Nanofluidics derived from low‐dimensional nanosheets and protein nanochannels are crucial for advanced catalysis, sensing, and separation. However, polymer nanofluidics is halted by complicated ...preparation and miniaturized sizes. This work reports the bottom‐up synthesis of modular nanofluidics by confined growth of ultrathin metal–organic frameworks (MOFs) in a polymer membrane consisting of zwitterionic dopamine nanoparticles (ZNPs). The confined growth of the MOFs on the ZNPs reduces the chain entanglement between the ZNPs, leading to stiff interfacial channels enhancing the nanofluidic transport of water molecules through the membrane. As such, the water permeability and solute selectivity of MOF@ZNPM are one magnitude improved, leading to a record‐high performance among all polymer nanofiltration membranes. Both the experimental work and the molecular dynamics simulations confirm that the water transport is shifted from high‐friction‐resistance conventional viscous flow to ultrafast nanofluidic flow as a result of rigid and continuous nanochannels in MOF@ZNPM.
A rigid‐scaffold‐reinforced polymeric nanoparticles’ interfacial channel strategy is proposed for fabricating nanofluidic membranes that exhibit water permeance and dye/salt selectivity that are 1–2 orders of magnitude higher than conventional polymeric membranes. The unprecedented separation performance is due to the paradigm shift of water transport from conventional viscous flow to ultrafast nanofluidic flow in the membrane nanofluidics.
Ultrafiltration (UF) has become an accepted process for drinking water treatment, but membrane fouling remains a significant problem. Polyethersulfone (PES)/SiO₂ composite membranes were prepared by ...phase inversion method with nano-SiO₂ as additive. Water contact angle measurement was conducted to investigate the hydrophilicity and surface wettability of the membranes. The effect of SiO₂ nanoparticles on the membrane permeation properties, anti-fouling performances, and membrane morphologies and structures was examined and discussed. The influence of SiO₂ on the water permeability, anti-fouling of the PES membranes were evaluated by raw water UF experiments. The results showed that the membrane structure was not obviously affected by addition of SiO₂, and the membrane performances such as hydrophilicity and anti-fouling ability were enhanced by adding SiO₂ nanoparticles.
Carbon nanotube enhanced thin-film nanocomposite membranes were prepared by incorporating carbon nanotubes (CNTs) into the active layers of membranes used for water treatment. For inclusion into ...these active layers, a grafting procedure for carbon nanotubes was set up to increase their hydrophobicity. Multiwalled carbon nanotubes (MWNTs) grafted by poly(methyl methacrylate) (PMMA) were synthesized via a microemulsion polymerization of methyl methacrylate (MMA) in the presence of acid-modified multiwalled carbon nanotubes (c-MWNTs). Subsequently, polyamide thin-film nanocomposite (TFN) membranes containing PMMA–MWNTs were prepared via interfacial polymerization. Morphology studies demonstrate that MWNTs have been successfully embedded into the active polyamide layer. The rejection of Na2SO4 was high (99%), and the water flux was about 62% increased compared to the thin-film composite membrane when using 2g/L piperazine (PIP) in the aqueous phase, 4g/L trimesoyl chloride (TMC) and 0.67g/L PMMA–MWNTs in the organic phase, which demonstrates that PMMA–MWNTs significantly improve selectivity and permeability.
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•Incorporating hydrophobic enhanced PMMA–MWNTs into polyamide membrane.•Enhanced performance were exhibited compared to the membranes without PMMA–MWNTs.•A novel surface morphologies of TFN membranes were observed.
Bio-ethanol as a clean and renewable fuel has gained more attention; however greater energy inputs make a slow progress in industry. Membrane technology has potential in the bioethanol production ...process as a highly selective and energy-saving separation process. This review presented membrane technologies applied in three aspects: (i) microalgae harvesting, (ii) sugar concentration and detoxification, (iii) bioethanol recovery. The performance of different membrane processes was summarized and compared. The advantages and limitations of membrane technologies for these applications are discussed, and it was thought that the hybrid process has great potential in improving membrane efficiency.
In this work, a dendrimer trimesoyl amide amine (TMAAM) monomer was proposed to be used as a key functional monomer to modify the conventional aromatic polyamide thin-film composite (TFC) ...nanofiltration (NF) membrane, and a new kind of TMAAM-based semi-aromatic polyamide composite NF membrane was thus prepared by interfacial polymerization. The effects of the PIP/TMAAM ratio (PIP = piperazine) on the membrane chemical structure, surface properties and separation performances were investigated systematically. With the increase in TMAAM content loaded in the membrane, the water flux strongly increased but the salt rejection decreased only slightly. When the PIP/TMAAM ratio was 1, the membrane NF-2 exhibited a smoother and more hydrophilic surface, as a result of which it displayed an optimum separation performance for different valent salts. In addition, the TMAAM modified TFC membrane presented an extremely high rejection to negatively charged dye molecules and high permeation for monovalent salts, leading to good prospects for dye/salt separation application. Moreover, both the water flux and salt rejection of the TMAAM-based membrane were stable in a long-term running process, and the membrane showed a favourable anti-fouling property and efficient cleaning recovery. Therefore, this work provides a new type of semi-aromatic polyamide composite NF membrane fabricated by a facile and straightforward method
via
interfacial polymerization with high hydrophilicity, good stability and strong anti-fouling property.
TMAAM, a new dendrimer, was used to modify the conventional aromatic polyamide NF membrane
via
interfacial polymerization method, and the result TMAAM-based semi-aromatic polyamide NF membrane strong dye rejection, favourable antifouling property and good stability.
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In the face of human society's great requirements for health industry, and the much stricter safety and quality standards in the biomedical industry, the demand for advanced membrane ...separation technologies continues to rapidly grow in the world. Nanofiltration (NF) and reverse osmosis (RO) as the high-efficient, low energy consumption, and environmental friendly membrane separation techniques, show great promise in the application of biomedical separation field. The chemical compositions, microstructures and surface properties of NF/RO membranes determine the separation accuracy, efficiency and operation cost in their applications. Accordingly, recent studies have focused on tuning the structures and tailoring the performance of NF/RO membranes via the design and synthesis of various advanced membrane materials, and exploring universal and convenient membrane preparation strategies, with the objective of promoting the better and faster development of NF/RO membrane separation technology in the biomedical separation field. This paper reviews the recent studies on the NF/RO membranes constructed with various materials, including the polymeric materials, different dimensional inorganic/organic nanomaterials, porous polymeric materials and metal coordination polymers, etc. Moreover, the influence of membrane chemical compositions, interior microstructures, and surface characteristics on the separation performance of NF/RO membranes, are comprehensively discussed. Subsequently, the applications of NF/RO membranes in biomedical separation field are systematically reported. Finally, the perspective for future challenges of NF/RO membrane separation techniques in this field is discussed.
Polymeric nanomaterials, which have tuneable chemical structures, versatile functionalities, and good compatibility with polymeric matrices, have attracted increasing interest from researchers for ...the construction of polymeric nano-based separation membranes. With their distinctive nanofeatures, polymeric nano-based membranes show great promise in overcoming bottlenecks in polymer membranes, namely, the trade-off between permeability and selectivity, low stability, and fouling issues. Accordingly, recent studies have focused on tuning the structures and tailoring the surface properties of polymeric nano-based membranes via exploitation of membrane fabrication techniques and surface modification strategies, with the objective of pushing the performance of polymeric nano-based membranes to a new level. In this review, first, the approaches for fabricating polymeric nano-based mixed matrix membranes and homogeneous membranes are summarized, such as surface coating, phase inversion, interfacial polymerization, and self-assembly methods. Next, the manipulation strategies of membrane surface properties, namely, the hydrophilicity/hydrophobicity, charge characteristics, and surface roughness, and interior microstructural properties, namely, the pore size and content, channel construction and regulation, are comprehensively discussed. Subsequently, the separation performances of liquid ions/molecules and gas molecules through polymeric nano-based membranes are systematically reported. Finally, we conclude this review with an overview of various unsolved scientific and technical challenges that are associated with new opportunities in the development of advanced polymeric nano-based membranes.
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•Novel TFN membranes based on polyelectrolyte nanoparticles (PNPs) were prepared.•TFN-PNP membranes exhibited high water permeability and good selectivity for amino acids.•TFN-PNP ...membranes had good stability and anti-fouling property in nanofiltration process.
We have designed a novel type of thin-film nanocomposite (TFN) membranes with embedded polyelectrolyte nanoparticles (PNPs) and investigated their applicability in the separation of amino acids. PNP particles were mixed with piperazine (PIP) and interfacial polymerized with trimesoyl chloride (TMC), allowing for simultaneous improvement in water permeability, amino acid selectivity, and anti-fouling property. Separation performance could be conveniently tuned by modulating the chemical structure of PNPs and their content in TFN membranes, as well as adjusting the feed pH value. This work would promote the application of polyelectrolyte nanoparticles based TFN membranes in the separation and purification of amino acids.
In the face of serious environmental pollution and water scarcity problems, the membrane separation technique, especially high efficiency, low energy consumption, and environmental friendly ...nanofiltration, has been quickly developed. Separation membranes with high permeability, good selectivity, and strong antifouling properties are critical for water treatment and green chemical processing. In recent years, researchers have paid more and more attention to the development of high performance nanofiltration membranes containing "ion pairs". In this review, the effects of "ion pairs" characteristics, such as the super-hydrophilicity, controllable charge character, and antifouling property, on nanofiltration performances are discussed. A systematic survey was carried out on the various approaches and multiple regulation factors in the fabrication of polyelectrolyte complex membranes, zwitterionic membranes, and charged mosaic membranes, respectively. The mass transport behavior and antifouling mechanism of the membranes with "ion pairs" are also discussed. Finally, we present a brief perspective on the future development of advanced nanofiltration membranes with "ion pairs".
Separation of monovalent salt and antibiotics is of vital importance in membrane field. In this work, zwitterionic polyamide membrane was prepared by incorporating N, N-diethylethylenediamine (DEEDA) ...into interfacial polymerization firstly. Then, zwitterions were introduced into membrane matrix via grafting reaction with 1, 3-propanesultone (1, 3-PS). The resulting zwitterionic membrane exhibited optimal permeability of 14.6 L m−2 h−1.bar−1 and high rejection of organics. Meanwhile, owing to the incorporation of zwitterions, the zwitterionic membrane showed lower rejection of monovalent salt compared with that of the pristine polyamide membrane. Thus, the zwitterionic membrane behaved efficient separation ability of monovalent salt/antibiotics when NaCl/erythromycin mixture solution was chosen as the experimental solution. When bovine serum albumin was used as a foulant, the zwitterionic membrane also exhibited anti-fouling property. This work provided a facile way to prepare zwitterionic membrane with efficient separation ability of monovalent salt/antibiotics, which promoted the development of zwitterions in applications of nanofiltration membrane field.
•DEEDA and 1, 3-PS were utilized to prepare zwitterionic membrane.•Zwitterionic membrane exhibited high permeability and anti-fouling property.•Zwitterionic membrane could realize fast separation of ERY/NaCl.
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