Carbonaceous nanofiber membrane functionalized by beta-cyclodextrins for molecular filtration

Graphene oxide enabled self-assembly of silver trimolybdate nanowires into robust membranes for nanosolid capture and molecular separation

A graphene oxide (GO) assisted self-assembly strategy for growing a silver trimolybdate nanowire membrane with capabilities of nanosolid capture and small molecule separation is reported. Thanks to the GO bridges and the accurate self-assembly process, the resulting membrane exhibits outstanding mechanical properties (can withstand 4300 times its weight) and impressively high porosity (97%). On the basis of the robustness and high porosity of the membrane, column-shaped filter apparatus has been fabricated, in which the membrane served as a self-standing permeation barrier to assess its permeability and practical application as a nanosolid filter and molecule filter. The permeability test of the membrane with pure water uncovers that the membrane exhibits fast permeability while driven by hydrostatic pressure only because of its significantly high porosity. The separation test of the membrane with P25 TiO₂ solution, 13 nm Au solution, and yellow-emitting CdTe QDs reveals that all the tiny nanosolids are completely removed from the solution, which suggests that the membrane is an efficient nanosolid filter. Its efficiency is increased by the induction of surface collision from numerous nanowire barriers and the deposition of nanosolids on the nanowire surface. The separation test of the membrane with a mixed-dye solution reveals that sulfur containing methylene blue (MB) molecules are highly efficiently extracted under various chemical conditions, evidencing that the membrane is an ideal molecule filter too. Its high selectivity and high efficiency originated from the Ag-S bonding between the interlayered silver ions of the silver trimolybdate nanowire and the sulfur atom of MB molecules. Based on the above results, the silver trimolybdate nanowire membrane has been applied to purify drugs, which successfully removed sulbactam sodium impurity F from sulbactam sodium, demonstrating a purity increment from 98.92% to 99.93%. The present work should provide a significant step forward to bringing macroscopic 1D nanomaterial architectures much closer to real-world applications involving isolation and enrichment of catalyst reclamation, high-value chemical recovery, drug purification, and environmental remediation.

Surface Functionalization of Nanofibers: The Multifaceted Approach for Advanced Biomedical Applications

Nanocarriers are gaining significant importance in the modern era of drug delivery. Nanofiber technology is one of the prime paradigms in nanotechnology for various biomedical and theranostic applications. Nanofibers obtained after successful electrospinning subjected to surface functionalized for drug delivery, biomedical, tissue engineering, biosensing, cell imaging and wound dressing application. Surface functionalization entirely changes physicochemical and biological properties of nanofibers. In physicochemical properties, wettability, melting point, glass transition temperature, and initial decomposition temperature significantly change offer several advantageous for nanofibers. Similarly, biological properties include cell adhesion, biocompatibility, and proliferation, also changes by functionalization of nanofibers. Various natural and synthetic materials polymers, metals, carbon materials, functional groups, proteins, and peptides, are currently used for surface modification of nanofibers. Various research studies across the globe demonstrated the usefulness of surface functionalized nanofibers in tissue engineering, wound healing, skin cancers, melanoma, and disease diagnosis. The delivery of drug through surface functionalized nanofibers results in improved permeation and bioavailability of drug which is important for better targeting of disease and therapeutic efficacy. This review provides a comprehensive insight about various techniques of surface functionalization of nanofibers along with its biomedical applications, toxicity assessment and global patent scenario.

Biomimetic Organic-Inorganic Hybrid Membranes for Removal of Fluoride Ions

Carbon nanofibers (CaNFs) exhibit promising applications in the fields of environmental science and nanotechnology, and self-assembled peptide nanofibers (PNFs) are useful for the biomimetic synthesis of organic-inorganic hybrid nanomaterials and the fabrication of functional hybrid membranes for the removal of various pollutants from water. In this work, we report the biomimetic synthesis of hybrid nanomaterials by the interweaving of CaNFs and PNFs. Using the biomimetic mineralization properties of PNFs, ZrO₂ nanoparticles were synthesized along the nanofiber surface, and then functional nanohybrid porous membranes were prepared by the vacuum filtration technology. For the fabrication of membranes, the amount of PNFs and ZrO₂ precursors in the hybrid membrane were optimized. The designed organic-inorganic hybrid membranes exhibited high removal performance for fluorine ion (F⁻) from water, and the removal efficiency of the fabricated membranes towards F⁻ ion-containing aqueous solution with a concentration of 50–100 mg/L reached more than 80%. In addition, the nanofiltration membranes revealed good adsorption capacity for F⁻ ions. It is expected that the strategies shown in this study will be beneficial for the design, biomimetic synthesis, and fabrication of nanoporous membranes for economic, rapid, and efficient water purification.

Enhanced Ion Sieving of Graphene Oxide Membranes via Surface Amine Functionalization

Membranes based on two-dimensional (2D) nanomaterials have shown great potential to alleviate the worldwide freshwater crisis due to their outstanding performance of freshwater extraction from saline water via ion rejection. However, it is still very challenging to achieve high selectivity and high permeance of water desalination through precise d-spacing control of 2D nanomaterial membranes within subnanometer. Here, we developed functionalized graphene oxide membranes (FGOMs) with nitrogen groups such as amine groups and polarized nitrogen atoms to enhance metal ion sieving by one-step controlled plasma processing. The nitrogen functionalities can produce strong electrostatic interactions with metal ions and result in a mono/divalent cation selectivity of FGOMs up to 90 and 28.3 in single and binary solution, which is over 10-fold than that of graphene oxide membranes (GOMs). First-principles calculation confirms that the ionic selectivity of FGOMs is induced by the difference of binding energies between metal ions and polarized nitrogen atoms. Besides, the ultrathin FGOMs with a thickness of 50 nm can possess a high water flux of up to 120 mol m^-2 h^-1 without sacrificing rejection rates of nearly 99.0% on NaCl solution, showing an ultrahigh water/salt selectivity of around 4.31 × 10³. Such facile and efficient plasma processing not only endows the GOMs with a promising future sustainable water purification, including ion separation and water desalination, but also provides a new strategy to functionalize 2D nanomaterial membranes for specific purposes.

Superhydrophilic Sub-1-nm Porous Membrane with Electroneutral Surface for Nonselective Transport of Small Organic Molecules

The study of traditional Chinese medicines (TCMs) is receiving increasing attention worldwide because of their contribution to human health. Developing an effective and sustainable method for screening TCMs is highly desired to accelerate the modernization of TCMs. In this work, we report a neutrally charged membrane made of a positively charged polyelectrolyte electrostatically assembled on a negatively charged superhydrophilic nanoporous membrane. The composite membrane possesses stable electroneutrality in a wide pH range and can precisely and nonselectively separate various charged molecules in TCMs with a transmittance higher than 90% for molecules with molecular weight (M_w) < 400 and a high rejection of 90% for molecules with M_w > 800. In addition, the membrane exhibits a superior antifouling performance, and the recovery ratio observed during a continuous cycling test of a simulated TCM solution was more than 93%. The combination of superhydrophilicity and electroneutrality in a nanoporous membrane provides a new route for designing nanofiltration membranes for highly efficient molecule separation and is promising for screening TCMs.

The importance of spheroids in analyzing nanomedicine efficacy

The use of nanomedicines for cancer treatment holds a great potential due to their improved efficacy and safety. During the nanomedicine preclinical in vitro evaluation stage, these are mainly tested on cell culture monolayers. However, these 2D models are an unrealistic representation of the in vivo tumors, leading to an inaccurate screening of the candidate formulations. To address this problem, spheroids are emerging as an additional tool to validate the efficacy of new therapeutics due to the ability of these 3D in vitro cancer models to mimic the key features displayed by in vivo solid tumors. In this review, the application of spheroids for the evaluation of nanomedicines' physicochemical properties and therapeutic efficacy is discussed.

The efficient removal of methylene blue from water samples using three-dimensional poly (vinyl alcohol)/starch nanofiber membrane as a green nanosorbent

In the present study, a simple, fast, and economical method was introduced to eliminate methylene blue from dye wastewater water using a non-toxic, inexpensive, stable, and efficient adsorbent. The poly (vinyl alcohol) (PVA)/starch hydrogel nanofiber membrane with high surface area and the three-dimensional structure was fabricated in water via electrospinning strategy, and the cross-linking reaction was done by thermal treatment. The characterization of the nanofibers was carried out using Fourier-transform infrared spectrometer (FT-IR) and field-emission scanning electron microscopy (FE-SEM), and the cross-linked PVA/starch nanofiber was applied as a membrane for the removal of methylene blue (MB). The recovery of MB was performed by methanol solution containing 5% (v/v) HCl. Langmuir isotherm model successfully described the adsorption of MB on nanosorbent, and the maximum adsorption capacity (q_m) was 400 mg g^-1. Also, the kinetic of adsorption was well fitted by the pseudo-second-order model. In this study, because of the high stability of fabricated membrane (based on the tensile testing), it can be used as a filter for the fast separation of MB (cationic dye) and methyl orange (MO, anionic dye). Graphical abstract.

Nanowire Genome: A Magic Toolbox for 1D Nanostructures

1D nanomaterials with high aspect ratio, i.e., nanowires and nanotubes, have inspired considerable research interest thanks to the fact that exotic physical and chemical properties emerge as their diameters approach or fall into certain length scales, such as the wavelength of light, the mean free path of phonons, the exciton Bohr radius, the critical size of magnetic domains, and the exciton diffusion length. On the basis of their components, aspect ratio, and properties, there may be imperceptible connections among hundreds of nanowires prepared by different strategies. Inspired by the heredity system in life, a new concept termed the "nanowire genome" is introduced here to clarify the relationships between hundreds of nanowires reported previously. As such, this approach will not only improve the tools incorporating the prior nanowires but also help to precisely synthesize new nanowires and even assist in the prediction on the properties of nanowires. Although the road from start-ups to maturity is long and fraught with challenges, the genetical syntheses of more than 200 kinds of nanostructures stemming from three mother nanowires (Te, Ag, and Cu) are summarized here to demonstrate the nanowire genome as a versatile toolbox. A summary and outlook on future challenges in this field are also presented.

Advances of nanosystems containing cyclodextrins and their applications in pharmaceuticals

For many years, researchers have worked with supramolecular structures involving inclusion complexes with cyclodextrins. These studies have resulted in new commercially available drugs which have been of great benefit. More recently, studies using nanoparticles, including nanosystems containing cyclodextrins, have become a focus of academic research due to the versatility of the systems and their remarkable therapeutic potential. This review focuses on studies published between 2002 and 2018 involving nanosystems containing cyclodextrins. We consider the type of nanosystems, their importance in a health context, the physicochemical techniques used to show the quality of these systems and their potential for the development of novel pharmaceutical formulations. These have been developed in recent studies which have mainly been focusing on basic science with no clinical trials as yet being performed. This is important to note because it means that the studies do not include any toxicity tests. Despite this limitation, the characterization assays performed suggest that these new formulations may have therapeutic potential. However, more research is required to assess the efficacy and safety of these nanosystems.

Highly efficient carbonaceous nanofiber/layered double hydroxide nanocomposites for removal of U(VI) from aqueous solutions

The three-dimensional (3D) carbonaceous nanofiber and Ni-Al layered double hydroxide (CNF/LDH) nanocomposite was successfully prepared by a facile one-step hydrothermal methodology. Characterization of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), XRD, and Fourier transformed infrared spectroscopy (FTIR) provided a demonstration that the modified CNF/LDH nanocomposite possessed abundant functional groups, for instance, metal-oxygen surface bonding sites (Ni–O as well as Al–O) and free-metal surface bonding sites (C–O, C–O–C, as well as O–C=O). The elimination of representative radionuclide (i.e. U(VI)) on the CNF/LDH nanocomposite from aqueous solutions was explored as a key function of pH, ionic strength, contact time, reaction temperature as well as radionuclide preliminary concentrations with the use of the batch methodology. As revealed by the findings, the sorption of radionuclides on CNF/LDH nanocomposite adhered to the pseudo-second-order kinetic model as well as Langmuir model. The maximum elimination capacity of U(VI) amounted to be 0.7 mmol/g. The independent of ionic strength shed light on the fact that inner-sphere surface complexation mainly overpowered radionuclide uptake by the CNF/LDH nanocomposite, which was further verified through the combination of FTIR and XPS spectral analyses. The abovementioned analyses shed light on the fact that the CNF/LDH nanocomposite can be regarded as a latent material to preconcentration radionuclides for environmental remediation.

Rational design of carbonaceous nanofiber/Ni-Al layered double hydroxide nanocomposites for high-efficiency removal of heavy metals from aqueous solutions

Heavy metal pollution of water sources has raised global environmental sustainability concerns, calling for the development of high-performance materials for effective pollution treatment. Herein, we report a facile approach to synthesize carbonaceous nanofiber/NiAl layered double hydroxide (CNF/LDH) nanocomposites for high-efficiency elimination of heavy metals from aqueous solutions. The CNF/LDH nanocomposites were characterized by three-dimensional architectures formed by the gradual self-assembly of flower-like LDH on CNF. The nanocomposites exhibited excellent hydrophilicity and high structural stability in aqueous solutions, guaranteeing the high availability of active sites in these environments. High-efficiency elimination of heavy metal ions by the CNF/LDH nanocomposites was demonstrated by the high uptake capacities of Cu(II) (219.6 mg/g) and Cr(VI) (341.2 mg/g). The sorption isotherms coincided with the Freundlich model, most likely because of the presence of heterogeneous binding sites. The dominant interaction mechanisms consisted of surface complexation and electrostatic interaction, as verified by a combination of X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy analyses and density functional theory calculations. The results presented herein confirm the importance of CNF/LDH nanocomposites as emerging and promising materials for the efficient removal of heavy metal ions and other environmental pollutants.

Emerging Carbon-Nanofiber Aerogels: Chemosynthesis versus Biosynthesis

Carbon aerogels that are typically prepared using sol-gel chemistry have unique three dimensional networks of interconnected nanometer-sized particles and thus exhibit many fascinating physical properties and great application potentials in widespread fields. To boost the practical applications, it is necessary to develop efficient and low-cost methods to produce high-performance carbon aerogels on a large-scale, preferably in a sustainable way. In 2012, two new classes of aerogels consisting of carbon-nanofiber (CNF) networks were prepared from biomass-derived precursors by chemosynthesis (i.e. template-directed hydrothermal carbonization of carbohydrate) and biosynthesis (i.e. use of bacterial cellulose as precursor), respectively. This Review gives a critical overview of this emerging and rapidly developing field, focusing on the synthetic strategies of the carbon-nanofiber aerogels and their outstanding physical properties. We also discuss the multifunctional application potentials of the two sorts of carbon aerogels and their nanocomposites, and highlight the challenges and future opportunities in this field.

Porous PVdF/GO Nanofibrous Membranes for Selective Separation and Recycling of Charged Organic Dyes from Water

Graphene oxide (GO) membranes are robust and continue to attract great attention due to their fascinating properties, despite their potential issues regarding stability and selectivity in aqueous-phase processing. That being said, however, the functional moieties of GO could be used for membrane surface modification, while ensuring simultaneous removal and recycling of industrial organic dyes. Herein, we present a versatile porous structured polyvinylidene fluoride-graphene oxide (PVdF-GO) nanofibrous membranes (NFMs), prepared by using simple and straightforward electrospinning approach for selective separation and filtration. The GO nanosheets were distributed homogeneously throughout the PVdF nanofiber, regulating the surface morphology and performance of PVdF-GO NFM. The PVdF-GO NFMs possesses high mechanical strength and surface free energy (SFE), consequently resulting high permeation and filtration efficiency as compared to PVdF NFM. The selectivity (99%) toward positively charged dyes based on electrostatic attraction, while maintaining rejection (100%) for negatively charged dye from mixed solutions highlight the role of GO in PVdF-GO NFM, owing to uniform pores and negatively charged surface. In addition, the actual efficiency of NFMs could be recovered easily up to three consecutive filtration cycles by regeneration, thereby assuring high stability. The high permeation, purification and filtration efficiency, good stability and recycling of PVdF-GO NFMs are promising for use in practical water purification and applications, particularly for selective filtration and recycling of dyes.

Hierarchical Porous Structured SiO2/SnO2 Nanofibrous Membrane with Superb Flexibility for Molecular Filtration

The separation and purification of chemical molecules from organic media under harsh chemical environments are of vital importance in the fields of water treatment, biomedical engineering, and organic recycling. Herein, we report the preparation of a flexible SiO₂/SnO₂ nanofibrous membrane (SiO₂/SnO₂ NFM) with high surface area and hierarchical porous structure by selecting poly(vinyl butyral) as pore-forming agent and embedding crystalline phase into amorphous matrix without using surfactant as sacrificial template. Benefiting from the uniform micropore size on the fibers and negatively charged properties, the membranes exhibit a precise selectivity toward molecules based on electrostatic interaction and size exclusion, which could separate organic molecule mixtures with the same electrostatic charges and different molecular sizes with a high efficiency of more than 97%. Furthermore, the highly tortuous open-porous structures and high porosity give rise to a high permeate flux of 288 000 L m^-2 h^-1. In addition, the membrane also displays excellent stability and can be reused for ten consecutive filtration-regeneration cycles. The integration of high filtration efficiency, large permeate flux, good reutilization, and easy to industrialization provides the SiO₂/SnO₂ NFM for potential applications in practical molecular purification and separation science.

Processable graphene oxide-embedded titanate nanofiber membranes with improved filtration performance

Graphene oxide (GO)-embedded titanate nanofiber (TNF) membranes with improved filtration performance are prepared successfully by a two-step method including electrostatic assembly of GO and TNFs into hybrids and subsequent processing of them into membranes by vacuum filtration. The embedded contents of GO sheets in films and thickness of as-assembled films can be adjusted facilely, endowing such composite films with good processability. Owing to the skilful introduction of GO sheets, the pore and/or channel structures in these hybrid membranes are modified. By treating different dye solutions (Direct Yellow and Direct Red), the filtration properties of these membranes show that the introduction of certain amount of GO sheets efficiently improve the separation performance of the membranes. Interestingly, these GO-embedded TNF membranes also display superior selective separation performance on filtrating the mixture solutions of such two dyes, making these hierarchical membranes more flexible and versatile in water treatment areas.

Selective Adsorption and Separation through Molecular Filtration by Hyperbranched Poly(ether amine)/Carbon Nanotube Ultrathin Membranes

In response to the increasing public awareness of serious dye-contained wastewater contamination, we herein fabricated a novel anthracene-containing hyperbranched poly(ether amine) (hPEA-AN)/carbon nanotube (CNT) ultrathin membrane (UTM), which combined both the merits of the conventional dye adsorption strategy and membrane filtration process, to implement efficient selective adsorption of dye molecules and also the separation of dye mixtures by molecular filtration. Taking advantage of the π-π stacking interactions between anthracene and CNT sidewalls and hydrophobic interactions, CNTs were coated tightly with hPEA-AN to form the hPEA-AN@CNT complex, which can be well-dispersed very stably in water. The formation of the hPEA-AN@CNT complex was confirmed using X-ray photoelectron spectroscopy, Raman spectra, fluorescence spectra, and thermogravimetric analysis. Meanwhile, a simple filtration process was applied to prepare hPEA-AN@CNT UTMs with a thickness of 1.5 μm, which can be further cross-linked through photodimerization of anthracene moieties. The UTMs represented selective adsorption behaviors toward hydrophilic dyes even with similar backbones and the same charge states, namely, they showed high adsorption capacities (Q_eq) toward eosin B, erythrosin B (ETB), 4',5'-dibromofluorescein, and Evans blue (EVB) dyes up to 300 μmol/g while showing low adsorption capacities toward calcein (Cal), methyl red, and Ponceau S dyes. On the basis of this unique selective adsorption, molecular filtration was then realized toward mixed ETB/Cal and EVB/Cal dyes, with a separation efficiency of up to 100% and regeneration without an obvious efficiency decrease.

Macroscopic and Microscopic Investigation of U(VI) and Eu(III) Adsorption on Carbonaceous Nanofibers

The adsorption mechanism of U(VI) and Eu(III) on carbonaceous nanofibers (CNFs) was investigated using batch, IR, XPS, XANES, and EXAFS techniques. The pH-dependent adsorption indicated that the adsorption of U(VI) on the CNFs was significantly higher than the adsorption of Eu(III) at pH < 7.0. The maximum adsorption capacity of the CNFs calculated from the Langmuir model at pH 4.5 and 298 K for U(VI) and Eu(III) were 125 and 91 mg/g, respectively. The CNFs displayed good recyclability and recoverability by regeneration experiments. Based on XPS and XANES analyses, the enrichment of U(VI) and Eu(III) was attributed to the abundant adsorption sites (e.g., -OH and -COOH groups) of the CNFs. IR analysis further demonstrated that -COOH groups were more responsible for U(VI) adsorption. In addition, the remarkable reducing agents of the R-CH2OH groups were responsible for the highly efficient adsorption of U(VI) on the CNFs. The adsorption mechanism of U(VI) on the CNFs at pH 4.5 was shifted from inner- to outer-sphere surface complexation with increasing initial concentration, whereas the surface (co)precipitate (i.e., schoepite) was observed at pH 7.0 by EXAFS spectra. The findings presented herein play an important role in the removal of radionuclides on inexpensive and available carbon-based nanoparticles in environmental cleanup applications.

Synthesis of β-Cyclodextrin-Based Electrospun Nanofiber Membranes for Highly Efficient Adsorption and Separation of Methylene Blue

Water-insoluble β-cyclodextrin-based fibers were synthesized by electrospinining followed by thermal cross-linking. The fibers were characterized by field-emission scanning electron microscopic (FE-SEM) and Fourier transformed infrared spectrometer (FT-IR). The highly insoluble fraction obtained from different pH values (3-11) indicates successful cross-linking reactions and their usability in aqueous solution. After the cross-linking reaction, the fibers' tensile strength increases significantly and the BET surface area is 19.49 m(2)/g. The cross-linked fibers exhibited high adsorption capacity for cationic dye methylene blue (MB) with good recyclability. The adsorption performance can be fitted well with pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacity is 826.45 mg/g according to Langmuir fitting. Due to electrostatic repulsion, the fibers show weak adsorption toward negatively charged anionic dye methyl orange (MO). On the basis of the selective adsorption, the fiber membrane can separate the MB/MO mixture solution by dynamic filtration at a high flow rate of 150 mL/min. The fibers can maintain good fibrous morphology and high separation efficiency even after five filtration-regeneration cycles. The obtained results suggested potential applications of β-cyclodextrin-based electrospun fibers in the dye wastewater treatment field.

Controllable Preparation of Ultrathin Sandwich-Like Membrane with Porous Organic Framework and Graphene Oxide for Molecular Filtration

Porous organic frameworks (POFs) based membranes have potential applications in molecular filtration, despite the lack of a corresponding study. This study reports an interesting strategy to get processable POFs dispersion and a novel ultrathin sandwich-like membrane design. It was accidentally found that the hydrophobic N-rich Schiff based POFs agglomerates could react with lithium-ethylamine and formed stable dispersion in water. By successively filtrating the obtained POFs dispersion and graphene oxide (GO), we successfully prepared ultrathin sandwich-like hybrid membranes with layered structure, which showed significantly improved separation efficiency in molecular filtration of organic dyes. This study may provide a universal way to the preparation of processable POFs and their hybrid membranes with GO.

Highly Efficient Phosphate Scavenger Based on Well-Dispersed La(OH)3 Nanorods in Polyacrylonitrile Nanofibers for Nutrient-Starvation Antibacteria

La(OH)3 nanorods immobilized in polyacrylonitrile (PAN) nanofibers (PLNFs) were fabricated for the first time by electrospinning and a subsequent in situ surfactant-free precipitation method and then applied as a highly efficient phosphate scavenger to realize nutrient-starvation antibacteria for drinking water security. The immobilization by PAN nanofibers effectively facilitated the in situ formation of the aeolotropic and well-dispersed La(OH)3 nanostructures and, thus, rendered higher phosphate removal efficiency due to more exposed active sites for binding phosphate. The maximum phosphate capture capacity of La(OH)3 nanorods in PAN nanofibers was around 8 times that of the La(OH)3 nanocrystal fabricated by precipitation without PAN protection. Moreover, remarkably fast adsorption kinetics and high removal rate were observed toward low concentration phosphate due to the high activity of our materials, which can result in a stringent phosphate-deficient condition to kill microorganisms in water effectively. The present material is also capable of preventing sanitized water from recontamination by bacteria and keeping water biologically stable for drinking. Impressively, stabilized by PAN nanofibers, the La(OH)3 nanorods can be easily separated out after reactions and avoid leaking into water. The present development has great potential as a promising antimicrobial solution for practical drinking water security and treatment with a negligible environmental footprint.

Nanostructures formed by cyclodextrin covered procainamide through supramolecular self assembly--spectral and molecular modeling study

Inclusion complexation behavior of procainamide (PCA) with two cyclodextrins (α-CD and β-CD) were analyzed by absorption, fluorescence, scanning electron microscope (SEM), transmission electron microscope (TEM), Raman image, FT-IR, differential scanning colorimeter (DSC), Powder X ray diffraction (XRD) and (1)H NMR. Blue shift was observed in β-CD whereas no significant spectral shift observed in α-CD. The inclusion complex formation results suggest that water molecules also present in the inside of the CD cavity. The present study revealed that the phenyl ring of the PCA drug is entrapped in the CD cavity. Cyclodextrin studies show that PCA forms 1:2 inclusion complex with α-CD and β-CD. PCA:α-CD complex form nano-sized particles (46 nm) and PCA:β-CD complex form self-assembled to micro-sized tubular structures. The shape-shifting of 2D nanosheets into 1D microtubes by simple rolling mechanism were analysed by micro-Raman and TEM images. Thermodynamic parameters (ΔH, ΔG and ΔS) of inclusion process were determined from semiempirical PM3 calculations.

Large scale poly(vinyl alcohol-co-ethylene)/TiO2hybrid nanofibrous filters with efficient fine particle filtration and repetitive-use performance

A high-yielding nanofiber-based filtration material with excellent performance was developed and provides a promising way to control the severe air pollution at present.

Cyclodextrin-functionalized hollow carbon nanospheres by introducing nanogold for enhanced electrochemical sensing of o-dihydroxybenzene and p-dihydroxybenzene

A cyclodextrin–gold nanoparticles/hollow carbon nanospheres nanohybrid was prepared for the sensitive simultaneous electrochemical sensing of o- and p-dihydroxybenzene.

Poly(vinyl alcohol) electrospun nanofibrous membrane modified with spirolactam–rhodamine derivatives for visible detection and removal of metal ions

Reversible poly(vinyl alcohol) electrospun nanofibrous membrane modified with spirolactam–rhodamine derivatives for visible detection and removal of metal ions.

Multiplex templating process in one-dimensional nanoscale: controllable synthesis, macroscopic assemblies, and applications

Since their detection 20 years ago, carbon nanotubes (CNTs) have captured the interest of scientists, because one-dimensional (1D) nanostructures (nanowires, nanotubes, and nanoribbons) have fascinating physical properties and many potential technological applications. These are materials with structural features limited to the range of 1-100 nm in one dimension, and unlimited in the others. When their size goes down to certain characteristic lengths, such as the Bohr radius, the wavelength of incandescent light, and the phonon mean-free path, quantum mechanical effects can occur. This results in novel optical, magnetic, and electronic characteristics. These physical properties, along with unique transport features in the longitudinal direction and large surface-to-volume ratio, make 1D nanostructures attract extensive attention in both fundamental research and engineering applications. From a synthetic point of view, it is highly desirable to develop a simple route for fabricating 1D nanostructures in large scale at low cost. On the other hand, in order to transfer the intrinsic features of individual 1D nanostructures into macroscopic scale and realize practical applications, we need to explore highly efficient and scalable assembly methods to integrate 1D nanostructures into functional macroscopic architectures. In 2006, our group developed a simple hydrothermal method for synthesizing ultrathin Te nanowires (TeNWs) using conventional chemicals. As we found through systematic study over the past several years, we can use the ultrathin TeNWs as a versatile templating material to fabricate a series of high-quality 1D nanostructures by taking the unique advantages of TeNWs, such as large-scale synthesis, high processability, and high reactivity. The obtained 1D products inherit the dimensional (high aspect ratio) and mechanical (high flexibility) features of the original TeNW templates, thus allowing us to construct macroscopic architectures by using them as nanoscale building blocks. In this Account, we describe on our recent developments in the multiplex templating synthesis of 1D nanostructures, their macroscopic assemblies, and applications. We first introduce ultrathin TeNWs and their advantages as a templating material. Through the multiplex templating process, we can prepare a family of 1D nanostructures that covers a wide range of materials, including noble metals, metal oxides, semiconductors, carbon, polymers, and their binary and multiple hybrids. We emphasize the reactivity of templating materials and the versatility of templating processes in this Account. On the basis of the templated 1D products, we then describe a series of macroscopic assemblies of 1D nanostructures, including free-standing membranes, films, hydrogels, and aerogels. These exhibit enormous potential for attractive applications, such as liquid filtration and separation, continuous-flow catalysis, electrocatalysis, polymer-based nanocomposites, and superadsorbents, and elastomeric conductors. We believe that the great versatility of templating synthesis, a scalable assembling process, and large-scale synthesis can significantly enhance the application reliability of the 1D nanostructures.