含Cu-EDTA络合配离子废水的铁碳微电解处理

摘要

In order to break the complex bonds and treat the organic wastewater containing heavy metal,such as Cu-EDTA solution,a novel process of Fe-C micro-electrolysis was proposed.Based on the principle of iron-carbon micro-electrolysis reaction,·OH radicals which were generated under the acidic aerobic condition during the micro-electrolysis process attacked to the organic groups of coordination compounds,which resulted in complex bonds breaking.Therefore copper (Ⅱ) ions were removed via nascent gelatinous ferric hydroxide and ferrous hydroxide,and EDTA was degraded by ·OH radicals.Effects of pH value,temperature,electrolysis time and mass ratio of Fe to C on residual concentrations of total organic carbon (TOC) and Cu(Ⅱ)were studied.The mechanism of Fe-C micro-electrolysis was investigated and verified by analyzing micrographs of scanning electron microscopy (SEM),energy dispersive analysis (EDS) and Fourier transform infrared spectrometry (FTIR).The removal efficiency is optimal at pH value of 2.0,temperature of 25 ℃,the mass ratio Fe to C of 0.02,and reaction time of 60 min.Under above conditions,the concentration of TOC decreases from 200 mg/L to 40.66 mg/L and the residual concentration of Cu(Ⅱ) decreases from initial 60 mg/L to 1.718 mg/L.%为了破坏冶炼废水中重金属有机螯合物,例如Cu-EDTA配离子废水,研究一种破络并预处理的新方法.该方法基于铁碳微电解反应原理,OH在酸性有氧气存在的条件下产生,并在铁碳表面攻击吸附的有机基团导致螯合物的破坏,从而使铜离子将从有机物中剥离下来,然而EDTA将被OH降解.研究pH值、温度、微电解反应时间、Fe/C质量比对铜离子脱除率及总有机碳(TOC)残余含量的影响,通过扫描电子显微镜分析(SEM)、能谱分析(EDS)、红外光谱分析(FTIR)研究处理前、后样品的表面官能团变化及形貌推断铁碳微电解反应的机理.并进行工业条件优化,得到最佳工艺条件:pH值为2,温度为常温,Fe/C质量比≥.02,时间为60 min,有氧气存在.在该条件下TOC浓度为200mg/L、铜离子浓度为60 mg/L的废水反应完成后TOC和Cu残余浓度分别减低到40.66和1.718 mg/L;羟基自由基降解反应机理合理解释了该实验现象.