On the prediction of permeate flux for nanofiltration of concentrated aqueous solutions with thin-film composite polyamide membranes

摘要: Abstract The nanofiltration of binary aqueous solutions glucose, sucrose and sodium sulfate was investigated using thin-film composite polyamide membranes with different molecular weight cut-off's. NF experiments, in total recycle mode, were performed a plate-and-frame module Lab 20 (AlfaLaval), at 22 °C flowrate 8.2 L/min, the NF90, NF200 NF270 from FilmTec (Dow Chemical), for transmembrane pressures between 1 6 MPa osmotic 0.5 3.0 MPa. permeate flux predicted by pressure model, membrane hydraulic resistance solution viscosity inside pores, computing concentration polarization recourse to mass-transfer correlation specific used. predictions, pure water viscosity, agree reasonably experimental data only low most diluted solutions. For higher solute fluxes can be as far 2.5, 4.1 9.6 times than one, Na 2 SO 4 , glucose sucrose, respectively. These deviations are strongly reduced when is replaced adjacent membrane. In this case, maximum deviation predictions experiments occurs also concentration, but ratio values now 1.8, 2.1 2.9, Even membrane, systems investigated, model must used caution design purposes because it may over predict factor about high.