A novel approach to sustain Fe-0-electrocoagulation for Cr(VI) removal by optimizing chloride ions
A novel approach to sustain Fe-0-electrocoagulation for Cr(VI) removal by optimizing chloride ions
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通过优化氯离子维持 Fe-0 电凝聚去除 Cr(VI) 的新方法
DOI：
10.1016/j.seppur.2015.09.074
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发表时间：
2015
影响因子：
8.6
通讯作者：
Yang Xia
中科院分区：
文献类型：
--
作者：
Xu Hai-yin;Yang Zhao-hui;Luo Yuan-ling;Zeng Guang-ming;Huang Jing;Wang Li-ke;Song Pei-pei;Yang Xia
氯化物（Cl−）广泛用于使用金属铁（Fe 0-EC）的电凝聚法中的去钝化。然而，它的优化仍然是一个务实的方法，因此，有限的成功。本研究提出了一种新的方法，基于系统的调查，Cl−诱导点蚀溶解行为的Fe 0-EC的pH值和Cr（VI）（0 <$Cr（VI）（mg/L）<$520）的演变。通过动电位极化、循环伏安、恒电流测试和扫描电子显微镜（SEM）分析表征了其钝化行为。提出的优化Cl−去钝化的方法如下：（1）建立钝化区III中点蚀溶解（MCPD）的最小Cl−浓度数据库，作为pH和Cr（VI）的函数（MCD =f（pH，Cr（VI）;（2）记录pH和Cr（VI）演变的曲线函数（g）（g= {（pHi，Cr（VI）i），...，（pHf，Cr（VI）f）），在Fe 0-EC工艺中没有钝化;（3）结合曲线（g）和MCPD数据库，通过选择最大MCDs，获得用于去钝化（OCD）的Cl−的最佳浓度（OCD =Max{MCPD1，MCPD2，. MCPDn}）。与响应面法相比，该方法具有更高的准确度和稳定性。
Chloride (Cl−) is widely used for depassivation in electrocoagulation using metallic iron (Fe0-EC). However, its optimization is still on a pragmatic approach and thus of limited success. This study proposed a novel approach based on a systematic investigation of Cl−–induced pitting dissolution behavior of Fe0with the evolution of pH and Cr(VI) (0 ⩽ Cr(VI) (mg/L) ⩽ 520) in Fe0-EC. The depassivation behavior was characterized by potentiodynamic polarization, cyclic voltammograms (CVs), galvanostatic measurements, and scanning electron microscope (SEM) analysis. The proposed approach to optimize Cl−for depassivation was as follows: (1) Build a database of minimum Cl−concentrations for pitting dissolution (MCPD) as a function of pH and Cr(VI) in passivation region III (MCD =f(pH, Cr(VI))); (2) Record the curve function (g) of pH and Cr(VI) evolution (g= {(pHi, Cr(VI)i), …, (pHf, Cr(VI)f)}) without passivation in the Fe0-EC process; (3) Obtain the optimal concentration of Cl−for depassivation (OCD) by selecting the maximum MCDs by combining the curve (g) and the database of MCPD (OCD =Max{MCPD1, MCPD2, … MCPDn}). This method was more accurate and stable compared with RSM.