Polyoxometalate-Based Materials for the Removal of Contaminants from Wastewater: A Review

Abstract

Water pollution from the continuous disposal of hazardous substances has become a serious issue and a global concern for the environment and public health. Removal of these pollutants from water is an ongoing challenge, and several approaches have been proposed and applied for this purpose. Adsorption is one of the common and most efficient approaches often used because it is simple, quick processing, inexpensive, and eco-friendly. Polyoxometalates (POMs) are a well-known class of metal–oxygen cluster compounds with tunable structure and size and highly electronegative and oxo-enriched surfaces. Owing to their electronic and physical properties, they have attracted considerable attention in the field of pollutants removal from wastewater. This review discusses the advances made over the last 10 years in the removal of toxic pollutants from wastewater using POMs-based materials. Furthermore, we summarize the recent synthetic strategies used to modify POMs-based materials and their applications in adsorption of pollutants. Knowledge gaps and current challenges in this research area are also discussed to support the development prospect of these materials for industrial use.

Hybrid Cu-Containing Compounds Based on Lacunary Strandberg Anions: Synthesis under Mild Conditions, Crystal Structure, and Magnetic Properties

“…The purification of wastewater from dye contaminants has become one of the intensively studied processes, and recent reviews , reported the perspective on the use of POM-based compounds for this purpose. As it was shown in numerous studies, the main process of the removal of organic dyes from water is photocatalytic degradation. − The works where compounds acted as adsorbents were far fewer. , Previously, we reported the Strandberg-based complex activity toward the adsorption of cationic dye methylene blue (MB) for the first time . Compounds 1 and 2 were chosen as suitable candidates to continue this study due to their very low solubility in water and to compare their sorption ability depending on the type of POM.…”

“…52,53 Sorption Properties. The purification of wastewater from dye contaminants has become one of the intensively studied processes, and recent reviews 54,55 reported the perspective on the use of POM-based compounds for this purpose. As it was shown in numerous studies, the main process of the removal of organic dyes from water is photocatalytic degradation.…”

Improvement of the Hydrolytic Stability of the Keggin Molybdo- and Tungsto-Phosphate Anions by Cyclodextrins

“…Dodecamolybdophosphate and dodecatungstophosphate are among the most known and studied polyoxometalates (POMs) due to their important properties valuable for many applications in various fields of research such as catalysis, , energy, , biology, and the environment. , This class of highly soluble metal-oxo clusters was first discovered by Berzelius in the early 19th century, but their structure was not determined until more than 100 years later by Keggin . The heteropolyanion is composed of a metal-oxo shell containing 12 MO 6 polyhedra (M = Mo VI or W VI ) connected together that defined a central tetrahedral cavity in which a phosphorus atom P V is located (Figure a), leading to a general chemical formula PM 12 O 40 3– , hereafter abbreviated as {PM 12 }.…”

Two U(VI)-Containing Silicotungstates with Sandwich Structures: Lewis Acid–Base Synergistic Catalyzed Synthesis of Benzodiazepines and Pyrazoles

“…Since the Fukushima-Daiichi nuclear accident and the subsequent decision to release nuclear wastewater into the ocean, the international community has shown growing concern about radionuclide-related environmental pollution. , Polyoxometalates (POMs) are polynuclear metal–oxygen cluster compounds that are structurally diverse, designable, and soft, and almost all of the metal and non-metal elements could be introduced into POMs. Thus, POMs have shown promise for controlling radionuclide pollution. − Due to the unique features of 5f electrons, actinides always show abundant oxidation states and are well self-assembled members of POMs. The obtained actinide-containing POMs may exhibit fascinating structures and properties, − which may promote the development of the enrichment of radionuclides, separation and immobilization of spent fuel, and studies of the migration behavior of actinides. , Moreover, the study of actinide-containing POMs may also provide insight into the geochemical processes and new decontamination approaches. − …”