Electrochemical corrosion of cast iron pipes in reclaimed water containing disinfectant
Electrochemical corrosion of cast iron pipes in reclaimed water containing disinfectant
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含消毒剂中水对铸铁管道的电化学腐蚀
DOI：
10.20964/2018.09.74
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发表时间：
2018-09
影响因子：
1.5
通讯作者：
Song Yarong
中科院分区：
文献类型：
--
作者：
Zhang Haiya;Tian Yimei;Guo Hao;Kang Mengxin;Song Yarong
采用动电位极化曲线（PPC）和电化学阻抗谱（EIS）研究了铸铁管在含1、2和4 mg/L NaClO和ClO 2的再生水中的腐蚀特性。扫描电子显微镜（SEM）也被用来评估的腐蚀产物膜的形态。结果表明，NaClO和ClO 2的使用改变了电子传递途径和腐蚀产物的特性显着。在含1、2和4 mg/L次氯酸钠的再生水中，4 d时次氯酸钠优先于溶解氧与铁反应，加速了铁的腐蚀过程。然而，消耗的NaClO造成的短缺HClO与铁反应，并诱导再钝化的先前侵蚀的地区在30天的1 mg/L的NaClO实验。此外，高浓度的NaClO（2和4 mg/L）也增强了腐蚀过程中的30天。在1、2和4 mg/L ClO 2的实验中，ClO 2分子可以优先于DO与Fe反应生成铁的氯化物，增强了整个实验过程中的均匀腐蚀。此外，在对照实验中，铁氧化物或铁氢氧化物通常表现出致密的针状结构，而在消毒实验中，絮凝的铁氯化物是主要成分。此外，H +积累引起的酸化在2和4 mg/L ClO 2实验中浸泡4 d后开始明显的局部腐蚀，早于NaClO实验（30 d）。因此，仅从腐蚀控制的角度来看，NaClO是比ClO 2更好的消毒选择。
The corrosion characteristics of cast iron pipes in reclaimed water containing 1, 2, and 4 mg/L NaClO and ClO2 were investigated using potentiodynamic polarization curves (PPCs) and electrochemical impedance spectra (EISs). Scanning electron microscopy (SEM) was also used to evaluate the morphology of the corrosion scales. The results showed that NaClO and ClO2 utilization changed the electron-transfer pathway and corrosion-product characteristics significantly. In reclaimed water containing NaClO at 1, 2, and 4 mg/L HClO could take precedence over dissolved oxygen (DO) to react with Fe and enhance the corrosion process at 4 days. However, the consumption of NaClO caused a shortage of HClO reacting with iron and induced the re-passivation of previously eroded areas at 30 days in the 1 mg/L NaClO experiments. Furthermore, high concentrations of NaClO (2 and 4 mg/L) also enhanced the corrosion process at 30 days. In the 1, 2, and 4 mg/L ClO2 experiments, the ClO2 molecule could take precedence over DO to react with the Fe and formed iron chlorides, enhancing the uniform corrosion throughout the whole experiment. Additionally, iron oxides or iron hydroxides usually showed a compact, needle-like structure in the control experiments, while flocculated iron chlorides were the main components in the disinfection experiments. Moreover, the acidification caused by H + accumulation initiated distinct localized corrosion after 4 days of immersion in the 2 and 4 mg/L ClO2 experiments, earlier than that in NaClO experiments (30 days). Thus, from a corrosion control perspective alone, NaClO is a better disinfection choice than ClO2.