Abstract
This study aims to explore the stability of TiO2 nanoparticles in soil suspensions and their transport behavior through real soil columns. A classical filtration theory was used to describe transport behaviors of TiO2 nanoparticles. The results illustrated that TiO2 nanoparticles could remain suspended in soil suspensions even after settling for 8 d. At comparatively higher dissolved organic matter (DOM) and low ionic strength (IS) containing soils, considerable portion of TiO2 nanoparticles (32–34%) suspensions was observed in sedimentation experiments after 24 h. In addition, zeta potential (ZP) of soil suspensions as a function of soil pH, suggested that ZP played significant role than soil pH. In soils containing comparatively higher DOM, a considerable portion of TiO2 nanoparticles (51.8–90.6%) readily passed through soils columns, while TiO2 nanoparticles were retained by soils with comparatively higher ISs. The estimated travel distances of TiO2 nanoparticles in soils ranged from 45.03 to 625.86 cm, representing potential environmental risk of TiO2 nanoparticles to the environment.
Acknowledgments
This work is supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under the 2216-International Researchers Fellowship Programmes. The authors would like to thank the anonymous reviewers for their valuable comments and suggestions to improve the quality of the paper.