Dispersive liquid-liquid microextraction of zinc from environmental water samples using ionic liquid

Abstract

In this work, the Dispersive Liquid-Liquid Microextraction (DLLME) method has intensified the extraction of Zinc from aqueous solution utilizing 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆] and the retrieved metal was analyzed using UV-Vis spectrophotometer. Several extraction factors such as the volume of extraction solvent, centrifugation speed, pH, salt effect, the volume of dispersive solvent, sonication time, and temperature on extraction recovery using conventional DLLME, Temperature-controlled DLLME, and Ultrasound-assisted DLLME methods, respectively, were investigated. In the comparison of these three methods, the maximum extraction recovery was attained by the Ultrasound-assisted DLLME method with the optimum conditions of 60 µl extractant volume, 0.75 ml of dispersive solvent, 3000 rpm centrifugation speed at the pH of 6, and the temperature of 40 °C with 2 min of sonication. The ionic liquid used in the extraction process was completely recovered by sulfuric acid as a stripping agent and reused several times with less loss in its efficiency. The Ultrasound-assisted DLLME method was successfully applied to electroplating industrial effluent under the experimental optimum conditions and the extraction recovery was achieved by 87.4%.

Keywords:

• Dispersive liquid-liquid microextraction
• ionic liquid
• zinc
• extraction recovery
• industrial effluent

Acknowledgment

The authors gratefully acknowledge the Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai for providing their facilities to carry out the work successfully. The authors also thank all those who have helped in carrying out the research.