(3-Mercaptopropyl)trimethoxysilane (MPTMS) sols, xerogels, and membranes with and without H2O2 oxidation were prepared to improve NH3 affinity and selectivity particularly at high temperatures. ...Mercaptan (S–H) in MPTMS precursor can be completely oxidized to transform SO originated from various sulfur oxidization groups by mixing H2O2 to sol solution for enhancing NH3 affinity, as proven by FT-IR and XPS analyses. Thermogravimetric mass spectrometer (TG-MS) and N2 adsorption respectively verified the thermal stability and the dense structure of unoxidized and oxidized MPTMS xerogels around 300 °C. Furthermore, NH3 temperature-programmed desorption (NH3-TPD) revealed that oxidized MPTMS xerogels showed a strong NH3 affinity (NH3 adsorption amount of ∼1.41 mmol g−1), twice higher than that of unoxidized MPTMS xerogels (0.75 mmol g−1) owing to the strengthened acidity and increased acidic sites. Finally, oxidized MPTMS membranes expressed an excellent selectivity for NH3/H2 of 6 and NH3/N2 of 18 with an NH3 permeance of ∼1.4 × 10−7 mol m−2 s−1 Pa−1 at 300 °C for single gas permeation. NH3 permeance and selectivity at 300 °C in NH3/H2 and NH3/N2 mixed gas permeation were almost constant without any mixing-effects, consistent with those in single gas permeation.
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•Mercaptan (S–H) groups can be completely transformed to SO by H2O2 oxidation.•The oxidated MPTMS xerogel shows a high NH3 adsorption amount of ∼1.41 mmol g−1.•The unoxidized and oxidated MPTMS-based membranes were successfully fabricated.•The oxidated MPTMS membrane showed an excellent NH3 selectivity even at 300 °C.
L’encéphalomyélite progressive avec rigidité et myoclonie (PERM) est une encéphalopathie autoimmune rare, Nous rapportons un cas de PERM syndrome et discutons les principaux diagnostics différentiels ...qui peuvent faire errer le diagnostic.
Patient de 42 ans, jardinier de profession, ayant présenté depuis 2 mois un syndrome anxio-dépressif pour lequel il a été mis sous Sulpiride et Escitalopram. Le patient a été admis pour installation aiguë, depuis 2 semaines, d’une rigidité généralisée avec des spasmes indolores, des myoclonies stimuli-sensitives et une rétention urinaire. Le patient a été traité en réanimation comme tétanos vu l’urgence. Devant la non amélioration et la prédominance des myoclonies, le diagnostic a été redressé vers un PERM syndrome. L’IRM cérébrale était normale ainsi que le LCR. Les anticorps anti-GAD et les anticorps anti-récepteurs à la glycine (antiGlyR) étaient négatifs dans le sang et le LCR. Le patient a reçu un bolus de méthylprednisolone avec une bonne évolution. Le bilan paranéoplasique est revenu négatif.
Devant l’association de rigidité généralisée et de spasmes douloureux, un tétanos, un syndrome malin des neuroleptiques et un syndrome sérotoninergique doivent être évoqué. La présence de myoclonies, de signes dysautonomiques, d’hyperekplexie et de signes psychiatriques doit attirer l’attention vers PERM.
Devant un tableau de rigidité et myoclonies il faut savoir évoquer PERM syndrome qui nécessite un traitement immunomodulateur et une recherche paranéoplasique.
The synthesis of monovalent cation perm-selective membranes (MCPMs) to efficiently discriminate amongst cations from seawater is of great importance for several industrial applications. However, a ...technical approach is highly desired to construct MCPMs to obtain a high ionic flux and sustain perm-selectivity, simultaneously. In the present work, the thickness of the quaternized poly (2, 6-dimethyl-1, 4-phenylene oxide) (QPPO) layer on the surface of SPPO-PVA (SPVA) composite membrane was adjusted using a facile procedure to achieve high perm-selectivity without scarifying the ionic flux. The thickness of the selective layer was precisely controlled using various concentrations of the QPPO solution. By the introduction of the cationic layer on the SPVA membrane, the monovalent cation can be separated from the divalent cation by their difference in charge density. The influence of the selective barrier (thickness) endows MCPMs with high perm-selectivity up to 12.7 for 0.1 mol L−1 Li+/Mg2+ system, which is very satisfactory for polymeric membranes. The fabricated membranes have low electrical resistance and high limiting current density (ilim). Keeping in view the ED results, the prepared membranes with selective surface layer could be a viable candidate for Li+ selective separation from divalent cation Mg2+.
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•SPPO-based CEMs with a cationic layer were prepared for cation fractionation.•The influence of the positive layer's thickness reveals excellent perm-selectivity.•The membranes unveiled excellent operational stability for long-term application.
It remains a huge challenge to develop a high-performance nanofiltration (NF) membrane with excellent perm-selectivity and antifouling properties. Herein, we report a novel thin-film nanocomposite ...(TFN) membrane by in-situ incorporating zwitterionic nanocellulose during interfacial polymerization. Unlike commonly-used nanomaterials, the zwitterionic nanocellulose anchored with both quaternary ammonium and phosphate group is able to be well dispersible in water to ensure the formation of defect-free separation layer. The resultant membrane exhibited not only increased water permeance (14.4 L m‐−2 h−1 bar−1) but enhanced divalent salt rejection (RNa2SO4 = 98.3%) owing to the increased surface hydrophilicity and high surface area as well as the extra hydrophilic interfacial nanochannels. With the assistance of high monovalent ion permeability endowed by zwitterions, this TFN membrane also behaved highly efficient antibiotic desalination with elevated separation factor of around 4.3. Moreover, the antifouling capability and cleaning recovery ability was greatly improved when both of the negatively and positively charged bovine serum albumin were utilized as foulants. Under the synergism of nanocellulose and zwitterions, therefore, the developed membrane in this work possessed superior perm-selectivity and antifouling properties, which would have promising potentials in separation fields.
•Z-CNF possesses well water dispersibility and compatibility with PA layer.•Z-CNF@TFN membrane exhibits increased permeance and enhanced divalent salt rejection.•This membrane behaved efficient salt-mixture separation and antibiotic desalination.•The antifouling ability was improved when negatively/positively charged BSA was used.•Above superior performances were attributed to the synergy of CNF and zwitterions.
We investigate the theory of extending structures by the unified product for perm algebras, and the factorization problem as well as the classifying complements problem in the setting of perm ...algebras. For a special extending structure, non-abelian extension, we study the inducibility of a pair of automorphisms associated with a non-abelian extension of perm algebras, and give the fundamental sequence of Wells in the context of perm algebras. For a special extending structure, bicrossed product, we introduce the concept of perm bialgebras, equivalently characterized by Manin triples of perm algebras and certain matched pairs of perm algebras. We introduce and study coboundary perm bialgebras, and our study leads to the “S-equation” in perm algebras, which is an analogue of the classical Yang-Baxter equation. A symmetric solution of S-equation gives a perm bialgebra.
PSf-b-PEG block copolymers with different PEG contents were synthesized to fabricate the highly perm-selective and anti-fouling ultrafiltration (UF) membranes. PEG homopolymer was also blended into ...the polysulfone casting solutions to fabricate the control (PSf/PEG blend) membranes. The membrane pore structure, surface properties and separation performances of PSf-b-PEG block copolymer membranes and PSf/PEG blend membranes were investigated to identify the role of PEG block for the pore formation. Our results find that the higher PEG content in the PSf-b-PEG block copolymer and in the PSf/PEG blend system was favorable to form more pores and thinner top skin layer with the slightly larger pore size and the higher MWCO of the fabricated membranes. But under the same content, PEG in the block copolymer could help to generate more pores but with similar pore size than PEG in the blend system during the phase-inversion process, which is because of the micro-phase separation of PSf block and PEG block. The fabricated PSf-b-PEG21 (PSf-b-PEG having 21 wt% PEG) membrane had a high water permeation coefficient of 980.0 ± 33.0 LMH/bar and a high BSA rejection above 98%, succeeding the current perm-selectivity upper-bound of the reported polymeric UF membranes. Antifouling experiments confirmed that the PSf-b-PEG21 membrane exhibited a slow and less flux decline during the fouling stage, but a fast and high flux recovery after the backwash cleaning. Our work provides some insights on the relationship of PSf-b-PEG block copolymer composition and membrane structure-separation properties.
•PSf-b-PEG block copolymers with different PEG contents were used to fabricate UF membranes.•High PEG content in PSf-b-PEG facilitated the membrane formation with a high surface porosity and a very thin skin layer.•The PSf-b-PEG (having 21 wt% PEG) membrane exceeded the current perm-selectivity upper-bound of UF membranes.•The PSf-b-PEG21 membrane exhibited antifouling performances with less flux decline and fast flux recovery.
Electrodialysis (ED) technique is a typical and promising membrane process, for applications like water treatment and ion separation. Especially, the separation between monovalent and multivalent ...cations is a current central issue in many industries and academic researches. Herein, a series of novel cation exchange membranes were prepared from quaternized polyaniline modified sulfonated polyphenyl sulfone (SPPSU) by in-situ polymerization-deposited polyaniline followed by quaternizing with methyl iodide. Restricted divalent cation penetration and regulated monovalent cation transport were achieved by elevating the kinetic effect of electrostatic repulsion and narrowing water channel. Importantly, positive charge density of modification layer could be adjusted by controlling the degree of quaternization, which was accompanied by the change of water channel. When evaluated in a simulated mixed salt system (Mg2+/Na+ and Mg2+/Li+), the optimal quaternized polyaniline membrane exhibited a higher perm-selectivity (PNaMg=4.1, PLiMg=1.75) than initial polyaniline modified cation exchange membrane (PNaMg=0.8, PLiMg=0.75), and commercial monovalent-selective cations exchange membrane CIMS (PNaMg=3.56, PLiMg=1.11). This presented strategy is straightforward and effective, demonstrating the effect of surface positive charge layer on perm-selectivity.
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•CEMs were fabricated based on SPPSU modified by quaternized polyaniline.•The positive charge density of surficial layer could be adjusted by controlling the degree of quaternization.•The prepared membranes were successfully applied separation of mixed salt system (Mg2+/Na+ and Mg2+/Li+).•The as-prepared membrane showed better perm-selectivity (PNaMg) than polyaniline modified one and commercial CIMS.
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•Monovalent cation selective membranes with hydrophobic side chains were developed.•Hydrophobicity of alkyl spacer effectively enhanced the transport of Na+ over Mg+2.•QDBPO-SS/Zn ...have high limiting current density and excellent performance.•Zwitterion structure was established to promote mono/divalent cations selectivity.
Development of monovalent cations perm-selective membranes (MCPMs) for electrodialysis with the ability to improve cation flux, selectivity and reduce membrane swelling are the major concerns in different industrial applications, such as seawater desalination and wastewater purification. We designed and fabricated the novel MCPMs of quaternized poly(2,6-dimethyl phenylene oxide)s containing different lengths of alkyl spacers which were grafted directly to the nitrogen-centered cations connected to hydrophilic carboxylic and sulfonic acids groups. Pendant chains were in charge of tuning the membrane hydrophobicity and promoting the microphase separation. We observed that during changing the hydrophobicity of MCPMs, higher cation flux, greater perm-selectivity and more dimensional stability of monovalent cations perm-selective membrane can be achieved. The cations selectivity of prepared MCPMs was measured from electrodialysis in a Na+/Mg2+ system and compared with the commercial monovalent cation selective NeoseptaTM CIMS membrane. Highest perm-selectivity (PMg+2Na+) that reached up to 25.26 was observed for the MCPMs with the longest hydrophobic pendant chain which demonstrated that enhancement of membranes hydrophobicity considerably improved the monovalent cation perm-selectivity. These observations are quite interesting to expedite the improvement of monovalent cations perm-selective membranes for electrodialysis.
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•Monovalent cation perm-selective membranes were prepared based on controlling surface hydration energy barrier.•The hydrophobicity of surficial layer could be adjusted by tuning ...carbon chains length of quaternized reagents.•The prepared membranes were successfully applied separation of mixed salt system (Mg2+/Na+ and Mg2+/Li+).•The as-prepared membrane showed better perm-selectivity (PNaMg) than polypyrrole modified one and commercial CIMS.
Cationic separating the with different valence states is greatly desirable but technically challenging. Achieving such a precise separation using membranes requires accurately distinguishing tiny differences of cations on physico-chemical properties. Here, inspired by the ion dehydration effect, a series of cation exchange membrane with adjustable surface hydrophobicity based on quaternized polypyrrole were prepared. We demonstrate that improving hydrophobicity of modified layer substantially hinder cations with higher hydration energy to enter the modified layer due to their stronger binding ability with water molecules. When applied in electro-driven cation separation, the optimal membrane exhibited an outstanding perm-selectivity between monovalent and divalent cations (PNaMg = 12.95, PLiMg = 1.28) than commercial monovalent cation perm-selective membrane (PNaMg = 2.46, PLiMg = 1.07). Overall, our results indicate that the hydrophobicity of the modified layer governs the cations dehydration behavior through the polymeric pores due to ion-pore wall interactions, providing the scientific basis for the construction of membranes with high monovalent cation perm-selectivity.
Monovalent anion perm-selective membranes (MAPMs) were fabricated from poly (alkyl-biphenyl pyridine) backbone via Menshutkin reaction and in-situ thermal crosslinking. Compared to the commercial ACS ...membrane (Cl− flux of 2.44 mol m−2 h−1, selectivity of 5.55), the optimum MAPM exhibited superior Cl− ions flux of 2.78 mol m−2 h−1 and Cl−/SO42− selectivity of 10.5 at current density of 10 mA cm−2. Additionally, the optimum MAPM was successfully scaled up and comprehensively evaluated, demonstrating exceptional ion separation performance and operational stability. Notably, in the ion-distillation process, the scale-up membrane displayed an extremely high separation coefficient of Cl−/SO42− over 15,000. The membrane shows promise for practical applications in treating high salt wastewater and desalination processes requiring Cl−/SO42− separation.
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•High-performance pilot-scale MAPMs were produced via a one-pot synthesis route.•The MAPMs exhibited superior anion selectivity compared to commercial membrane.•The ion-distillation system achieved an impressive separation coefficient over 15,000.
