Recovery of Methyl Green from Aqueous Solution using NF Membrane

Abstract

Recovery of a cationic synthetic dye, methyl green by nanofiltration (NF 270–400) membrane from commercial source (Filmtec, USA) was used for this study. The effect of membrane characteristics, applied pressure gradient ( ΔP ) and aqueous phase concentration of dye on the rejection, membrane fouling and water flux was studied over a range of pressure and concentration of 2 to 5 bar and 0.01 mmole L^–1 to 0.05 mmole L^–1 respectively. The solution flux increases with pressure in the pressure range studied indicate the effect of concentration polarization is not significant in this range. The cation shield effects of the dye on the negatively charged polyamide membrane perhaps result in decrease of permeate flux with concentration. The permeation phenomenon has been analyzed on the basis of pore flow transport model and the data analysis revealed that adsorption of dye on the membrane surface and intrinsic membrane resistance control the permeate flux.