Copper-Ion Adsorption and Gold-Ion Reduction by Polyphenols Prepared by the Enzymatic Reaction of Horseradish Peroxidase

Polyphenols were synthesized via a horseradish peroxidase reaction from phenol, catechol, and pyrogallol for use as copper-ion adsorbents. The molecular weights of the polyphenols ranged from about 1000 to 3000 g/mol. The hydroxyl group contents in the polyphenols from phenol, catechol, and pyrogallol were 5.9, 4.0, and 0.94 mol/kg, respectively, as determined by titration. The saturation binding capacity for copper ions of the polyphenols from phenol, catechol, and pyrogallol were calculated to be 1.44, 0.88, and 0.22 mol/kg, respectively, at pH 4.5. Copper ions were efficiently adsorbed via an ion-exchange interaction by the synthesized polyphenols with vicinal hydroxyl groups, and those polyphenols could be applied to metal adsorption. Gold ions were selectively reduced by the phenol group in polypyrogallol in acid media to form gold particles. The reduced gold particles were eluted with a solution of 1.0M thiourea plus 0.5M HCl. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 247-252, 2010