| 题名 | 铜络合物的氧化破络合及电还原回收铜研究 |
| 作者 | 曾华斌 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 赵旭 |
| 关键词 | 光电催化，电镀废水，破络合，铜回收 Photoelectrocatalysis, Electroplating wastewater, Decomplexation,Cu recovrey |
| 其他题名 | Decomplexation of Cu Complexes and Recovery of Cu by Electro-Recution |
| 学位专业 | 环境工程 |
| 中文摘要 | 铜络合物常见于电镀工业废水中，传统工艺对重金属络合物的去除能力有限。电镀废水中常见的络合剂有EDTA和CN-等。本文选择Cu-EDTA和Cu(CN)32-为目标污染物，详细研究了外加双氧水、氯化钠和过硫酸根对光电催化氧化破络合与同步铜回收的强化效果以及强化的过程机理，同时对实际含铜络合物废水的处理效果也进行了考察。本论文主要研究内容和结果如下： （1）首先详细研究了外加双氧水对光电催化氧化破络合 Cu-EDTA和铜回收的强化作用（H2O2-PEC），结果发现与光电催化体系（PEC）相比，双氧水的加入可以实现将体系的破络合过程和铜回收过程的强化：在光电催化体系中加入了双氧水后，破络合过程的一级动力学拟合常数从 0.0677 min-1(R2=0.966)提高到了0.0880 min-1(R2=0.968)；铜回收过程中的动力学常数从 0.0607 min-1(R2=0.976)提高到了 0.0749 min-1 (R2 =0.986)。高电流密度、高双氧水浓度和2.5~3.5的初始 pH值有利于 H2O2-PEC体系。氯离子的加入同样可以实现光电催化过程 的强化（EC-PEC）：在光电催化体系中加入了双氧水后，破络合过程的一级动力学拟合常数从0.0272 min-1 (R2=0.987)提高到了 0.0632 in-1 (R2=0.987)；铜回收过程中的动力学常数从0.0249min-1(R2 =0.954)提高到了0.0565min-1(R2=0.993)。高氯离子浓度、低初始 pH值和 1.0 mA/cm2的电流密度有利于EC-PEC在破络合氧化与铜回收的进行。通过在相同条件下对 PEC、H2O2-PEC和 EC-PEC三个体系进行比较，发现 EC-PEC体系对光电催化破络合与铜回收过程的强化效果最明显，但是 H2O2-PEC过程的出水中有机物的矿化度更高。 （2）过硫酸根的加入对光电催化破络合过程和铜回收过程具有明显的强化作用，在 PEC/S2O82-体系中，当电流密度为 0.2 mA/cm2时，铜络合物的去除率从 47.5%提高到了98.4%，相应的，铜回收率从47.4%提高到了 98.3%。高电流密度有利于强化过程；过硫酸根投加量过高或过低均不利于强化作用，本体系中 5mM的过硫酸根加量强化效果最好。过硫酸根具有明显的酸化作用，初始 pH值影响较小。实验证明：在本体系内，过硫酸根不仅可被紫外光活化，还可以被阴极活化产生硫酸根自由基。在反应初期体系内的过硫酸根可以被紫外光和阴极快速活化，从而实现 Cu-EDTA的快速破络合；同时，由于过硫酸根的酸化作用，体系将会迅速降低到酸性，这将有利于 Cu-EDTA及其中间产物的进一步降解和后续的铜回收。 （3）最后，针对实际含铜电镀废水，采用直接电沉积和化学沉淀法对不同形态的铜废水进行处理和比较。以浓度在 800~900 mg/L的含铜废水为原水，酸铜废水、焦铜废水、碱铜废水和上色废水 60 min电化学铜回收率分别为 85.15%、59.29%、32.32%和 10.43%。结果表明：铜回收从难到易分别为酸铜废水>焦铜废水>碱铜废水>上色废水。高电流密度、低 pH值利于铜回收。加入次氯酸钠则可以实现碱铜废水和上色废水中铜氰络合物的氧化破络合与铜的同步沉淀回收。 |
| 英文摘要 | Cu-complexes widely existed in wastewater from the electroplating industry.However, the complexation of Cu2+ between chelating agents may impede the efficient treatment by conditional processes. The EDTA and CN- are the commonly used chelating agent in the wastewater, hence, we chose the Cu-EDTA and Cu(CN)32- as the target pollutants and investigated the enhancement of photoelectrocatalytic (PEC) decomplexation and Cu recovery with the addition of H2O2, Cl- and S2O82- and the treatment of real wastewater containing Cu complexes by electrochemical processes and chemical precipitation. The results are exhibited below. (1) Firstly, we investigated the enhancement of H2O2 addition in the processes of PEC decomplexation and Cu recovery. Compared with the pure PEC process, the addition of H2O2 can provided efficient decomplexation of Cu-EDTA and rapid recovery of Cu. After the addition of H2O2, the first-order kinetics constant of decomplexation was increased from 0.0677 min-1 (R2=0.966) to 0.0880 min-1(R2=0.968), and the first-order kinetics constant in the Cu recovery process was increased from 0.0607 min-1 (R2 =0.976) to 0.0749 min-1 (R2 =0.986). High current density, high concentration of H2O2 and initial solution pH of 2.3~3.5 benefited the performance of H2O2-PEC process. Similar enhancement was observed by adding Cl- into the PEC process (EC-PEC process). After the addition of Cl-, the first-order kinetics constant of decomplexation was increased from 0.0272 min-1 (R2=0.987) to 0.0632 min-1 (R2=0.987), and the first-order kinetics constant in the Cu recovery process was increased from 0.0249 min-1 (R2 =0.954) to 0.0565 min-1 (R2 =0.993). High concentration of Cl- addition, low initial solution pH and the current density of 1 mA/cm2 were the optimum parameters in the EC-PEC process. The enhancement performance in the EC-PEC process was more obvious than that in the H2O2-PEC process, while the effluent of H2O2-PEC process was more environmental-friendly due to its higher mineralization degree and less generation of the by-products. (2) The obvious enhancement of both PEC decomplexation of Cu-EDTA and Cu recovery was observed in our study. At a current density of 0.2 mA/cm2, the removal efficiency of Cu complexes was increased from 47.5% in the PEC process to 98.4% with the S2O82- addition into the PEC process (PEC/S2O82-). Correspondently, recovery percentage of Cu2+ ions was increased to 47.4% from 98.3% within 60 min. High current density and the S2O82- addition of 5 mM benefited the PEC process with addition of S2O82- (PEC/S2O82-). As the acidification of S2O82- can be obtained, consequently, nearly no influence of S2O82- on the PEC/S2O82- process was observed. On the other hand, besides the activation of UV irradiation, the activation of S2O82- into SO4•- radicals by cathodic reduction also occurred. In conclusion, combined with cathodic activation, SO4•- radicals can be activated by UV irradiation of S2O82-, the generated SO4•- radicals enhanced the oxidation of Cu-EDTA. After the consumption of S2O82-, the Cu recovery via cathodic reduction proceeded quickly. (3) Finally, we treated various real electroplating wastewaters by electrodeposition and chemical precipitation. Using the wastewater at the Cu2+ concentration of 800~900 mg/L, the recovery ratio of Cu in the Suantong wastewater, Jiaotong wastewater, Jiantong wastewater and Shangse wastewater were 85.15%, 59.29%, 32.32% and 10.43%, respectively. Results indicated that the recovery difficulty of Cu is shown following: Suantong wastewater > Jiaotong wastewater > Jiantong wastewater > Shangse wastewater. It can be concluded that high current density and low solution pH was beneficial to the Cu recovery by electrodeposition treating various wastewater. The addition of sodium hypochlorite into Jiantong wastewater and Shangse wastewater can obtain the decomplexation of Cu(CN)32- and simultaneous recovery of Cu. |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/36778]  |
| 专题 | 生态环境研究中心_环境水质学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 曾华斌. 铜络合物的氧化破络合及电还原回收铜研究[D]. 北京. 中国科学院研究生院. 2016. |
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