Recovery of Ru(III) from hydrochloric acid by cloud point extraction with 2-Mercaptobenzothiazole-functionalized ionic liquid

An arisen and environment-friendly method of cloud point extraction (CPE) which involved Octylphenoxypolyethoxyethanol (TX-114) as surfactant and 2-Mercaptobenzothiazole-functionalized ionic liquid as extractant was carried out to separate Ru(III) from aqueous phase to bottom surfactant phase for the first time. A host of variable ( e.g. , the extractant concentration, hydrochloric acid concentration, nitric acid concentration, TX-114 mass fraction, TX-114 volume and sodium chloride concentration) were evaluated and optimized to investigate the extraction behavior. At optimized experimental conditions, the extraction percentage of Ru(III) was found to be 82%, together with the enrichment factor of 40. A special complexation extraction mechanism of Ru(III) in CPE process was studied systemically and confirmed via job method, UV–vis spectrum and FT-IR spectrum in detail. Taking together, the rational-designed functional ionic liquid as a novel extractant exhibited superior extractability for Ru(III) in CPE system.