Correlating metal ionic characteristics with biosorption capacity using QSAR model

The relationship between metal ionic characteristics and the maximum biosorption capacity (qmax) was established using QSAR model based on the classification of metal ions (soft, hard and borderline ions). Ten kinds of metal ions (Ag+, Cs+, Zn2+, Pb2+, Ni2+, Cu2+, Co2+, Sr2+, Cd2+, Cr3+) were selected and the waste biomass of Saccharomyces cerevisiae obtained from a local brewery was used as biosorbent. Eighteen parameters of physiochemical characteristics of metal ions were selected and correlated with qmax. Classification of metal ions could improve the QSAR models and different characteristics were significant in correlating with qmax, such as polarizing power Z2/r or the first hydrolysis constant |logKOH| or ionization potential IP. Xm2r seemed to be suitable for metal ions including soft ions, and Z2/r, |log KOH| and IP suitable for only soft ions or metal ions excluding soft ions. It provided a new way to predict the biosorptive capacity of metal ions.