Study Of White-rot Fugus In Treating Dye Wastewater

White-rot fungi have an extremely good character on dye degradation.A representative white-rot fungus Pleurotus ostreatus was used to treat phthalic cyanide dyes direct fast turquoise blue and azo dyes acid red.The effect of pH value and temperature on adsorption of dye direct fast turquoise blue by white rot fungi Pleurotus ostreatus was investigated.The experimental results showed that decoloration efficiency of dye wastewater by treatment of Pleurotus ostreatus reached more than 90% within 24h at pH value of 4~6 and temperature of about 20℃,moreover,maximum decoloration efficiency was obtained at pH value of about 5.The bio-adsorption of Pleurotus ostreatus to dye accords with Langmuir adsorption isotherm,and the saturated adsorption capacity of Pleurotus ostreatus was 19.86 mg dye/g gross biomass at the proportion of culture medium 20%.The adsorption kinetics of Pleurotus ostreatus for direct fast turquoise blue from aqueous solutions was in good agreement with the pseudo-second rate equation.It was found that mycelium adsorbing dye decolorized gradually and became white finally by microscopic observation,which indicated that neogenetic mycelium was activated to biodegrade dye and used repeatedly.It was verified that biomass adsorbed dye and biodegraded subsequently by infrared diffuse reflectance spectroscopy.Moreover,the ultraviolet spectrum analysis confirmed that the maximum absorption band decreased gradually and disappeared finally,simultaneously, new absorption band produced and all absorption band disappeared finally in treatment of dye wastewater by Pleurotus ostreatus.Pleurotus ostreatus treated dye wastewater by two mechanis- ms of adsorption and biodegradation.The experimental results showed that maximum decoloration efficiency of acid red waste water was obtained at pH value of about 3 and temperature of about 22℃.The decoloration efficiency was effected by the proportion of culture medium,the more density of the medium the better degradation result.The ultraviolet spectrum analysis confirmed that the molecules of dye was absorped by mycelium and laterly degradated by extracellular enzyme.Moreover,a number of complex intermediates were produced in the.process of azo dyes degradation.The experimental results showed that maximum decoloration efficiency of acid brilliant blue waste water was obtained at pH value of about 3 and temperature of about 25-30℃.The live mycelium was proved to be better character than the dead mycelium in decoloration efficiency.The ultraviolet spectrum analysis confirmed that the molecules of dye was absorped by mycelium and laterly degradated by extracellular enzyme,but dyes were not degradated completely,with a result of a number of absorption peak areas remained in UV-visible region. Pleurotus ostreatus was confirmed to have different treatment result of the dye wastewater when the differences were appeared in the molecular structure of dyes.