Talaromyces pseudofuniculosus leaching-mineralization coupled process: enhanced Ca2+ extraction from wollastonite for CO2 sequestration

Microbial methods offer environmentally friendly, low-energy strategies for enhanced mineral CO 2 sequestration. Most studies focus on mineral leaching, and while coupling leaching with mineralization to achieve efficient carbon fixation remains limited. In this study, Talaromyces pseudofuniculosus . hzt-3′ was employed to promote wollastonite dissolution. Leaching conditions were optimized using single-factor experiments and response surface methodology (RSM), evaluating the effects of initial pH, inoculum size, pulp density, and temperature on Ca 2+ and Si 4+ leaching. Optimal parameters were initial pH 7.35, inoculum size 1.17 %, pulp density 0.4 %, and temperature 30 °C, achieving 88.79 % Ca 2+ and 12.61 % Si 4+ extraction. Residue analysis revealed reduced lattice spacing, more dispersed Ca 2+ distribution, and that fungal-secreted organic acids lowered solution pH and complexed with Ca 2+ , promoting dissolution; hyphal mechanical action disrupted the mineral lattice, enhancing reactivity. Carbonation of the leachate under alkaline conditions (40 °C, CO 2 flow rate 100 mL/min, stirring speed 500 rpm, NH 3 ·H 2 O concentration 1.2 mol/L) reached 97.29 % Ca 2+ mineralization efficiency within 5 min. Compared with the mineralization products obtained from CaCl 2 solution, the proportion of calcite increased and crystal morphologies became more diverse, indicating that crystal growth in the system was significantly regulated. Residual organic matter modulated Ca 2+ –CO2- 3 interactions and local ion migration, effectively reducing random nucleation, promoting calcite formation, and binding CaCO 3 particles to form thermodynamically more stable organic–inorganic composite aggregates. This work establishes a fungal-enhanced wollastonite leaching and indirect mineralization strategy for CO 2 sequestration, providing theoretical and experimental foundations for industrial low-energy, high-efficiency mineral carbonation.