| With the large-scale development of the food,textile,pharmaceutical and cosmetic industries,more than 100,000 dyes have been put into production and application in recent years.In the dyeing production and the dyeing process of various industries,about 20-60%of dyes are inevitably discharged into the wastewater system.If left untreated,it will lead to a large number of dye wastewater with high-color,complex components,high organic content and poor biodegradability directly pollute the natural water environment,causing great life threat to aquatic plants and humans.Dye wastewater has become the focus of current environmental governance.Based on the structure,properties and usage of dye,it can be divided into many categories.In terms of current consumption,biological toxicity,processing difficulty of dye,this study selected three kinds of dyes including metal complex dyes,azo dyes and cationic dyes to perform decolorization experiments.Conventional treatments of dye wastewater can be divided into physicochemical and biochemical types,among which biological treatment and adsorption are widely used because of their high efficiency,low cost and large amount of treated waterIn this study,strain P sp.CF10-13 was used as the basic tool,and mainly research contents about the treatment of three representative dyes of naphthol green B(NGB),cationic dyes methylene blue and azo dyes Congo red are as follows:1.under anaerobic conditions,strain P sp.CF10-13 was used to remove NGB,high performance liquid chromatography-mass spectrometry(HPLC-MS)to analysis biodegradation products and possible degradation processes,cyclic voltammetry and other experiments to explore the biological decolorization mechanism,and to explore the characterization and speculation formation mechanism of black synthetic particles in the process of decolorization;2.strain P sp.CF10-13 was used to reduce graphene oxide(GO),and the concentration of reduction system was mixed with sodium alginate(SA)to prepare SA-CF-rGO hydrogc1 microspheres;the prepared reduced graphene oxide(rGO)and SA-CF-rGO hydrogcl microspheres were subjected to ultraviolet spectroscopy,Raman spectroscopy,X-ray diffraction,photoelectron spectroscopy,atomic force microscopy,scanning electron microscopy,high power transmission electron microscopy and other analytical characterization.3.According to the adsorption effect of SA-CF-rGO hydrogcl microspheres on cationic dye-methylene blue and azo dye-Congo red,optimize the preparation conditions of the hydrogc1 microspheres(including bacterial inoculum,rGO addition,SA concentration and calcium chloride concentration)and adsorption conditions(including pH,temperature,ions concentration,dye concentration,adsorption dose).Thermodynamic and kinetic fitting of SA-CF-rGO hydrogc1 microspheres to methylene blue and Congo red was carried out under optimized conditions.The adsorbed SA-CF-rGO hydrogel microspheres were placed in different desorption solutions to select the best desorbent,and finally the hydrogel microspheres were tested for their cycle regeneration performance.The experimental results show that the marine P sp.CF10-13 can degrade NGB based on extracellular electron transport mechanism.And iron-sulfur nanoparticles were synthesized in the process of decolorization which not only achieved low-cost and safe decolorization of NGB,but also realized dye resource recovery;P sp.CF10-13 also can reduce GO to rGO with good properties.The SA-CF-rGO hydrogcl microsphere has strong adsorption effect on MB and GR,stable property,wide application range and good reproducibility.Also,the preparation process avoided the use of toxic reagents,reduced the preparation cost of graphene-based adsorbent materials,and achieved high efficiency,low pollution and cost-effective MB and GR adsorption.In conclusion,this study not only broadens the engineering application range of functional strains in dye removal,but also provides some theoretical basis for the reducing mechanism of bacteria. |
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