To better simulate the dynamic natural water environment, the aggregation of TiO₂ nanoparticles was studied not by the widely applied static experimental method, but by a batch experiment conducted in a shaker.

Both ionic sodium dodecyl sulfate (SDS) and non-ionic nonylphenol ethoxylate (NPEO) surfactants can remarkably reduce the aggregation of nano-TiO₂ and stabilize the aggregate when the surfactant concentration exceeds 0.015% (w:v).

The aggregation and sedimentation of nano-TiO₂ are more remarkable in environmental aqueous matrices than in Milli-Q water, but surfactants are effective in reducing the aggregation and retarding the sedimentation of TiO₂.