Enhanced desulfurization performance and stability of Pebax membrane by incorporating Cu+ and Fe2+ ions co-impregnated carbon nitride

Mussel-Inspired Polydopamine Composite Mesoporous Bioactive Glass Nanoparticles: An Exploration of Potential Metal-Ion Loading Platform and In Vitro Bioactivity

Exploring new approaches to realize the possibility of incorporating biologically active elements into mesoporous silicate bioactive glass nanoparticles (MBG NPs) and guaranteeing their meso- structural integrity and dimensional stability has become an attractive and interesting challenge in biomaterials science. We present a postgrafting strategy for introducing different metal elements into MBG NPs. This strategy is mediated by polydopamine (PDA) coating, achieving uniform loading of copper or copper-cobalt on the particles efficiently and ensuring the stability of MBG NPs in terms of particle size, mesoporous structure, and chemical structure. However, the PDA coating reduced the ion-binding free energy of the MBG NPs for calcium and phosphate ions, resulting in the deposition of minimal CaP clusters on the PDA@MBG NP surface when immersed for 7 days in simulated body fluid, indicating the absence of hydroxyapatite mineralization.

Efficient Lithium/Sodium-Ion Storage by Core-Shell Carbon Nanospheres@TiO2 Decorate by Epitaxial WSe2 Nanosheets Derived from Bimetallic Polydopamine Composites

Metal-polydopamine coordination chemistry attracts great attention owing to the synergistic effect of adjustable components and advantageous structures. However, few efforts have been devoted to exploring bimetal-polydopamine composites, especially for multistructural composites with high-capacity components and high stability. In this regard, the TiO₂ @C-WSe₂ core-shell nanospheres are designed and fabricated based on Ti-W-polydopamine composites after selenization, in which the TiO₂ nanoparticles are encapsulated or embedded in the carbon nanospheres and the external WSe₂ nanosheets are grown epitaxially on the carbon surfaces, featuring multiple channels for ion diffusion and abundant active edges for electrochemical reactions. The introduction of WSe₂ not only greatly improves the capacity but also results in exponential growth of the active edge. As a result, the as-prepared TiO₂ @C-WSe₂ displayed long-term cycling performance in lithium-ion batteries. Furthermore, the anode is assembled into sodium-ion batteries, manifesting a stable capacity of 352 mA h g^-1 at 1.0 A g^-1 even after 2000 cycles, one of the best performances for polydopamine-based composites. Enhanced performance can be attributed to the synergies of high-capacity components and different dimensional materials. This work highlights that the rational design of functional structures provides a novel inspiration for electrodes with effective nanoarchitectures.

Effect of Nanofillers on Properties and Pervaporation Performance of Nanocomposite Membranes: A Review

In recent years, a well-known membrane-based process called pervaporation (PV), has attracted remarkable attention due to its advantages for selective separation of a wide variety of liquid mixtures. However, some restrictions of polymeric membranes have led to research studies on developing membranes for efficient separation in the PV process. Recent studies have focused on preparation of nanocomposite membranes as an effective method to improve both selectivity and permeability of polymeric membranes. The present study provides a review of PV nanocomposite membranes for various applications. In this review, recent developments in the field of nanocomposite membranes, including the fabrication methods, characterization, and PV performance, are summarized.

Organic molecular sieve membranes for chemical separations

Molecular separations that enable selective transport of target molecules from gas and liquid molecular mixtures, such as CO2 capture, olefin/paraffin separations, and organic solvent nanofiltration, represent the most energy sensitive and significant demands. Membranes are favored for molecular separations owing to the advantages of energy efficiency, simplicity, scalability, and small environmental footprint. A number of emerging microporous organic materials have displayed great potential as building blocks of molecular separation membranes, which not only integrate the rigid, engineered pore structures and desirable stability of inorganic molecular sieve membranes, but also exhibit a high degree of freedom to create chemically rich combinations/sequences. To gain a deep insight into the intrinsic connections and characteristics of these microporous organic material-based membranes, in this review, for the first time, we propose the concept of organic molecular sieve membranes (OMSMs) with a focus on the precise construction of membrane structures and efficient intensification of membrane processes. The platform chemistries, designing principles, and assembly methods for the precise construction of OMSMs are elaborated. Conventional mass transport mechanisms are analyzed based on the interactions between OMSMs and penetrate(s). Particularly, the 'STEM' guidelines of OMSMs are highlighted to guide the precise construction of OMSM structures and efficient intensification of OMSM processes. Emerging mass transport mechanisms are elucidated inspired by the phenomena and principles of the mass transport processes in the biological realm. The representative applications of OMSMs in gas and liquid molecular mixture separations are highlighted. The major challenges and brief perspectives for the fundamental science and practical applications of OMSMs are tentatively identified.

Metal-Containing Polydopamine Nanomaterials: Catalysis, Energy, and Theranostics

Polydopamine (PDA) is a major type of artificial melanin material with many interesting properties such as antioxidant activity, free-radical scavenging, high photothermal conversion efficiency, and strong metal-ion chelation. The high affinity of PDA to a wide range of metals/metal ions has offered a new class of functional metal-containing polydopamine (MPDA) nanomaterials with promising functions and extensive applications. Understanding and controlling the metal coordination environment is vital to achieve desirable functions for which such materials can be exploited. MPDA nanomaterials with metal/metal ions as the active functions are reviewed, including their synthesis and metal coordination environment and their applications in catalysis, batteries, solar cells, capacitors, medical imaging, cancer therapy, antifouling, and antibacterial coating. The current trends, limitations, and future directions of this area are also explored.

Novel Polyester Amide Membranes Containing Biquinoline Units and Complex with Cu(I): Synthesis, Characterization, and Approbation for n-Heptane Isolation from Organic Mixtures

The wide possibilities of designing a chemical structure and creating complexes with transition metals make polymers of heteroaromatic structure interesting objects, from both scientific and practical aspects. In this work, modern biquinoline-containing polymers, namely polyester amide (PEA) and its metal–polymer complex (PEA–Cu(I)), were synthesized and used to form dense flat membranes. A comparative study of their morphology, same physical properties (density, free volume, and contact angles), and thermomechanical characteristics was carried out. The transport properties of the modern membranes were studied during pervaporation, to solve a problem of n-heptane isolation from its binary mixtures with thiophene and methanol. It was shown that only the PEA membrane is selective for the separation of thiophene impurities from the mixture with n-heptane. In pervaporation of methanol/n-heptane mixture, the РЕА–Cu(I) membrane exhibits significantly higher pervaporation separation index, as compared with that of the РЕА membrane.

Effects of Protonation, Hydroxylamination, and Hydrazination of g-C₃N₄ on the Performance of Matrimid®/g-C₃N₄ Membranes

One of the challenges to continue improving polymeric membranes properties involves the development of novel chemically modified fillers, such as nitrogen-rich 2-D nanomaterials. Graphitic carbon nitride (g-C₃N₄) has attracted significant interest as a new class of these fillers. Protonation is known to afford it desirable functionalities to form unique architectures for various applications. In the work presented herein, doping of Matrimid^® with protonated g-C₃N₄ to yield Matrimid^®/g-C₃N₄ mixed matrix membranes was found to improve gas separation by enhancing the selectivity for CO₂/CH₄ by up to 36.9% at 0.5 wt % filler doping. With a view to further enhancing the contribution of g-C₃N₄ to the performance of the composite membrane, oxygen plasma and hydrazine monohydrate treatments were also assayed as alternatives to protonation. Hydroxylamination by oxygen plasma treatment increased the selectivity for CO₂/CH₄ by up to 52.2% (at 2 wt % doping) and that for O₂/N₂ by up to 26.3% (at 0.5 wt % doping). Hydrazination led to lower enhancements in CO₂/CH₄ separation, by up to 11.4%. This study suggests that chemically-modified g-C₃N₄ may hold promise as an additive for modifying the surface of Matrimid^® and other membranes.