A kinetic model of ferrous iron oxidation by Acidithiobacillus ferrooxidans in a batch culture

Abstract

The batch oxidation kinetics of ferrous iron by Acidithiobacillus ferrooxidans were examined at different oxygen transfer rates and pH in an aerated stirred tank and a bubble column. The microbial growth, oxygen consumption rate and ferrous and ferric iron were monitored during the biooxidation. A kinetic model was established on the basis of the Michaelis-Menten kinetic equation for bacterial growth and the constants estimated from experimental data (maximum specific growth rate 0.069 h-1, saturation constant 2.9 g/dm3, and biomass yield coefficient based on ferrous iron 0.003 gd.w./gFe). Values calculated from the model agreed well with the experimental ones regardless of the bioreactor type and pH conditions.U radu je proucavana kinetika oksidacije gvozdje(II)-jona pomocu bakterije Acidithiobacillus ferrooxidans u bioreaktoru sa mesalicom i barbotaznoj koloni, a pod razlicitim uslovima aeracije i pH. U toku biooksidacije pracena je promena biomase, potrosnja kiseonika i promena koncentracije gvozdje(II)- i gvozdje(III)-jona. Na osnovu Michaelis-Menten-ove kineticke jednacine za mikrobni rast i konstanti izracunate na osnovu eksperimentalnih podataka (maksimalna specificna brzina mikrobnog rasta ?max = 0,069 h-1, saturaciona konstanta Ks = 2,9 g/dm3, koeficijent prinosa biomase u odnosu na supstrat Yx/s = 0,003 gd.w./gFe) razvijen je matematicki model. Vrednosti dobijene numerickom integracijom jednaci-na modela pokazuju dobro slaganje sa eksperimentalnim podacima (koeficijenti korelacije R = 0,990-0,999) sa eksperimentalnim podacima nezavisno od vrste koriscenog bioreaktora i pH.