Study On Biosorption Of Azo Dye By Yeast

With the high speed development of economy, the dye pollution of water resourceshas been more and more serious. What is more, the azo dyes pollution is beingaggravated. Azo dye wastewater has been discharged into the water body, impacted onthe water solubility and light transmittance, water ecosystem has been damaged, causedto harm people’s health, and even cancer. Therefore, the treatment with azo dyes inwastewater becomes very important. Biological adsorption has the advantages of widesources of adsorbent, low cost, no double pollution and so on. It has broad developmentprospect.In this paper, the biological of Reactive Brilliant Red X-3B and Acid Scarlet3Rfrom aqueous solution, using yeast, was investigated in batch system.Throughexperiments, the effect of pH, dosage of yeast, adsorption temperature, adsorptiontime, coexisting ions on the biosorption peocess of Reactive Brilliant Red X-3B andAcid Scarlet3R were studied. And the adsorption kinetics and adsorptionthermodynamics were studied. Experiments were also conducted for the pretreatmentand chemical modification on yeast, the effect of the adsorption properties of yeast werestudied. Experiments were also investigated SA or SA+PVA immobilized yeastadsorped azo dyes. Mechanism of yeast absorped azo dyes is also discussedpreliminarily.Through the study of the culture conditions of yeast, when using the3d of yeast asadsorbent, the initial pH of solution is2, the yeast has higher adsorption capacity onReactive Brilliant Red X-3B and Acid Scarlet3R, removal rates were80.72%and75.31%. It has a little positive effect on the adsorption for azo dyes by yeast in thesolution with different concentration of Na+, K+, Mg2+, Ca2+, but the solution that hasthe cation of Fe3+, Al3+have a obvious influence in yeast’s adsorption.The anion Cl-,NO3-, SO42-, CO32-had little influence on the adsorption of yeast for Reactive BrilliantRed X-3B and Acid Scarlet3R. By using0.1mol/L NaOH as strippant, thedesorption efficiency for Reactive Brilliant Red X-3B and Acid Scarlet3R was ideal. The study of adsorption isotherm showed that, adsorption behavior of yeast forReactive Brilliant Red X-3B and Acid Scarlet3R was in lined with the Langmuirisotherm equation, of which correlation coefficient was greater than0.99. Thebiosorption kinetic date on Brilliant Red X-3B and Acid Scarlet3R could be describedby quasi-second-order kinetic model well.Yeast, were used by a variety of pretreatment and chemical modification hadbetter adsorption for aze dyes. The adsorption amount of carboxyl esterification andsaturated CaCl2pretreated yeast has higer than yeast, the former raised13.39%,31.03%and the later increased14.34%,25.08%.The optimal conditions of pellets embedded yeast were determined as1%of SA,0.3%of yeast,2%of CaCl2and1h of cross-linking. The removal rate of ReactiveBrilliant Red X-3B and Acid Scarlet3R had very good effect by immobilized yeastpellets adding0.05%CS.When1%SA and2%PVA embedded yeast, the pellet has good effect on azo dyesin removal rate. Reactive Brilliant Red X-3B and Acid Scarlet3R was adsorped byimmobilized pellets adding0.2%Fe3O4, the removal rate was92.41%,85.35%.The SEM showed that saturated CaCl2pretreated and carboxyl esterified yeast arerougher than untreated yeast. FT-IR spectra analysis showed that, the infrared spectra ofyeast with adsorption of Reactive Brilliant Red X-3B and Acid Scarlet3R had noobvious change, only drift and no new bands. The main adsorption role was-NH2group.According to the FT-IR of carboxyl esterified yeast after adsorped azo dyes, the mainadsorption role was still N-H group after absorping Reactive Brilliant Red X-3B andAcid Scarlet3R.