A nickel-substituted Anderson-type arsenomolybdate used as an adsorbent with high efficiency and selectivity toward methylene blue

Abstract

To achieve efficient removal of methylene blue (MB) dye from aqueous solutions, a nickel-substituted Anderson-type arsenomolybdate (H₂en)₃[(NiO₆)Mo₆O₁₈(AsO)₆]Cl₂ (Z1) was synthesized in this work, and its adsorption performance for MB was investigated. The structure of Z1 was characterized by IR spectroscopy, UV-vis spectroscopy, single-crystal X-ray diffraction and thermogravimetric analysis. Structural analysis showed that Z1 is an ionic compound composed of a modified Anderson-type cluster [(NiO₆)Mo₆O₁₈(As₃O₃)₂]⁴⁻ and protonated ethylenediamine cations. Adsorption performance tests demonstrated that Z1 exhibited significant adsorption capacity for MB. After four adsorption cycle tests, no obvious attenuation in its adsorption efficiency was observed, confirming its good repeatability and stability. Furthermore, in mixed dyes containing rhodamine B (RhB) & MB or methyl orange (MO) & MB, Z1 could efficiently and rapidly capture MB, which proved its excellent selectivity and practicality in treating multi-component dye-contaminated water.