Modeling the transport of TiO2 nanoparticle aggregates in saturated and unsaturated granular media: Effects of ionic strength and pH

► Mobility of TiO2 NPAs was explored both in saturated and unsaturated conditions. ► Decreasing the water saturation did not enhance the retention of TiO2 NPAs in sand columns. ► The two-site kinetic attachment model provided a good description for the transport of TiO2 NPAs.