Lacunary Keggin-type Polyoxometalate-Based Framework: Design of aHeterogeneous Catalyst for Efficient Degradation of Dye from AqueousSolution

In the past decades, serious water pollution due to organic dyes and pigments affected theearth's environment, and animal and human health. Catalysts based on polyoxometalates (POMs)have been extensively studied in water treatment due to their superior removal capacity inheterogeneous and homogeneous processes [۱]. It is well known that lacunary derivatives are morereactive than the original Keggin anion due to the presence of multiple labile terminal oxo ligands.Lacunary POMs with a set of remarkable properties such as high coordination reactivity, rigidity,oxidative and thermal stability are an important sub-class of POMs. The lacunary species withhigh negative charge and nucleophilic oxygen-enriched surfaces can interact with various cations[۲-۴]. In this work, a new hybrid based on lacunary polyoxotungstate (K۸[SiW۱۱O۳۹]), Copper(II)nitrate trihydrate (Cu(NO۳)۲•۳H۲O) and chelidamic acid (C۷H۵NO۵) was synthesized.Furthermore, the synthesized hybrid showed high catalytic activity in the degradation of methyleneblue (MB) as an organic pollutant and degradation efficiency reached ۹۳.۸۳% within ۱۲۰ min.

Keywords:

Polyoxometalate , Lacunary , Keggin , Catalysis , Methylene Blue