A lumped-parameter model has been developed to predict the performances of diffusion dialysis using anion-exchange membrane (NEOSEPTA(R)-AFN) fur hydrochloric acid recovery in terms of various operating parameters. The operating parameters investigated in this study included the feed concentration, the retention time, and the ratio of reed to water (recipient) flow rate. The mass transfer coefficients of liquid films in continuous dialyzer were estimated from the Sherwood number (Sh) which was correlated to the Schmidt number (Sc) and the Reynolds number (Re). The results obtained from diffusion dialysis using continuous dialyzer showed that the model gave reasonably good agreement with the experimental results in predicting the recovery yield and the recovered acid concentration in the range of 0.05-3 mol dm(-3) HCl.