Preparation of Fe3O4@polyoxometalates Nanocomposites and Their Efficient Adsorption of Cationic Dyes from Aqueous Solution

• Published in: Nanomaterials (Basel, Switzerland) Vol. 9; no. 4; p. 649
• Main Authors: Li, Jie, Zhao, Haiyan, Ma, Chenguang, Han, Qiuxia, Li, Mingxue, Liu, Hongling
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 23.04.2019; MDPI
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Cationic dyes; Cations; Dyes; Fourier transforms; Hybrids; Infrared spectroscopy; Iron oxides; magnetic adsorbents; Methylene blue; Nanocomposites; Nanoparticles; organic dyes; Oxidation; Photocatalysis; Photoelectron spectroscopy; Photoelectrons; Polyoxometallates; Recycling; Selective adsorption; Solvents; Temperature dependence; Wastewater treatment; X ray photoelectron spectroscopy; Beijing China; United States > US; China; Germany
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano9040649

In this work, two magnetic adsorbents Fe3O4@1 and Fe3O4@2 were prepared by combining Fe3O4 nanoparticles and polyoxometalate hybrids [Ni(HL)2]2H2[P2Mo5O23]·4H2O (1), [H2L]5H[P2Mo5O23]·12H2O (2) (HL = 2-acetylpyridine-thiosemicarbazone). The temperature-dependent zero-field-cooled (ZFC) and field-cooled (FC) measurements indicated the blocking temperature at 160 K and 180 K, respectively. The Brunauer–Emmett–Teller (BET) surface area of Fe3O4@1 and Fe3O4@2 is 8.106 m2/g and 1.787 m2/g, respectively. Cationic dye methylene blue (MB) and anionic dye methyl orange (MO) were investigated for selective dye adsorption on Fe3O4@1 and Fe3O4@2. The two adsorbents were beneficial for selective adsorption of cationic dyes. The adsorption efficiency of MB was 94.8% for Fe3O4@1, 97.67% for Fe3O4@2. Furthermore, the two adsorbents almost maintained the same adsorption efficiency after seven runs. The maximum MB adsorption capacity of Fe3O4@1 and Fe3O4@2 is 72.07 and 73.25 mg/g, respectively. The fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) spectra of the adsorbents collected after adsorption of MB are very similar to the initial as-synthesized Fe3O4@polyoxometalates indicating the high stability of the two adsorbents. The adsorption kinetics indicated that the MB removal followed the pseudo-second-order model. These results showed that the two adsorbents had a potential application in treating wastewater.