Selective Separation Of Heavy Metal Ions By EDI Coupled With Coordination Reaction

With the progress of the world,the development of science and technology and the process of industrialization,the problem of environmental pollution is becoming more and more serious,especially in heavy metal pollution.Heavy metal ions with high solubility in water environment is Easily absorbed by passive plants and amplified with the food chain,so it is harm to human health.In the environment and the production,there are lower concentration heavy metal ions in the wastewater.We need to selective separation of trace heavy metal ions in order to recycle.Traditional water treatment methods are difficult to achieve the above purpose.Therefore,in this paper,the coupling of coordination reaction and the EDI process is established,which provides a theoretical and technical basis for the development of a new type of low concentration heavy metal wastewater treatment technology.In this paper,the separation of low concentration Cu²⁺ and Ni²⁺ mixed solution by the EDI process was investigated.In order to select the suitable operating conditions,this paper studies the EDI process of fresh water Continuous and concentrated water cycle to separate Cu²⁺ and Ni²⁺.The effects of operating current,raw water flow rate and raw water concentration on the enrichment ratio and separation ratio were investigated.The experimental results show that the appropriate increase of current and raw water flow is beneficial to the selective separation of the appropriate separation of Cu²⁺ and Ni²⁺.Through the analysis of experimental data,It was found that when the flow rate of the reactor was 60mL/min and the current was 190mA,the concentration of copper ions was 119.31,and the separation ratio was up to 7.99.On this basis,the coupling of coordination reaction with EDTA and the EDI process separating low concentration Cu²⁺ and Ni²⁺ mixture were investigated.When adding EDTA,the same concentration of Cu²⁺ and Ni²⁺ mixed solution was investigated.Under the condition of the flow of 60mL/min and the current of 190,A,the concentration of Cu²⁺ was 159.31,and the separation ratio was up to 11.47.At the same time,the results showed that EDI had a better effect on selective separation of Cu²⁺ and Ni²⁺ in the presence of complexing agent.The effects of different complexing agents such as EDTA,sodium citrate,EDTA,potassium sodium tartrate and DTPA on the separation selectivity were investigated.Under the condition that the working current is 190mA and the raw water flow rate is 60mL/min,the raw water solution with different concentration ratio is treated.EDI in the presence of EDTA,the mixture of Cu²⁺ and Ni²⁺ concentration ratio of 1:2 was studied and the concentration of Cu²⁺ was 228.90,the separation ratio was 41.58.The results show that the coupling of coordination reaction with EDTA and the EDI process is a promising method.