Figures (4)  Tables (0)

    • Figure 1. 

      (a) Transmission electron microscope (TEM) images, (b) high-angle annular dark-field (HAADF) images, and the corresponding EDS-mapping images of Fe/C-250V composite catalyst. (c) X-ray diffraction spectra, (d) Fe 2p X-ray photoelectron spectroscopy spectra, and (e) Raman spectra of the Fe/C-250V composite catalyst.

    • Figure 2. 

      (a) Sulfamethoxazole (SMX) removal performance of Fe/C-250V composite catalyst and carbon substrate (Note: carbon substrate represents individual biochar treated by C-FJH at 250 V). (b) SMX removal performance and (c) cumulative concentrations of hydroxyl radicals (•OH) in various systems with Fe/C-250V composite catalyst. (d) SMX removal performance of Fe/C catalysts fabricated by FJH treatment with different initial voltage. (Reaction conditions: SMX = 10 mg/L, Fe/C catalysts or carbon substrate = 1.0 g/L, pH = 7, temperature = 298 K).

    • Figure 3. 

      (a) Effect of initial SMX concentration on the performance of Fe/C-250V composite catalyst for SMX removal (Reaction conditions: SMX = 1−50 mg/L, Fe/C-250V catalyst = 1.0 g/L, pH = 7, temperature = 298 K). (b) Effect of pH on the performance of Fe/C-250V composite catalyst for SMX removal (Reaction conditions: SMX = 10 mg/L, Fe/C-250V catalyst = 1.0 g/L, pH = 3−9, temperature = 298 K). (c) Effect of different dosages of Fe/C-250V composite catalyst on SMX removal efficiency (Reaction conditions: SMX = 10 mg/L, Fe/C-250V catalyst = 0.25−1.50 g/L, pH = 7, temperature = 298 K). (d) Comparison of cumulative •OH/Fe with other previous reported materials in the literature. More details can be found in Supplementary Table S1. (e) SMX removal performance and (f) Cumulative •OH generation kinetics of Fe/C-250V composite catalyst in aqueous solutions containing cinnamon soil (Reaction conditions: SMX = 20 mg/L, Fe/C-250V composite catalyst or carbon substrate = 1.0 g/L, cinnamon soil = 100 g/L, pH = 7, temperature = 298 K).

    • Figure 4. 

      Electron paramagnetic resonance (EPR) spectra recorded for the reactive oxygen species (a) O2•−, (b) •OH, and (c) 1O2 from the reaction of Fe/C-250V composite catalyst with oxygen. Cumulative concentrations of ·OH produced by Fe/C-250V composite catalyst after the addition of (d) 1,000 U/mL CAT and (e) 120 U/mL SOD. (f) Cumulative concentrations of •OH after the addition of different concentration of H2O2. (g) Evolution of dissolved Fe species. (h) The line fit of •OH concentration and total dissolved Fe. (i) The line fit of •OH concentration and SMX removal (Reaction conditions: SMX = 10 mg/L, Fe/C-250V catalyst = 1.0 g/L, pH = 7, temperature = 298 K).