Biosorption of lanthanum using sericin/alginate/polyvinyl alcohol beads as a natural cation exchanger in a continuous fixed-bed column system

Over the last years, the recovery of lanthanum from secondary sources have received high interest because of their importance in many industrial applications. In this study, we investigated the continuous biosorption of lanthanum in fixed-bed column system using sericin/alginate/polyvinyl alcohol-based beads. Effects of lanthanum solution flow rate, lanthanum inlet concentration, and regeneration cycles were investigated. At the flow rate of 30.0 mL/h and inlet concentration of 69.10 mg/L, the lowest mass transfer zone (4.00 cm) and highest amount of lanthanum biosorption at saturation (98.60 mg/g) were found. Over the four biosorption cycles, around 7000 mL of lanthanum solution with a removal efficiency at breakthrough of practically 100% were treated. Lanthanum desorption was successful with over 95% of the recovery in four regeneration cycles. Additionally, the breakthrough curves were well described by dual site diffusion phenomenological model. These results demonstrate that the sericin/alginate/polyvinyl alcohol-based beads are an effective biosorbent for the continuous recovery of lanthanum, paving the way for a separation system of rare-earths based on waste biomass.