Selective cloud point extraction of thorium (IV) using tetraazonium based ionic liquid

Abstract

This study involves the synthesis and characterization of a new tetra-cationic surface-active ionic liquid (SAIL) based on tetraazonia-tricyclo[3.3.1.13,7]decane derivative. The surface properties of the synthesized SAIL revealed good surface activity, self-aggregation and clouding ability indicating its feasibility in surfactant-mediated extraction applications. Applying the synthesized SAIL combined with Triton X-100 as a mixed surfactant system in cloud point extraction of Th(IV) ions resulted in a sensitive and selective extraction procedure. Arsenazo III was used as Th(IV) chelating agent and the pre-concentrated chelate was spectrophotometrically determined. The main variables affecting the extraction efficiency were systematically investigated. The highest extraction efficiency was achieved at pH 5.0 with 2.5 × 10−3 mol L-1 SAIL and 1.0 % (v/v) Triton X-100. At the optimized conditions, the developed method exhibited a linear working range from 10.0 to 100.0 ng mL-1 with a detection limit of 77.0×10-2 ng mL−1. The interfering impact of various ions on Th(IV) extraction efficiency was evaluated. The applicability and reliability of the developed method were evaluated by determining Th(IV) at trace levels in various water samples and the obtained recovery values were ranging from 98.0 to 101.4%. The developed CPE method is sensitive, simple, reliable and consistent with the green chemistry principles.