Yolk–shell microspheres assembled from Preyssler‐type NaP5W30O11014− polyoxometalate and MIL‐101(Cr) metal–organic framework: A new inorganic–organic nanohybrid for fast and selective removal of cationic organic dyes from aqueous media

• Published in: Applied organometallic chemistry Vol. 33; no. 2
• Main Authors: Hoseini, Akram‐Alsadat, Farhadi, Saeed, Zabardasti, Abedin
• Format: Journal Article
• Language: English
• Published: Chichester Wiley Subscription Services, Inc 01.02.2019
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Cations; Chemical synthesis; Chemistry; Chromium; dye adsorption; Dyes; inorganic–organic nanohybrid; Metal-organic frameworks; Metals; metal–organic framework (MOF); Methylene blue; Microspheres; Preyssler‐type polyoxometalate; Reaction kinetics; Rhodamine; Selective adsorption; Terephthalic acid; yolk–shell microspheres
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.4656

Novel inorganic–organic yolk–shell microspheres based on Preyssler‐type NaP5W30O11014− polyoxometalate and MIL‐101(Cr) metal–organic framework (P5W30/MIL‐101(Cr)) were synthesized by reaction of K12.5Na1.5[NaP5W30O110], Cr(NO3)3·9H2O and terephthalic acid under hydrothermal conditions at 200°C for 24 h. The as‐prepared yolk–shell microspheres were fully characterized using various techniques. All analyses confirmed the incorporation of the Preyssler‐type NaP5W30O11014− polyoxometalate into the three‐dimensional porous MIL‐101(Cr) metal–organic framework. The results revealed that P5W30/MIL‐101(Cr) demonstrated rapid adsorption of cationic methylene blue (MB) and rhodamine B (RhB) with ultrahigh efficiency and capacity, as well as achieving rapid and highly selective adsorption of MB from MB/MO (MO = methyl orange), MB/RhB and MB/RhB/MO mixtures. The P5W30/MIL‐101(Cr) adsorbent not only exhibited a high adsorption capacity of 212 mg g−1, but also could quickly remove 100% of MB from a dye solution of 50 mg l−1 within 8 min. The effects of some key parameters such as adsorbent dosage, initial dye concentration and initial pH on dye adsorption were investigated in detail. The equilibrium adsorption data were better fitted by the Langmuir isotherm. The adsorption kinetics was well modelled using a pseudo‐second‐order model. Also, the inorganic–organic hybrid yolk–shell microspheres could be easily separated from the reaction system and reused up to four times without any change in structure or adsorption ability. The stability and robustness of the adsorbent were confirmed using various techniques. Novel inorganic–organic yolk–shell microspheres based on Preyssler‐type polyoxometalate and MIL‐101(Cr) metal–organic framework (P5W30/MIL‐101(Cr)) were synthesized under hydrothermal conditions and used as an excellent adsorbent for removal of cationic methylene blue and rhodamine B dyes from aqueous solutions.