REMOVAL AND RECOVERY OF COPPER-ION (CU2-IMMOBILIZED CELLS OF PSEUDOMONAS-PUTIDA 5X() FROM ELECTROPLATING EFFLUENT BY A BIOREACTOR CONTAINING MAGNETITE)

Copper ion (Cu2+) is one of the major heavy metal ions in electroplati ng effluent and the amount of copper-laden waste production is the hig hest among all heavy metals in Hong Kong. A copper-resistant bacterial strain, P. putida 5X, were immobilized on magnetites (Fe3O4) to remov e large amount of Cu2+ from electroplating effluent. The removal capac ity (RC) of the immobilized cells could reach 14 mg Cu2+/g immobilized dry cells under optimal conditions (retention time of 25 min, tempera ture at 24 degrees C and pH 5.5). A computer-operated stirring tank re actor containing magnetic-immobilized cells was used to study the cont inuous adsorption of Cu2+. Under optimal conditions (retention time of 25 min and flow rate of 80 ml/min), the RC was 13.39 mg Cu2+/g immobi lized dry cells and the removal efficiency (RE, mg Cu2+ removed/mg Cu2 + added, %) could reach 90.28% before the breakpoint. The breakpoint a nd exhaustion appeared at 100 and 385 min, respectively. The feasibili ty of using this bioreactor to treat Cu2+ in electroplating will be di scussed. Copyright (C) 1996 Elsevier Science B.V.