Development of a natural polymeric bioadsorbent based on sericin, alginate and poly(vinyl alcohol) for the recovery of ytterbium from aqueous solutions

Abstract

The recovery of rare-earth elements (REEs) from wastewater is extremely important because of its different industrial applications and high market prices. The recovery of these metals in secondary sources is of high environmental and economic interest, by reusing resources already extracted in a new production cycle. Bioadsorption is an alternative technology with high potential for the treatment of wastewater. This research aimed to investigated the use of sericin/alginate particles crosslinked with poly(vinyl alcohol) (SAPVA) for batch bioadsorption of ytterbium. Kinetic study was carried in three ytterbium initial concentrations (0.0005, 0.0011, and 0.0015 mol/L). Kinetic equilibrium time was reached after ∼300 min. The kinetics modeling of the experimental data revealed that the ytterbium bioadsorption was described by pseudo first-order and external diffusion. Ytterbium desorption was evaluated using several eluents. Among these eluents, nitric acid at a concentration of 0.3 mol/L showed the highest recovery efficiency. Alternatively, bioadsorption kinetics with the regenerated particles showed an equilibrium time of 120 min with the complete release of calcium. The characterization of SAPVA particles before and after bioadsorption process suggested that the ytterbium ions uptake and calcium release involve ion exchange mechanism between carboxyl and hydroxyl groups and ytterbium. The use of SAPVA particles showed great potential for recovery of ytterbium from wastewater.