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Adsorption Properties toward Trivalent Rare Earths by Alginate Beads Doping with Silica

Wang, Fuchun, Zhao, Junmei, Pan, Feng, Zhou, Huacong, Yang, Xingfu, Li, Wensong, Liu, Huizhou
Industrial & Engineering Chemistry Research 2013 v.52 no.9 pp. 3453-3461
adsorbents, adsorption, alginates, engineering, pH, rare earth elements, silica, strength (mechanics)
Novel alginate hybrid beads were prepared by doping with silica (abbreviated as ALG/SiO₂), and their adsorption behavior toward rare earths(III) had been investigated. For the whole lanthanides, it exhibits a distinct “tetrad effect” with increasing atomic number. Taking Nd as an example, the effects of the pH, adsorption kinetics, isotherms, and regeneration of adsorbents had been studied systematically. Doped SiO₂ can enhance the mechanical strength of the beads, and the hybrid adsorbents show no observable swelling during the adsorption process. It is interesting to note that Ndᴵᴵᴵ adsorption can be improved about 0.1 mmol/g after the first cycle and shows no apparent decline until the 12th cycle. Finally, it can be concluded that ALG/SiO₂ is superior to the other hybrid alginate adsorbents for the adsorption of rare earths.