Preparation Of Iron-based Porous Materials And Their Applications In Water

Iron-based porous material is considered to be a kind of material with special properties.There are many unconnected,semi-connected or connected holes in it.Iron-based porous materials also have good magnetic properties,high specific surface area,many active sites and other excellent properties.Therefore they are widely used in catalysis,magnetic resonance imaging,dye adsorption,dye catalytic degradation,water catalytic cracking and other fields.Among many iron-based porous materials,Prussian blue?PB?,as the first synthetic dye,was discovered by Heinrich diesbach,a paint manufacturer in Berlin in the early 18th century.It is also known as China blue,Berlin blue,millori blue,etc.Due to its good biocompatibility and magnetism,the application of Prussian blue in the field of biological imaging contrast agent has become a research hotspot in recent years.Fe₃O₄/C as another kind of iron-based porous material,has high specific surface area and more adsorption sites.Therefore,it has been widely concerned in the field of magnetic recovered dye adsorbents.Based on this,the preparation,characterization and application of Prussian blue and Fe3O4/C were studied.The specific research contents are as follows:1.In this work,Prussian blue with cube structure was prepared by water bath method,and then a series of porous Prussian blue was obtained by etching Prussian blue with cube structure by hydrochloric acid solution of different concentration.It is found that the zeta potential???and relaxation rate?r2/r1?can be adjusted by changing the concentration of hydrochloric acid.Further study shows that with the increase of hydrochloric acid concentration,the zeta potential first increases and then decreases,while the relaxation rate has exactly the opposite trend.Then two formulas about hydrochloric acid concentration can be obtained by fitting the curve of zeta potential and relaxation rate with Gauss formula.Finally,the relationship between zeta potential and relaxation rate can be obtained by using hydrochloric acid concentration as a bridge.According to the results of previous studies,the relationship is verified,and the results are proved to have high reliability.Finally,a method to calculate the relaxation rate of the sample by Zeta potential is obtained.2.Fe₃O₄/C was prepared by template method,and then etched with concentrated hydrochloric acid.After etching,most of the Fe₃O₄ particles in the Fe₃O₄/C structure are dissolved by concentrated hydrochloric acid,leaving tens of nanometers regular hexagonal pores,which are called ordered mesoporous carbon?OMC?.Fe₃O₄/C and OMC were used to study the adsorption of methylene blue and Congo red.The results showed that OMC had higher adsorption capacity for both dyes than Fe3O4/C.Moreover,the adsorption capacity of OMC to Congo red dye was significantly higher than that of methylene blue.Therefore,OMC was used in the selective adsorption study.The results showed that the adsorption capacity of OMC to Congo red was 7.43times that of methylene blue,which indicated that OMC had a good selective adsorption capacity for Congo red.The study of adsorption mechanism shows that OMC adsorbs Congo red mainly through hydrogen bond and?-?interaction.Finally,in order to verify the stability of OMC,the adsorption performance of OMC was tested.The results show that the adsorption capacity of OMC to Congo red can still reach more than 95%of the initial adsorption capacity after multiple cycles.