Abstract

IPARRAGUIRRE, Ernesto et al. Biosorption of gold (III) by means quaternary chitosan and cross-linkage quaternary chitosan. Rev. Soc. Quím. Perú [online]. 2010, vol.76, n.4, pp.355-365. ISSN 1810-634X.

The adsorption of gold (III) by means of quaternary chitosan with different treatments was investigated as: a function of initial pH, adsorbent mass, ionic strength, initial metal concentration, and adsorption kinetics. Batch equilibrium and kinetics experiments were performed at room temperature. Four types of adsorbents were produced: powder quaternary chitosan (QC1), powder cross-linked quaternary chitosan (QC2), gel beads of quaternary chitosan (QC3) and gel beads of cross-linked quaternary chitosan (QC4). The maximum adsorption capacity followed the trend: QC2>QC1>QC4>QC3 with values of 500, 333, 111, and 13 mgAu/g of adsorbent, respectively; according the adsorption isotherms of Langmuir, Dubinin-Radushkevich, and Freundlich. The optimized pH parameters were of 4 for QC1 and QC2, whereas a pH value of 3 was observed for QC3 and QC4. The adsorbent dose and ionic strength had a negative effect on the adsorption. The adsorption kinetics was fitted to the pseudo-second order model and achieved the equilibrium within 3h for QC1 and QC2 whereas it took 8h for QC3 and QC4, due to intraparticular diffusion. The results indicate that these adsorbents are effective candidates for the removal of gold (III) ions from aqueous solutions.

Keywords : Quaternary chitosan; cross-linkage quaternary chitosan; gold (III) ion; adsorption; adsorption isotherm; pH.

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