Background: Rare earth elements, REEs, are used for many high-tech applications; the rarefaction
of the resource requires developing methods for their recovery from low-grade sources and their
recycling from waste materials. Sorption processes, including biosorbents, represent an interesting
method for their recovery from dilute effluents.
Objective: This work investigates the sorption of 3 REEs using a cheap, renewable biosorbents: microcrystalline
cellulose (considered as a reference material for on-going research on chemically modified
Methods: Sorption properties are studied considering the effect of pH, the uptake kinetics, the sorption
isotherms, the thermodynamic parameters, the recycling of the material and its reuse for successive
Results: Metal sorption increases with pH, uptake kinetics are relatively fast with an equilibrium
reached within 3-4 hours. The kinetic profiles are well fitted by the pseudo-second order rate equation.
Maximum sorption capacity reaches 31-53 mg metal g-1, and the Langmuir equation fits well sorption
isotherms. The reaction is endothermic and spontaneous. Metal ions can be readily desorbed with 0.5 M
HNO3 solutions and the sorbent can be recycled for at least 4 cycles of sorption/desorption with limited
decrease in performance (less than 3 %). FTIR and XRD analyses contribute to the characterization of
the material and the interpretation of sorption mechanism.
Conclusion: Microcrystalline cellulose has low sorption capacities for La(III), Nd(III), and Er(III);
however, this renewable resource with high effectiveness in terms of recycling and re-use is a promising
support for metal recovery.