| الوصف: |
This study investigated the degradation of 1,4-dioxane by the photoelectro-peroxone (PEP) process, which combines conventional ozonation, UV photolysis, and electrochemical hydrogen peroxide (H 2 O 2 ) generation to effectively produce hydroxyl radicals ( OH) for advanced oxidation wastewater treatment. Results show that the combination of ozonation, ultraviolet (UV), and electro-generation of H 2 O 2 could lead to significant synergistic effects that enhanced the pseudo-first order rate constant for 1,4-dioxane degradation to 33 times that of the simple linear addition of the three single processes. In addition, the PEP process could mineralize total organic carbon (TOC) from 1,4-dioxane solutions much faster than the three single processes, as well as their binary combinations (UV/O 3 and the electro-peroxone (EP) process). After 45 min of treatment, the UV/O 3 , EP, and PEP processes removed ∼70%, 37%, and 98% TOC with a specific energy consumption (SEC) of ∼0.38, 0.22, and 0.30 kW h/g TOC removed , respectively. Increasing ozone (O 3 ) dose, applied current, and solution pH increased generally the rate of TOC removal during the PEP process. When sodium chloride (NaCl) was used as the supporting electrolyte, chlorine (Cl 2 ) and hypochlorous acid/hypochlorite (HClO/ClO − , formed from anodic oxidation of Cl − ) would react with H 2 O 2 , thus diminishing its synergistic effects with O 3 and UV for pollutant degradation. Consequently, TOC removal was much less efficient when the PEP process was conducted in NaCl electrolytes than in sodium sulfate (Na 2 SO 4 ) electrolytes, especially when using anodes (ruthenium and iridium oxide coated titanium, RuO 2 -IrO 2 /Ti) with higher chlorine evolution activity. These results indicate that careful optimizations of the operational parameters are critical to maximize the synergistic effects of the PEP process for pollutant degradation. |
