A resin-free, precipitation-free and reusable technique was developed for the removal of toxic metal ions and fluoride from extremely polluted water. Credit: ACSFluoride and metal ions are easily removed from potable water with a compound synthesized from picric acid and N,N′-dicyclohexylcarbodiimide. The compound, labeled "Zwitterionic spirocyclic Meisenheimer complex 1" was developed by researchers from the Indian Institute of Science Education and Research Kolkata using low-cost starting materials and a one-pot synthesis technique.

The material is characterized by a high chelating propensity for toxic metals and can detect fluoride up to 12.8 ppb level and remove 82 percent of aqueous fluoride from 1000 mL of 100 ppm fluoride solution in a single contact. The compound successfully removed large amounts of lead, mercury, copper, iron and fluoride — reducing most to levels below World Health Organization standards. Polystyrene sponges coated with the hydrophobic complex were also effective in mopping up oil spill and organic solvents from a biphasic mixture.

The research is published in the journal ACS Omega.