An empirical model was developed using the experimental results, to predict the removal of nickel ions under the effect of an external electric field applied to an ultrafiltration membrane, electroultrafiltration (EUF) process. Two commercial membranes from Millipore PLCC5 (regenerated cellulose, 5 kDa) and PBCC5 (polyethersulfone, 5 kDa) were selected to conduct the experiments. The rejection of nickel ions increases with an increment of the applied voltage. The maximum rejection of the metal was found to be 60% obtained with the PBCC5 membrane and applying a potential difference of 3.5 and 4.5 V. The results have shown that the application of an external electric field increases the removal capacity of UF membranes and enhances EUF system efficiency. The experimental data for removal of nickel ions in the system were analyzed using the Takagi-Sugeno-Kang (TKS) fuzzy model. The goodness of fit for the TKS fuzzy model used was at least 98%.