Removal of Metals by Biomass Derived Adsorbent in Its Granular and Powdered Forms: Adsorption Capacity and Kinetics Analysis

Abstract

Among the various existing metals, zinc and copper are predominant metals in several effluents from industries such as electroplating, plastics production and mining. Technical methods have been applied in the treatment of effluents containing metals, including chemical removal, adsorption, ion exchange, membrane technologies and electrochemistry. However, it is necessary to develop technologies that minimize costs and increase treatment quality while reducing residual sludge generation. Adsorption using biological materials stands out for removing metals, a low-cost technique and high efficiency. Thus, this study evaluated metal adsorption using an adsorbent from granular and powdered anaerobic sludge, followed by a kinetic analysis, aiming at a new alternative for wastewater treatment. Evaluation of the copper and zinc adsorption process using granular and powdered biomass resulted in maximum removals of 72.9% and 62.7% for zinc, respectively, and 92.8% and 85.0% for copper, respectively. Analyzing the kinetic models, the pseudo-second-order model fitted the data better. Applying the kinetics of other studies in the literature for copper and zinc removal by other adsorbents, the pseudo-second-order model was the most representative model. In this context, kinetic modeling allowed the determination of the solute removal rate, estimating the adsorption mechanism.