DETERMINATION OF HEAVY-METAL CONCENTRATION IN FEED AND PERMEATE STREAMS OF POLYMER ENHANCED ULTRAFILTRATION PROCESS

Polymer enhanced ultrafiltration (PEUF) is a newly developed method fo r the removal of heavy metals from aqueous solutions. This method was applied for the removal of mercury and cadmium with the presence of po lyethyleneimine (PEI) as a water soluble polymer. After ultrafiltratio n experiments for metal-polymer mixtures, two separate streams, namely , retentate and permeate, former of which contains mainly metal-polyme r complex and free polymer molecules while latter of which mainly cont ains free metal ions, were obtained. At the end of PEUF experiments, p erformance of operation was determined by concentration analyses which was achieved by atomic absorption spectroscopy (AAS) applied in a dif ferent way for permeate and retentate streams considering the effect o f presence of polymer. For mercury analysis, cold vapor AAS was applie d. It was observed that the presence of PEI did not affect the atomic absorption signal when 10% HCl was added to the sample solutions. For calcium and cadmium, flame AAS was used. It was observed that change i n PEI concentration results in change in measured concentration of cal cium and cadmium. Therefore, two new approaches were developed for acc urate measurement of concentrations of calcium and cadmium. It was als o observed that presence of other metals did not affect the accuracy o f the measurement of a particular metal in the concentration range stu died. (C) 1998 Elsevier Science B.V. All rights reserved.