Study On The Effect And Decolorization Mechanism Of Azo Dye Wastewater Treatment By Micro Electrolysis

The production and usage of azo dyes in China are huge.With the development of national economy,the demand for dyes at home and abroad is constantly increasing.In 2018,the output of national dyeing and pigments reached 1.03 million tons,and the printing and dyeing industry increased a lot compared with that in 2017.With its unique advantages,azo dyes occupy more than 70% of China’s annual production and usage,but at present,azo dyes in the process of industrial production and actual use will be generated and lost in probability.A large number of untreated or substandard azo dye wastewater discharge has caused a great impact on people’s living environment,therefore,to explore the effective treatment of azo dye wastewater is imminent.Micro-electrolysis has a good effect on industrial wastewater which is difficult to degrade.This method has attracted people’s attention because of its good treatment effect and low cost.This research adopts the aluminum carbon micro electrolytic method,with acid scarlet 3 r acid dyes,acid orange 7,cationic dye cationic red GTL,cationic blue X-ray GRRL four kinds of azo dye as the main removing process of contaminants,aluminum carbon micro electrolysis was studied in different varieties of azo dye wastewater removal effect,find out the various factors affecting removal effect of all kinds of azo dye as well as the best treatment process of combination,in the form of single factor experiment and orthogonal experiment to explore carbon micro electrolysis aluminum optimum reaction conditions of different azo dye,The decolorization process and products of azo dyes were analyzed by SEM,UV-Vis absorption spectroscopy and Fourier transform infrared spectroscopy,which provided a theoretical basis for the treatment of azo dyes wastewater by aluminum carbon micro-electrolysis.The results showed that:(1)In the single factor experiment,the removal rate of acid red 3R treated by aluminum carbon micro-electrolysis was 95.83%,that of iron carbon micro-electrolysis was 71.54%,that of acid orange 7 treated by aluminum carbon micro-electrolysis was 93.24%,and that of acid orange 7 treated by iron carbon micro-electrolysis was 68.31%.The removal rate of cationic red GTL and cationic blue X-GRRL by aluminum carbon micro-electrolysis was89.00%,89.38%,67.83% and 69.19% respectively.Under the same conditions,the removal effect of aluminum carbon micro-electrolysis method on several azo dyes is much higher than that of iron carbon micro-electrolysis method.Moreover,the treatment effect of aluminum carbon micro-electrolysis method on acid bright red 3R and acid orange 7 is better under alkaline conditions,while the treatment effect of iron carbon micro-electrolysis method on acid bright red 3R and acid orange 7 is poor under this condition.(2)The orthogonal test results show that the optimum conditions for the treatment of acid bright red 3R,acid orange 7,cationic red GTL and cationic blue X-GRRL by aluminum carbon microelectrolysis are as follows: mass ratio of aluminum to carbon 3:1,initial p H=9,oscillation speed of 200r/min and oscillation time of 240 min,respectively.The mass ratio of aluminum to carbon is 3:1,the initial p H is 9,the oscillation speed is 150r/min,and the oscillation time is 180 min.The mass ratio of aluminum to carbon is 3:1,the initial p H is 10,the oscillation speed is 200r/min,and the oscillation time is 180 min.The mass ratio of aluminum to carbon is 2:1,the initial p H is 10,the oscillation speed is 150r/min,and the oscillation time is 180 min.Under the optimal conditions,the removal rate of acid red 3R reached 99.56%.The removal rate of acid orange 7 reached 94.55%.The removal rate of cationic red GTL was 93.37%.The removal rate of cationic blue X-GRRL reached 94.43%.Several dyes have been well removed.(3)The decolorization effect of acid red 3R and acid orange 7 is better after aluminum carbon micro-electrolysis reaction,and the two acid dyes can be better removed;However,the cationic red GTL and cationic blue X-GRRL quickly reached the equilibrium point in the Al/C micro-electrolysis reaction,and the removal rate did not increase any more,and the decolorization effect was poor,which indicated that the Al/C micro-electrolysis method had better decolorization effect on the two acidic dyes than the two cationic dyes.(4)The surface difference of aluminum chips and activated carbon before and after micro-electrolysis reaction is obvious,which is the result of the combined action of original battery reaction,physical adsorption,chemical flocculation and electrochemical enrichment in the micro-electrolysis process.