<p>N-doped activated carbon (AC) was employed in a three-dimensional electrode system (3DES) to enhance the removal of sulfur-containing volatile organic compounds (S-VOC). The technical parameters for preparing N-doped AC were optimized based on CS<sub>2</sub> removal and COS accumulation, where the mass ratio of AC to urea was 1:1.0, and the activation temperature and heat-treatment time were 400 °C and 120 min, respectively. When the mixing S-VOC were purified under an operating voltage of 8 V and peroxydisulfate concentration of 0.15 mol/L, CS<sub>2</sub> removal in the 3DES system with N-doped AC reached 100% within 75 min, and was above 83% as purification time extended to 200 min. Additionally, the COS content in the outlet gas was usually undetectable within 120 min, and was lower than that in the other electrochemical systems. Modification of raw AC through urea impregnation and subsequent heat treatment significantly improved its surface structure and pore size distribution. Moreover, polar functional groups, such as C=O and pyridinic-N, increased noticeably, enhancing the S-VOC adsorption capacity and dielectric properties. Consequently, highly reactive substances were more efficiently activated in 3DES system with N-doped AC, and oxidizing species HO • and <sup>1</sup>O<sub>2</sub> had important contributions to S-VOC purification compared to SO<sub>4</sub><sup>−</sup>• radicals. A pathway was proposed to elucidate the transformation of sulfur-containing components, such as CH<sub>3</sub>SH and CS<sub>2</sub>. This study provides an efficient approach for S-VOC purification.</p>

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N-doped activated carbon promoting sulfur-containing VOC removal in three-dimension electrode system

  • Rui Luo,
  • Shugen Liu,
  • Senlin Tian,
  • Chen Li,
  • Ping Ning

摘要

N-doped activated carbon (AC) was employed in a three-dimensional electrode system (3DES) to enhance the removal of sulfur-containing volatile organic compounds (S-VOC). The technical parameters for preparing N-doped AC were optimized based on CS2 removal and COS accumulation, where the mass ratio of AC to urea was 1:1.0, and the activation temperature and heat-treatment time were 400 °C and 120 min, respectively. When the mixing S-VOC were purified under an operating voltage of 8 V and peroxydisulfate concentration of 0.15 mol/L, CS2 removal in the 3DES system with N-doped AC reached 100% within 75 min, and was above 83% as purification time extended to 200 min. Additionally, the COS content in the outlet gas was usually undetectable within 120 min, and was lower than that in the other electrochemical systems. Modification of raw AC through urea impregnation and subsequent heat treatment significantly improved its surface structure and pore size distribution. Moreover, polar functional groups, such as C=O and pyridinic-N, increased noticeably, enhancing the S-VOC adsorption capacity and dielectric properties. Consequently, highly reactive substances were more efficiently activated in 3DES system with N-doped AC, and oxidizing species HO • and 1O2 had important contributions to S-VOC purification compared to SO4• radicals. A pathway was proposed to elucidate the transformation of sulfur-containing components, such as CH3SH and CS2. This study provides an efficient approach for S-VOC purification.