Fixed bed biosorption of silver and investigation of functional groups on acidified biosorbent from algae biomass.

This work investigated the use of acidified dealginated residue from Sargassum filipendula algae for biosorption of silver in fixed bed column. This biosorbent was esterified for carboxyl and sulfonate groups to investigate the influence of these groups on silver removal percentage. Potentiometric titration was also evaluated on acidified and esterified biosorbents. Porosity and specific weight were determined by helium picnometry and mercury porosimetry techniques. The results showed that carboxyl and sulfonate groups were significant on silver biosorption. Potentiometric titration showed that esterified and acidified biosorbents presented different acid groups. The porosity of the acidified biosorbent was around 40%. Fixed bed assays were conducted to evaluate the influence of inlet concentration and feed flow rate of silver. Higher percentage removal of silver was obtained at 1.0 mmol · L-1 and 0.5 mL · min-1. Modified dose-response model obtained the best prediction of experimental data among breakthrough curve models.