Wen's Research Group
New paper published on PFAS rejection in commercial reverse osmosis (RO) and nanofiltration (NF) processes
Dr. Wen Zhang’s group at New Jersey Institute of Technology published a paper in Journal of Water Process Engineering (https://doi.org/10.1016/j.jwpe.2024.106039 or https://authors.elsevier.com/a/1jhe07taLYXQ%7Ei), which evaluated various factors impacting PFAS rejection in commercial RO and NF processes. These findings are crucial for developing efficient PFAS removal methods and optimizing existing treatment systems, thereby contributing significantly to the ongoing efforts to combat PFAS contamination.
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张文博士团队在新泽西理工学院的研究深入探讨了不同表面活性剂、离子价态和溶液温度对商业反渗透（RO）和纳滤（NF）膜过程中PFAS（全氟和多氟烷基物质）去除效率的影响。研究结果表明，阳离子表面活性剂（如十六烷基三甲基溴化铵（CTAB））会通过与带负电荷的全氟辛酸（PFOA）和全氟丁酸（PFBA）结合，通过尺寸排阻作用阻止它们穿过膜孔，从而增加了对两种选定的全氟羧酸（PFOA和PFBA）的截留率、十二烷基硫酸钠（SDS）等阴离子表面活性剂的存在增加了对全氟辛烷磺酸的排斥则是由于吸附在膜表面的SDS使得膜的静电斥力增加，进而阻止了全氟辛烷磺酸接近和吸附到膜表面。此外，离子价较高的阴阳离子（如 Al3+ 和 PO43-）可通过增加有效分子尺寸和电负性来提高对 PFOA 和 PFBA 的抑制率。最后，只有 45 °C 的高溶液温度才会明显降低全氟羧酸的抑制效率，因为膜孔会受热膨胀，从而增加全氟羧酸的通过率。这些研究结果对优化PFAS去除技术至关重要。了解表面活性剂、离子价态和温度的作用，可以帮助工程师和科学家更好地设计和调整RO和NF系统，以提高处理受污染水源中PFAS的效率。
Wen Zhang, Ph.D., P.E., BCEE
Principal Investigator
Professor
Phone: (973) 596-5520
Fax: (973) 596-5790
Email: wen.zhang@njit.edu
Office Location: Colton Hall 211
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Especially, this study assessed the rejection or removal efficacy of PFAS by commercial reverse osmosis (RO) and nanofiltration (NF) membranes and examined the impacts of surfactants, ion valency and solution temperature that are inadequately explored. The results reveal that the presence of cationic surfactants such as cetyltrimethylammonium bromide (CTAB) increased the rejection of two selected PFAS compounds, perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA), by binding with negatively charged PFAS and preventing them from passing through membrane pores via size exclusion, whereas the presence of anionic surfactants such as sodium dodecyl sulfate (SDS) increased the PFAS rejection because the increased electrostatic repulsion prevented PFAS from approaching and adsorbing onto the membrane surface. Moreover, aqueous ions (e.g., Al3+ and PO43−) with higher ion valency enabled higher rejection of PFOA and PFBA through increased effective molecular size and increased electronegativity. Finally, only high solution temperature at 45 °C significantly reduced PFAS rejection efficiency because of the thermally expanded membrane pores and thus the increased leakage of PFAS.
This research was carried out in the NSF Industry/University Cooperative Research Center for Membrane Science, Engineering and Technology that has been supported by the NSF Award IIP-1822130. The authors want to thank the constructive feedback from the project mentors, Uwe Beuscher from W.L. Gore & Associates, Inc. and Albert Wu from 3M as well as support from the MAST center's industrial advisory board (IAB) members
Sep.2024: Dr. Zhang’s team was awarded the 2024 USDA grant on nanobubble research