Applied Nanoscience最新文献

The spectroscopic characteristics of the common flower Clitoria ternatea are explored for the first time. When excited, the extract shows two emission crests at 436 and 663 nm corresponding to anthocyanin delphinidin and betalains betacyanin, respectively. For practical utility, the extract is made into thin films, giving a broad emission band from 450 to 530 nm. But by this line, the luminescence spectra showed a falloff with time, through a decay rate of 0.2463 cps/h owing to aging. An anti-oxidizing agent (Y₂O₃)–extract complexes with different extract concentrations (1–5 ml) under different heating conditions (100–200 °C) are produced to overcome this scenario. The XRD and Raman spectra depict the fruitful complex formation in cubic structure with space group Ia3. Using UV–visible info, the bandgap is computed to be 2.381 eV. When Y₂O₃ and Clitoria extract are taken in the same measure, decent emission bands around 450–550 nm and 630–690 nm are observed by the FRET mechanism; giving a ninefold increment in PL intensity with CIE coordinates in the vicinity of near-white light. The trials are repeated numerous times to ensure reproducibility and the outcomes are compared with the conventional Y₂O₃:Dy³⁺-doped system, showing prime results by the Y₂O₃:Clitoria complex (1:1, 100 °C). This unprecedented investigation concludes the enhanced photoluminescence from Clitoria extract, which could replace conventional rare earth doping and provide a novel methodology for designing and fabricating lighting devices.

Membrane-based desalination technology stands out as a promising solution to obtain potable water by creating opportunities for water recovery. The productivity and fouling of the reverse osmosis (RO) membranes are the most common problems in desalination processes. The effect of Melamine-grafted graphene Oxide (MEL/GO) in the RO membrane preparation has a gap in existing knowledge through understanding the specific effects and synergies of these materials in membrane synthesis and desalination performance. In this study, we employed the phase inversion technique to synthesize polyamide (PA) RO membranes incorporating MEL/GO. Various membrane properties were investigated, including hydrophilicity, porosity, surface and cross-sectional morphology, permeability, and membrane performance. It was found that the optimum MEL and GO concentrations were 0.1 and 0.3% w/w, respectively. The performance of MEL, GO, and MEL/GO-incorporated membrane (Mm0.1, MG0.3, and Mm0.1/G0.3, respectively) with previously mentioned optimized concentrations resulted in enhanced performance characteristics against plain membrane (M0) free from MEL and GO. Specifically, the water flux significantly increased from 10.01 LMH/bar for M0 to 73.47 LMH/bar, 23.35 LMH/bar, and 88.21 LMH/bar for the Mm0.1, MG0.3, and Mm0.1/G0.3 membranes, respectively. Moreover, the salt rejection percentage experienced a substantial enhancement from 71.74% for the M0 to 96.57% for the Mm0.1/G0.3 membrane. This study's novelty was introducing MEL into the GO layer for the first time, enriching the amine functional group and facilitating water transportation. The results highlight the potential of these highly hydrophilic nanofillers for advanced membrane technology in desalination applications.

Polymer nanomaterials are an emanating area of research incited by the wide range of applications in solar cells, catalysis, sensors, drug delivery, electronics, bioimaging, etc., due to their outstanding mechanical, optical and electronic properties. Small dimensions in the nanometre range and a high surface-to-volume ratio of polymer nanomaterials possess distinctive features compared to bulk counterparts. In this work, doped polyvinyl alcohol (PVA) nanostructures were prepared by a one-step hydrothermal synthesis method and studied the morphological, structural and optical properties. The attained nanomaterials exhibit a spherical shape, and their average size was calculated as 3.98 nm by HR-TEM analysis. The obtained nanomaterials are dissolved in N,N-dimethyl formamide (DMF) solvent and can be employed for optoelectronic devices due to their amorphous structure and direct bandgap. Green luminescence was observed under UV light, and non-biocidal activity showed against Escherichia coli, Pseudomonas fluorescens, E. coli DH5α, Bacillus subtilis and Staphylococcus aureus.

Antibiotics are life-saving drugs that fight bacterial infections by killing or inhibiting their reproduction. However, the overuse and misuse of this drug can contaminate water as it can reach the water surface very quickly through various pathways. The consumption of contaminated water may lead to the development of antibiotic resistance, which has been proliferating across the world recently. Azithromycin (AZM), an essential antibiotic drug, has been identified in wastewater and surface water, prompting apprehension regarding its potential environmental and public health consequences. The present investigation assessed the efficacy of photocatalytic degradation of AZM in water samples under sunlight. Exploiting the surface chemistry and high surface area of cellulose nanocrystals (CNC), nanocomposites with high loading (80 wt%) of titanium dioxide (TiO₂) nanoparticles on a minimal amount of scaffold (20 wt% CNC) were synthesized and used as catalysts. Maximum removal efficiency of 98.8% was achieved in 5 h at a catalyst dose of 175 mg/L for an AZM solution with 10 mg/L concentration. Synthesized CNC–TiO₂ nanocomposites demonstrated superior performance both in terms of high degradation efficiency and lowest catalyst loading per the g of AZM compared the material reported in the literature for the degradation of AZM. In conclusion, CNC–TiO₂ nanocomposites are highly effective catalysts for the photocatalytic degradation of AZM. The developed method further ensures the hygiene of water sources and prevents the spread of antibiotic resistance.

The potential cooling solutions for the next generation are represented by nanofluids, offering several advantages for various technological applications. The intriguing realm of glycine-based acetone-based ({{text{Al}}}_{2}{{text{O}}}_{3}) nanofluids was explored in the present investigation, with meticulous attention to details given to scrutinizing their stability and thermophysical properties. The stability of the nanofluids was determined through a trifecta of analytical methods, namely visual inspection, UV absorbance measurement, and zeta potential analysis, all applied with caution. The results revealed that stability was observed for a duration of 3 days without glycine, and an impressive 6 week period was achieved when supplemented with the surfactant. The incorporation of glycine enhanced the stability of the colloidal suspension without compromising its thermophysical attributes. Furthermore, the study involved an in-depth examination of the density, viscosity, specific heat, and thermal conductivity of the prepared nanofluids, yielding interesting outcomes. The data showed a marked increase in nanofluid density, viscosity, and thermal conductivity with a corresponding rise in volume concentration, while specific heat exhibited a noticeable reduction. These significant observations were meticulously compared to various existing theoretical models and proposed correlations in the literature. The heat transfer performance of the nanofluid in the context of pulsating heat pipes was evaluated and the results proved riveting. The nanofluid demonstrated superior performance compared to the base fluid, confirming its remarkable efficacy.

In the current paper, hematite (α Fe₂O₃) nanoparticles (NPs) were prepared by the chemical co-precipitation method. These synthesized nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Raman spectroscopy, and vibrating sample magnetometry (VSM). The XRD studies for the nanoparticles revealed rhombohedral symmetry with space group: R3c (167), and the particle size is about 33.34 nm. The morphological studies carried out by SEM indicated that these prepared samples have a spherical morphology with some porosity. The specific surface area of this sample was calculated by the Brunauer–Emmett–Teller (BET) technique. FTIR spectroscopy confirms the Fe–O and O–Fe–O vibrations corresponding to stretching at the expected positions (520 cm⁻¹) related to the structure. From Raman data, modes corresponding to α-Fe₂O₃ are seen. From DC magnetisation studies, the current sample shows ferrimagnetic behavior. In addition, the value of M_s is 1.027 and value of M_r is 322.787×10^–6. Further nanofluids of these nanoparticles with different concentrations of transformer oil were prepared. The performance of this nanofluid as a coolant in transformer oil was also studied. The 0.2 g/l concentration shows the maximum improvement in breakdown voltage. Hence, under optimal conditions, these ferrofluids can perform well for insulating purposes.

Schiff base compounds were reported to make a complex with Cu²⁺ and Ag⁺ and subsequent reduction produced Cu⁰ and Ag⁰ nanoparticles separately via UV irradiation. Here, we synthesized a Schiff base, which initially formed a complexation with Cu²⁺ and made Cu⁰ nanoparticles after 8 h aging. In that reaction mixture, addition of Ag⁺ resulted in Ag⁰ nanoparticles. Emissive semi-carbazone (a Schiff base synthesized from semicarbazide and salicylaldehyde) was employed for the first time to selectively and sensitively detect Cu²⁺ (linear range of detection 10^–4 to 5 × 10^–8 M and limit of detection 13 μM) with the formation of copper oxide nanoparticles via complexation–reduction method. The introduction of Ag⁺ in it produced Ag⁰ and Cu⁰ (CuO via aerial oxidation) nanoparticles with a gigantic increase of fluorescence to obtain selective and sensitive Ag⁺ detection (linear detection range 10^–3–10^–7 M, and limit of detection 7. 7 μM). Thus, Cu²⁺ and Ag⁺ were detected based on turn-off/on fluorescence in one pot. As the evolution of copper and silver nanoparticles was the fundamental reason for sensing, response time is similar to the stable fluorescence behavior of oxidized SC (capping agent) with in situ generated copper and silver nanoparticles. CuO-induced fluorescence quenching was due to the formation of the trapped plasmon, while Ag⁺-induced fluorescence enhancement was owing to the lightning rod effect. The synergism of Cu and Ag was also investigated in this paper as a driving force of the lightning rod effect for the first time. Both the metals (Cu and Ag) were estimated in natural water, justifying the utility of the sensing platform for practical applications. Besides, the evolution of brilliant red color with semi-carbazone for Ag⁺ was employed for the colorimetric sensing of Ag⁺.

Green-synthesized nitrogen-doped carbon quantum dots (N-CQDs), offering an excellent platform for the ultra-sensitive dual detection of tannic acid and Hg²⁺ ions, were explored in this work. The N-CQDs were synthesized in a straightforward, cost-effective, and environmentally friendly hydrothermal method. These N-CQDs exhibited remarkable and dynamic “on-off-on” luminescent characteristics, demonstrating an exceptional sensitivity and selectivity towards tannic acid and Hg²⁺ ions. The specific interactions between the N-CQDs and tannic acid, along with the reversible binding with Hg²⁺ ions, contribute to the distinct dual-detection capabilities. The sensing system covers a linear concentration range of 10–80 µM to tannic acid and 0.1 to 1 nm for Hg²⁺, showcasing its versatility for different concentration range with a lower detection limit of 25 nM and 3 nM, respectively. Furthermore, the N-CQDs displayed high stability and minimal interference from typical interfering species, making them a desirable tool for environmental monitoring and quality control. Validation through real sample analysis substantiates the accuracy and reliability of the developed sensing approach in practical scenarios. This study not only underscores the promise of green-synthesized N-CQDs as enhanced fluorescence probes but also contributes to the development of efficient and environmentally friendly materials for dual sensing applications.

Increasing mechanical properties without losing electrical properties is of great importance for the development of advanced electronic textile products and their use in different areas. In this study, a cost-effective and facile preparation of MXene/cellulose nanocrystal-coated cotton fabrics by drop-casting was carried out to investigate electrical and mechanical properties of plain woven cotton fabrics. MXene (Ti₃C₂T_x) and cellulose nanocrystal dispersions of MXene (5 wt.%, 10 wt.% and 15 wt.% cellulose nanocrystal content) were applied to cotton fabrics, and the coated fabrics were characterized in terms of their morphological and structural properties for their suitability for wearable electronics. The surface resistivity and mechanical properties were also determined to evaluate the effectiveness of coating. Ti₃C₂T_x/cellulose nanocrystal dispersions are suitable to obtain a low electrical resistivity (186.4 Ω/sq) in cotton fabrics. The results also showed that increasing cellulose nanocrystal content results in a more stable coating layer on the cotton fabric and a high tensile (63.2 MPa) and elongation at break values are obtained (30.2%) as a result of that.

In third-world countries, the biosynthesis of multi-purpose copper oxide nanoparticles is a crucial solution for pollution, but studies on controlling their properties through internal structure are still limited. This work generated copper oxide nanoparticles (CONPs) using bee propolis as a reducing and capping agent, employing an ecologically benign, simple, inexpensive, and economical technique. The pH of this biosynthesis was varied (6.4, 7.8, 9.2, 10.4, and 11.7). The study computed various structural and optical parameters of biosynthesized CONP samples, revealing nonlinear changes with pH, including unit cell, Cu–O bond length, crystal size, microstrain, energy band gap, Urbach energy, and more. The current research has shown promising results in blocking ultraviolet rays effectively. The blocking parameters were calculated for CONPs samples, and it was found that the pH 8 sample had the best blocking capacity at both regions A and B (90.31 and 91.31%, respectively). The study effectively investigated CONPs’ potential as a catalyst for increasing dye photodegradation. The pH 6.4 sample showed the highest degradation rate (94.15%). The UV-blocking and photodegradation properties of the CONPs samples were explained using the structural and optical parameters.