MODELLING ION TRANSPORT IN AN AMINE SOLUTION THROUGH A NANOFILTRATION MEMBRANE

摘要

The performance of a flat sheet polyamide nanofiltration membrane in rejection of a binary mixture of heat stable salts(acetate and sulfato from methyl-diethanolamine(MDEA)solution was investigated.The effects of pressure and concentration of MDEA solution on rejection of acetate and sulfate ions were studied.At MDEA concentration of 20% wt.and pressure of 70 bar,80% and 98% rejection can be obtained for acetate and sulfate ions,respectively.Membrane performance and transport coefficients were investigated using the Spiegler-Kedem-Katchalsky(SKK)model,film theory and extended Nernst-Planck(FT-ENP)model.The results of the FT-ENP model show accurate agreement with experimental results.This result can be obtained due to considering the charge repulsion of sulfate ions.For sulfate ions,both models show errors less than 1% with>R~2=0.98.In the case of acetate,errors less than 3%(>R~2=0.75)and 2%(>R~2=0.89)were obtained for the SKK and FT-ENP models,respectively.