Tio2 nps

Al₂O₃ NPs, TiO₂ NPs, SiO₂ NPs, MWCNTs, BCs, and GOs were purchased from XFNANO Materials Tech Co., Ltd. (Nanjing, China), and graphenes were provided by Strem Chemicals, Inc (Newburyport, MA, USA). FeOx NPs were synthesized using iron (III) chloride hexahydrate (FeCl₃·6H₂O) according to a mechanochemical method with a few modifications (three times KCl addition) [14 (link)]. The urban particulate matter sample (SRM 1648a), obtained from the National Institute of Standards and Technology (NIST), was used as a standard for comparative toxicity evaluation between PM and NPs.
All particles were subjected to the same procedure for characterization. After dispersion in the culture medium by ultrasonication (5 min), number-weighted hydrodynamic diameters and zeta potentials were characterized by dynamic light scattering (DLS, Brookhaven NanoBrook 90Plus PALS, Holtsville, NY, USA) and zeta potential analyzer (Malvern, Zetasizer Nano ZS90, Worcestershire, UK), respectively. The shape, size, and agglomeration status of NP/PM samples were then determined using a field emission scanning electron microscope (FESEM, Hitachi SU8220, Tokyo, Japan).

The soil was sampled from a paddy field (0–30 cm) in Huizhou, Guangdong, South China (114°49′, 23°01′). Soil samples were air dried and passed through a 2 mm sieve. The content of soil organic matter was determined using a Multi N/C Total Organic Carbon Analyzer (Carl Zeiss, Jena, Germany). The cation exchange capacity was determined according to the ammonium acetate method. The content of organic matter was 2.45%, and the cation exchange capacity was 8.5 cmol kg⁻¹(Supporting Information (S1) Table S1).
TiO₂ NPs (Nanjing XFNANO Materials Tech Co., Ltd) properties were measured in our laboratory and reported in a previous study (Supporting Information (S1) Figure S1) [20 ]. The diameter size of TiO₂ NPs ranges between 20–40 nm; the specific surface area is 77.4 m² g⁻¹.

The metal oxide nanoparticles (TiO₂-NPs, ZnO-NPs and CuO-NPs) used in this research were purchased from Nanjing XFNANO Materials Tech Co., Ltd, (Nanjing, China), and the purity of the nanomaterials is above 99.9%. The characterizations of nanoparticles were performed in the Key laboratory of nano-micro materials, Peking University Shenzhen Graduate School. The size of the metal oxidize nanoparticles was detected by a field emission scanning electron microscope (ZEISS SUPRA^® 55, Carl Zeiss, Jena, Germany), and the specific surface area was detected by an Accelerated Surface Area and Porosimetry System (ASAP 2020 HD88, Micromeritics, Atlanta, GA, USA). The diameter size of these MNPs in the range of 20–40 nm. The specific surface areas of the TiO₂-NPs, ZnO-NPs and CuO-NPs were 77.4 m²·g⁻¹, 21.5 m²·g⁻¹ and 131 m²·g⁻¹, respectively.