Removal of chromium from aqueous solution by complexation - Ultrafiltration using a water-soluble macroligand

A process for purifying waste waters containing heavy and toxic metal such as chromium has been studied. A batch complexation-ultrafiltration process was used to concentrate and recover chromium from sulphate solution. As the chromium ions cli e tao small to be retained by the filter, they are fil s t complexed with a water-soluble macroligand (polyethylene-imine), Factors affecting the rejection late and permeate flux such as pH, concentration li gand. chloride and sulphate concentration, membrane pore size, applied pres sure and extraction factor were investigated. Best operating conditions can be obtained in order to achieve high levels of removal (>95%). Then, decom plexation is obtained so that metal can be separated from macroligand by se cond ultrafiltration plant to reuse the macroligand. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.