The Experimental Study Of Dyeing Wastewater With Three-dimensional Electrode And Electro-Fenton Method

In China,a great of waste water is appeared from printing and dyeing industry,and the dye waste water has the characters of high quantity,deep color and complex composition.The deep color of dye wastewater makes light transmittance rate reduced,resulting in the water ecosystem damaged.The wastewater can bio-accumulate and have three effect on human(carcinogenic,teratogenic, mutagenic).The harm which is caused by the dye wastewater to the environment and the human being attractes a great deal of attention.The treatment and reuse of printing and dyeing wastewater has become a major field of study in the current environment study.Three-dimensional electrode and electro-Fenton method has the characters of low investment,less operating costs,small occupation area,simple operation and good treatment effect.The experiment treat the simulated dyeing wastewater which is acid red solution through three-dimensional electrode and electro-fenton method,and review the removal factors and treatment effects of organic in the printing and dyeing wastewater,optimize the experimental conditions, explore the mechanism of the degradation of organic matter,provide the basis for industrial applications.Based on the orthogonal experiment of 5 factors and 4 levels,the experiment determine the effect of various factors for the removal effect of acid red by three-dimensional electrode and electro-fenton method,then determine the optimum reaction conditions through single-factor experiment according to experimental results,get the optimal treatment.The results showes that:in acidic conditions,the Fenton reagent which is formed from ferrous ion and hydrogen peroxide by electrolysis process is conducive to oxidative degradation of organic matter.The removal effect of acid red in acidic conditions is better than the removal effect in neutral and alkaline conditions;The parameters of cell voltage,current density,reaction time,electrode spacing,initial pH,Fe²⁺ dosage,the concentration of raw water and so on has certain influence for the decoloring rate and chemical oxygen demand(COD) removal rate;The optimum operating parameters indicate:cell voltage 20V,current density 4A/L,plate spacing 5cm,the initial pH 3.0,Fe²⁺ dosage 0.75g/L.Under these conditions,color and COD removal rate reached 98.25%and 79.53%separately.This paper analyzes the decomposition products of acid red 3R by UV-visible spectrum.The result indicates that the decoloring cause of acid red 3R is mainly due to the fracture of azo bond.Reaction mechanism of three-dimensional electrode have been discussed.Three-dimensional electrode reactor have a better effect for one-azo,double-azo,three-azo,triarylmethane,anthraquinone dyes and other types of different structure.The efficiency of three-dimensional electrode and electro-fenton method is significantly higher than that of ordinary fenton and ordinary three-dimensional electrode method.