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The performance of a rotating fixed bed reactor in recovering copper from industrial waste solutions by cementation has been studied in the laboratory under various operating conditions. The rotating fixed bed was made of closely stacked horizontal steel screens discs (with a diameter of 15 cm) held together by an insulated stainless steel wire. This arrangement was able to present a large area per unit volume and promote high turbulence. Variables studied were initial CuSO4 concentration, bed rotation speed, mesh number of the screens and bed thickness. The presence of baffles was found to increase the rate of cementation. The results were correlated using a dimensionless mass transfer equation and were found to be suitable for the scale-up and operation of the rotating bed reactor., 30 refs., The performance of a rotating fixed bed reactor in recovering copper from industrial waste solutions by cementation has been studied in the laboratory under various operating conditions. The rotating fixed bed was made of closely stacked horizontal steel screens discs (with a diameter of 15 cm) held together by an insulated stainless steel wire. This arrangement was able to present a large area per unit volume and promote high turbulence. Variables studied were initial CuSO4 concentration, bed rotation speed, mesh number of the screens and bed thickness. The presence of baffles was found to increase the rate of cementation. The results were correlated using a dimensionless mass transfer equation and were found to be suitable for the scale-up and operation of the rotating bed reactor.

© 2017 American Chemical Society. An electrochemical technique is developed to activate graphene oxide (GO) at relatively low temperature and assemble it into porous electrodes. The activation process is carried out in molten KOH by switching the polarity between 2 symmetrical GO electrodes. The electrochemically activated graphene (ECAG) showed a specific surface area as high as 2170 m2 g-1 and nanometer-sized pore created at a temperature as low as 450 °C. The ECAG electrode shows a significant enhancement in the electrochemical activity and thus improved electrochemical performance when being used as electrodes in supercapacitors and capacitive deionization (CDI) cells. A specific capacitance of 275 F g-1 is obtained in 6 M KOH electrolyte, and 189 F g-1 in 1 M NaCl electrolyte, which maintains 95% after 5000 cycles. The desalination capacity of the electrodes was evaluated by a batch mode electrosorption experiment. The ECAG electrode was able to remove 14.25 mg of salts per gram of the active materials and satisfy a high adsorption rate of 2.01 mg g-1 min-1. The low energy consumption of the CDI system is demonstrated by its high charge efficiency, which is estimated to be 0.83.