Conventional ultrafiltration as effective strategy for dye/salt fractionation in textile wastewater treatment

Mei Jiang, Kunfeng Ye, Jiajie Deng, Jiuyang Lin*, Wenyuan Ye, Shuaifei Zhao, Bart Van der Bruggen

*Corresponding author for this work

    Research output: Contribution to journalArticle

    37 Citations (Scopus)

    Abstract

    Use of tight ultrafiltration (UF) membranes has created a new pathway in fractionation of dye/salt mixtures from textile wastewater for sustainable resource recovery. Unexpectedly, a consistently high rejection for the dyes with smaller sizes related to the pore sizes of tight UF membranes is yielded. The potential mechanism involved in this puzzle remains unclear. In this study, seven tailored UF membranes with molecular weight cut-offs (MWCOs) from 6050 to 17530 Da were applied to separate dye/salt mixtures. These UF membranes allowed a complete transfer for NaCl and Na2SO4, due to large pore sizes. Additionally, these UF membranes had acceptably high rejections for direct and reactive dyes, due to the aggregation of dyes as clusters for enhanced sizes and low diffusivity. Specifically, the membrane with an MWCO of 7310 Da showed a complete rejection for reactive blue 2 and direct dyes. An integrated UF-diafiltration process was subsequently designed for fractionation of reactive blue 2/Na2SO4 mixture, achieving 99.84% desalination efficiency and 97.47% dye recovery. Furthermore, reactive blue 2 can be concentrated from 2.01 to 31.80 g·L-1. These results indicate that UF membranes even with porous structures are promising for effective fractionation of dyes and salts in sustainable textile wastewater treatment.

    Original languageEnglish
    Pages (from-to)10698–10708
    Number of pages11
    JournalEnvironmental Science and Technology
    Volume52
    Issue number18
    Early online date17 Aug 2018
    DOIs
    Publication statusPublished - 18 Sep 2018

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