A simple correlation to estimate the biosorption of zinc ions by algae

Contamination of water sources with the heavy metals such as zinc, copper, lead and cadmium is a serious environmental problem. Zinc ion has undesirable effects on plants and animals at concentrations higher than the threshold limit. Amongst traditional methods of heavy metals removal, the biological removal is considered as a low cost and environmentally friendly method. In this study, the removal of zinc ions from aqueous solutions by algae is estimated as a function of pH and the ratio of initial zinc ions to algae. Genetic programming is used to construct an empirical relation to correlate the removal of zinc ions to pH and the ratio of initial concentration of zinc ions to the concentration of algae. The experimental data used in this study, consists of 122 data, including the removal of zinc ions, pH and the concentrations of zinc ions and algae. About 70% of the data was used to calculate the empirical equation and the remaining 30% was used for verification of the equation. The average absolute relative deviation obtained for 122 data points is 4.08%, which verifies the accuracy of the correlation in the estimation of the removal of zinc ions from aqueous solutions.