This study aims to investigate the retention and transport of Cu2+ in saturated porous media under varying ionic strength (IS) conditions, taking into account the presence of biofilms and magnetic nanoparticles (MNPs). The findings reveal that the presence of biofilm promotes Cu2+ retention in the medium, whereas an increase in IS results in ion competitive adsorption, leading to enhanced Cu2+ transport. Furthermore, MNPs serve as carriers for Cu2+ transport while competing with it for adsorption sites. Results indicate that ion competitive adsorption dominates Cu2+ transport with increasing IS in quartz sand; however, agglomerative deposition of MNPs inhibits Cu2+ transport. These conclusions are supported by characterization tests and modeling analyses. This study contributes to a better understanding of environmental risks associated with heavy metals in complex systems involving biofilms and MNPs. Additionally, there is a need to further explore the role of natural organic/inorganic colloids and engineered nanomaterials in soil environments when interacting with microbial biofilms.
