Treatment Of High Concentration Copper-containing Wastewater By Cross-flow Extraction

Among the types of industrial wastewater,copper-containing industrial wastewater has a great threat to the ecological environment and human health because of its extensive sources,complex components and difficult biodegradation.Therefore,the effective treatment of copper containing wastewater has a very significant academic value and challenging application prospects.In this study,copper-containing wastewater was used as the research target,and the basic principle of single-stage cross-flow extraction of copper-containing wastewater was studied.The effects of extraction system,extractant concentration,extraction ratio(A/O),oscillation time,and temperature on the removal rate of Cu2+ during single-stage cross-flow extraction were investigated.Furthermore,by designing the response surface method to explore the interaction between the influencing factors,through the analysis of the response surface curve,it can be seen that the effect of each influencing factor on the Cu2+ removal rate in the single-stage cross-flow extraction process is as follows: Time> Extraction vs.(A/O)> Extractant N902 concentration.Secondly,according to the detailed analysis of the principle of multi-stage cross-flow extraction reaction,combined with specific processing targets and production actualities,a multi-stage cross-flow extraction process was preliminarily designed to treat copper-containing wastewater.The design content includes the determination of the process flow,the layout of the plant,the selection of equipment and engineering economic analysis.Through engineering and economic analysis of project construction costs,equipment costs,drug consumption and other costs,the economic feasibility of the three-stage cross-flow extraction process is given.It is confirmed that the three series of packing extraction columns and stripping columns had a radius of 6 m,a column height of 8 m,a wall thickness of 0.004 m,and the material is made of stainless steel.High-efficiency flat ring packing is used as the filler.And the loaded organic phase was subjected to a back-extraction operation using a sulfuric acid solution to recover the copper resources in the waste water and recycle the extractant.The effects of back-extractant concentration and back-extraction ratio on stripping efficiency were analyzed.The optimal experimental conditions were as follows: sulfuric acid was used as back-extractant at room temperature,and H2SO4 concentration was 4 mol/L.When the ratio is 1/2,the back extraction efficiency can reach 96.77%.Finally,the mechanism of cross-flow extraction reaction for treating copper-containing wastewater is discussed.The experimental results show that the reaction process of Cu2+ is first-order endothermic reaction.In the process of treating Cu2+ with a cross-flow extraction reaction using N902 as the main extractant,two N902 molecules are required to bind one Cu2+ for each extract molecule.