Search Results (68)

High permeance combined with high salt/dye separation efficiency is a prerequisite for achieving zero-liquid-discharge treatment of saline textile wastewater by membrane technology. Thin-film nanocomposite (TFN) membranes incorporating porous nanoparticles offer a promising route to overcome the permeability–selectivity trade-off of conventional polymer membranes. In this study, a vacuum-assisted method was used to co-blend ZIF-67 and SiO₂ nanoparticles, while branched polyethyleneimine (PEI) served as a cross-linking bridge, resulting in a high-performance TFN membrane for salt/dye separation. Acting as a molecular connector, PEI coordinated with ZIF-67 through metal–amine complexation and simultaneously formed hydrogen bonds with surface hydroxyl groups on SiO₂, thereby linking ZIF-67 and SiO₂. The resulting membrane exhibited good hydrophilicity and excellent dye separation performance (water flux = 359.8 L m⁻² h⁻¹ bar⁻¹; Congo Red rejection = 99.2%) as well as outstanding selectivity in dye/salt mixtures (Congo Red/MgCl₂ selectivity of 1094). The optimal ZIF@SiO₂-PEI membrane maintained stable dye rejection over a wide range of trans-membrane pressures, initial concentrations, and pH values. These results reveal the huge potential of applying the ZIF@SiO₂-PEI TFN membranes for resource recovery in sustainable textile wastewater systems. Full article

Industrial wastewater poses a significant environmental challenge due to its harmful effects. The development of sustainable membrane processes for water treatment and the environmentally friendly production of polymer membranes is one of the major challenges of our time. An alternative approach is to prepare polyelectrolyte complex (PEC) membranes using the aqueous phase separation (APS) method without the use of toxic solvents. In this work, PEC nanofiltration membranes of poly(sodium-p-styrenesulfonate) (PSS)/polyethylenimine (PEI) modified with carbon nanoparticles (graphene oxide, polyhydroxylated fullerene (HF), multi-walled carbon nanotubes) were developed for enhanced water treatment from anionic food dyes and heavy metal ions. The effect of varying the PSS/PEI monomer ratio, carbon nanoparticles, the content of the optimal HF modifier, and the cross-linking agent on the membrane properties was studied in detail. The changes in the structure and physicochemical properties of the PEC-based membranes were investigated using spectroscopic, microscopic, thermogravimetric analysis methods, and contact angle measurements. The PSS and PEI interactions during PEC formation and the effect of PEI protonation on membrane properties were investigated using computational methods. The optimal cross-linked PEC/HF(1%) (1:1.75 PSS/PEI) membrane had more than 2 times higher permeability compared to the pristine PEC membrane, with dye and heavy metal ion rejection of 99.99 and >97%, respectively. Full article

Antibiotic resistance poses a significant global health challenge, undermining the effectiveness of conventional treatments and increasing mortality rates worldwide. Factors such as the overuse and misuse of antibiotics in healthcare and agriculture, along with poor infection control practices, have accelerated the emergence of resistant bacterial strains. The stagnation in the development of new antibiotics, compounded by economic and biological challenges, has necessitated alternative approaches to combat resistant infections. Nanotechnology provides a promising solution using nanoparticles (NPs), which combat bacteria through mechanisms like membrane disruption and reactive oxygen species (ROS) generation. Metal-based nanoparticles such as silver and zinc oxide possess intrinsic antimicrobial properties, while polymer- and carbon-based nanoparticles enhance drug delivery and biofilm penetration. Unlike conventional antibiotics, nanoparticles operate through multi-mechanistic pathways, reducing the likelihood of resistance development and improving treatment efficacy. This review aims to provide an updated, in-depth look at recent advances in nanoparticle research targeting antibiotic resistance, discussing different types of nanoparticles, mechanisms of action, and current challenges and opportunities. By exploring the evolving role of nanotechnology in addressing this crisis, this review intends to highlight the potential for nanoparticles to transform the treatment landscape for resistant bacterial infections and inspire further research into these innovative solutions. Full article

The development of functional materials and the use of nanotechnology are ongoing projects. These fields are closely linked, but there is a need to combine them more actively. Nanoarchitectonics, a concept that comes after nanotechnology, is ready to do this. Among the related research efforts, research into creating functional materials through the formation of thin layers on surfaces, molecular membranes, and multilayer structures of these materials have a lot of implications. Layered structures are especially important as a key part of nanoarchitectonics. The diversity of the components and materials used in layer-by-layer (LbL) assemblies is a notable feature. Examples of LbL assemblies introduced in this review article include quantum dots, nanoparticles, nanocrystals, nanowires, nanotubes, g-C₃N₄, graphene oxide, MXene, nanosheets, zeolites, nanoporous materials, sol–gel materials, layered double hydroxides, metal–organic frameworks, covalent organic frameworks, conducting polymers, dyes, DNAs, polysaccharides, nanocelluloses, peptides, proteins, lipid bilayers, photosystems, viruses, living cells, and tissues. These examples of LbL assembly show how useful and versatile it is. Finally, this review will consider future challenges in layer-by-layer nanoarchitectonics. Full article

Scaffolds for regenerative therapy can be made from natural or synthetic polymers, each offering distinct benefits. Natural biopolymers like chitosan (CS) are biocompatible and biodegradable, supporting cell interactions, but lack mechanical strength. Synthetic polymers like polyvinyl alcohol (PVA) provide superior mechanical strength and cost efficiency but are not biodegradable or supportive of cell adhesion. Combining these polymers optimizes their advantages while adding metal oxide nanoparticles like calcium oxide (CaO NPs) enhances antimicrobial properties by damaging bacterial membranes. In this study, we obtained the formation of CaO NPs by calcinating eggshells, which were mixed in a polymeric network of CS and PVA to obtain four different membrane formulations for subdermal tissue regeneration. The spherical nanoparticles measured 13.43 ± 0.46 nm in size. Their incorporation into the membranes broadened the hydroxyl bands in the Fourier transform infrared (FTIR) analysis at 3331 cm⁻¹. X-ray diffraction (XRD) analysis showed changes in the crystalline structure, with new diffraction peaks at 2θ values of 7.2° for formulations F2, F3, and F4, likely due to the increased amorphous nature and concentration of CaO NPs. Additionally, higher CaO NPs concentrations led to a reduction in thermal properties and crystallinity. Scanning electron microscopy (SEM) revealed a heterogeneous morphology with needle-like structures on the surface, resulting from the uniform dispersion of CaO NPs among the polymer chains and the solvent evaporation process. A histological examination of the implanted membranes after 60 days indicated their biocompatibility and biodegradability, facilitated by incorporating CaO NPs. During the degradation process, the material fragmented and was absorbed by inflammatory cells, which promoted the proliferation of collagen fibers and blood vessels. These findings highlight the potential of incorporating CaO NPs in soft tissue regeneration scaffolds. Full article

Integrating nanomaterials into membranes has revolutionized selective transport processes, offering enhanced properties and functionalities. Mixed-matrix membranes (MMMs) are nanocomposite membranes (NCMs) that incorporate inorganic nanoparticles (NPs) into organic polymeric matrices, augmenting mechanical strength, thermal stability, separation performance, and antifouling characteristics. Various synthesis methods, like phase inversion, layer-by-layer assembly, electrospinning, and surface modification, enable the production of tailored MMMs. A trade-off exists between selectivity and flux in pristine polymer membranes or plain inorganic ceramic/zeolite membranes. In contrast, in MMMs, NPs exert a profound influence on membrane performance, enhancing both permeability and selectivity simultaneously, besides exhibiting profound antibacterial efficacy. Membranes reported in this work find application in diverse separation processes, notably in niche membrane-based applications, by addressing challenges such as membrane fouling and degradation, low flux, and selectivity, besides poor rejection properties. This review comprehensively surveys recent advances in nanoparticle-integrated polymeric membranes across various fields of water purification, heavy metal removal, dye degradation, gaseous separation, pervaporation (PV), fuel cells (FC), and desalination. Efforts have been made to underscore the role of nanomaterials in advancing environmental remediation efforts and addressing drinking water quality concerns through interesting case studies reported in the literature. Full article

Filtration membranes coated in metals such as copper have dramatically improved biofouling resistance and pathogen destruction. However, existing coating methods on polymer membranes impair membrane performance, lack uniformity, and may detach from their substrate, thus contaminating the permeate. To solve these challenges, we developed the first electroless deposition protocol to immobilize copper nanoparticles on electrospun polyacrylonitrile (PAN) fibers for the design of antimicrobial membranes. The deposition was facilitated by prior silver seeding. Distinct mats with average fiber diameters of 232 ± 36 nm, 727 ± 148 nm and 1017 ± 80 nm were evaluated for filtration performance. Well-dispersed copper nanoparticles were conformal to the fibers, preserving the open-cell architecture of the membranes. The copper particle sizes ranged from 20 to 140 nm. Infrared spectroscopy revealed the PAN fiber mats’ relative chemical stability/resistance to the copper metallization process. In addition, the classical cyclization of the cyano functional group in PAN was observed. For model polystyrene beads with average sizes of 3 μm, Cu NP–PAN fiber mats had high water flux and separation efficiency with negligible loss of Cu NP from the fibers during flow testing. Fiber size increased flux and somewhat decreased separation efficiency, though the efficiency values were still high. Full article

Addressing water scarcity and pollution is imperative in tackling global environmental challenges, prompting the exploration of innovative techniques for effective water and wastewater treatment. Nanotechnology presents promising solutions through the customization of nanoparticles and nanocomposites specifically designed for water purification applications. This review delves into recent advancements in nanoparticle-based technologies for water treatment, with a particular focus on their synthesis methodologies, intrinsic properties, and versatile applications. A wide range of nanoparticles, ranging from metal nanoparticles to carbon-based nanomaterials, along with hybrid nanocomposites such as metal/metal oxide-based nanocomposites, polymer-based nanocomposites, and others, were emphasized for eliminating contaminants from water and wastewater matrices. Furthermore, this review elucidates the underlying mechanisms governing pollutant removal processes, encompassing adsorption, catalysis, and membrane filtration, facilitated by nanoparticles. Additionally, it explores the environmental implications and challenges associated with the widespread deployment of nanoparticle-based water-treatment technologies. By amalgamating existing research findings, this review provides valuable insights into the potential of nanoparticles and nanocomposites in mitigating water-related challenges and presents recommendations for future research trajectories and technological advancements in this domain. Full article

Magnetic nanofibers were prepared by electrospinning polymer/metal solutions of poly(acrylonitrile) (PAN) with magnetite (Fe₃O₄) nanoparticles. At a mass ratio of PAN:magnetite of 2:1, the total solid content in the dimethyl sulfoxide (DMSO) solution was varied between 15 wt.% and 25 wt.%, which represents the limits of the spinnable range. The results show that the most homogeneous nanofiber mats were 21 wt.% solid contents. At 15 wt.% solid contents, a nano-membrane with some fibrous regions was produced. Nanofibers at 25 wt.% had a much larger and more inhomogeneous diameter. Nevertheless, the magnetic properties of all samples were very similar, indicating that the distribution of magnetite nanoparticles in the fibers is comparable in all samples. The results also suggested that the samples spun from solutions with near-ideal solid contents (19–21 wt.%) contain agglomerations of the nanoparticles inside the nanofibers. Full article

Polymer-based membranes represent an irreplaceable group of materials that can be applied in a wide range of key industrial areas, from packaging to high-end technologies. Increased selectivity to transport properties or the possibility of controlling membrane permeability by external stimuli represents a key issue in current material research. In this work, we present an unconventional approach with the introduction of silver nanoparticles (AgNPs) into membrane pores, by immobilising them onto the surface of polyethyleneterephthalate (PET) foil with subsequent physical modification by means of laser and plasma radiation prior to membrane preparation. Our results showed that the surface characteristics of AgNP-decorated PET (surface morphology, AgNP content, and depth profile) affected the distribution and concentration of AgNPs in subsequent ion-track membranes. We believe that the presented approach affecting the redistribution of AgNPs in the polymer volume may open up new possibilities for the preparation of metal nanoparticle-filled polymeric membranes. The presence of AgNPs on the pore walls can facilitate the grafting of stimuli-responsive molecules onto these active sites and may contribute to the development of intelligent membranes with controllable transport properties. Full article

Carbon molecular sieve membranes (CMSMs) were prepared by carbonizing the high free volume polyimide BTDA-BAF that is obtained from the reaction of benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA) and 9,9-bis(4-aminophenyl) fluorene (BAF). The bulky cardo groups prevented a tight packing and rotation of the chains that leads to high permeabilities of their CMSMs. The incorporation of metal–organic polyhedra 18 (MOP-18, a copper-based MOP) in the BTDA-BAF polymer before pyrolysis at 550 °C prevented the collapse of the pores and the aging of the CMSMs. It was found that upon decomposition of MOP-18, a distribution of copper nanoparticles minimized the collapse of the graphitic sheets that formed the micropores and mesopores in the CMSM. The pillared CMSMs displayed CO₂ and CH₄ permeabilities of 12,729 and 659 Barrer, respectively, with a CO₂/CH₄ selectivity of 19.3 after 3 weeks of aging. The permselectivity properties of these membranes was determined to be at the 2019 Robeson upper bound. In contrast, the CMSMs from pure BTDA-BAF aged three times faster than the CMSMs from MOP-18/BTDA-BAF and exhibited lower CO₂ and CH₄ permeabilities of 5337 and 573 Barrer, respectively, with a CO₂/CH₄ selectivity of 9.3. The non-pillared CMSMs performed below the upper bound. Full article

Nanocomposites are high-performance materials with exceptional characteristics that possess properties that their individual constituents, by themselves, cannot provide. They have useful applications in many fields, ranging from membrane processes to fuel cells, biomedical devices, and anti-corrosion protection. Well-tailored nanocomposites are promising materials for anti-corrosion coatings on metals and alloys, exhibiting simple barrier protection or even smart auto-responsive and self-healing functionalities. Nanocomposite coatings can be prepared by using a large variety of matrices and reinforcement materials, often acting in synergy. In this context, recent advances in the preparation and characterization of corrosion-resistant nanocomposite coatings based on metallic, polymeric, and ceramic matrices, as well as the incorporation of various reinforcement materials, are reviewed. The review presents the most important materials used as matrices for nanocomposites (metals, polymers, and ceramics), the most popular fillers (nanoparticles, nanotubes, nanowires, nanorods, nanoplatelets, nanosheets, nanofilms, or nanocapsules), and their combinations. Some of the most important characteristics and applications of nanocomposite coatings, as well as the challenges for future research, are briefly discussed. Full article

The aim of this work is to effectively combine the advantages of polymer and ceramic nanoparticles and improve the comprehensive performance of lithium-ion batteries (LIBs) diaphragm. A flexible film composed of electro-spun P(VDF-HFP) nanofibers covered by a layer of mesoporous silica (P(VDF-HFP)@SiO₂) was synthesized via a sol–gel transcription method, then used as a scaffold to absorb organic electrolyte to make gel a electrolyte membrane (P(VDF-HFP)@SiO₂-GE) for LIBs. The P(VDF-HFP)@SiO₂-GE presents high electrolyte uptake (~1000 wt%), thermal stability (up to ~350 °C), ionic conductivity (~2.6 mS cm⁻¹ at room temperature), and excellent compatibility with an active Li metal anode. Meanwhile, F-doping carbon/silica composite nanofibers (F-C@SiO₂) were also produced by carbonizing the P(VDF-HFP)@SiO₂ film under Ar and used to make an electrode. The assembled F-C@SiO₂|P(VDF-HFP)@SiO₂-GE|Li half-cell showed long-cycle stability and a higher discharge specific capacity (340 mAh g⁻¹) than F-C@SiO₂|Celgard 2325|Li half-cell (175 mAh g⁻¹) at a current density of 0.2 A g⁻¹ after 300 cycles, indicating a new way for designing and fabricating safer high-performance LIBs. Full article

Potentiometric sensors are the largest and most commonly used group of electrochemical sensors. Among them, ion-selective electrodes hold a prominent place. Since the end of the last century, their re-development has been observed, which is a consequence of the introduction of solid contact constructions, i.e., electrodes without an internal electrolyte solution. Research carried out in the field of potentiometric sensors primarily focuses on developing new variants of solid contact in order to obtain devices with better analytical parameters, and at the same time cheaper and easier to use, which has been made possible thanks to the achievements of material engineering. This paper presents an overview of new materials used as a solid contact in ion-selective electrodes over the past several years. These are primarily composite and hybrid materials that are a combination of carbon nanomaterials and polymers, as well as those obtained from carbon and polymer nanomaterials in combination with others, such as metal nanoparticles, metal oxides, ionic liquids and many others. Composite materials often have better mechanical, thermal, electrical, optical and chemical properties than the original components. With regard to their use in the construction of ion-selective electrodes, it is particularly important to increase the capacitance and surface area of the material, which makes them more effective in the process of charge transfer between the polymer membrane and the substrate material. This allows to obtain sensors with better analytical and operational parameters. Brief characteristics of electrodes with solid contact, their advantages and disadvantages, as well as research methods used to assess their parameters and analytical usefulness were presented. The work was divided into chapters according to the type of composite material, while the data in the table were arranged according to the type of ion. Selected basic analytical parameters of the obtained electrodes have been collected and summarized in order to better illustrate and compare the achievements that have been described till now in this field of analytical chemistry, which is potentiometry. This comprehensive review is a compendium of knowledge in the research area of functional composite materials and state-of-the-art SC-ISE construction technologies. Full article

Since the water pollution problem still affects the environmental system and human health, the need to develop innovative membranes has become imperious. Lately, researchers have focused on developing novel materials to help diminish the contamination problem. The aim of present research was to obtain innovative adsorbent composite membranes based on a biodegradable polymer, alginate, to remove toxic pollutants. Of all pollutants, lead was chosen due to its high toxicity. The composite membranes were successfully obtained through a direct casting method. The silver nanoparticles (Ag NPs) and caffeic acid (CA) from the composite membranes were kept at low concentrations, which proved enough to bestow antimicrobial activity to the alginate membrane. The obtained composite membranes were characterised by Fourier transform infrared spectroscopy and microscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TG-DSC). Swelling behaviour, lead ion (Pb²⁺) removal capacity, regeneration and reusability were also determined. Further, the antimicrobial activity was tested against selected pathogenic strains (S. aureus, E. faecalis sp., P. aeruginosa, E. coli and C. albicans). The presence of Ag NPs and CA improves the antimicrobial activity of the newly developed membranes. Overall, the composite membranes are suitable for complex water treatment (removal of heavy metal ions and antimicrobial treatment). Full article