Tight ultrafiltration membranes for enhanced separation of dyes and Na2SO4 during textile wastewater treatment

Jiuyang Lin, Wenyuan Ye, Marian Cornel Baltaru, Yu Pan Tang, Nicole J. Bernstein, Peng Gao, Stefan Balta, Maria Vlad, Alexander Volodin, Arcadio Sotto, Patricia Luis, Andrew L. Zydney, Bart Van der Bruggen

Research output: Contribution to journalArticlepeer-review

394 Scopus citations


Nanofiltration (NF) membranes have been used previously for the recovery of dyes, salts, and water from textile wastewaters with high salinity. However, commercially available NF membranes have a high rejection for divalent salts (i.e., Na2SO4), substantially reducing the salt recovery and membrane flux when treating textile wastewater containing Na2SO4. In this study, a tight ultrafiltration membrane (UH004, Microdyn-Nadir) was proposed to fractionate the dye and Na2SO4 in the textile wastewater. The UH004 membrane with a molecular weight cutoff of 4700 Da provided complete passage of monovalent salts, with little rejection of Na2SO4. This significantly increases the filtrate flux that can be achieved with high-salinity wastewater since osmotic pressure and concentration polarization effects are minimized. Furthermore, the retention behavior of four different dyes was evaluated to determine the efficiency of this membrane process. This tight ultrafiltration membrane offered the high retention for direct dyes (i.e., direct red 80, direct red 23, and Congo red) and reactive blue 2. For instance, the UH004 membrane yielded >98.9% rejection for all of the dyes at a pressure of 4 bar even in the presence of 60 g L-1 Na2SO4. Subsequently, an ultrafiltration-diafiltration process was designed to separate a dye/Na2SO4 aqueous mixture with 98% desalination efficiency and greater than 97% dye recovery after 5 diavolumes. These results clearly demonstrate that tight ultrafiltration membranes can be a stand-alone alternative to NF membranes for the effective fractionation of dye and Na2SO4 in the direct treatment of high-salinity textile wastewater.

Original languageEnglish (US)
Pages (from-to)217-228
Number of pages12
JournalJournal of Membrane Science
StatePublished - Sep 15 2016

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation


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