New perception of the continuous biosorption of cadmium on a seaweed derivative waste

Abstract

This study investigated the alginate extraction residue from brown seaweed Sargassum filipendula for cadmium removal by biosorption in a fixed-bed system. This residue is frequently thrown into the sea, causing pollution concerns. The condition selected for the study of biosorption-desorption cycles was: flow rate of 0.5 mL/min and inlet concentration of 1.5 mmol/L. Two biosorption-desorption cycles were performed using CaCl2 as the eluent; however, the MTZ length increased substantially after the first cycle, indicating decreased column efficiency. The Yan model was the most descriptive for the experimental data. The FTIR analysis indicated the involvement of sulfurous, amine, and carboxylic groups. SEM/EDX results suggested the participation of an ion exchange mechanism and revealed a homogeneous deposition of metal ions on the biosorbent surface. The cost estimation showed that the employment of the dealginated residue is economically beneficial, similarly to bagasse fly ash, compared to commercial activated carbon.