Anatase nano tio2

Nano-TiO₂, an anatase-rutile mixture of nano-TiO₂ P25 (Degussa Company, Essen, Germany), anatase nano-TiO₂ (Sigma Company, St. Louis, MO, USA) and rutile nano-TiO₂ (Macklin, Shanghai, China) were obtained from commercial sources. UV light was generated by an ultraviolet lamp (ZF-5, 365 nm, 8 W, 0.6 mW/cm², Shanghai Huxi Instrument, Shanghai, China).
Fetal bovine serum (FBS), Dulbecco’s modified Eagle medium (DMEM), phosphate-buffered saline (PBS, pH 7.4), penicillin, streptomycin, and trypsin-EDTA were purchased from Gibco (Invitrogen, Carlsbad, CA, USA). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 2′,7′-dichlorofluorescin diacetate (DCFH-DA) were purchased from Sigma (St. Louis, MO, USA). Sambucus nigra lectin (SNA) labeled with fluoresceinIsothiocyanate (FITC) FITC and Maackia amurensis lectin I (MAL-I) were purchased from Vector labs (Burlingame, CA, USA).
Anhydrous dimethyl sulfoxide (DMSO) and vitamin C (VC) were purchased from Sigma Aldrich (St. Louis, MO, USA). ROSup was purchased from Beyotime (Shanghai, China).

Anatase nano-TiO₂ with a particle size of 25±10 nm and a specific area of 20–80 m²/g were acquired from Sigma-Aldrich Co. Nanoparticles were added into ultrapure water as the concentration of 1 g/L and treated with ultrasonic wave at 33 W for 30 min to scatter it equably. The stock solutions of tetracycline and erythromycin were also made with ultrapure water as the concentration of 1 g/L and then stored at 4 °C.
After attaining partial nitrification, three kinds of Nano-TiO₂, tetracycline and erythromycin stock solutions were added into influent respectively or together, to keep the initial doses as Table 1. These concentrations were selected in agreement with previous descriptions in wastewater influents [17 (link)].