The Surface Chemical Reaction Of Nanostructured Mesoporous Ferrite

Spinel ferrite is a kind of iron oxide as the main component of composite oxide. It’schemical formula is MFe2O4, which M is divalent metal ions. And it has the same type ofcrystal structure, belonging to the cubic crystal system. As a kind of important inorganicfunctional material, spinel-type metal oxides have been extensively applied to drug delivery,information storage, photocatalytic degradation, environmental protection and many otherfields for its excellent magnetic, catalytic degradation, absorbing properties of wave,easypreparation and low cost properties. However, due to the material prepared by traditionalmethod of high temperature solid phase sintering exist many shortcomings such as pooruniformity, smaller specific surface area and so on, its applications are limited. On the otherhand, spinel-type materials with special structure often show many excellent properties whichare superior to other materials. Therefore, there is urgent need to design or develop a morepractical and versatile new method to synthesize spinels. Up to now, research on the surfacechemical properties of spinel-type mineral is relatively few, and determining the surfacecomplexation constants of spinel can provide a theoretical basis and guidance in using anddeveloping this kind of material, therefore it has a very vital significance.In this paper spinel ferrite MFe2O（4M=Co2+, Zn2+，Cu2+）nanoparticles were successfullyprepared by microwave-assisted heating method. The synthetic MFe2O4samples weresystematically characterized by powder X-ray diffraction (XRD), Fourier transform infraredspectroscopy (FTIR), nitrogen adsorption/desorption analysis and Zeta potential analyzermethods. The results indicate that all the prepared spinels are mesoporous materials and theyhave larger specific surface area and an amount of pore volume.Special emphasis was laid on the absorption behaviors of butyl xanthate at the surface ofspinel ferrited. Based on the experimental and calculation results, the adsorption type and thereaction mechanisms of butyl xanthate at the surfaces were confirmed. We proposed thatadsorption model of spinel ferrited absorb butyl xanthate fit the BET adsorption model. And itis suggested that adsorption of butyl xanthate on spinel ferrited surface belongs to multilayeradsorption. And then we studied the process of the Butyl xanthate photocatalyticphotodegradation using spinel ferrited photocatalysts, it shows that the spinel ferrited can accelerate oxidation and decomposition of butyl xanthate under visible light, the results showthat the butyl xanthate can be degraded in50min with the CuFe2O4nanoparticles, and the butylxanthate can be degraded in70min with the ZnFe2O4nanoparticles. Most of the degradationproduct can be thiocarbonate and perxanthate.The absorption of butyl xanthate from aqueous solution onto the synthesized mesoporousMFe2O4（M=Co2+, Zn2+，Cu2+）solid surfaces was studied by a continuous, online, in situattenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) technique.The adsorption results show that mesoporous MFe2O4（M=Co2+, Zn2+，Cu2+） has a highchemisorption capacity for xanthate, which reaches140mg·g-1、109mg·g-1and117mg·g-1forbutyl xanthate, respectively, within100min. The adsorption kinetics can be described by apseudo-second-order reaction model.Finally, by using the automatic potentiometric titration technique and WinSGW software,we determined the surface acid-base equilibrium constants of the four prepared mesoporousspinels MFe2O4（M=Co2+, Zn2+，Cu2+）. As the used spinels minerals were mesoporousmaterials with high purity, the obtained relevant surface acid-base equilibrium constant hasuniversalism. As well konw, the surface acid-base equilibrium constants are very fundamentalto further studing surface chemical properties of spinel.