Low-concentration Solutions Research Articles

Surface modification and spatial optimization of pre-lithiation TiO2 ion sieves for efficient extraction of lithium

The closed pores and slow kinetics of conventional Ti-based adsorbents (HTO) hinder their industrial application in the selective adsorption of Li+ from wastewater. Herein, a surface modification and spatial optimization strategy was developed to improve the adsorption performance of HTO for Li+. The strong hydrophilicity caused by high roughness of modified HTO increases the contact area between the Li+-containing solution and the absorbent, which shortens the diffusion path of Li+ to the adsorbent surface and accelerates the migration of Li+ to the adsorbent surface. The excellent lithium affinity of N heteroatom on the surface of modified HTO promotes the conversion of hydrated Li+ into activated Li+, which can be easily captured by the adsorbent. The large specific surface area of modified HTO provides abundant absorption sites of Li+. The material with rich pores provides sufficient space to improve the adsorption capacity of Li+. The small particle size shortens the transport path of Li+ from the adsorbent surface to its interior, thereby reducing the transport resistance, which accelerates the migration of Li+ into the adsorbent and releases a large number of active sites on the surface. The experimental results show that the Li+ adsorption rate is increased from 0.37 mg·g−1·min−1 to 0.82 mg·g−1·min−1 after modification. The adsorption capacity of the adsorbent is 49.05 mg·g−1 and it remains 96.7 % after 5 cycles, indicating excellent adsorption performance and recyclability. This study provides a strategy for effective extraction of Li+ from low concentration solutions.

A dilute sodium hydroxide technique for radiolarian extraction from cherts

Radiolarians have been used to determine geological ages and have contributed markedly to our understanding of Earth’s history. Hydrofluoric acid (HF) has traditionally been used to extract radiolarian fossils from siliceous deposits (i.e., radiolarian cherts), but this acid is strictly regulated because of environmental and human health concerns. Here we report on the successful extraction of radiolarians from cherts using a low-concentration NaOH solution (1 mol/L NaOH) as an alternative to HF. The degree of chert dissolution in NaOH is strongly temperature-dependent and is limited at < 80 °C. However, even a 1 mol/L NaOH solution is sufficient to dissolve chert at 100 °C. Our new NaOH method yields better-preserved radiolarian fossils compared with the conventional HF method. The 1 mol/L NaOH solution is less hazardous, easier to handle, and has fewer effects on the environment and human health than HF. Therefore, this method can be widely used for research and teaching purposes in studies of radiolarian fossils, even in institutions where HF cannot be used owing to chemical restrictions.

Unconventional extraction of uranium from seawater through microenvironment-specific conjugated microporous poly(aniline)s

The sustainability of uranium-based nuclear energy relies on the development of quick and effective uranium adsorbents. Herein, we propose a facile post-synthetic technique by grafting amino-functional groups onto the fluorenone-functionalized conjugated microporous poly(aniline)s (CMPs) network to acquire a novel class of N decorated polymers for uranium capture. By leveraging the abundant N sites and microenvironment-containing molecular structure, CMPA-F-BDA showcases excellent UO22+ adsorption performance with fast adsorption kinetic with initial adsorption rate up to 43.78 mg g−1 min−1, Langmuir adsorption capacity of 443 mg g−1 and exceptional adsorption selectivity of Kd = 1.3 × 107 mL g−1 even in the serious presence of competitive cations. Additionally, CMPA-F-BDA could treat up to 18.5 L g−1 of low-concentration uranium solution (1 mg L−1) and actual seawater, removing 87.9% of uranium from 10 L of seawater, and has excellent reusability. This study demonstrates the bright future of CMPs for the extraction of low-concentration uranium.

Optimizing crystal transitions in low-temperature, low-concentration NaOH solutions to prepare cellulose I and II composite materials

Optimizing crystal transitions in low-temperature, low-concentration NaOH solutions to prepare cellulose I and II composite materials

An Experimental Study on the Solubility of Betulin in the Complex Solvent Ethanol-DMSO

Betulin is a promising natural organic substance due to its antibacterial, fungicidal, and antitumor properties, as are their derivatives. The particle size of betulin can reach several tens of micrometers, and its thickness is several microns. There are various ways of processing betulin, but the most promising are solution methods (applying thin layers, impregnation, etc.). Application or impregnation of various materials is carried out using betulin; however, currently known solvents do not allow obtaining solutions with the necessary content of it. Since a number of direct solvents are already known for betulin, which provides only low-concentration solutions, the use of complex systems based on two solvents can become the optimal solution to the problem. The literature data show that the use of mixtures of solvents allows for the preparation of homogeneous solutions, for example, for natural polymers like cellulose, etc. This approach to obtaining solutions has become the basis for the processing of betulin. The use of a mixed solvent based on ethanol and DMSO for the preparation of betulin solutions has been proposed for the first time. The solubility of betulin in a mixture system with a ratio of components of 50 wt.% to 50 wt.% was studied, and a solubility curve was plotted. It is shown that the use of a two-component solvent makes it possible to transfer up to 10% of betulin into solution, which is almost twice as much as compared to already known solvents. The rheological properties of the obtained solutions have been studied. The viscosity of betulin solutions in a complex solvent depends on its content and temperature, so for 7% solutions at 70 °C, it is approximately 0.008 Pa*s. Applying betulin to the surface of the cardboard increases its hydrophobic properties and repellency.

Improving the Device Stability by Controlling the Morphology of Quantum Dot Emissive Layer Via a Coating Process in Blue QLEDs

AbstractBlue light‐emitting CdSe@ZnS/ZnS quantum dot (QD) nanoparticles (NPs) were synthesized and their photophysical properties in both solution and film phases were investigated. The morphological properties of films prepared by different coating methods i. e. single layer coating from low to high concentrations of QD solutions and layer‐by‐layer (multilayer) coating within constant low QD solution concentration, were also examined in detail. Varying the concentration (1–10 mg/mL) and the number of layers (from 1–16) did not essentially affect the photophysical properties of QD films, although it resulted in a direct increment in QD film thickness. The concentration and layer‐dependent films were used as an emissive layer (EML) in QD light‐emitting diodes (QLEDs). Although the “6 mg/ml−1 Layer” QD EML‐based device exhibited relatively high device efficiency compared to the “1 mg/ml−10 Layers” based one at working voltage region, it had ~2‐fold higher efficiency roll‐off at high voltage region. The performance differences for both devices with the same QD EML thickness were attributed to the morphological variations for the QD layer in terms of surface roughness, void density, aggregates/clusters, and trap sites that were directly related to the charge injection balance and Auger recombination.

Diffusiophoresis in Polymer and Nanoparticle Gradients.

Diffusiophoresis is the movement of the colloidal particles in response to a concentration gradient and can be observed for both electrolyte (e.g., salt) and nonelectrolyte (e.g., glucose) solutes. Here, we investigated the diffusiophoretic behavior of polystyrene (PS-carboxylate surface) microparticles in nonadsorbing charged and uncharged solute gradients [sodium polystyrenesulfonate (NaPSS), polyethylene glycol (PEG), and nanoscale colloidal silica (SiO2)] using a dead-end channel setup. We compared the diffusiophoretic motion in these gradient types with each other and to the case of using a monovalent salt gradient. In each of the nonadsorbing gradient systems (NaPSS, PEG, and SiO2 nanoparticles), the PS particles migrated toward the lower solute concentration. The exclusion distance values (from the initial position) of particles were recorded within the dead-end channel, and it was found that an increase in solute concentration increases exclusion from the main channel. In the polyelectrolyte case, the motion of PS microparticles was reduced by the addition of a background salt due to reduced electrostatic interaction, whereas it remained constant when using the neutral polymer. Particle diffusiophoresis in gradients of polyelectrolytes (charged macromolecules) is quite similar to the behavior when using a PEG gradient (uncharged macromolecule) in the presence of a background electrolyte. Moreover, we observed PS microparticles under different concentrations and molecular weights of PEG gradients. By combining the simulations, we estimated the exclusion length, which was previously proposed to be the order of the polymer radius. Furthermore, the movement of PS microparticles was analyzed in the gradient of silica nanoparticles. The exclusion distance was higher in silica nanoparticle gradients compared to similar-size PEG gradients because silica nanoparticles are charged. The diffusiophoretic transport of the PS microparticles could be simulated by considering the interaction between the PS microparticles and silica nanoparticles.

Luminescent Silicon Nanocrystals as Metal Ion Sensors.

At relatively low concentrations in aqueous solution, Fe3+, Fe2+, Cu2+, and Ni2+ quench the photoluminescence (PL) of the undecenoic acid-capped silicon (Si) nanocrystals. The PL could be restored by adding a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), to remove the ions. Fe3+ and Cu2+ also significantly increase the PL lifetime. Other metal ions, including Cd2+, Mn2+, Pb2+, Zn2+, In3+, K+, and Ca2+, had no effect on the Si nanocrystal PL. The limits of detection (LODs) for Fe3+ and Cu2+ of 370 and 150 nM, respectively, are low enough for metal ion sensing applications.

A New Bioactive Thiazolidinone-based Azo Dye for Naked-eye Colorimetric Detection of Cyanide Ions

Abstract: A new bioactive azo dye embedding a thiazolidinone heterocyclic core was designed and synthesized for antibacterial application and colorimetric sensing of cyanide ion (CNˉ) in organic solutions. The structure of the prepared dye was elucidated from its 1H NMR, FT-IR and UV-Vis spectral data. It proved to be a fast and sensitive colorogenic sensor for detection of CNˉ. Spectroscopic studies were carried out to investigate the effect of different CNˉ concentrations on the detection efficiency. Moreover, the studies revealed no significant competition or influence of other anions on the sensitivity of CNˉ detection by the synthesized dye. A Job's plot indicated a 1:1 stoichiometry of the dye and CNˉ in their colorful complex. Further development of the method for naked-eye detection of CNˉ in low-concentration aqueous solutions was achieved by using the cellulose papers painted with the dye. The as-prepared testing paper allowed CNˉ sensing in concentrations as low as 2 μM. Evaluation of the dye for antibacterial activities using the well diffusion technique displayed that its inhibitory activity is at least as good as and in some cases superior to ampicillin against the bacterial strains employed in the zone assay. In response to CN¯, the dye changes color from yellow to reddish brown which accounts for its significant interactions with CNˉ and affords a naked-eye sensing method without resorting to any spectroscopic instrumentation.

Composite ellipsoids to model charge anisotropy in particle-scale simulations of kaolinite

This paper outlines a new approach to use coarse-grained molecular dynamics (CGMD) and the Gay–Berne (GB) potential to simulate the compression of kaolinite saturated with water at an acidic pH ( = 4) in a low (1 mM) ion concentration solution. To overcome the limitations of the standard GB potential and capture the charge heterogeneity on the surface of kaolinite particles under acidic pH conditions, each clay platelet is modelled using a two-ellipsoid composite particle. The molecular dynamics software Large-scale Atomic/Molecular Massively Parallel Software was employed to generate virtual monodisperse samples containing 1000 composite particles and to simulate isotropic compression at 100 kPa. The observed macro-scale response in void ratio–effective stress space lay above the response obtained in a simulation that used an equivalent CGMD model developed to simulate alkaline (pH = 8) pore water conditions. This is in qualitative agreement with available experimental data for one-dimensional compression. A post-compression qualitative observation of two virtual samples revealed a book-house-type fabric in the sample with acidic pore fluid, whereas a turbostatic-type fabric was observed when an alkaline pore fluid was simulated. These observations are also in qualitative agreement with scanning electron microscopy data reported in the literature.

Highly sensitive detection of low-concentration sodium chloride solutions based on a gold-coated prism in Kretschmann setup

A gold-coated Kretschmann setup has been constructed and explored as a surface plasmon resonance (SPR) platform, specifically tailored for the detection of low-concentration sodium chloride (NaCl) solutions. The setup employs a BK7 prism coated with a 50 nm gold layer, serving as a plasmonic layer, to induce resonance. This resonance arises from the interplay between light waves and free electrons propagating at the interface of two media. The experimental findings reveal a notable resonance angle shift of 10° when the NaCl concentration is varied from 0 to 2.5 %. Furthermore, angle interrogation provides insightful details about the sensor's response to changes in the refractive index, showcasing a commendable sensitivity of 2400°/RIU, a high level of linearity at 0.9771, and an impressive resolution of 0.217 %. The demonstrated capabilities of this sensor underscore its potential for widespread applications, particularly in the monitoring of salt concentration across diverse domains such as seawater analysis, food processing, and fermentation processes. The robust performance and precision of this proposed sensor position it as a valuable tool with promising prospects for addressing the needs of various industries dependent on accurate salt concentration measurements.

Limits of pressure-based ice detection during isochoric vitrification

Vitrification under isochoric (constant-volume or volumetrically confined) conditions has emerged as an intriguing new cryopreservation modality, but the physical complexities of the process confound straight-forward interpretation of experimental results. In particular, the signature pressure-based ice detection used in many isochoric techniques becomes paradoxical during vitrification, wherein the emergence of a sharp increase in pressure reliably indicates the presence of ice, but avoidance of this increase does not necessarily indicate its absence. This phenomenon arises from the rich interplay between thermochemical and thermovolumetric effects in isochoric systems, and muddies efforts to confirm the degree to which a sample has vitrified. In this work, we seek to aid interpretation of isochoric vitrification experiments by calculating thermodynamic limits on the maximum amount of ice that may form without being detected by pressure, and by clarifying the myriad physical processes at play. Neglecting kinetic effects, we develop a simplified thermodynamic model accounting for thermal contraction, cavity formation, ice growth, solute ripening, and glass formation, we evaluate it for a range of chamber materials and solution compositions, and we validate against the acutely limited data available. Our results provide both counter-intuitive insights— lower-concentration solutions may contract less while producing more pressure-undetectable ice growth for example— and a general phenomenological framework by which to evaluate the process of vitrification in isochoric systems. We anticipate that the model herein will enable design of future isochoric protocols with minimized risk of pressure-undetectable ice formation, and provide a thermodynamic foundation from which to build an increasingly rigorous multi-physics understanding of isochoric vitrification.

Rapid preparation of Mo2CTx MXene by hydrothermal etching in ammonium hydrogen fluoride solution

In this paper, we report a novel method to rapidly prepare two-dimensional Mo2CTx MXene in a low-concentration etching solution. By this method, highly pure Mo2CTx MXene was synthesized from Mo2Ga2C by hydrothermal etching at 180 ℃ in the solution of ammonium hydrogen fluoride (NH4HF2). The whole process requires only 2 h and the etching solution concentration is only 1 M. Compared with the acid solutions used in other methods, NH4HF2 used in this method is in solid state and its water solution is mild for handling. Compared with other methods, this method requires a lower concentration of etching solution and a much shorter etching time. The Mo2CTx MXene made this method have comparable microstructure and properties with those made by other methods. The initial discharge capacity as an anode of lithium-ion batteries (LIB) was 139.35 mAh g-1 at 0.1 A g-1. After 150th cycles, the final discharge capacity was 62.42 mAh g-1 at 0.1 A g-1. The electrochemical performance is slightly higher than the sample made by general HF etching. This is the first report to make Mo2CTx MXene from the etching of bifluoride salt. Due to the short etching time and low concentration of the etching solution, this method can rapidly make Mo2CTx MXene at in low cost, which provides a route to explore the large-scale production of Mo2CTx MXene.

Enhancement of waterborne pathogen removal by functionalized biochar with ε-polylysine ″dynamic arms″: Potential application in ultrafiltration system

Widespread outbreaks of threatening infections caused by unknown pathogens and water transmission have spawned the development of adsorption methods for pathogen elimination. We proposed a biochar functionalization strategy involving ε-polylysine (PLL), a bio-macromolecular poly(amino acid)s with variable folding conformations, as a "pathogen gripper" on biochar. PLL was successfully bridged onto biochar via polydopamine (PDA) crosslinking. The extension of electropositive side chains within PLL enables the capture of both nanoscale viruses and micrometer-scale bacteria in water, achieving excellent removal performances. This functionalized biochar was tentatively incorporated into ultrafiltration (UF) system, to achieve effective and controllable adsorption and retention of pathogens, and to realize the transfer of pathogens from membrane surface/pore to biochar surface as well as flushing water. The biochar-amended UF systems presents complete retention (∼7 LRV) and hydraulic elution of pathogens into membrane flushing water. Improvements in removal of organics and anti-fouling capability were observed, indicating the broken trade-off in UF pathogen removal dependent on irreversible fouling. Chemical characterizations revealed adsorption mechanisms encompassing electrostatic/hydrophobic interactions, pore filling, electron transfer, chemical bonding and secondary structure transitions. Microscopic and mechanical analyses validated the mechanisms for rapid adsorption and pathogen lysis. Low-concentration alkaline solution for used biochar regeneration, facilitated the deprotonation and transformation of PLL side chain to folded structures (α-helix/β-sheet). Biochar regeneration process also promoted the effective detachment/inactivation of pathogens and protection of functional groups on biochar, corroborated by physicochemical inspection and molecular dynamics simulation. The foldability of poly(amino acid)s acting like dynamic arms, significantly contributed to pathogen capture/desorption/inactivation and biochar regeneration. This study also inspires future investigation for performances of UF systems amended by poly(amino acid)s-functionalized biochar under diverse pressure, temperature, reactive oxygen species of feeds and chemical cleaning solutions, with far-reaching implications for public health, environmental applications of biochar, and UF process improvement.

Structural Evolution of Liquid Metals and Alloys.

Low-melting liquid metals are emerging as a new group of highly functional solvents due to their capability to dissolve and alloy various metals in their elemental state to form solutions as well as colloidal systems. Furthermore, these liquid metals can facilitate and catalyze multiple unique chemical reactions. Despite the intriguing science behind liquid metals and alloys, very little is known about their fundamental structures in the nanometric regime. To bridge this gap, this work employs small angle neutron scattering and molecular dynamics simulations, revealing that the most commonly used liquid metal solvents, EGaIn and Galinstan, are surprisingly structured with the formation of clusters ranging from 157to 15.7Å. Conversely, noneutectic liquid metal alloys of GaSn or GaIn at low solute concentrations of 1, 2, and 5 wt%, as well as pure Ga, do not exhibit these structures. Importantly, the eutectic alloys retain their structure even at elevated temperatures of 60 and 90°C, highlighting that they are not just simple homogeneous fluids consisting of individual atoms. Understanding the complex soft structure of liquid alloys will assist in comprehending complex phenomena occurring within these fluids and contribute to deriving reaction mechanisms in the realm of synthesis and liquid metal-based catalysis.

Fabrication and Properties of Bi2S3 Nanowire Thin Film Solar Cells by Spin Coating with Varying Sulfur Concentrations in the Precursor

We conducted a simple solution-based method to fabricate Bi2S3 nanowire thin film solar cells by spin coating with varying sulfur-to-bismuth ratios. Spherical nanoparticles were observed in the thin film with low-concentration sulfur solution, with these nanoparticles gradually changing to nanorods. Finally, nanowires of Bi2S3 were observed in the thin film with a high sulfur concentration in solution. The band gap gradually decreased with the increase in sulfur concentration. The solar cell performance was significantly improved with the nanowire structure. During film fabrication, sulfur vacancy defects appeared primarily because of high annealing temperatures. These defects were somewhat reduced by the high concentration of sulfur in the solution, supported by the energy-dispersive x-ray spectroscopy (EDS) results. The elemental chemical composition of Bi2S3 material showed an increase in the sulfur-to-bismuth ratio, reaching saturation at almost 0.9. In this work, we systematically observed the effect on the optical properties, surface morphology, and photovoltaic properties by changing the concentration of sulfur in the precursor. The nanowire structure with a high concentration of sulfur in the solution is a promising way to improve the Bi2S3 thin film solar cell.

Optimizing Nickel Electroplating in Low-Ni Environments for Efficient Source Production in Small Plating Baths

Electroplating nickel-63, a radioactive isotope used in betavoltaic batteries and random number generators, requires precise control due to its limited availability and the generation of radioactive waste. To minimize waste and ensure effective plating, small plating baths are employed, optimizing the process within constrained conditions. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were utilized to determine the optimal plating conditions and limiting conditions for nickel electroplating in a small plating bath. This study focuses on the use of low-concentration nickel solutions and small plating equipment, in contrast to the common industrial practice of using high concentrations of nickel. Here, it is important to optimize the plating parameters, especially the nickel concentration, current density, and bath temperature. An average thickness of 1.8 μm was found when plating with a nickel concentration of 0.06 M, a current density of 5 mA/cm2, and a solution temperature of 40 °C, while ideal conditions were found to achieve the theoretical maximum energy and 90% release rate when plating with nickel-63 instead of Ni.

Selective separation of rare earths and aluminum from low-concentration rare earth solution via centrifugal extraction

The separation of rare earths (REs) and aluminum (Al) has always been a practical challenge in the rare earth industry. In this paper, the effects of contact time, the concentrations of Al3+ and RE3+ on the extraction and separation of REs and Al during the solvent extraction of low-concentration rare earth sulfate solution using P507 were investigated. Significant differences in the extraction kinetics between REs and Al can be observed at the same contact time. For instance, when the contact time is 10 s, the extraction efficiency of Y reaches up to 97.5 %, whereas that of Al is only 9.1 %. Under the conditions of initial pH of the rare earth solution 4.0, Al3+ concentration 0–20.0 mmol/L, and RE3+ concentration 1.5–12.0 mmol/L, both the separation factors of Gd/Al (βGd/Al) and Y/Al (βY/Al) are higher than 100 at the contact time of 10–300 s, indicating that M−HREs can be easily separated from Al through solvent extraction using P507. The separation factors of La/Al (βLa/Al) and Nd/Al (βNd/Al) are 10.8–12.3 and 40.5–58.7, respectively, at the contact time of 15–30 s, which are much lower than those of M−HRE (such as Gd and Y), but are much higher than those at the contact time of 300 s (βLa/Al = 2.8, βNd/Al = 31.5). It means that the separation of LRE and Al serves as the key for the separation of REs and Al in the low-concentration rare earth solution, and controlling the contact time in the range of 15–30 s is conducive to the separation of LREs from the Al. The increase in the Al3+ concentration in the rare earth solution has no significant impact on the separation of REs and Al at the contact time of 10–60 s, but the increase in the RE3+ concentration induces the separation of REs and Al. In conclusion, REs in the low-concentration rare earth solution can be selectively separated from the Al via centrifugal extraction technology.

Osmosis: A Natural Approach for Treating Constipation

Osmosis is a natural process that occurs in living organisms and plays a vital role in maintaining their health. This abstract investigates the effectiveness of treating constipation with salt water after getting out of bed in the morning using the process of osmosis. Constipation is a common bowel problem caused by diet, lifestyle, medications, or other factors that make stool hard or impede the ability to pass it comfortably, affecting people of all ages worldwide. By conducting osmosis, where solute molecules move through a semi permeable membrane from low solute concentration to high solute concentration, salt water treatment softens stool and facilitates bowel movements. This paper presents an overview of treatment protocols, including materials, methods and observational results. Preliminary findings indicate promising results, with participants experiencing increased frequency and ease of bowel movements after consuming salt water. This paper explores the benefits of osmosis in treating constipation and how it works. We discuss the osmosis and their mechanisms of action, as well as their safety and efficacy. Overall, we conclude that osmosis is a safe and effective way to treat constipation and has the potential to change the life style of millions of people across the Globe.

Green-process preparation and characterizations of optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate composite films

High-performance regenerated silk-hyaluronate composite films prepared by an environment-friendly process were highly desirable for medical dressing base material. In this study, sericin was removed from silk by steam treatment without using any chemical reagent, and a low concentration solution of Na2CO3 was used as a green process to dissolve silk fibers. Then the obtained silk fibroin was physically blended with sodium hyaluronate to generate optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate films. The results of structural characterizations and property tests showed that the insoluble silk short fibers prepared by the dissolution of Na2CO3 were dominated by a β-sheet crystalline structure while the soluble silk fibroins by an amorphous structure. Moreover, both insoluble silk short fibers and soluble silk fibroins could form uniform composite films with a low coefficient of thermal expansion after being blended with sodium hyaluronate, which were named as insoluble silk film (ISH) and soluble silk film (SSH), respectively. The tensile strength of ISH could reach 138.8 MPa and SSH reached 153.9 MPa, which were 65.7 % and 30.5 % higher than that of the commercial control insoluble fibroin film (83.8 MPa) and commercial control soluble fibroin film (117.9 MPa), and 173.2 % and 203.0 % higher than that of pure hyaluronate film (50.8 MPa), respectively. Also, ISH and SSH had a modulus higher than 3 GPa. In this study, the low-concentration Na2CO3 method provides a simple and green technique for the preparation of high performance silk-hyaluronate composite materials.