Removal of reactive dye from textile effluent through submerged filtration using hollow fiber composite nanofiltlration membrane

The removal of reactive dye from textile effluent through submerged nanofiltration (NF) was investigated in this study. The textile effluent containing reactive dye of Reactive Black 5 was treated with a hollow fiber membrane module manufactured from laboratory-fabricated composite NF membranes with a molecular weight cutoff of 760Da. The submerged NF system was evaluated for dye removal efficiency, permeate flux and permeation resistance as a function of transmembrane pressure (TMP) and volume concentrating factor (VCF). It was found that, under the suction pressure of lower than 1.0bar, the membrane retained nearly all the dye molecules presented in the textile effluent but retained the electrolytes to a much low extent, so that the submerged filtration system could be operated under low suction pressure. Dye removal efficiency increased with increasing TMP, while permeability decreased with increasing TMP and VCF. Average dye removal rate of higher than 99.8% and steady flux of 5.75l/m(2)h could be achieved by the submerged NF system operated under the TMP of 0.8bar and VCF of 4.0. Furthermore, the submerged NF system possessed good antifouling property and high water cleaning efficiency.