Polyoxometalate-based materials against environmental pollutants: A review

Environmental pollution has been a threat since the industrial revolution. Environmental pollution has extensively increased in the last few decades because of human activity and the rapid expansion of modern industry and agriculture. Different pollutants like dyes, heavy metals, etc. can not only affect human health, but also that of other living things. Therefore, there is an urgent need for the application of suitable approaches and materials to mitigate toxic pollutants in the environment. Polyoxometalates (POMs), representing a group of metal-oxide clusters with high thermal stability, high negative charges, modification capability, and remarkable redox and ligand capabilities, are examples of materials used in environmental chemistry. They can function as remediation adsorbents and catalysts in pollution monitoring and control. This article gives a state-of-the-art overview of POMs and their synthetic strategies and presents the recent progress of POM-based materials (POMBMs) used in environmental pollution studies. It examines different POM-based composites and their applications in pollutant/contaminant monitoring (in conjunction with various analytical techniques) and abatement. Possible adsorption and catalytic degradation mechanisms are also described. Finally, the current challenges, gaps, future directions and prospects for improving the utility and applicability of POMBMs are presented. It is hoped that the article is timely and provides a comprehensive perspective on designing, constructing and applying POMs and POMBMs as adsorbents and/or catalysts for environmental pollution research.