut bark (Bertholletia excelsa l.), which is a waste material produced from the use of seeds in foodstuffs and cosmetics, is shown. Results: The absorbent was carbonized at 400 °C in 3 h and activated at 800 °C in 2 h, having received the name of AC2, and, the specific area, pore size, real and apparent densities, porosity, scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), pH, moisture, fixed carbon and surface functional groups by Boehm method and Fourier transformed infrared spectroscopy (FTIR) were characterized. According to the results, the carbon presented alkaline characteristic, mesoporosity, average pore diameters of 2.203 nm and specific surface area by BET of 464.835 m2 g-1. The efficiency of removal was performed in synthetic solutions of copper sulphate (II) pentahydrate (CuSO4.5H2O), evaluating the influence of pH, initial concentration of copper solution (II), particle diameter and time contact of the adsorbent in solution. The results of higher removal percentages were to pH 5.09, initial concentration of 50, 100 and 150 mg-1 diameter 0.595 < D < 1.19 mm and time contact of 5 min. Conclusions: The Brazil nut bark is shown to be an important bio-waste, being an excellent alternative material for the low-cost production of activated carbon for use in processes involving iterations of adsorption.