Fouling on ion-exchange membranes: Classification, characterization and strategies of prevention and control.

Measurement of complexation properties of humic and fulvic acids in natural waters with lead and copper ion-selective electrodes.

Fouling of electrodialysis membranes by organic substances

Effects of pulsed electric fields on membrane fouling in electrodialysis of NaCl solution containing humate

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.

P.M. Heertjes

Papers

The poisoning of anion-selective membranes by sodium dodecylsulphate

The poisoning of anion-selective membranes by humic substances