| At present, wastewater treatment has become more and more important due to the growing problem of water pollution. The adsorption method plays an important role in wastewater treatment because of high efficiency and simplicity. However, during the process of adsorption, it is difficult to separate or recover the used adsorbent. The magnetic nanocomposites as a promising adsorption material have received more attention due to their good magnetic property and the functionality of imported materials in recent years. So, based on the good magnetic responsibility and adsorption of the magnetic nanocomposites, Fe3O4@Mg O nanocomposites and hydrophobic Fe3O4@Si O2 nanocomposites were prepared, and in order to investigate the adsorption properties of the as-synthesis nanocomposites for removal of heavy metals and oil pollutants respectively, their application in adsorbing Pb2+ and lubricant oil in the contaminated water were also studied. The details were summarized as follows:Fe3O4@Mg O nanocomposites were prepared by the coprecipitation method. TEM and XRD were applied to characterize their phase constitution and structure, and their average particle size of 30 nm was observed. The results obtained from VSM and TGA indicated that the Fe3O4@Mg O nanocomposites exhibited superparamagnetism and good stability. The adsorption of Pb2+ using Fe3O4@Mg O was investigated under different conditions, such as the initial adsorbate concentration, contact time, adsorbent dosage and the initial p H. The results showed that the Fe3O4@Mg O nanocomposites had fast adsorption rate, the adsorption equilibrium was attained within 50 minutes; the adsorption efficiency of Pb2+increased gradually with the increase of p H value in the range of 2-6, the maximum adsorption efficiency was obtained at p H=6; When the adsorbent dosage was up to 300 mg/L with the initial Pb2+ concentration of 200 mg/L, the removal efficiency would reach to over 99%; The maximum adsorption capacity was711.5 mg/g. Furthermore, the isotherm evaluations revealed that the Langmuir modelbetter fitted to the experimental equilibrium data than the Freundlich model. In addition,adsorption kinetic data followed a pseudo-second-order rate.Fe3O4@Si O2 nanocomposites were synthesized by a simple one-pot coprecipitation method. The nanocomposites exhibited superparamagnetic and superhydrophobic properties after hydrophobical modification with hexadecyltrimethoxysilane. The samples were characterized using SEM?XRD?FT-IR?TGA and VSM. The effect of adsorption time and p H value on the adsorption capacity, as well as its regeneration capacity were mainly studied to investigate the adsorption properties of hydrophobic Fe3O4@Si O2 nanocomposites for removal of lubricating oil. The results showed that the nanocomposites had excellent adsorption performance in the p H range of 5-8, the adsorption equilibrium could be reached within 30 min, and the maximum adsorption capacity was about 1.40 g/g; Moreover, the adsorption capacity of nanocomposites did not obviously decrease after repeated use for 6 times, and the used adsorbent still show good hydrophobicity(contact angle only dropped from 153.4° to 143.9°). In a word, the synthesized hydrophobic Fe3O4@Si O2 nanocomposites were excellent oil-adsorbing materials due to high adsorption capacity with easy recovery and reusability. |
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