Long-term performance of hollow fibre membrane solvent extraction modules used for Cr(VI) recovery from electroplating rinse water

The long-term performance of a hollow fibre membrane solvent extraction uni t has been investigated for the recovery of Cr(VI) from plating rinse water . A pilot scale experiment was performed in a local electro-plating plant u sing . membrane modules with an area of 0.17 m(2). The separation of Cr(VI) from the rinse liquor was carried out in two hollow fibre membrane modules , and is compared with a single module supported liquid membrane (SLM) whic h was also used in the same service. The Cr(VI) flux declined gradually to half the initial value after 25 days. This was Found to be due to the membr ane fouling combined with the degradation of organic solvent. The loss of o rganic solution was initially severe but stabilized after a few days and be came negligible. The flux in the SLM mode appeared similar but the life tim e was very short, less than a day, however continuous operation was attaina ble by periodic replenishment of the membrane. Using both designs, it has b een shown that Cr(VI) could be extracted from dilute feed into the strippin g solution with an enrichment factor of 10 - 20 times using this technique.