Jes fa200

Samples were prepared at room temperature by adding 4.0 mM H₂O₂, and 25.0 mM DMPO with different concentrations of ficin, and then adding a 20 mM PBS buffer (pH = 5.0) into a plastic tube. Subsequently the prepared sample solution was transferred to a quartz capillary tube and placed in the EPR cavity. Spectra were recorded afterwards. DMPO was used to trap the •OH radicals to form the DMPO/•OH spin adduct. The EPR spectra were obtained on a JESFA200 (JEOL, Japan) with a microwave bridge (modulation width, 0.2 mT; modulation amplitude, 2 Gauss; frequency power, 1 mW; modulation frequency, 100 kHz).

In a typical experiment, an LED lamp (30 W, 460 nm, Xujia Company, China) was employed as the light source.^{34 (link)} 0.1 g Cu–Bi₂WO₆ photocatalyst was added to 50 mL of NOF solution (15 mg L⁻¹). Before the light was turned on, the mixture was magnetically stirred in the dark for 60 min. Then, PMS was added to the system, and the LED light was turned on. The sample was taken out and filtered through 0.22 μm membrane filters, and the concentrations of NOF and TOC were measured by HPLC (Agilent 1100 LC/MSD, C18 column) and TOC (Elementar Vario) analyzers, respectively. Each sample was measured three times, and the average values are shown in the figures. Electron spin resonance (ESR, JES FA200, JEOL) was used to measure the intensity of the free radicals. The copper leaching measurements were performed using an ICP-MS (Agilent 7000). The intermediate products from the NOF degradation were identified using liquid chromatograph-mass spectrometry (LC-MS, Thermo Fisher, TSQ Endura). In the batch experiments, the degradation of NOF was fitted well using a pseudo-first-order kinetic model, which can be expressed as eqn (1). where C refers to the concentration of NOF at time t, C₀ refers to the initial NOF concentration, k_app refers to the kinetic rate constant, and t refers to the reaction time.

Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images were performed on a Hitachi S-4800 SEM and a JEOL 2100 TEM, respectively. HAADF-STEM images were collected on a JEOL ARM200F microscope with a STEM aberration corrector operated at 200 kV. The convergent semi angle and collection angle were 21.5 and 200 mrad, respectively. EELS spectra were collected using a Titan Themis Cubed G2 60-300 operated at 200 kV. EPR measurements were carried out on a JEOL JES-FA200. The inductively coupled plasma mass spectrometry (ICP-MS) measurements were performed on an Agilent 7700x. X-ray diffraction (XRD) characterization was carried out on a Bruker D8 Advance diffractometer with Cu Kα radiation. The X-ray absorption fine structure spectra of Ru K-edge were performed at 4B9A beamline in Beijing Synchrotron Radiation Facility (BSRF). The storage rings of BSRF was operated at 2.5 GeV with a stable current of 400 mA. The OER Faradaic efficiency of RuO₂/CoO_x was measured by a gas chromatograph (GC-2014, Shimadzu, Japan) equipped with a thermal conductivity cell detector.

4,4’,4”-nitrilotribenzoic acid (H₃TCA) and other reagents were purchased from Sinopharm Chemical Reagent Co., Ltd. in analytical grade. Powder X-ray diffraction data (PXRD) were performed by a Rigaku MiniFlex600 (40 kV, 15 mA) with a graphite-monochromatized Cu Kα radiation. Electron paramagnetic resonance (EPR) was conducted on a spectrometer (JEOL, JES FA-200). The data was collected with microwave field power of 0.7 mW. The modulation frequency was 100 kGHz and the microwave frequency was 9.7 GHz. Thermogravimetric analysis (TGA) was conducted on an SDT Q600 analyzer with a heating rate of 10 °C/min under N₂ (100 mL/min) atmosphere. ¹H NMR spectra was conducted in DMSO-d6 solution by JNM-ECZ400S (400 MHz) spectrometer.

Membrane morphology was observed through SEM (Zeiss Merlin Compact, Germany) and TEM (JEM-2100F, Japan). Elemental distribution and chemical composition of the membrane were determined through TEM mapping and XPS (ESCALAB 250Xi, Thermo Scientific, England), respectively. Membrane crystal structure was investigated with XRD (D8/Aduance, Bruker, Germany). Membrane molecular structure was evaluated with a Raman spectrometer (LabRAM HR Evolution, Horiba Co., Ltd., France) at 532 nm. An X-band ESR spectrometer (JES-FA200, JEOL, Japan) was employed to reveal the defective structures. The peak-to-peak width of the singlet in the obtained ESR spectra was recorded as ΔH_pp (mT). Membrane conductivity was assessed with a four-probe tester (280SJ, Four Dimensions, USA).