Removal of phosphate in presence of interfering sulphate and arsenate by a tripodal thiourea receptor by precipitation through crystallization in semi-aqueous medium

Abstract

A cyanuric acid platform based tripodal thiourea receptor, L shows encapsulation of phosphate, sulphate and arsenate anions in semi-aqueous medium. Solution phase 1H NMR showed selective recognition of phosphate anion in presence of various anions (e.g. Cl−, Br−, I−, NO3−, HSO4−, CH3CO2− and H2PO4− as TBA salts) in DMSO-d6 at 298 K. L showed partial removal and separation of phosphates from semi-aqueous solution in the presence of interfering arsenate and sulphate via precipitation through crystallization. In the absence of phosphate, L is found to remove/separate arsenate from semi-aqueous medium in presence of sulphate which is the first report of partial removal of arsenate from semi-aqueous medium by a neutral anion receptor. In absence of phosphate and arsenate anions, L could partially remove sulphate anions from mixture of other anions from semi-aqueous solution. All the extracted complexes were characterized by NMR, PXRD, TEM-EDX and Single crystal X-Ray diffraction analysis.