Abstract

The removal of metal ions from effluents is of importance to many countries of the world both environmentally and for water re-use. A comparison was made of the linear least-squares method of the widely used pseudo-second order kinetic model for the sorption of some divalent metal ions onto Sida acuta leaves. Four pseudo-second order kinetic linear equations were used for this study. The results obtained from the experimental data for S. acuta leaves of 1.0 g with particle size range of 0.25 to 0.5 mm and at 300 rpm with initial concentrations of 5.0, 4.0, 20 and 2.5 mg/dm³ for Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ ions, respectively showed that when the four pseudo-second order kinetic linear equations were compared, the Type 2 model with regression values for Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ ions as 0.979, 0.995, 0.991 and 0.965 respectively showed best fit for the sorption onto S. acutaleaves. This provided the evidence that the divalent metal ions sorption unto S. acutafollowed the pseudo-second – order kinetic expression.

Key words: Sida acuta, sorption, divalent metal ions, kinetic model, effluents .