Diffusion dialysis (DD) is widely used to recover acid from waste water. This study examined the acid adsorption phenomenon from the non-steady state to dynamic equilibrium in a continuous dialyzer, and obtains the breakthrough curves at different acid concentrations and for different acid species (HNO3, H2SO4, H3PO4). Then the dynamic adsorption capacities (Q(ads)) were calculated from breakthrough curves via the integration method, and they were identical to the Freundlich equilibrium isotherm. Finally, the operating conditions, such as the volumetric liquid flow rate of the feed, flow ratio and temperature were optimized on the basis of the adsorption and diffusion phenomenon in the DD process. (C) 2013 Elsevier B.V. All rights reserved.