Preparation of the MCM-41 supported magnetite nanoparticles and their adsorption characteristics on Cu(Ⅱ)
The MCM-41 supported magnetite nanoparticles(MCM-41/Mag)were prepared by using the co-precipitation method.The structure,thermal stability,and Cu(Ⅱ)adsorption characteristics of the MCM-41/Mag have been investigated in this paper.Magnetite nanoparticles in the MCM-41/Mag are distributed on the outer surface and in the mesoporous mesopore channels of the MCM-41.The supported sample containing 17.33％magnetite(MCM-41/Mag0.3)has a specific surface area of 631.6 m2/g,which is much higher than that(91.1 m2/g)of the pure magnetite nanoparticles(Mag-NPS).This result was attributed to the good dispersion of magnetite nanoparticles on the MCM-41 and the large specific surface area of the supporter(MCM-41).The DSC results show that the phase transition temperature of magnetite in the MCM-41/Mag0.3 is obviously higher than that of the Mag-MPS.The adsorption of Cu(Ⅱ)by the MCM-41/Mag0.3 can reach equilibrium at 120 min,with the adsorption isotherm of MCM-41/Mag0.3 fitting well with the Sips model,and a maximum adsorption amount of 10.44 mg/g.The adsorption mechanisms include chemisorption and physical adsorption.Part of Cu(Ⅱ)could be adsorbed on magnetite nanoparticle surface by the Fe—O—Cu bond,and part of Cu(Ⅱ)was adsorbed on the sample surface by the electrostatic attraction.The maximum adsorption of Cu(Ⅱ)by unit magnetite in the MCM-41/Mag03 was 62.78 mg/g,which is significantly higher than those of other Fe(hydro)oxides reported in the literature.Due to the fast adsorption rate and high adsorption capacity,the MCM-41/Mag0.3 can be used as an adsorbent for removing heavy metal ions from water.The results of this study are helpful to expand the application of magnetite in the field of environmental treatment and could provide a theoretical reference for the development of new heavy metal adsorbents with good adsorption performance.
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