Xue Yudong, Zheng Shili, Sun Zhi, Zhang Yi, Jin Wei
National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Chemosphere. 2017 Sep;183:156-163. doi: 10.1016/j.chemosphere.2017.05.115. Epub 2017 May 20.
Alkaline electrochemical advanced oxidation processes for chromium oxidation and Cr-contaminated waste disposal were reported in this study. The highly graphitized multi-walled carbon nanotubes g-MWCNTs modified electrode was prepared for the in-situ electrochemical generation of HO. RRDE test results illustrated that g-MWCNTs exhibited much higher two-electron oxygen reduction activity than other nanocarbon materials with peak current density of 1.24 mA cm, %HO of 77.0% and onset potential of -0.15 V (vs. Hg/HgO). It was originated from the highly graphitized structure and good electrical conductivity as illustrated from the Raman, XRD and EIS characterizations, respectively. Large amount of reactive oxygen species (HO and ·OH) were in-situ electro-generated from the two-electron oxygen reduction and chromium-induced alkaline electro-Fenton-like reaction. The oxidation of Cr(III) was efficiently achieved within 90 min and the conversion ratio maintained more than 95% of the original value after stability test, offering an efficient and green approach for the utilization of Cr-containing wastes.
本研究报道了用于铬氧化和含铬废物处理的碱性电化学高级氧化工艺。制备了高度石墨化的多壁碳纳米管修饰电极用于原位电化学生成羟基自由基。旋转环盘电极测试结果表明，高度石墨化的多壁碳纳米管表现出比其他纳米碳材料更高的两电子氧还原活性，其峰值电流密度为1.24 mA/cm²，羟基自由基产率为77.0%，起始电位为-0.15 V（相对于Hg/HgO）。分别通过拉曼、X射线衍射和电化学阻抗谱表征表明，这源于其高度石墨化的结构和良好的导电性。通过两电子氧还原和铬诱导的碱性类电芬顿反应原位电生成大量活性氧物种（羟基自由基和超氧阴离子自由基）。在90分钟内有效地实现了Cr(III)的氧化，稳定性测试后转化率保持在原始值的95%以上，为含铬废物的利用提供了一种高效且绿色的方法。
