Extraction and Determination of Copper(II) from Wastewater with Hydrophilic Ionic Liquid-Salt Aqueous Two-Phase System

Abstract

In this paper, a novel method of extraction and spectrophotometric determination of copper in ionic liquid aqueous two-phase system(ATPS) formed by a hydropilic ionic liquid 1-ethyl-3- methylimidazolium ethyl sulfate [C₂mim][ESO₄] and K₂HPO₄ was developed. In the ionic 1iquid aqueous two-phase system of pH 8, the complex formed by acid chromium blue K and Cu²⁺ had a high absorbance with the maximum absorption of 541 nm. The effects of ionic liquid dosage, solution acidity, the dosages of acid chromium blue K and salt on the extraction determination of copper were studied. Beer’s law was obeyed in the range of 0.040-2.0 μg/mL Cu²⁺. The method has been applied to the determination of copper in electroplating wastewater and standard copper sample GBW(E)08036.