Zhou Weizhu, Chen Jiansuxuan, Dai Ruobin, Wang Zhiwei
State Key Laboratory of Water Pollution Control and Green Resource Recycling, Shanghai Institute of Pollution Control and Ecological Security, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
State Key Laboratory of Water Pollution Control and Green Resource Recycling, Shanghai Institute of Pollution Control and Ecological Security, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
Water Res. 2025 Aug 15;282:123762. doi: 10.1016/j.watres.2025.123762. Epub 2025 May 1.
The effective separation and treatment of high-salinity chemical industrial wastewater has become a critical issue for the chemical industry. Membrane separation technology, including ultrafiltration (UF) and nanofiltration (NF) membranes, are potential candidates for selectively separating inorganic salts and organic compounds. In this study, we investigated the selective separation performance of real high-salinity chemical industrial wastewater by a series of commercial UF (UF10k, UF5k, UF3k, and UF1k) and NF (NF270, NF90, BSY90, BSY60, BSY30) membranes. UF1k exhibited the best separation performance among the various UF membranes, owing to its lowest molecular weight cut-off (MWCO) of 1 kDa. Further two-pass UF and coagulation-UF cannot effectively improve the separation performance of UF as the presence of low molecule weight organics in the wastewater. Among the NF membranes, we surprisingly found that some NF membranes, despite having smaller pore sizes theoretically, exhibited even lower rejection of organic matters than UF1k in high-salinity environments. Mechanistic investigation revealed that increased salt concentrations led to pore swelling, pore-wall dehydration and charge shielding effects in NF membranes, which resulted in a substantially enlarged MWCO. BSY90, the tightest NF membrane, exhibited the best performance in the rejection of organic compounds from the high-salinity chemical industrial wastewater, owing to its smallest pore size and highest zeta potential. Our findings offer guidance for the proper selection of UF and NF in the precise selective separation of substances in high-salinity chemical industrial wastewater.
高盐度化工废水的有效分离与处理已成为化工行业的关键问题。包括超滤（UF）和纳滤（NF）膜在内的膜分离技术是选择性分离无机盐和有机化合物的潜在选择。在本研究中，我们通过一系列商用超滤膜（UF10k、UF5k、UF3k和UF1k）和纳滤膜（NF270、NF90、BSY90、BSY60、BSY30）研究了实际高盐度化工废水的选择性分离性能。UF1k在各种超滤膜中表现出最佳的分离性能，这归因于其最低的截留分子量（MWCO）为1 kDa。由于废水中存在低分子量有机物，进一步的两级超滤和混凝-超滤不能有效提高超滤的分离性能。在纳滤膜中，我们惊讶地发现，一些纳滤膜尽管理论上孔径较小，但在高盐环境中对有机物的截留率甚至低于UF1k。机理研究表明，盐浓度的增加导致纳滤膜的孔膨胀、孔壁脱水和电荷屏蔽效应，从而导致截留分子量大幅增大。最紧密的纳滤膜BSY90在从高盐度化工废水中去除有机化合物方面表现出最佳性能，这归因于其最小的孔径和最高的zeta电位。我们的研究结果为在高盐度化工废水的物质精确选择性分离中正确选择超滤和纳滤提供了指导。
