Utilização da fibra do coco como adsorvente para o cobre (II)

Abstract

Nowadays the study of the use of biodegradable materials as biosorbent of metals and organic compounds, has become increasingly larger, it is known that before were only waste, however due to its abundance, low cost and being a renewable source have become increasingly more constant use for environmental purposes. Studies highlight the importance of the method and its effectiveness in dealing with current environmental needs. Coconut is a fruit of high consumption in the beaches of all Brazil and its discarding is done in the majority of the times of improper form, it is known that its decomposition can take many years. The objective of this work was to evaluate the adsorption capacity of the coconut fiber from the internal part of the fruit (mesocarp), with and without chemical modifications in the biosorption of copper ions (Cu2+) for future applications in the decontamination of aqueous effluents produced by industries. At first, the material was activated with an alkaline solution of 0.1 M NaOH, which according to the literature induces the increase of the porosity of the fiber, making it more efficient for the aggregation of metals. The obtained materials were characterized by the following techniques: Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and X-Ray Fluorescence (XFR). Coconut Mesocarp (CM) and Activated Coco Mesocarp (AMC) samples were submitted to finite bath tests at a speed of 300 rpm for a period of 3 hours and then analyzed by Differential Pulse Voltammetry (DPV), extremely sensitive and inexpensive electrochemical technique when comparing with Atomic Absorption Spectrophotometry (AAS) and this is the most used in area studies. The amount of adsorbed metal ions was determined by equation based on the literature obtaining the values of 105.2 mg.g-1 of Cu2+ ions adsorbed to CM and 108 mg.g-1 for AMC. The results are promising to show that the application of coconut fibers as biosorbent of copper ions has adsorption capacity and can be used for environmental purposes and probably with other metals.