A novel positively charged nanofiltration membrane stimulated by amino-functionalized MXene Ti3C2Tx for high rejection of water hardness ions

• Published in: Journal of membrane science Vol. 671
• Main Authors: Li, Qingqing, Zhang, Tianmeng, Dai, Zhixiang, Su, Fangyan, Xia, Xiangwei, Dong, Ping, Zhang, Jianfeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.04.2023
• Subjects: Interfacial polymerization; MXene membrane; Positively charged nanofiltration membrane; Separation performance; Water softening; MXene membrane; Water softening; Interfacial polymerization; Positively charged nanofiltration membrane; Separation performance
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2023.121385

The demand to address issues such as drinking water safety and industrial fouling caused by high-hardness ions has still emphasized the development of advanced membrane materials. In this study, through a maneuverable amide-cross-linking strategy, a new positively-charged polyamide (PA) nanofiltration membrane was developed for the first time by incorporating amino-functionalized Ti3C2Tx nanoparticles (Ti3C2Tx-NH2, TN). In addition to the induced electropositivity, the hydrophilicity of the as-obtained PA-TN membrane was also elevated with a maintained nodular structure by tailoring the interfacial polymerization reaction process of piperazine (PIP) with trimesoyl chloride (TMC). Therefore, the newly developed PA-TN membrane exhibited both superhigh rejection of Ca2+ and Mg2+ over 96%, and the flux increased 2–3 times even for the salinity solutions than many similar NF membranes reported in literature. Furthermore, the enhanced long-term stability and fouling resistance of the PA-TN membrane was also validated due to its new organic-inorganic structural coupling and improved hydrophilicity. This work provides a new strategy for the preparation of organic-inorganic hybrid positively charged nanofiltration membranes for water softening treatment. [Display omitted] •Ti3C2Tx-NH2 was applied to positively-charged PA NF membrane for the first time.•Ti3C2Tx-NH2 induced electropositivity and elevated the hydrophilicity of the PA-TN.•PA-TN had great separation performance for Ca2+ and Mg2+.•PA-TN had good long-term stability and fouling resistance.