A novel effect of combining microorganisms and graphene oxide for solidifying simulated nuclides strontium

Inspired by microbial diagenesis and mounding, microbial mineralization technology has been widely used in the treatment of heavy metal and radionuclide contamination. S. pasteurii can decompose urea as a source of energy to produce CO₃^2- in the microbial mineralization system. Therefore, strontium-contaminated radioactive wastewater can be effectively treated by combining CO₃^2- with surrounding strontium ions (Sr²⁺) to form strontium carbonate (SrCO₃). Herein, we investigated how the concentration of graphene oxide (GO) and mineralization time influence the morphology of SrCO₃ and the mineralization efficiency. GO was used as a crystal regulator to solidify the radionuclide strontium in the microbial mineralization system to obtain large-scale rock-like SrCO₃ minerals. The results showed that GO can adsorb the surrounding Sr²⁺ with oxygen-containing functional groups on its surface to form SrCO₃ complexes, directly influencing the morphology and consolidation percentage of SrCO₃. Considering the leaching behaviour of nuclides, we further studied the stability of consolidated SrCO₃ minerals. The results indicated that the presence of GO improved the stability of the mineralized samples obtained in the microbial mineralization system.