Study On The Formation Mechanism And Properties Of Coordination Polymers Of Zinc Ferrite And Cadmium 5-mercaptoisophthalate

Zinc ferrite and coordination polymers have attracted great attention due to their wide applications in photocatalysis,adsorption,gas storage and separation,and drug delivery.In this paper,a series of ZnxFe3-xO4 magnetic nanoparticles with different Zn content were successfully prepared by a solvothermal method with urea.The effects of Zn concentration on its magnetic properties and photo-Fenton activity were studied.The in situ microcalorimetry was used to study the growth mechanism of Zn0.2Fe2.8O4 nanoparticles.The formation of cadmium-organic framework based on 5-Mercaptoisophthalic acid was researched by the in situ microcalorimetry and the adsorption capacity was compared.The main conclusions are listed as the following:1.A series of monodisperse Zn-doped Fe3O4 magnetic nanoparticles[ZnxFe3-xO4(0?x?1.0)]with different Zn concentration were successfully prepared by solvothermal method using urea as the alkali source and ethylene glycol as the solvent.XRD measurements showed that all the samples had a cubic spinel structure.The morphologies and particle sizes of the samples were characterized by TEM.The results showed that the ZnxFe3-xO4 samples were monodisperse nanoparticles with uniform particle size distribution.The magnetic results of VSM measurements showed that the saturation magnetization of the sample increases with the increase of Zn doping amount.When the Zn doping amount was 0.2,the saturation magnetization of the sample reaches a maximum of 80 emu/g,further increasing the Zn content to 1.0,its saturation magnetization gradually decreases.The photo-Fenton activity of Zn-doped Fe3O4 nanoparticles were investigated by removing RhB in the presence of visible light and H2O2.It was found that the amount of Zn doped x=0 showed higher photo-Fenton activity,and its dye degradation rate could reach 95%.2.The Zn0.2Fe2.8O4 nanoparticles with superparamagnetism and high saturation magnetization was selected as the aiming sample.In situ microcalorimetry was used to further explore the growth 'process of the nanoparticles,and combined with other different characterization techniques of XRD,TEM,FT-IR,TG and XPS.The results shown that a-(Fe,Zn)OOH and ?-Fe2O3 were formed directly with the increase of temperature during the whole process.Then part of Fe3+ in the reaction system was first reduced by ethylene glycol to Fe2+ and Fe3O4 is formed.Finally,Fe3O4 was transformed into Zn0.2Fe2.8O4.The photo-Fenton activity of Zn0.2Fe2.8O4 nanoparticles and nanoclusters were studied,and the results found that the photo-Fenton activity of the nanoparticles were better than nanoclusters.It has been proved that zinc ferrite with a particle size morphology,and suitable for specific surface area are advantageous for removing of organic dyes in wastewater.3.According to the ligand of 5-Hydroxystilbenephthalic acid(H3MIPA),and reacted with cadmium metal(Cd2+)ions in 4 mL DMA and 1 mL H2O at 150? for 72 h to obtain[((CH3)2NH2)Cd(MIPA)]4 xG coordination polymer.The in situ microcalorimetry was used to study the formation process.The microcalorimetry curve results indicated that chemical reactions occurred firstly,which was an endothermal process,and the crystal nucleation and growth followed the reaction,which were exothermal processes.Combined with XRD and FT-IR characterization,the results shown that the[((CH3)2NH2)Cd(MIPA)]4 xG coordination polymer can be obtained at 150? a shortening time for 60 h.The comparison of dye adsorption property showed that the complexes obtained by the synthesis at 150? for 60 h have better decolorization rate on methylene blue(MB).The maximum adsorption capacity for MB was 397.5 mg·g-1 and the decolorization rate was 99.4%.In RhB+/MB+,MO-/MB+ and PR/MB+three dye mixtures,MB can be quickly,efficiently,and selectively adsorbed into the framework.