Chemical characterization of biomass flour of the babassu coconut mesocarp (Orbignya speciosa) during biosorption process of copper ions

Abstract

Abstract Population and industrial growth over the decades, have resulted in increased generation of effluents contaminated with potentially toxic metals that if released directly in the ecosystem contaminate the soil, subsoil and groundwater. The search for new technologies for environmental decontamination, of low cost and environmentally correct are encouraged. Biosorption emerges as a promising, inexpensive and ecologically viable biotechnological process. In the literature several biomasses are evaluated as biosorbents of metals, however the absence of studies that characterize the biosorptive process, impede their understanding. This work has as objective to characterize the biomass flour of babassu coconut mesocarp and assess its biosorption potential of copper ions through the techniques of potential zero charge (PZC) according to the methodology of Regalbuto, functional groups by the Boehm method, FTIR, XRD, DLS and SEM. The results showed that the (PZC) of the biomass was in the range of 4.0 indicating that above this range there will be biosorption of cations. The biomass surface is partially acid, according to the Boehm methodology, but possibly free hydroxyl groups and CH3, CH2 are involved in the biosorptive process according to the FTIR spectrograms. The characterization by XRD revealed interaction between biomass and the metal copper, since there was disappearance of phases, displacement and change in the intensity of the peaks. The particle size distribution by DLS also demonstrated that there was an interaction, indicating that the biosorptive process decreased the particle size distribution and made the distribution monomodal. The micrographs obtained by SEM revealed that there was no apparent surface modification in the biomass into contact with metal. In relation to the biosorptive potential, the biomass showed 84% removal, being considered, therefore a good biosorbent and had a better adjustment to the model of non-linear Freundlich isotherm.