Study On Treatment Of Simulated And Dye Wastewater By Electrocoagulation And Electrocoagulation Combined With Magnetic Flocculation

As one of the main sources of industrial wastewater in China,dye wastewater have caused serious damage to the water environment and ecological health due to characteristics of large fluctuations in water quality,high concentration of COD,poor biodegradability,high chroma,high turbidity and difficulty in treatment.The treatment of dye wastewater becomes a key point in the field of environmental water pollution treatment at home and abroad.Due to poor effect and high cost by single physical-chemical treatment unit,it is mainly treated by complex combination treatment,which not only has a complicated treatment process,but also has high operation and running costs.The study on high-efficiency and low-consumption treatment technology has important guiding significance for the development of dye wastewater treatment technology.In this paper,Reactive Black KN-B was used as processing target to study the effect of electrocoagulation process as well as magnetic flocculation process on dye wastewater,which combines the charge neutralization,electro-oxidation,coagulation and electro-flotation of electrocoagulation process with adsorption and "magnetic core" of magnetic flocculation process to improve the effect of electrocoagulation process.Firstly,The effect of electrocoagulation process for treatment of Reactive Black KN-B simulated dye wastewater has been investigated in this paper.And by controlling the electrolyte,electrodes combinations,initial pH,current intensity,distance between electrodes and stirring speed on electrocoagulation efficiency,the optimum conditions of the electrocoagulation process have been obtained.Secondly,based on electrocoagulation,the magnetic flocculation was formed by Fe3O4 nanoparticles,and the effect of enhanced treatment,of dye wastewater was studied by the combination of magnetization and electrocoagulation.Subsequently,UV spectrum,IR spectrum and LC/MS analysis have been used to study the main degradation mechanism of the combined treatment of simulated dye wastewater.Lastly,the energy consumption of combined treatment of Reactive Black KN-B simulated dye wastewater have been investigated.The results showed that electrocoagulation process has a remarkable effect on Reactive Black KN-B simulated dye wastewater and is influenced by the conditions of electrolyte,the electrodes material and combinations etc.At the optimum condition of the electrocoagulation process(electrolyte of NaCl with 1000mg/L,the electrodes combination of Fe-Al,the current density of 0.4A,the distance between electrodes of 15mm and the stirring speed of 900r/min,initial pH of 7.0),the decolorization rate and COD removal rate by electrocoagulation process were 95%and 63%respectively after 10min.the effect of electrocoagulation process for simulated dye wastewater have been improved by implemented magnetic nanoparticles,the decolorization rate and COD removal rate have reached to 99%and 72%respectively at the optimum condition of the electrocoagulation process.The research and analysis showed that the electricity consumption of the 1000mg/L Reactive Black KN-B simulated dye wastewater is 1.134kW·h/m3.The electrocoagulation process combined with magnetic flocculation process can save the energy consumption by 9.4%.The UV spectrum and LC/MS spectrum of the water sample and IR spectrum of the floc showed that electrocoagulation process of Reactive Black KN-B simulated dye wastewater is complicated,which includes the floc adsorption formed by the dissolution of the metal anode and electro-oxidation.During the electrocoagulation process,Reactive Black KN-B was partially adsorbed by flocs and oxidized into small molecule products.The addition of Fe3O4 nanoparticles generated the magnetic effect and the adsorption effect to improved the effect of electrocoagulation process.