450 gc 320 ms

IR was carried out on an EQUINOX 55 spectrometer in the range from 4,000 to 400 cm^–1. The solid samples were grounded with dried KBr powder and compressed into a disk prior to analysis. ¹H NMR and ¹³C NMR spectra were acquired on a Unity Inova 600 at 50°C using DMSO‐d6 as solvent and tetramethylsilane as internal standard. The quantitative analysis of the reaction product was performed on a LC‐100 PLUS HPLC equipped with reversed‐phase Novapak‐C18‐100 silica column (4.6 × 150 mm, 4 μm) and UV detector. The mixture of acetonitrile: 1 wt% phosphoric acid solution (12:88, V/V) was employed as mobile phase at the flow rate of 1.2 ml/min with column temperature at 32°C. The product was also qualitatively analysis by LC‐HRMS and GC‐MS. LC‐HRMS was performed on a UFLC‐20A high‐performance liquid chromatography (Shimadzu) and AB SciexTripleTOF 5,600 mass spectrometer equipped with an Agilent XDB‐C18 (2.1 × 100 mm, 3.5 μm). GC‐MS was performed on a Varian 450 GC‐320 MS equipped with a VF‐5 MS capillary column (30 m × 0.32 mm × 0.25 μm).

The typical catalytic ozonation of DCAA is similar to our previous work33 (link). In details, the mixture of ozone and oxygen was bubbled into a 500 mL glass conical flask containing 200 mL of DCAA aqueous solution (100 mg L⁻¹) with 10 mg of the as-prepared catalyst at room temperature under magnetic stirring. The flowing rate of O₃ was 100 cm³ min⁻¹ (4.47 mmol min⁻¹). The initial pH of the catalytic system was adjusted by NaOH (0.05 mol L⁻¹) or HCl (0.05 mol L⁻¹). The initial concentration of DCAA was detected after adsorption equilibrium with the catalyst. In specified reaction intervals, 0.5 mL of DCAA solution was taken out from the conical flask during the reaction process. The taken solution was filtrated and then 0.1 mg of sodium thiosulfate and 0.1 mg of sodium sulphite were added to remove the residual O₃. The concentration of residual DCAA and intermediates produced in ozonation were analyzed by a gas chromatography-mass spectrometry (Varian450GC-320MS) equipped with an electron ionization detector and HP-5 columns (0.25 μm, 30 × 0.25 mm) chosen selected ion monitoring (SIM) mode. Tentative identification of reaction products was achieved by comparing the authentic standards based on their retention times and mass spectra. The pH_PZC of FMOG was determined by the solid addition method.