Research On The Preparation Of Transition Metal Oxides And Their Application In Printing And Dyeing Wastewater Degradation

In recent years,transition metal oxides have shown a great prospect of application in the treatment of printing and dyeing wastewater because of their stable chemical properties,wide source,low cost and environment friendliness.However,it is not easy for the material to form a stable structure when the sample is prepared,the general particle size is larger,the product can be used smaller than the surface,and the optical electrons and holes of semiconductor materials are easy to compound,limiting the application of materials in wastewater treatment.The purpose of this thesis is to design transition metal oxides with different morphology and structure,and to improve the adsorption capacity and photocatalytic degradation efficiency of organic dyes by constructing some unique structures.The structure,morphology,growth mechanism and properties of the prepared materials were systematically studied.The main research work is as follows:1.Study on hydrothermal synthesis and adsorption properties of nanometer ZrO2(1)A series of nano-ZrO2 with novel morphology were synthesised by the hydrothermal method at 180℃.using ZrOC1l·8H2O as zirconium source and CH3COONa·3H2O as sedimentation agent.The CH3COO-plays a key role in the morphological regulation of ZrO2.And the photocatalytic degradation of methylene blue and bacteriostatic properties of nano-ZrO2 with different morphology were further studied(2)Facile synthesis of nano-ZrO2(t-ZrO2)powders with quadrilateral crystalline facies by the method of hydrothermal at 180 ℃.It is to be found that the effects of the pH and temperature of the reaction liquid are not the main factors to change the crystallin phase of ZrO2.However.When an appropriate proportion of glycine/potassium chloride(CH2(NH2)COOH/KCl)is added,the transition from m-ZrO2 to t-ZrO2 could be achieved.As a result,CH2(NH2)COOH/KCl plays a key important in regulating the ZrO2 phase.Further mechanism studies have found that molecular complexes and the kinetic disturbance of gases are the main factors to change their phase.The adsorption properties of m-ZrO2,t-ZrO2 and mixed phase were further detected by methyl orange adsorption experiment,and the results showed that m-ZrO2 had high adsorption performance,t-ZrO2 and mixed phase ZrO2 were more lower,and it was seen that the phase of nano-ZrO2 had a certain influence on their adsorption properties2.Preparation of nanometer Ag2O and its modified materials(Ag/Ag2O)Pure nano-Ag2O was prepared by direct mixing of AgNO3 and NaOH at room temperature with the condition of light avoidance,and the photocatalytic degradation performance of nano-Ag2O was determined by using methyl orange to simulate printing and dyeing wastewater.The results showed that the degradation rate in 50 min was only 42%.In order to improve its performance,Ag/Ag2O polyhedrons,cubes and octahedron-like crystals have been fabricated via a simple chemical precipitation at room temperature.Based on the experimental results,it is found that the concentration of NaOH plays acrucial role in the formation of Ag/Ag2O composites with different morphology,and the possible crystal growth mechanism is put forward accordingly.Subsequently,we further used the synthesized samples for photocatalytic degradation of methyl orange experiments to detect its photocatalytic degradation properties.It was found that all Ag/Ag2O complexes showed better photocatalytic degradation performance than pure Ag2O,of which the cubic Ag/Ag2O showed the highest photocatalytic degradation,and the degradation rate reached almost 100%in 50 minutes,which may due to the cubic Ag/Ag2O has strong visible light absorption properties,tremendous amount of free radicals and high separation rate of electron-hole pairs.In addition,the photo-induced free radicals were measured by electron paramagnetic resonance(EPR)measurement.Research demonstrates that the·O2-and ·OH radicals are the predominant active species.And the feasible mechanism of photo-catalytic degradation is further discussed in detail3.Preparation,photocatalytic and bacteriostatic properties of Cu2O and ZrO2/CU2OA series of nano-Cu2O with different morphology were prepared by simple liquid phase reduction method.using CuCh·2H2O as raw material.The phase composition and microstructure of nano-Cu2O were characterized by XRD.SEM and other testing methods.The photocatalytic degradation of methylene blue was carried out by using the synthesized target product as photocatalyst,and the photocatalytic degradation properties of Cu2O with different morphology were analyzed and studied Results showed that Cu2O with reaction time of 7.5h had the highest photocatalytic degradation performance.In order to expand the performance application of nano-Cu2O,the related bacteriostatic properties were also further researched,It showed that Cu2O with reaction time of 7.5h still had the best performance.Finally,In order to improve the correlation performance of four-angle stellate nano-ZrO2,modified materials with a load ratio of 1/1 and 1/3 were prepared by combining ZrO2 and Cu2O with better photocatalytic and bacteriostatic properties.And the related properties of ZrO2/Cu2O are further analyzed.It showed that nano-Cu2O can be used to improve the related properties of other substances.