Removal and recovery of copper ion (Cu2+) from electroplating effluent by a bioreactor containing magnetite-immobilized cells of Pseudomonas putida 5X

Copper ion (Cu2+) is one of the major heavy metal ions in electroplating effluent and the amount of copper-laden waste production is the highest among all heavy metals in Hong Kong. A copper-resistant bacterial strain, P. putida 5X, were immobilized on magnetites (Fe3O4) to remove large amount of Cu2+ from electroplating effluent. The removal capacity (RC) of the immobilized cells could reach 14 mg Cu2+/g immobilized dry cells under optimal conditions (retention time of 25 min, temperature at 24 degrees C and pH 5.5). A computer-operated stirring tank reactor containing magnetic-immobilized cells was used to study the continuous 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 immobilized dry cells and the removal efficiency (RE, mg Cu2+ removed/mg Cu2+ added, %) could reach 90.28% before the breakpoint. The breakpoint and exhaustion appeared at 100 and 385 min, respectively. The feasibility of using this bioreactor to treat Cu2+ in electroplating will be discussed. Copyright (C) 1996 Elsevier Science B.V.