Effect of organic surfactant TRITON CG-110 on bioleaching of chalcopyrite

• CG-110 promoted ferric ion regeneration kinetics and maintained higher oxidative redox potential during bio-oxidation. • Adding 20 ppm of CG-110 enhanced chalcopyrite dissolution with mesophilic bacteria. • CG-110 modified surface wettability, improving ferric interaction and increasing electrochemical activity at high potentials. • XPS analysis revealed enhanced sulfur oxidation in the presence of surfactant. • The combination of CG-110 improved copper leaching by enhancing wettability and surface accessibility. Chalcopyrite leaching in acidic solutions is often hindered by slow kinetics due to surface passivation, which reduces copper leaching efficiency. This study explored the effects of Triton CG-110, a non-ionic surfactant, on chalcopyrite bioleaching facilitated by mesophilic acidophilic bacteria. Bio-oxidation experiments demonstrated that bacterial metabolism was enhanced with the addition of CG-110; at a concentration of 20 ppm, the oxidation of Fe 2+ to Fe 3+ was accelerated, indicating improved bacterial activity. However, at concentrations exceeding 500 ppm, CG-110 inhibited bacterial metabolism, highlighting the importance of optimizing surfactant dosage to maximize chalcopyrite dissolution. The addition of 20 ppm CG-110 enhanced leaching efficiency by altering the surface wetting properties, which increased the interaction between ferric ions and the chalcopyrite surface, thereby improving the copper leaching rate. This surfactant also reduced the impact of surface passivation by promoting greater contact between ferric ions and the mineral surface, facilitating copper dissolution. Electrochemical analysis revealed that CG-110 improved charge transfer at higher potentials without participating in chemical oxidation, thus enhancing anodic activity. Surface analysis using X-ray photoelectron spectroscopy (XPS) showed a decrease in elemental sulfur accumulation—a key contributor to passivation—on the chalcopyrite surface in the presence of CG-110. Additionally, 16S rRNA sequencing showed that CG-110 influenced microbial community shifts, increasing the relative abundance of bacteria associated with enhanced sulfate formation and reduced elemental sulfur accumulation, favoring bioleaching conditions.