An approach to fouling characterization of an ion-exchange membrane using current-voltage relation and electrical impedance spectroscopy.
Fouling phenomena of an anion-exchange membrane by bovine serum albumin (BSA) were investigated using current-voltage relation and electrical impedance spectroscopy (EIS) in this study. Electrochemical parameters of the Neosepta CMX cation- and AMX anion-exchange membrane (Tokuyama Corp., Japan) such as limiting current density (LCD), transport number, plateau length, and fraction of the conducting phase were measured. Fraction of the conducting phase of the ion-exchange membranes, calculated from the modified Sand equation, played an important role in determining the electrochemical parameters in the presence of foulants such as BSA. Fraction of the conducting phase of the AMX membrane significantly decreased in the presence of BSA. Two distinguishable slopes were observed in the over-LCD region of the current-voltage (I-V) curve, indicating the change of resistance. To further elucidate the phenomena, the electrical impedance spectroscopic study was carried out using the offset alternating current. It was found that the negatively charged loose fouling layer changed to the dense deposited BSA on the surface of the AMX membrane occurring along with enhanced water dissociation phenomena at the surface of the fouled AMX membrane at a higher current density. This result was confirmed by water dissociation experiments in a six-compartment electrodialysis cell.
Park
Jin-Soo
JS
Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Gwangju 500-712, South Korea. park@kier.re.kr
Choi
Jae-Hwan
JH
Yeon
Kyeong-Ho
KH
Moon
Seung-Hyeon
SH
D000327:Adsorption; D003956:Dialysis / Q000379:methods; D017097:Electric Impedance; D004563:Electrochemistry; D004868:Equipment Failure; D007474:Ion Exchange; D008564:Membrane Potentials; D008567:Membranes, Artificial; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods; D055672:Static Electricity; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D008567:Membranes, Artificial; D014867:Water; D012710:Serum Albumin, Bovine