Novel chitosan-based ions imprinted bio-adsorbent for enhanced adsorption of gallium(III) in acidic solution

Abstract Ga (III) imprinted bio-adsorbent (Ga(III)-AA-CS) based on acrylic-functionalized chitosan had been synthesized and applied for selective adsorption of Ga(III) from aqueous medium containing a certain competitive metal ions. The chemical structure, adsorption mechanism, thermal stability of Ga(III)-AA-CS were characterized by SEM, FTIR and elemental analysis. The influence of various infactors, such as the optimum adsorption conditions, selectivity and regeneration ability, was evaluated through a series of experiments. The corresponding results showed that the data fitted the pseudo-second-order model. At the same time, the equilibrium isotherms of the Ga(III)-AA-CS were well described by Langmuir model and the maximum adsorption capacity reached 192.40 mg g−1 at pH 3. The adsorption mechanism of Ga(III) was the cations exchange between Ga(OH)2+, Ga(OH)2+ and protonated amino hydrogen ions (R-NH3+) on the cavities of the Ga(III)-AA-CS. Moreover, the prepared Ga(III)-AA-CS exhibited outstanding affinity toward the targeted Ga(III) even in the presence of other similar competitive ions. In addition, Ga(III)-AA-CS can maintain about 90.25% efficiency after recycling six times.