Recycling of Direct Dyes Wastewater by Nylon-6 Nanofibrous Membrane

Textile processing industry generally requires significant amounts of process water for cleaning, rinsing, and dyeing purposes and therefore releases significant amounts of dye polluted waste streams into the environment. In recent years considerable attempts have been made to remove pollutants from these waste streams. One of the promising methods in this regard is membrane filtration. Utilizing this separation method would necessitate the manufacture of effective membranes, such as nanofibrous membranes. Electrospinning is a relatively simple method to produce nanofibers from solutions of different polymers and polymer blends. This paper presents the results of a research on manufacturing a membrane filter by electrospinning Nylon-6 nanofibers on a carbon coated polyurethane substrate and implementing this membrane for dye removal in a filtration system. The membrane sample contained nanofibers with an average diameter of 211 nm. Experiments were run with C.I. Direct yellow 12 as a typical dye pollutant. The effect of coating time, transmembrane pressure, and two different pretreatment methods were investigated and it was observed that by the application of 150ppm coagulant material at 0.75 bar pressure, a filtration efficiency of 98% was achieved.