Centrifugal polyelectrolyte enhanced ultrafiltration for removal of copper-citrate complexes from aqueous solutions

To replace the conventional dead-end polyelectrolyte enhanced filtration (PEUF), which is a time consuming process in the optimization of process variables, centrifugal polyelectrolyte enhanced ultrafiltration was investigated to remove copper-citrate complex in aqueous phase with a cationic polyelectrolyte, poly(diallydimethylammonium chloride) (PDADMAC). Effects of concentration ratios between polyelectrolyte, copper, and citrate and pH were observed. Below pH 3, copper was not removed by centrifugal PEUF. At the same concentration (1 mM) of citrate and copper, removal of copper at pH 5 was the highest value of 54%, 90%, and 98% with 5, 10, and 20 mM PDADMAC, respectively. Removal of copper decreased with the logarithmic ionic strength. Since the centrifugal PEUF is very economical in time compared with conventional dead-end PEUF, the present method should be a valuable tool in the optimization of process variables.