Chlorine Dioxide Gas Generation System

The gaseous ClO₂ was obtained using a novel gaseous chlorine dioxide treatment system developed by our previous study, and the schematic of the ClO₂(g) treatment system is shown in Figure 1 [25 (link)]. Briefly, 0.4 mL of 20% NaClO₂ solution was injected in equal amounts into four absorbent pads (1 cm × 1 cm × 1 cm; CoSoFth Co., Jinjiang, China), which were affixed to the inside wall of a self-made treatment chamber (15 L). Then, CO₂ gas was generated using 5 ± 0.2 g of dry ice (BaiQuan Co., Fuzhou, China). The CO₂ gas was absorbed by the absorbent pads and dissolved in the solution to form H₂CO₃, which then reacted with NaClO₂ to produce ClO₂ gas. The equations for ClO₂ gas generation are as follows. The intensity of chlorine dioxide gas is calculated by the cumulative exposure of chlorine dioxide (mg·L⁻¹).
$${\mathrm{C}\mathrm{O}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\leftrightarrow {\mathrm{H}}_2{\mathrm{C}\mathrm{O}}_3$$
$$2{\mathrm{H}}_2{\mathrm{C}\mathrm{O}}_3+5{\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{N}\mathrm{a}}_2{\mathrm{C}\mathrm{O}}_3+4{\mathrm{C}\mathrm{l}\mathrm{O}}_2\left(\mathrm{g}\right)+\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$$