Influence of natural soil colloid’s stability on transport of copper-based nanoparticles in saturated porous media

•Soil colloids influenced CuO retention, showing dominance over pore water chemistry.•Black and alluvial soil colloids were unstable resulted in high CuO retention.•CuO co-transport enhanced with stable red and lateritic soil colloids.•Flow velocity impacted CuO co-transport only in stable suspension systems.