Study On Treatment Of Dye By Fungi And Nano-sized Powder Complex

Industrial dyes in wastewater cause environmental problems and are difficult to be degraded because of its complicated structures,multifarious variety and good stabilization.Traditional physical chemistry method has its limitations including secondary pollution and high cost.Traditional biochemistry method is of low efficiency,and some kind of dyes are not propitious to this method.Nano-sized TiO2 has excellent photocatalytic adsorption,decoloration and degradation performance on dyes in wastewater.However,reusing and immobilization of nano sized TiO2 still face challenges.White Rot Fungi contains broad-spectrum abilities of decoloration and degradation,which is easy to obtain from natural world.In this thesis,effects of white rot fungi pellets,nano sized TiO2 and their complex are respectively evaluated on decoloration of different dyes.Three type of dyes were selected to evaluate the decolaoration performance.Firstly,three types of dyes,namely Congo red by azo dyes,Methylene blue by phenothiazine dyes,Crystal violet by triphenylmethane dyes,respectively,were chosen to evaluate the fungi's decoloration performance.White rot fungi pellets were formed by culturing in nutrient media to certain size and then were used to study the adsorption and decolorization of different dyes.Based on the data of pH,OD and FTIR,adsorption mechanism was discussed in detail.The results show that white rot fungi pellets had good adsorption and the decolonization rate as more than 94%to Congo red within 1 hour,and 75%to Methylene Blue within 3 hour,86%to neutral red within 1.5 hour,74%to crystal violet within 0.5 hour,but both neutral red and crystal violet grows unabsorbed.One kind of lab-made TiO2 powders were used to evaluate the photocatalysis performance to the dyes in wastewater.The results show that the lab-made TiO2 powders was easy to settlement and has low efficiency on dyes degradation.Two kinds of commercial TiO2 powders were used to photocatalysis decolorate of different dyes.Morphology and structure of nano TiO2 were characterized by XRD,SEM and IR.The photocatalysis conditions are 10000Lx,80rpm in a shaker and the results show that the decoloration was over 80%within 50 minutes to deal with Congo red.Study on the complex of white rot fugus and nano sized TiO2 on the decoloration of different dyes.Surface charge conditions were analysed based on the data of pH,zeta potential.The stabilities and mechanisms of the complex were analyzed according the data of IR.The results indicate that the fugus-nano particle complex performed fairly on the decoloration of azo and phenazine dyes but poorly on phenothiazine dyes.The pH of dye system declined during the adsorption to Congo red.Zeta of dye system was affected by white rot fungi and nano TiO2 both while the fungi pellets play the main role in the later period.IR spectrums show that the complex was formed by physically adsorption between fungi and TiO2 powders.