Isolation of Chromium(VI) from Aqueous Solution by Electromembrane Extraction

摘要

Electromembrane extraction (EME) is a powerful extraction and preconcentration technique for ionizable species. However, the ionic contents in the sample can influence the extraction efficiency and system stability due to electrolysis. In this work, the electromembrane extraction of chromium(VI) was developed using various levels of ionic samples. 2-Nitrophenyl octyl ether was the most suitable supported liquid membrane that delayed the electrolytic occurrence of air bubbles at the electrodes due to its high viscosity and high dielectric constant properties. The electromembrane extraction method was optimized using 5mM NaCl (630 mu Scm(-1)); the applied potential was 100V and the extraction time was 15min. The enrichment factor of 80 was obtained over a linear working range of 10.0-80.0 mu gL(-1). The method performance was tested using mineral water, drinking water, tap water, and surface water. The method recoveries based on matrix-matched calibration were 95-125% with standard deviations within 15%.