Removal of hexavalent chromium by nanofiltration

Removal of chromate CrO42- from water was investigated using nanofiltration as a possible alternative to the conventional methods of CrVI removal from aqueous solution. Retention measurements with single reference salt reveal ed that Donnan exclusion plays an important role. The phenomenological para meters sigma and P were calculated using the Spiegler-Kedem equation. The r ejection rate depends on the ionic strength and pH. The increasing of ionic strength decreases the retention. The effect of pH was clarified by using a stable diagram of the CrVI-H2O system. Better retention was obtained at b asic pH.