화학공학소재연구정보센터
Electrochimica Acta, Vol.140, 529-534, 2014
Impedance spectra of anodic dissolution of iron in distillery vinasse
Electrocoagulation technique has a great application potential to treat distillery vinasse, a liquid effluent generated from alcohol distilleries. The anodic dissolution of carbon steel in this effluent in the potential range of -750 mV to -100 mV was investigated by potentiodynamic polarization; likewise, the electrochemical impedance spectroscopy spectra were registered over anodic potentials of -560 mV, -500 mV and -400 mV (overpotentials of 20 mV, 80 mV and 180 mV) corresponding to the active dissolution region in order to propose a mechanism for describing the behavior of the carbon steel electrodissolution. Were explored the effects of the flow regime (Reynolds number of 5,500 and 11,500) and the temperature (60 degrees C and 80 degrees C) over the behavior of the spectra. At low current densities the impedance behavior can be satisfactorily described by the combination of the catalytic and non-catalytic mechanism of iron dissolution. It was also found that the dissolution must be carry out at current densities closely to 1 mA cm(-2) to prevent the possible formation of iron oxide layers on the anode. The anodic dissolution was favored by increasing the flow regime and temperature as well. (C) 2014 Elsevier Ltd. All rights reserved.