Wu Donghai, Lu Guanghua, Zhang Ran, Lin Qiuhong, Yan Zhenhua, Liu Jianchao, Li Yi
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, P.O. Box 2606, 202 Haihe Road, Harbin, 150090, China.
Environ Sci Pollut Res Int. 2015 Oct;22(20):15812-20. doi: 10.1007/s11356-015-4783-1. Epub 2015 Jun 4.
Combination of ozone together with electrolysis (ozone-electrolysis) is a promising wastewater treatment technology. This work investigated the potential use of carbon nanotube (CNT)-based gas diffusion cathode (GDC) for ozone-electrolysis process employing hydroxyl radicals (·OH) production as an indicator. Compared with conventional active carbon (AC)-polytetrafluoroethylene (PTFE) and carbon black (CB)-PTFE cathodes, the production of ·OH in the coupled process was improved using CNTs-PTFE GDC. Appropriate addition of acetylene black (AB) and pore-forming agent Na2SO4 could enhance the efficiency of CNTs-PTFE GDC. The optimum GDC composition was obtained by response surface methodology (RSM) analysis and was determined as CNTs 31.2 wt%, PTFE 60.6 wt%, AB 3.5 wt%, and Na2SO4 4.7 wt%. Moreover, the optimized CNT-based GDC exhibited much more effective than traditional Ti and graphite cathodes in Acid Orange 7 (AO7) mineralization and possessed the desirable stability without performance decay after ten times reaction. The comparison tests revealed that peroxone reaction was the main pathway of ·OH production in the present system, and cathodic reduction of ozone could significantly promote ·OH generation. These results suggested that application of CNT-based GDC offers considerable advantages in ozone-electrolysis of organic wastewater.
臭氧与电解相结合（臭氧 - 电解）是一种很有前景的废水处理技术。本研究以羟基自由基（·OH）的产生为指标，考察了基于碳纳米管（CNT）的气体扩散阴极（GDC）在臭氧 - 电解过程中的潜在应用。与传统的活性炭（AC） - 聚四氟乙烯（PTFE）和炭黑（CB） - PTFE阴极相比，使用CNTs - PTFE GDC提高了耦合过程中·OH的产生量。适当添加乙炔黑（AB）和成孔剂Na2SO4可以提高CNTs - PTFE GDC的效率。通过响应面法（RSM）分析获得了最佳的GDC组成，确定为CNTs 31.2 wt%、PTFE 60.6 wt%、AB 3.5 wt%和Na2SO4 4.7 wt%。此外，优化后的基于CNT的GDC在酸性橙7（AO7）矿化方面比传统的钛和石墨阴极更有效，并且具有良好的稳定性，经过十次反应后性能没有衰减。对比试验表明，过氧反应是本系统中·OH产生的主要途径，阴极臭氧还原可显著促进·OH的生成。这些结果表明，基于CNT的GDC在有机废水的臭氧 - 电解中具有相当大的优势。
