Biossorção de metais utilizando casca de híbrido eucalyptus urograndis: uma alternativa de pós-tratamento de efluente da indústria de papel e celulose

Abstract

Biosorption is a technique with promising results, which consists of the adsorption of heavy metals using different plant biomasses. This study aimed to evaluate the potential of the hybrid Eucalyptus urograndis bark as a biosorbent for cadmium and copper present in aqueous solution. The peels were collected and prepared in the laboratory, following the steps of: washing, drying and cutting. The aqueous solution was prepared in order to simulate an effluent generated by the pulp and paper industry containing cadmium and copper, with concentrations of 10 mg L-1 for these metals. The experiment was carried out in batch and organized in triplicate in contact times of: 0, 15, 30, 60, 90, 120, 150, 180 and 240 min. The biosorbent was characterized via Infrared Spectroscopy and zero load point. The adsorption kinetics was analyzed by pseudofirst order and pseudosecond order models. The removal of Cd and Cu was evaluated as a function of contact time under different pH conditions. Through Infrared Spectroscopy it was possible to identify common functional groups of cellulose, which may be associated with the adsorption process. Zero load point obtained was 4.64. The kinetic study demonstrated that the pseudosecond order model fitted better to the experimental data. For Cd removal, the initial pH of 5.02 showed greater removal, reaching 96.42% at 240 min. As for Cu, the condition that best presented removal was pH 3.03 with removal of 92.53%. In view of the results, it was clear that the biosorbent was efficient in removing Cd and Cu from the aqueous solution, with application indications for real effluent.