LAUSR

Abstract A breakthrough curve in nanofiltration (NF) is observed when micropollutants adsorption and subsequent diffusion through the membrane occur at environmentally relevant low concentrations. The role of hydrodynamics and operative conditions to characterize the curve shape is unknown. In this study, the impact of mass transport and residence time on the breakthrough curve shape of loose NF270 and tight NF90 is determined. Cross flow and stirred cell filtration systems are used to evaluate the breakthrough curve shape at different range of external mass transfer (km) and estradiol (E2) residence time in the boundary and active layers, respectively. Residence time is a relevant parameter to control the breakthrough curve S-shape of loose NF270, when equilibrium in the permeate is reached at low cumulative permeate volume. km controls the curve steepness (hence permeate concentration) and adsorption in both cross flow and stirred cell without variation of initial S-shaped curve. The latter is observed only when the intraporous mass transfer is significantly higher compared to km. These novel findings are important for evaluation of breakthrough curve of new NF membrane materials by an appropriate selection of operative and hydrodynamic conditions.