Escamilla Paula, Monteleone Marcello, Percoco Rita Maria, Mastropietro Teresa F, Longo Mariagiulia, Esposito Elisa, Fuoco Alessio, Jansen Johannes C, Elliani Rosangela, Tagarelli Antonio, Ferrando-Soria Jesus, Amendola Valeria, Pardo Emilio, Armentano Donatella
Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Paterna, Valencia 46980, Spain.
Institute on Membrane Technology, CNR-ITM, Via P. Bucci 17/C, Rende, Cosenza 87036, Italy.
ACS Appl Mater Interfaces. 2024 Sep 25;16(38):51182-51194. doi: 10.1021/acsami.4c12363. Epub 2024 Sep 13.
Heavy metal ions are a common source of water pollution. In this study, two novel membranes with biobased metal-organic frameworks (BioMOFs) embedded in a polyacrylonitrile matrix with tailored porosity were prepared via nonsolvent induced phase separation methods and designed to efficiently adsorb heavy metal ions from oligomineral water. Under optimized preparation conditions, stable membranes with high MOF loading up to 50 wt % and a cocontinuous sponge-like morphology and a high water permeability of 50-60 L m h bar were obtained. The tortuous flow path in combination with a low water flow rate guarantees maximum contact time between the fluid and the MOFs, and thus a high heavy metal capture efficiency in a single pass. The performances of these BioMOF@PAN membranes were investigated in the dynamic regime for the simultaneous removal of Pb, Cd, and Hg heavy metals from aqueous environments in the presence of common interfering ions. The new composite adsorbing membranes are capable of reducing the concentration of heavy metal pollutants in a single pass and at much higher efficiency than previously reported membranes. The enhanced performance of the mixed matrix membranes is attributed to the presence of multiple recognition sites which densely decorate the BioMOF channels: (i) the thioether groups, deriving from the -methyl-l-cysteine and ()-methionine amino acid residues, able to recognize and capture Pb and Hg ions and (ii) the oxygen atoms of the oxamate moieties, which preferentially interact with Cd ions, as revealed by single crystal X-ray diffraction. The flexibility of the pore environments allows these sites to work synergically for the simultaneous capture of different metal ions. The stability of the membranes for a potential regeneration process, a key-factor for the effective feasibility of the process in real life applications, was also evaluated and confirmed less than 1% capacity loss in each cycle.
重金属离子是常见的水污染来源。在本研究中，通过非溶剂诱导相分离法制备了两种新型膜，其在具有定制孔隙率的聚丙烯腈基质中嵌入了生物基金属有机框架（BioMOF），并设计用于从低矿化水中有效吸附重金属离子。在优化的制备条件下，获得了具有高达50 wt%的高MOF负载量、连续海绵状形态以及50 - 60 L m⁻² h⁻¹ bar高水渗透性的稳定膜。曲折的流道与低水流速率相结合，保证了流体与MOF之间的最大接触时间，从而在单次通过时具有高重金属捕获效率。在动态条件下，研究了这些BioMOF@PAN膜在存在常见干扰离子的情况下，从水性环境中同时去除Pb、Cd和Hg重金属的性能。新型复合吸附膜能够在单次通过时降低重金属污染物的浓度，且效率比先前报道的膜高得多。混合基质膜性能的提高归因于多个识别位点的存在，这些位点密集地修饰了BioMOF通道：（i）源自L - 甲基 - 半胱氨酸和（） - 蛋氨酸氨基酸残基的硫醚基团，能够识别并捕获Pb和Hg离子；（ii）草氨酸酯部分的氧原子，如单晶X射线衍射所示，其优先与Cd离子相互作用。孔隙环境的灵活性使这些位点能够协同工作，以同时捕获不同的金属离子。还评估了膜在潜在再生过程中的稳定性，这是该过程在实际应用中有效可行性的关键因素，并确认每个循环中的容量损失小于1%。
