Effect of pine oil on the adhesion and biofilm formation of Acidianus manzaensis on chalcopyrite

Abstract

Pine oil, commonly used as a flotation frother, could affect the bioleaching process. The attachment and biofilm development of acidophiles on metal sulfides were essential for bioleaching. This study focused on the role of pine oil in the early adhesion and biofilm development by Acidianus manzaensis YN-25 on the chalcopyrite surface. It was revealed that pine oil had a negative effect on the adhesion amount of A. manzaensis on the chalcopyrite surface. After having reached adhesion equilibrium, the percentage of attached cells decreased as the concentration of pine oil increased. The addition of pine oil was found to decrease the negative charge of chalcopyrite and cells, resulting in a higher attraction of acid-base interaction energy and total interaction force. This ultimately led to a stronger adhesion force between chalcopyrite and A. manzaensis. While the addition of pine oil initially delayed the formation of cell microcolonies during the first stage of biofilm formation, which ultimately resulted in larger biofilm coverage compared with the control group. The microcolonies on the mineral surface were also larger and the corrosion pits were bigger with the addition of pine oil. Furthermore, the addition of pine oil weakened the passivation effect and promoted the biological dissolution of chalcopyrite. This study offers a better understanding of the effect of pine oil on the bioleaching of chalcopyrite.