Biossorção do íon metálico Cd²+ utilizando biomassas residuais como adsorventes alternativos

Abstract

The environment is constantly being contaminated by metals as a result of industrial and agro-industrial activities. The consequences of this type of contamination are worrying, damaging fauna, flora and human beings. It is therefore necessary to work to solve this problem by decontaminating liquid effluents through the recovery or removal of metals from the environment. However, the conventional treatments used have low removal efficiency and their application requires a high level of investment. The aim of this study was to analyze the ability of two biomasses, identified as B1 and B2, to adsorb the metal Cd2+ in a synthetic solution. The surface characteristics of the biomass were evaluated by determining the zero charge point. For the tests, 6 g.L-1 of each biomass was used, in contact with synthetic Cd2+ solutions with concentrations of 10 mg.L-1 and 20 mg.L-1. Both biomasses were subjected to the same experimental conditions. The adsorption capacity of the biomasses was determined through kinetic studies. The Zero Charge point of biomasses B1 and B2 are at pH 5.5 and pH 4.7, respectively. For the analyses, the differential pulse voltammetry technique was used, using a polarograph coupled to a potentiostat, employing a mercury drop electrode (HMDE) for the determination of cadmium. At the end of the experiments, it can be concluded that the biomasses showed satisfactory results, especially biomass B2. This is because biomass B1 showed an adsorption capacity of 63% after 90 min in contact with 10 mg.L-1 of the metal and 47% in the first 30 min. In the case of biomass B2, the adsorption capacity was 100% in the first 30 min for the two metal concentrations studied. Thus, it was concluded that the biomasses have satisfactory potential in the Cd2+ metal removal process.