Decolorization of reactive dyebath containing high exhaust and low salt dyes by nanofiltration and its reuse

Abstract

AbstractNanofiltration (NF) is a relatively new field in membrane technology, which has the potential to be the front‐runner in management of reactive dyeing effluents with respect to removal of color to enable reuse of salt. This paper discusses the performance of NF‐270‐2540 FILMTEC NF membrane for color removal and salt recovery from exhausted reactive dyebaths. Simulated dyebaths containing high exhaust (CI Red 120, CI Yellow 84 and CI Blue 4) and low salt (Cibacron Red LS6G, Yellow LSR, Blue LSG) reactive dyes were prepared for light, medium, and dark shades. The dye retention decreased at high salt concentrations of 60 and 90 g/L. The chemical oxygen demand (COD) and total organic carbon removal efficiency was in the range of 80–90%. The permeate flux significantly decreased beyond a salt concentration of 40 g/L. The reusability studies on the recovered permeate showed that it could be reused for light, medium, and dark shades. © 2008 American Institute of Chemical Engineers Environ Prog, 2008