Application of direct contact membrane distillation for textile wastewater treatment and fouling study

Direct contact membrane distillation (DCMD) process was applied for the treatment of textile dyes solutions using a flat-sheet polyvinylidene fluoride (PVDF) membrane. Both cationic (Maxilon Blue 5G, Drimarene Yellow K-2R) and anionic (Sodium Fluorescein) dyes have been considered. A model-type of a textile wastewater solution containing salts and the three cited dyes have also been tested to simulate real discharges of textile industries. The effects of DCMD operating parameters on the permeate flux and separation factor have been studied. Fouling phenomenon on both the membrane surface and in its pores was investigated by means of various characterization techniques and the permeate flux reduction factor together with the irreversible fouling index were determined. Different fouling mechanisms in DCMD could be established for each type of dye.