Efficient hollow fiber supported liquid membrane system for the removal and preconcentration of Cr(VI) at trace levels

A hollow fiber supported liquid membrane (HFSLM) system for the removal and preconcentration of Cr(VI) has been developed and characterized using Aliquat 336 as carrier. The influence of the chemical composition on the efficiency of the membrane system has been investigated, such as the organic solvent and the stripping composition. Among the stripping reagents tested, a solution of 0.5 M HNO3 was found to be the most effective to strip Cr(VI) from the loaded organic phase. Moreover, physical parameters such as the stability of the membrane and the operation mode of the module were also evaluated. The results demonstrated the effectiveness of the HFSLM system during 8 non-stop days’ operation. This membrane-based separation system has effectively been used to remove Cr(VI) from different aqueous samples, such as industrial waters and spiked natural waters at μg L−1 levels. Moreover, the system has allowed both the separation and enrichment of the metal and, thus, facilitating the detection of chromate contained in aqueous samples and reducing the volume of polluted water to be treated.