Encapsulation of K6P2W18O62 into magnetic nanoporous Fe3O4/MIL-101 (Fe) for highly enhanced removal of organic dyes

Abstract In this work, a magnetic P2W18O62@ Fe3O4/MIL-101 (Fe) nanocomposite as a stable and effective ternary adsorbent was fabricated by the hydrothermal method and utilized for the elimination of organic dyes from aqueous solutions. Characterization of magnetic nanocomposite was accomplished by FT-IR, XRD, SEM, EDX, BET specific surface area, and VSM measurements. The findings demonstrated the prosperous encapsulation of P2W18O62 heteropolyanions within the porous MIL-101(Fe) framework. The encapsulated sample with a less pore volume and surface area compared with the MOF, displayed a considerable diminish in both pore volume and surface area due to the incorporation of huge Dowson-type POM within the cages of MOF. The fabricated nanocomposite was used as an efficient adsorbent for the elimination of cationic dyes (such as rhodamine B and methylene blue) from aqueous solutions. Influencing factors including primary dye concentration, pH, temperature, and adsorbent dose on the adsorption potency of the P2W18O62@ Fe3O4/MIL-101 (Fe) were checked. Adsorption isotherms were investigated by Freundlich and Langmuir models and obtained results confirmed that dyes adsorption pursued the Langmuir model. Moreover, the fabricated nanocomposite had high stability and recoverability without any alter in structure. According to these results, P2W18O62@ Fe3O4/MIL-101 (Fe) can act as a reusable effective adsorbent for the fast elimination of diverse cationic dyes from aqueous solutions.