Unprecedented acid-tolerant ultrathin membranes with finely tuned sub-nanopores for energetic-efficient molecular sieving

Progress of Ultrafiltration-Based Technology in Ion Removal and Recovery: Enhanced Membranes and Integrated Processes

“…Commonly, NF can be applied to separate monovalent/multivalent ions through the electrostatic interaction and steric exclusion. 27,28 Electrodialysis (ED) is an electric-driven process that uses an electric field as a driving force to separate ions from one solution to another solution through the ion exchange membranes. 29,30 Membrane distillation (MD) is a thermal-driven membrane process that uses the temperature pressure difference across a porous hydrophobic membrane for achieving water vapor from the feed stream to the permeate stream.…”

“…In contrast, the membrane pore range and operating pressure requirements for NF membranes are between those of UF and RO. Commonly, NF can be applied to separate monovalent/multivalent ions through the electrostatic interaction and steric exclusion. , Electrodialysis (ED) is an electric-driven process that uses an electric field as a driving force to separate ions from one solution to another solution through the ion exchange membranes. , Membrane distillation (MD) is a thermal-driven membrane process that uses the temperature pressure difference across a porous hydrophobic membrane for achieving water vapor from the feed stream to the permeate stream. , Among pressure-driven membranes, UF is always operated with the advantages of lower operation pressure, lower footprint requirements, less chemicals addition, mild operating temperature, and higher permeability than RO and NF. In addition, UF requires lower costs due to the lower energy usage during operation compared to MD and ED. , Therefore, UF shows great potential in wastewater treatment among the current membrane-based technologies.…”

Thin-Film Nanocomposite Membrane Based on Mineral Silicate Maifanite for Organic Solvent Reverse Osmosis

“…Mixed matrix membranes (MMMs), which comprise an organic polymer matrix and an inorganic segment, have received considerable attention owing to the excellent operability and molecular sieving performance offered by the combined advantages of the organic polymers and inorganic segments . Based on these characteristics, MMMs have been widely used in gas purification, CO 2 capture, olefin/paraffin separation, ion sieving, and textile wastewater treatment. − MMM formation pathways can be divided into two types: directly doping inorganic fillers into the polymer segment and using the determined reaction . Yusof et al built an MMM by incorporating a tannin-modified metal–organic framework (MOF) into a polyethersulfone (PES) matrix to improve the surface hydrophilicity and antifouling ability of the original PES membrane.…”

Ionic Sieving at Sub-Angstrom Precision Enabled by Metal Organic Frameworks

“…Therefore, the key to synthesizing a membrane suitable for extracting cesium from liquids is to construct pores that fit the size of the cesium ion and enable distinguishing ions differing in size by only a few angstroms . Utilizing traditional polymer membrane synthesis routes, it is often difficult to precisely regulate the pore structure since the fabrication process involves random cross-linking reactions, , thereby giving rise to broad pore size distribution and low ion selectivity. Advances in nanotechnology have brought intriguing techniques, including top-down and bottom-up synthesis approaches, for creating membranes composed of more defined pore structures. − Among them, the porous organic framework is an emerging class of nanomembrane materials, and metal–organic framework (MOF) is one of their representatives. , The structure of MOF materials can be precisely designed and constructed by the precursors, i.e., metal nodes and organic linkers, , and the pore size can be further tuned by chemical modification with specific functional groups .…”

“…12 Therefore, the key to synthesizing a membrane suitable for extracting cesium from liquids is to construct pores that fit the size of the cesium ion and enable distinguishing ions differing in size by only a few angstroms. 13 Utilizing traditional polymer membrane synthesis routes, it is often difficult to precisely regulate the pore structure since the fabrication process involves random cross-linking reactions, 14,15 thereby giving rise to broad pore size distribution and low ion selectivity. Advances in nanotechnology have brought intriguing techniques, including top-down and bottom-up synthesis approaches, for creating membranes composed of more defined pore structures.…”