Su 70

The surface of all samples was examined using a field emission scanning electron microscope (FE-SEM) Hitachi SU-70 (Hitachi, Naka, Japan) with an X-ray microanalysis UltraDry EDS detector (acceleration voltage 15 kV) and a Magnaray WDS detector, Thermo Scientific Noran System 7 (Madison, WI, USA). The WDS analysis was performed at an accelerating voltage of 10 kV and an electron beam current of approximately 20 nA using CrSc80, NiC80, and TAP diffracting crystals for nitrogen, carbon, and oxygen, respectively. The WDS quantitative analytical procedures were based on the following standards: Cr₂N, WC, and Cr₂O₃ for nitrogen, carbon, and oxygen, respectively. The “PROZA” correction method was applied for WDS quantitative analysis and the estimated standard uncertainty for the WDS measurements was 0.1 at.% X-ray diffraction (XRD) phase analysis was performed using CuKα, using X-ray tube parameters of 35 kV and 45 mA and a Bragg–Brentano geometry (X’Pert–PRO, Panalytical, Almelo, The Netherlands). The applied step of the goniometer was 0.05, and the acquisition time was 200 s. The acquired data were processed using X’Pert HighScore (v. 2.2.1) software provided by Panalytical.

The silicon wafers were coated by drop casting a thin film of WDWs onto the surface. Cells were cultured on the wafers under standard culturing conditions for 24 hr. The wafers where than rinsed with PBS and placed in 4% PFA for 30 min at 37°C. They were than rinsed with PBS and immersed in 0.5% Osmium tetroxide (Sigma- ReagentPlus) in PBS for 1 hr at room temperature. A dehydration step followed by submersing the sample in (20%, 50%, 75%, 90%, 100%) of ethanol and PBS for 20 minutes at room temperature. Next, samples where immersed in HDMS (Sigma- Corning) for 3 min before gently blotting and storing in a desiccator. Samples were coated with a thin film of gold using a sputter Emitech K550 at 20 mA for 10 sec before viewing on the SEM Hitachi SU-70 at 3 KV.

The surface morphology was assessed using a scanning electron microscope (SEM), the Hitachi SU-70 (Hitachi, Tokyo, Japan). Two sets of each HCSC, containing 3 cylindrical 10 × 1 mm specimens per set, were prepared as described in Table 1 and stored in gelatinized HBSS for 24 h (1st set) and 28 days (2nd set). After the specified time period, the specimens were dried in a vacuum desiccator without coating, attached to an aluminum stub and examined under SEM at ×4.0k and ×10.0k magnifications.

The pH and conductivity of the water samples were recorded on 96pH-L2 (Samsan Korea Ltd., Yongin, Korea) and EC96 (M-Cubic Co., Ltd., Daejeon, Korea), respectively. The concentration of anions was determined using Thermo Scientific™ Dionex™ ICS-5000, and the cationic concentration was analyzed on Thermo Scientific™ Dionex™ ICS-1000. The characterization of virgin and fouled membranes was conducted by X-ray diffractometer (XRD, Rigaku Corp., Tokyo, Japan) and Scanning Electron Microscopy (SEM, Hitachi SU-70, Hitachi Ltd., Tokyo, Japan) coupled with Energy Dispersive Spectroscopy (EDS).

Infrared (IR) spectra were acquired using a PerkinElmer Spectrum One B FT-IR spectrometer, in the range of 500 to 4000 cm⁻¹ at a resolution of 4 cm⁻¹ with KBr pellet technique. UV-visible spectra were recorded on a Perkin Elmer Lambda 25 UV/Vis spectrometer. Thermal analyses were carried out under the nitrogen atmosphere with a flow rate of 50 mL/min using a Shimadzu TGA-50 instrument at a heating rate of 10 °C/min. The field emission scanning electron microscope (FE-SEM) used in this work was a Hitachi SU-70 (Hitachi Ltd., Tokyo, Japan), and measurements were conducted using an acceleration voltage of 20 or 30 kV and a working distance of 10 mm. Spin-coating was performed using an ACE-200 spin coater (Dong Ah Trade Corp, Seoul, Korea). Current-voltage (I-V) characteristics were measured using a Keithley 2634 sourcemeter under ambient air and temperature conditions. The voltage was applied to the top electrode while the bottom electrode was grounded, and measurements were conducted utilizing a tungsten tip.