Zirconium-based nanoclusters as molecular robots for water decontamination.

Water contamination owing to anionic pollutants is a persisting and ubiquitous global threat. The current remediation technologies are mostly low in efficiency, expensive in materials and often associated with complicated processes. Herein, we report a characteristic zirconium-based nanocluster that can work as molecular robots for the efficient remediation of anions-contaminated water with great effectiveness and molecular-level accuracy. It exhibits a stimuli-responsive behavior to facilitate the water treatment process: dissolve in acidic aqueous solutions for molecular-level decontamination and quickly aggregate for post-remediation collection. It can precisely capture the representative anionic pollutants, whilst featuring satisfactory capacities (ca. 175 mg-arsenic/g, 60 mg-chromium/g, 45 mg-fluoride/g, 70 mg-phosphorus/g, respectively), super-fast kinetics (finishing uptake within seconds, which is two to four orders of magnitude faster than typical sorbents), as well as multi-cycle applications without appreciable loss of activity. The coexisting common ions show no effect on the target uptake. The responsible active site investigation shows that four active sites are responsible for the monovalent pollutant removal, and the active sites work in pairs to capture divalent chromate species. Cost analysis shows its economical applicability in practical applications. This work would lead to the development of effective water decontamination with higher effectiveness, more convenience, lower cost and more practical application value.