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Protonated form (Hy) of yeast was subjected to thermal analysis (TGA and DTG) in the temperature range 60-800 degrees C. Chemically bound water volatilizes around 200 degrees C and the matrix undergoes extensive oxidative decomposition at 450 degrees C, the weight loss reaching 75% at 800 degrees C. The sorption capacity of the matrix for nickel(II) ion increases on heat treatment from 60 to 200 degrees C (from 16.9 to 25.0 mg/g), but was reduced on heating to higher temperatures at an initial nickel(II) ion concentration of 1200 mg/g. The FTIR spectra of Hy and nickel(II) ion saturated yeast, indicated that biosorption occurs on the sugar and nucleic acid regions, possibly involving --COOH and --NH groups.
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