Xu Peng, Wang Lei, Liu Xin, Xie Shiqi, Hou Baolin
Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China.
Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China.
Chemosphere. 2023 Jun;326:138481. doi: 10.1016/j.chemosphere.2023.138481. Epub 2023 Mar 21.
The conventional zero-valent iron/peracetic acid (ZVI/PAA) system is severely limited owing to the passivation of ZVI and the low recovery of Fe. In this study, a reducing agent, vitamin C (HA), was used for the first time to enhance the ZVI/PAA system as a way to improve its degradation performance. Under optimal conditions, the removal efficiency of the HA/ZVI/PAA system was 82.9%, while that of the HA/PAA and ZVI/PAA systems were only 19.0% and 25.6%. Free radical quenching and electron paramagnetic experiments (EPR) confirmed that CHC(O)O•, •OH and CHC(O)OO• were the major active species for acid orange 7 (AO7) degradation with contributions of 9.7%, 75% and 14.4%, respectively. The degradation mechanism was proposed through UV-vis full-wavelength scanning and chemical oxygen demand (COD) experiments. The removal of AO7 was not affected in the presence of Cl, SO and HCO, while inhibition occurred with humic acid. ZVI exhibited excellent catalytic properties and stability, and the removal efficiency of AO7 exceeded 70% after three cycles. Additionally, the HA/ZVI/PAA system showed good ability to remove AO7 in well water, lake water, river water and reservoir water, and the elimination efficiency of MO, DCF and ACE also exceeded 70%. Overall, this study contributes new cognition for enhancing the ZVI/PAA system to degrade contaminants, which is expected to achieve a cleaner water environment.
传统的零价铁/过氧乙酸（ZVI/PAA）体系由于ZVI的钝化和铁的回收率低而受到严重限制。在本研究中，首次使用还原剂维生素C（HA）来增强ZVI/PAA体系，以提高其降解性能。在最佳条件下，HA/ZVI/PAA体系的去除效率为82.9%，而HA/PAA和ZVI/PAA体系的去除效率分别仅为19.0%和25.6%。自由基猝灭和电子顺磁共振实验（EPR）证实，CHC(O)O•、•OH和CHC(O)OO•是酸性橙7（AO7）降解的主要活性物种，其贡献分别为9.7%、75%和14.4%。通过紫外可见全波长扫描和化学需氧量（COD）实验提出了降解机理。在存在Cl、SO和HCO的情况下，AO7的去除不受影响，而腐殖酸会产生抑制作用。ZVI表现出优异的催化性能和稳定性，经过三个循环后，AO7的去除效率超过70%。此外，HA/ZVI/PAA体系在井水、湖水、河水和水库水中表现出良好的去除AO7的能力，对甲基橙（MO）、双氯芬酸（DCF）和醋氯芬酸（ACE）的去除效率也超过70%。总体而言，本研究为增强ZVI/PAA体系降解污染物提供了新的认识，有望实现更清洁的水环境。
