Study On Enhancing Decoloriazation Of Azo Dye In Aqueous And The Influencing Factors By Microbial Electrolysis

Dyes are one of the most important organic of human life and production, it is widely used in the textile, food, printing and dyeing, pharmaceutical, chemical, agricultural, paper and other industries.Along with industrialization advancement speeding up,there are a lot of dyes go into the environment.These dyes includeseveral structural varieties ofdyes, such as acidic, reactive, basic, disperse, azo, diazo et al.And azo dyescover80 percent of all dyes. They are characterized by containingone or more azo groups ( ? N ? N?).It is difficult for dye effluent to be treated because of its complex component, high chroma, increasing amount and non-biodegradability.Most physicochemical methods can remove dye efficiently,but are not feasible due to their expensive cost, limitedversatility and sensitivity to other wastewater constituents. Alternatively,biological treatment may present a relatively inexpensiveway to remove dyes from wastewater.But, it limits in the long treatment time.It is significant to finda highly effective method for azo dye decoloration.In thisstudy we investigate the use ofbio-cathode for decolorization of an azodye,Aizarin Yellow,where the process is driven by power supply. Carbon brush is used as electrode in anode where microbial oxidation of acetateandcarbon clothis used in cathode compartment where is fed with NaHCO3.The reactor used in the study is Biocathode Bioelectrochemical Reactor.Firstly, two ways are adopted in this paper to domestica the dominant bacteria, then we put forward the BiocathodeReactordomesticationstrategy for startup optimization.Results show that the startup time which with functional bacterial from static conditions is shorter than that bacterial without static domestication.Then we compare the ohm internal resistance for the BiocathodeReactor, The result show that, when using the BiocathodeReactor with bacterial from static conditions, the ohm internal resistance is just1.921Ωand 6.82Ωof the value of using the bacterial without static domestication.Secondly, we compare the decolorizationperformance when using the biocathode and abiocathode.The result show that the BiocathodeReactor enhanced action of azo dyesdecolorization.The decoloration efficiencycan achieve 97% in 48 hours by bio-cathode , while the abio-cathode need more than 60 hours,and the BiocathodeReactor(open circuit) need more than 150 hours.The reduced product of Aizarin Yellow is P-phenylenediamine and 5-Aminosalicylic acid.Finally,we analysis the key factors affecting biocathode reactor. The results show that a highdecoloration efficiency can be achieved when power supplied for biocathode reactoris as low as 0.5V. When the additional voltagedecreased , the conversion from P-nitroaniline to P-phenylenediamine is limited .When the concentration of Aizarin Yellow is 100mg/L, biocathode reactor had a highdecoloration efficiency.When the concentration increased to 200mg/L,even 300mg/L ,the decoloration efficiency is very low.The effect of the pH at the cathode on the Aizarin Yellow decolorizationprocess was examined.The resulted showe that it can achieved a highdecoloration efficiency when pH rangefrom 5.2 to 8.3.