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

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 source of 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 0.86 µg/L, with a crystal composition of 0.44 ± 0.1 µg/L amorphous, 0.14 ± 0.03 µg/L anatase and 0.28 ± 0.06 µg/L rutile. The removal performance of the TNP at a full-scale conventional drinking water treatment plant indicated that 58.8% of TNP was removed via coagulation/sediment, sand filtration and disinfection/clear water reservoir. The coagulation/sediment process accounted for approximately 76.6% of the total removed TNP. The finished water contained 0.33 µg/L TNP with a crystal composition of 0.24 ± 0.13 µg/L anatase and 0.09 ± 0.05 µg/L rutile. This study is the first that reported the presence and transport of TNP in a drinking water treatment system.

Efficient nitrate removal from water using an integrated photocatalyst-adsorbent based on chitosan-titanium dioxide nanocomposite

“…Titanium dioxide (TiO 2 ), a semiconductor material has got wide environmental applications, especially in the eld of water treatment for the removal of various pollutants such as organic dyes, heavy metals, harmful anions such as nitrates, phosphates, etc. due to its low toxicity, low cost, high physical/chemical stability and unique photocatalytic activity (Liu et al 2022). Photocatalytic property of titanium dioxide depends on the crystalline phase and surface area of the material and the wide band gap energy of 3.2 eV usually limits its application under UV light which demands band gap modi cation to enable its use under sunlight/visible light (Marcelino et al 2019).…”