Occurrence of titanium dioxide nanoparticle in Taihu Lake (China) and its removal at a full-scale drinking water treatment plant.

Zhiyuan Liu,Min Rui,Shuili Yu

doi:10.1007/s11356-021-15775-5

Abstract

The occurrence of titanium dioxide nanoparticle (TNP), an emerging contaminant, in Taihu Lake of China was investigated. Ti was present at a concentration of 224 ± 59 μg/L in the water samples collected from a water source in east Taihu Lake. Approximately 0.19% of the Ti-containing matter was at the nano-scale. Scanning Electron Microscope analysis verified the existence of Ti-containing components, such as TiOx and FeTiOx. Furthermore, Ti K-edge X-ray absorption near-edge structure spectroscopy was used to detect the phase composition of nano-scaled Ti-containing matter. The spectra showed the three characteristic peaks of TiO2 in the samples, suggesting the occurrence of TNP in Taihu Lake. A least-squares linear combination fitting analysis indicated that the TNP concentration in the water source was ~0.77 μg/L in water and ~0.85 μg/g-dry in sediment. The removal performance of the TNP at a full-scale conventional drinking water treatment plant indicated that ~61% of TNP was removed via coagulation/sediment, sand filtration, and disinfection/clear water reservoir. The coagulation/sediment process accounted for approximately 70% of the total removed TNP. The finished water contained ~ 0.30 μg/L TNP. This study is the first that reported the presence and transport of TNP in a full-scale drinking water treatment system.

Highlights

Engineered nanoparticles (ENPs) represent an important class of emerging contaminants due to their release into the environment (Gottschalk et al 2015; Kiser et al 2009; Mueller and Nowack 2008)
A similar exposure pathway of Titanium dioxide nanoparticle (TNP) was proposed in previous studies (Gottschalk et al 2015; Gottschalk et al 2009; Mueller and Nowack 2008), which implied the presence of TNP in the lake along with sewage and agricultural runoff
A comprehensive and systematic survey was performed to evaluate the occurrence of TNP in the water source of east Taihu Lake (China) and its removal performance at a conventional full-scale drinking water treatment plant

Summary

Introduction

Engineered nanoparticles (ENPs) represent an important class of emerging contaminants due to their release into the environment (Gottschalk et al 2015; Kiser et al 2009; Mueller and Nowack 2008). Most of the environmental risk assessments of ENPs report that TNP is one of the highest risk ENPs in the aqueous environment based on their toxicology data and the predicted environmentally relevant concentration (Gottschalk et al 2015; Gottschalk et al 2009; Mueller and Nowack 2008). Taihu Lake is located in the core area of the Yangtze River delta in China. It is one of the most important water sources of the ambient cities, including Shanghai, Suzhou, Nanjing and Wuxi. The status quo concentration of TNP in Taihu Lake remains unknown

Methods

Results

Conclusion