Xiaohua Cai's research while affiliated with The Ohio State University and other places

Biosorption of aqueous Cd by Chlamydomonas reinhardtii was examined. Cd uptake increased from pH 2 to 10, and was measured at different initial Cd concentrations (0.09 – 8.75 mM). Proton affinity models of potentiometric titration data indicated the presence of two major functional group clusters on the cell walls, corresponding to ionic strength dependent pK a values in the ranges 3.8–4.7 and 8.3 – 9.6, with an average functional group acidity of approximately 2 mmol of protonable charge per g of lyophilized cells. Cd-binding was not significantly affected by the presence of equimolar (and greater) concentrations of aqueous macro-ions Ca 2 + and K + . FTIR spectra indicated that Cd-binding was dominated by complexation to carboxylic functional groups, and Cd sorption could be modeled with a single-site Gaussian distribution model. This study shows the potential for the use of C. reinhardtii for cadmium recovery in various water and wastewater treatment applications. © 2002 Elsevier Science B.V. All rights reserved.