Liquid membrane transportation of fluoride ions with alizarin based azacrown ether Zr-complex

A new alizarin based azacrown ether N-(alizarin-4-methylene)-4-azadibenzo-18-crown-6 (AMADCE) was synthesized, for the transportation of fluoride ions, by reacting 4-aza dibenzo 18-crown-6 with alizarin in the presence of formaldehyde. The compound forms a stable purple-red coloured complex with Zr(IV) in 0.5–1.0 M hydrochloric acid and gets quantitatively extracted into diphenyl ether. This diphenyl ether extract of the Zr(IV) complex instantaneously transfers fluoride ions from the aqueous phase, which was utilised for the sensitive determination and transportation of fluoride ions through the liquid membrane. The conditions like concentration of membrane phase, acidity of the source phase and the receiving phase, and the transportation time were optimized. The continuous transportation of fluoride ions was achieved by adding receptor ions like La3+ and Ca2+ in the receiving phase. The rate constant K and t1/2 for the transportation were determined. The studies were extended for the removal of fluoride ions through the liquid membrane from the ground water samples and industrial effluent.

Alizarin is substituted on azacrown ether through methylene bridge to give sensitive interaction and complex formation with zirconium and the colored complex was further utilized for the sensitive determination of fluoride by quenching technique. The water insoluble Zr(IV)–alizarin azacrown ether complex also can be used for the liquid membrane transportation of fluoride for the removal of the ion.Figure optionsDownload as PowerPoint slide