Adsorption Behaviors Of Rhodotorula Sp. In The Bioleaching Process Of Acidithiobacillus Ferrooxidans

Excessive heavy metal ions in a bioleaching solution can negatively affect Acidithiobacillus ferrooxidans and consequently reduce the leaching rate. This work aims to verify the adsorption mechanisms of Rhodotorula sp. in collaborative bioleaching with A. ferrooxidans and Rhodotorula sp. and investigate the adsorption process with the competitive adsorption model. Experimental results indicate that collaborative bioleaching is more effective than bioleaching with A. ferrooxidans only. Results of Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX) characterization prove the adsorption ability of Rhodotorula sp. The calculation results of the adsorption experiment reveal that Cd does not participate in competitive adsorption among the heavy metals tested. The equilibrium adsorption concentration and the adsorption velocity constants of Cu, Mn, and Pb in competitive adsorption are lower than those in single-element biosorption. The adsorption capacities of Pb and Mn even decrease in later stages. The final competition coefficients of Cu, Mn, and Pb in the competitive adsorption of the three ions are 0.84, 0.14, and 0.02. Rhodotorula sp. can adsorb 67.4% Cd, 52.4% Cu, 1.0% Mn, and 8.6% Pb in the leaching solution, thereby increasing the bioleaching rate of A. ferrooxidans.