This research focused on the influence of post-treatment using alkali-catalyzed hydrolysis with a full-aromatic nanofiltration (NF) polyamide membrane and its application to the efficient removal of selected dyes. The post-treated membranes were characterized through Fourier transform infrared spectroscopy, goniometry, and zeta-potential analysis to analyze the treatment-induced changes in the intrinsic properties of the membrane. Furthermore, the changes in permeability induced by the post-treatment were evaluated via the measurement of water flux, NaCl rejection, and molecular weight cutoff (MWCO) under different pH conditions and post-treatment times. Major changes induced by the post-treatment in terms of physicochemical properties were the enhancement of permeability, hydrophilicity, and negative charge due to the hydrolysis of the membrane's amide bonds. Four different dyes were selected as representative organic pollutants considering the MWCO of the post-treated membranes. Compared with the pristine NF membrane, membranes post-treated at pH 13.5 showed better water flux with similar rejection of the target dyes. On the basis of these results, the proposed post-treatment method for NF membranes can be applied to the removal of organic pollutants of various size.
Bibliographical noteFunding Information:
The authors are grateful to the three anonymous reviewers for their insightful and constructive comments, which greatly improved the quality of the paper. This study was funded by the Korea Ministry of Environment (The SEM projects, 2018002470005, South Korea), and Basic Science Research Program through the National Research Foundation of Korea supported by the Ministry of Education (NRF-2018R1A6A1A03024962). APC was funded by University of South Carolina and Water.
© 2019 by the authors.
- Alkali-catalyzed hydrolysis
- Dyes removal
- Polyamide membrane