On the biosorption kinetics of Pb~(2+) on yeast in different single and double-ion heavy metal systems

On the basis of covering technical literatures published in the recent 30 years on the biosorption of heavy metal ions, the given paper is to present our study results on the kinetics working mechanism of the biosorption of Pb~(2+)on the autoclaved baker's yeast in different single-ion and double-ion heavy metal systems. For our research purpose, we have chosen single-ion systems operating at different temperatures and initial concentrations of Pb~(2+) and double-ion systems of different initial concentrations of Cu~(2+)-Pb~(2+)and Ni~(2+)-Pb~(2+)as our case study samples. To make sure the working principle of the iron systems we are interested in, we have tested their biosorption effect by using the instruments known as AAS (atomic absorption spectra) . The results of our testing and measurement have shown that the baker s yeast is by nature a kind of quick and efficient biosorbent, which is expected to display its biosorptive capacity for Pb~(2+) in different kinetic processes in correspondence with the secondorder kinetic model. Within the range of experimental temperatures we have chosen from 10℃,20℃ to 30℃, it is found that with the increase of temperature, less time will be needed to get to equilibrium. On the contrary, under the condition of initial concentration of Pb~(2+) in the solutions of 0.5 mmol/L, 1.0 mmol/L and 2.0 mmol/L, it would take longer time to get to equilibrium state. Thus, kinetics biosorption theory for double ions systems tends to prove that the effect of Cu~(2+)and Ni~(2+) to the biosorption of Pb~(2+) is likely to be positively correlated with their initial concentration. The antagonism of Cu~(2+) to Pb~(2+) seems bigger than that of Ni~(2+) to Pb~(2+). The adsorption quantity of baker' s yeast to Pb~(2+) tends to get reduced to 72.5 % while the initial concentration coexistence Cu~(2+) is 4.0 mmol/L in the double ions system. The obvious effect on the bisoroption of Pb~(2+) by the concurrent ions in the double-ion system can thus be affirmed, though the complex mechanism remains to be further studied in the future.