MESOCARPO DE COCO VERDE (Cocos nucífera) E PÓ DE SERRAGEM DA TATAJUBA (Bagassa Guianensis Aubl) COMO ADSORVENTES EM MEIO AQUOSO

Abstract

In this work the efficiency of two Brazilian waste materials, wood residues and coconut mesocarp, as adsorbents towards metallic ions (Ni2+, Cu2+) and two representative textile dyes (Red and Violet Brilliant Remazol) was investigated. The humidity, carbohydrates, protein, grease, ash and fiber contents of both natural matrices were measured, and they were also characterized by infrared spectroscopy, X-ray diffratometry, scanning electron microscopy, specific surface area analysis and thermogravimetry. The adsorption of dyes was monitored by using UV-Vis spectroscopy. It was verified that while both adsorbents, coconut mesocarp and wood residue can adsorb towards the investigated dyes, they release extractives to the solution and showed no affinity towards those metal ions. Furthermore, it was verified that the adsorption is strongly pH dependent and, as a general behavior, an increase in the pH value is associated with a decrease of the total amount of adsorbed dye. The adsorption of violet dye onto coconut mesocarp is well described by the Langmuir model, while all the others systems fitted not well by the Langmuir and Freundlich´s equations.