Reduction Of Silver Nitrate Research Articles

Hydroxyapatite-nanosilver composites with plasmonic properties for application in surface-enhanced Raman spectroscopy

Two routes for preparation of nanocomposites based on hydroxyapatite (HA) doped with Ag nanoparticles (HA@AgNPs) were investigated aiming towards the development of novel materials for sensing and biomedical applications. Both routes are based on using commercially available HA and Creighton colloidal silver prepared by reduction of silver nitrate with sodium borohydride. A number of composites with different HA to Ag ratios were synthesized and evaluated by transmission electron microscopy, X-ray diffraction analysis, infrared and Raman spectroscopy. It was found that the position of phosphate band in 940–970 cm−1 range of Raman spectra can be used as an independent marker of successful HA loading with Ag NPs in addition to XRD analysis. The ability of HA@AgNPs nanocomposites to localized surface plasmon resonance was demonstrated by the UV-Vis spectroscopy and surface-enhanced Raman scattering (SERS) study performed with acridine as a test molecule. The grafted SERS activity can be utilized for optical control of bone healing either for identification of various analytes, participating in bone metabolism.

Spectrophotometric and Spectrofluorimetric Quantification of Urea via Silver Nanoparticles Prepared by Wet Chemical Method

Silver nanoparticles have been utilized in an easy, sensitive, and effective approach through spectrophotometry and spectrofluorimetry to quantify urea in water samples. Here, 1,3-di-(1H-imidazole-1-yl) -2-propanol (DIPO) was employed to stabilize Ag NPs produced from the reduction of aqueous silver nitrate by sodium borohydride (NaBH<sub>4</sub>). Beer-Lambert's law was applied for determination using the complexation of Ag NPs with urea molecules. The results show urea can be assessed concurrently with good results and percent recoveries. The UV-visible absorbance and fluorescence emission calibration curves were plotted at 445 and 471 nm wavelengths, respectively. Beer-Lambert’s law was obeyed in the 0.1-15 mM concentration range. A linear correlation for both UV-visible spectrophotometry and spectrofluorimetry was obtained on optimum conditions using the suggested methods having a limit of detection (LOD) was found to be 0.897 and 0.048, respectively. The percent recovery ± RSD by the spectrophotometric and spectrofluorimetric method was found to be 88 ± 19.7%, 96.67 ± 21.53%, 130.8 ± 1.33% and 102.3 ± 12.7%, 97.26 ± 5.63%, 111.4 ± 3.8%, respectively. Following a comparison of the obtained data, it may be possible to identify spectroscopic approaches with greater efficacy and efficiency that may be used to determine urea's presence in actual samples of biological and non-biological fluids.

Investigation of eco-friendly fluorescence quenching probes for assessment of acemetacin using silver nanoparticles and acriflavine reagent

The non-steroidal anti-inflammatory medication acemetacin was assessed via two straightforward green spectrofluorimetric techniques. The quenching-dependent derivatizing spectrofluorimetric reactions are the master point of this study. Acriflavine-based method (Method I) depends on forming an ion association complex between acriflavine and the drug in a ratio of 1:1, decreasing the former's fluorescence intensity. Acriflavine or Ag NP's intensity-related quenching action goes linearly with the acemetacin concentration in the 2.0–20.0 µg/mL and 1.0–16.0 µg/mL ranges, respectively. The second quenching mechanism depends on using the silver nanoparticles (Ag NP's) as a fluorescence probe (Method II); Ag NP's were prepared from reducing silver nitrate using sodium borohydride. Both methods could be applied to determine pure and pharmaceutical dosage forms of acemetacin. The methods proved valid according to the international conference on harmonization (ICH) guidelines. In addition to this, this work has been estimated under green criteria assessment tools. There is no significant difference between the proposed and the comparison methods after the statistical interpretation.

Tectona grandis Seed Mediated Green Synthesis of Silver Nanoparticles and Their Antibacterial Activity

Nanobiotechnology is a fast expanding scientific field with potential applications in life sciences and human health care. Silver is a precious metal that occurs naturally, most commonly as a mineral or in combination with other elements. Aqueous T. grandis plant seed extract was utilized in the current investigation as a reducing and capping agent in the biogenesis of silver nanoparticles. Nanoparticles were examined using different techniques like UV-visible spectral analysis, Fourier transform infrared spectra technique, X-ray diffraction technique, and transmission electron microscopy technique. The peak at 429 nm of the surface plasmon resonance by using UV-visible spectra, confirmed the synthesis of nanoparticles. Utilizing Fourier transforms infrared spectral analysis, the explicit functional groups that reduced silver nitrate to create silver nanoparticles in seed extract were found. X-ray diffraction analytical technique was utilized to found the crystalline nature and Face-centered cubic (FCC) configuration of green synthesized silver nanoparticles. Silver nanoparticles with sizes ranging from 32 to 62 nm are visible in images taken using transmission electron microscopy. Using disc diffusion technique, the generated silver nanoparticles showed remarkable antibacterial activity against selected organism, Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa. AgNPs demonstrated broad spectrum antibacterial action as a result at lower concentrations, and they may provide an effective therapeutic alternative in the future like, development of new antibacterial drugs. This research identified a quick and eco-friendly green synthetic method for producing stable silver nanoparticles. HIGHLIGHTS Preparation of synthesis from selected traditional medicinal plant Tectona grandis Bio synthesis and characterization of silver nanoparticles synthesized using Tectona grandis Seed extract and evaluate its antibacterial activity against selected pathogens The present study established a rapid, economical cheap way of synthesizing silver nanoparticles Synthesized plant mediated nanoparticles can be used against human pathogens acts as antimicrobial drug and have more medicinal applications GRAPHICAL ABSTRACT

Optimization of microfluidic synthesis of silver nanoparticles: A generic approach using machine learning

The properties of silver nanoparticles (AgNPs) are affected by various parameters, making optimisation of their synthesis a laborious task. This optimisation is facilitated in this work by concurrent use of a T-junction microfluidic system and machine learning approach. The AgNPs are synthesized by reducing silver nitrate with tannic acid in the presence of trisodium citrate, which has a dual role in the reaction as reducing and stabilizing agent. The study uses a decision tree-guided design of experiment method for the size of AgNPs. The developed approach uses kinetic nucleation and growth constants derived from an independent set of experiments to account for chemistry of synthesis, the Reynolds number and the ratio of Dean number to Reynolds number to reveal effect of hydrodynamics and mixing within device and storage temperature to account for particle stability after collection. The obtained model was used to define a parameter space for additional experiments carried out to improve the model further. The numerical results illustrate that well-designed experiments can contribute more effectively to the development of different machine learning models (decision tree, random forest and XGBoost) as opposed to randomly added experiments.

Silver Nanoshells with Optimized Infrared Optical Response: Synthesis for Thin-Shell Formation, and Optical/Thermal Properties after Embedding in Polymeric Films.

We describe a new approach to making ultrathin Ag nanoshells with a higher level of extinction in the infrared than in the visible. The combination of near-infrared active ultrathin nanoshells with their isotropic optical properties is of interest for energy-saving applications. For such applications, the morphology must be precisely controlled, since the optical response is sensitive to nanometer-scale variations. To achieve this precision, we use a multi-step, reproducible, colloidal chemical synthesis. It includes the reduction of Tollens' reactant onto Sn2+-sensitized silica particles, followed by silver-nitrate reduction by formaldehyde and ammonia. The smooth shells are about 10 nm thick, on average, and have different morphologies: continuous, percolated, and patchy, depending on the quantity of the silver nitrate used. The shell-formation mechanism, studied by optical spectroscopy and high-resolution microscopy, seems to consist of two steps: the formation of very thin and flat patches, followed by their guided regrowth around the silica particle, which is favored by a high reaction rate. The optical and thermal properties of the core-shell particles, embedded in a transparent poly(vinylpyrrolidone) film on a glass substrate, were also investigated. We found that the Ag-nanoshell films can convert 30% of the power of incident near-infrared light into heat, making them very suitable in window glazing for radiative screening from solar light.

Preparation of functional and reactive nanosilver nanogels using oxidized carboxymethyl cellulose

The designing of functional and reactive nanosilver has been carried out by in-situ reduction of silver nitrate using oxidized carboxymethyl cellulose (OCMC). The reduction process is also accompanied by the stabilization of nanoparticles using the OCMC polymer chain, leading to the formation of a structure where nanosilver is entrapped within OCMC gel. The silver nanogels characterized using transmission electron microscopy (TEM) are found to be ∼22 nm. By virtue of the presence of dialdehyde functionality around the silver nanogels, they have the ability to react with a polymer having a complementary functional group. The nanogels have exhibited prominent antimicrobial activity against both gram-negative and gram-positive bacteria. It has been observed that a 0.3 mM concentration of silver nanogel is active in inhibiting bacterial growth. The antibacterial activity of the synthesized Ag nanogels was dose-dependent, with 99.9 % of E. coli and S. aureus destroyed within 5 h at a concentration of 0.4 mM Ag nanogels. The nanogels disrupted the bacterial cell wall and generated reactive oxygen species inside the cell, which resulted in cell death. This investigation provides a very interesting application as a coating for biomedical implants and devices.

Silver Nanoparticles Stabilized with a Chitosan Shell: Physical-Chemical Properties and Features of the Toxic Effect in Vivo

The results of investigating the in-vivo toxicity and safety of colloidal solutions of chitosan–silver nanocomposites with different concentrations of Ag (0.19, 1.9 mg/mL) obtained by the “green chemistry” technique via the chemical reduction of silver nitrate with chitosan under hydrothermal conditions are presented. The synthesized samples possess high aggregative stability (the values of their ζ potential are 37.3 ± 0.2 and 43.2 ± 2.5 mV) and pronounced antimicrobial properties against Staphylococcus aureus, Salmonella dublin, and Escherichia coli (inhibition zones of 11–16 mm). It is found that the nanocomposites are not very dangerous in the case of acute intragastric administration, are relatively safe in the case of intraperitoneal administration, and do not possess dermal irritation. A hydrosol of the nanocomposite with a high concentration of silver (1.9 mg/mL) induces reversible eye irritation in laboratory animals as well as has a pronounced sensitizing action, inducing the development of an allergy by the delayed hypersensitivity mechanism.

A New Green Coating for the Protection of Frescoes: From the Synthesis to the Performances Evaluation

This work presents the formulation and characterization of a new product for the protection of outdoor frescoes from aggressive environmental agents. The formulation is designed as an innovative green coating, prepared through a zero-waste one-pot-synthetic method to form silver nanoparticles (AgNPs) directly in a chitosan-based medium. The AgNPs are seeded and grown in a mixed hydrogel of chitosan, azelaic, and lactic acid, by the reduction of silver nitrate, and using calcium hydroxide as precipitating agent. The rheological properties of this coating base are optimized by the addition of a solvent mixture of glycerol and ethanol with a 1:1 volume ratio. The new formulation and two commercial products (Paraloid® B72 and Proconsol®) are then applied by brush to ad hoc mock-ups to be evaluated for chemical stability, color and gloss variations, morphological variation, hydrophobicity, and water vapor permeability via Fourier-transform infrared spectroscopy (FT-IR) in attenuated total reflection (ATR) mode, spectrophotometer analysis, stereomicroscope observations, UNI EN 15802, and UNI EN 15803, respectively. The results show that the application of the hybrid chitosan-AgNPs coating is promising for the protection of outdoor frescoes and that it can underpin the development of new products that address the lack of conservation strategies specifically designed for wall painting.

New Ionic Liquid Microemulsion-Mediated Synthesis of Silver Nanoparticles for Skin Bacterial Infection Treatments.

This work reports a new approach for the synthesis of extremely small monodispersed silver nanoparticles (AgNPs) (2.9-1.5) by reduction of silver nitrate in a new series of benzyl alkyl imidazolium ionic liquids (BAIILs)-based microemulsions (3a-f) as media and stabilizing agents. Interestingly, AgNPs isolated from the IILMEs bearing the bulkiest substituents (tert-butyl and n-butyl) (3f) displayed almost no nanoparticle agglomeration. In an in vitro antibacterial test against ESKAPE pathogens, all AgNPs-BAIILs had potent antibiotic activity, as reflected by antibacterial efficiency indices. Furthermore, when compared to other nanoparticles, these were the most effective in preventing biofilm formation by the tested bacterial strains. Moreover, the MTT assay was used to determine the cytotoxicity of novel AgNPs-BAIILs on healthy human skin fibroblast (HSF) cell lines. The MTT assay revealed that novel AgNPs-BAIILs showed no significant toxic effects on the healthy cells. Thus, the novel AgNPs-BAIILs microemulsions could be used as safe antibiotics for skin bacterial infection treatments. AgNPs isolated from BAIIL (3c) was found to be the most effective antibiotic of the nanoparticles examined.

Bioynthesis of silver nanoparticles using Dunaliella salina and its antibacterial applications

In this study, an aqueous extract of Dunaliella salina was used to reduce silver nitrate and create silver nanoparticles (AgNPs). Silver nanoparticles were created as soon as silver particles made in contact with the microalgae extract, showing the speedy preparation process. The microalgae extract was prepared and used for biosynthesis of silver nanoparticles. Synthesized nanoparticles were characterized using UV–Vis, SEM-EDX, XRD and FTIR analysis. Antibacterial assays were performed using disc-diffusion method. A peak at 454 nm was found in the UV–Vis range of the aqueous media containing silver particles, which was related to the plasmon absorbance of AgNPs. Scanning electron microscope (SEM) demonstrated size of 35 nm of AgNPs. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of AgNPs, which revealed a solid flag in the silver region. X-ray diffraction (XRD) confirmed the formation of crystalline nanoparticles. The presence of functional groups in AgNPs was confirmed using Fourier transform infrared (FTIR) analysis. Antibacterial property of synthesized nanomaterials was also found to have a possible antibacterial effects on Escherichia coli, Bacillus subtilis, as well as Enterobacter tobbaci. Thus, silver nanoparticles were biosynthesized using Dunaliella salina microalgae extract and tested for antibacterial effects.

Transformation of silver nanospheres into triangular nanoplates through a photoinduced process

Triangular silver nanoplates exhibit excellent optical and catalytic properties in many fields, such as catalysts, sensors and bio-medicine. In this paper, triangular nanoplates were generated just in the presence of sodium citrate through a light-induced ripening process, which were converted from spherical silver nanoparticles by reducing silver nitrate with sodium borohydride. By using UV–Vis spectroscopy, particle size analyzer, transmission electron microscopy (TEM) and Ag+ concentration analysis, the effects of precursors during the preparation of triangular nanoplates were systematically investigated and the optimal experimental conditions were determined. Based on density functional theory (DFT), the adsorption energies of citrate ion, malate ion and tartronate ion on Ag (111), (110) and (100) were calculated. In addition, theoretical calculations coupled with experimental observations showed that citrate ion as capping agent could more preferentially bind to Ag (111) and thus blocked Ag (111) while only allowing extensive growth along the lateral direction. This well explains sodium citrate is an efficient agent in preparing triangular silver nanoplates.

Green Synthesis of Flower-Like Carrageenan-Silver Nanoparticles and Elucidation of Its Physicochemical and Antibacterial Properties.

Herein, we report the green synthesis of flower-like carrageenan-silver nanoparticles (c-AgNPs) through a facile hydrothermal reaction at 90 °C for 2 h. The reduction of silver nitrate (AgNO3) to c-AgNPs was evident by the colour change of the solution from colourless to dark brown and further confirmed by a UV-Vis surface plasmon resonance (SPR) peak at ~420 nm. The FTIR spectra showed that the abundance of functional groups present in the carrageenan were responsible for the reduction and stabilisation of the c-AgNPs. The XRD pattern confirmed the crystalline nature and face-centred cubic structure of the c-AgNPs, while the EDX analysis showed the presence of a high composition of elemental silver (85.87 wt%). Interestingly, the morphological characterisations by SEM and FE-SEM revealed the formation of flower-like c-AgNPs composed of intercrossed and random lamellar petals of approximately 50 nm in thickness. The growth mechanism of flower-like c-AgNPs were elucidated based on the TEM and AFM analyses. The c-AgNPs displayed promising antibacterial properties against E. coli and S. aureus, with zones of inhibition ranging from 8.0 ± 0.0 to 11.7 ± 0.6 mm and 7.3 ± 0.6 to 9.7 ± 0.6 mm, respectively, as the concentration of c-AgNPs increased from 0.1 to 4 mg/mL.

Green synthesis of silver nanoparticles and their antibacterial activities

Abstract Nanotechnology offers a solution to bacterial antibiotic resistance, which poses a serious threat to global health. Green synthesis of metallic nanoparticles is gaining increasing attention due to its environmental benefits. This study aimed to biosynthesize silver nanoparticles (AgNPs) by microwave irradiation through silver nitrate reduction using starch and microalgae biomass; characterize them using UV–visible spectroscopy, scanning electron microscopy-energy-dispersive X-ray microanalysis, and X-ray diffraction; and evaluate their antibacterial activity against Escherichia coli, Bacillus clausii, and Staphylococcus aureus using disk diffusion and broth dilution methods. Synthesized AgNPs showed a single peak related to surface plasmon resonance at 430 nm. Size range of spherical AgNPs was 40–150 or 90–400 nm for starch- or biomass-mediated NPs, respectively. Biomass-mediated AgNPs exhibited antibacterial activity with the inhibition zones of 8, 12, and 10.5 mm against E. coli, B. clausii, and S. aureus, respectively; those starch-mediated showed inhibition of 7, 13, and 12 mm, respectively. AgNPs’ minimum inhibitory concentrations were 6.25 μg·mL−1 toward both E. coli and S. aureus and 12.5 μg·mL−1 against B. clausii when using starch in biosynthesis, whereas they were 19.6 μg·mL−1 against both E. coli and S. aureus and 9.81 μg·mL−1 toward B. clausii when using biomass. Synthesized AgNPs have promising antibacterial potential.

Synthesis of silver nanoparticles using Emilia sonchifolia plant for treatment of bloodstream diseases caused by Escherichia coli

Among infectious diseases, bloodstream infection (BSI) caused by gram-negative bacteria (E.coli) is the leading cause of death worldwide. However, the bacteria have produced resistance to many of these antibiotics. Thus, the present study aimed to develop silver nanoparticles (AgNPs) loaded with Emilia sonchifolia (ES) extract (ES-AgNPs) to treat BSI efficiently. AgNPs were synthesized by reduction of silver nitrate (AgNO3) solution by ES extract. Furthermore, these ES-AgNPs were characterized for particle size and zeta potential, crystallinity by powder X-ray diffraction (P-XRD) technique, in vitro antibacterial activity, time-kill assay, film bio adhesion, and fluorescence assay. Surface plasmon resonance (SPR) has been used to confirm the formation of AgNPs by seeing a shift in colour to dark-brown. The ES-AgNPs displayed a mean particle size of 137±3nm (PDI of 0.168±0.02) and zeta potential of 18.2±0.8mV. Furthermore, according to P-XRD results, the developed AgNPs are highly crystalline. The ES-AgNPs showed effective antibacterial action against E.coli with minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of 0.4±0.02μg/mL and 0.8±0.03μg/mL, respectively. In addition, ES-AgNPs inhibited biofilm formation and bacterial adhesion in a dose-dependent manner with 100% inhibition obtained in 48h at MBC. Present research work revealed that the ES-AgNPs obtained by green synthesis holds a prominent antibacterial activity in the treatment of BSIs caused by E.coli and they may be used as a competent substitute for current treatments. However, further, in vivo antibacterial studies are required to establish its efficacy in the treatment of BSIs.

Silver Nanoparticles, Synthesized using Hyptis suaveolens (L) Poit and their Antifungal Activity against Candida spp.

AbstractSilver nanoparticles (AgNPs), due to their interesting properties and many potential applications have attracted enormous interests in recent years. An attempt has been made in this present study to synthesize AgNPs through biological reduction of silver nitrate, with leaf extract of Hyptis suaveolens (L) Poit serving as a reducing agent. AgNPs formed were characterized with spectral (UV‐Vis, XRD, FTIR) and electron microscopic investigations. Dispersed spherical nanosilver particles in the range of 2 nm–85 nm were observed through microscopic analysis and the crystalline nature was evidenced through XRD analyses. Anticandidal activity of biosynthesised AgNPs was evaluated against two Candida albicans strains. The minimum inhibitory concentration (MIC) values for AgNPs against the two clinical strains were 0.27±0.03 μg/ml and 0.97±0.13 μg/ml. AgNPs were found to be more effective than the amphotericin‐B used as control against the strains of the test pathogens. Scanning electron microscopic (SEM) analyses of the Candida cells treated with AgNPs shows change in the surface morphology, suggesting cell wall disruption to be a potential mode of anticandidal activity. Based on our observations, AgNPs synthesized with leaf extract of Hyptis suaveolens could be potentially used in combating candidal infections.

One‐step synthesis of silver nanoparticles exposed on the chitosan‐covered polyamide 6 electrospinning nanofibers

AbstractA one‐step method was developed for synthesizing Ag nanoparticles exposed on the chitosan‐covered polyamide 6 (CS‐Ag@PA6) nanofibers by the in‐situ reduction of silver nitrate during the electrospinning process. The bioderived CS was employed as a stabilizer and chelating carrier of Ag0/Ag+ through its functional groups. CS was also used as a tractive agent to promote the surface migration of Ag atoms owing to its polyelectrolytic properties and immiscibility with PA6. Formic acid was used as the co‐solvent for PA6 and CS and the reducing agent for Ag+. It was verified that the Ag nanoparticles (AgNPs) with 31.7% Ag0 were embedded inside the pure PA6 nanofibers. However, the incorporation of CS achieved the AgNPs with an improved reduction efficiency (i.e., 67.5% of Ag0). In particular, the CS nanolayers were covered on the PA6 nanofiber skeleton, where the AgNPs migrated on the surface of the CS nanolayers. This surface migration of CS and AgNPS endowed a significantly enhanced catalytic activity to the reduction of 4‐nitrophenol, where the reduction rate constant (k) and turnover frequency (TOF) were an order of magnitude higher than that of the CS‐free nanofibers.

Biological Synthesis and Characterisation of Silver Nanoparticles of Zingiber officinalis and Evaluation of its Biological Activity

Ginger (Zingiber officinale) belongs to Zingiberaceae family is one of the famous spices all over the world. It is a perennial creeping plant with long leaves, yellow green flowers and thick tuberous rhizome. Silver nanoparticles’ potential uses in Green Chemistry have received attention. The current study focuses on the rapid biological production of silver nanoparticles using different plant materials and characterizations using UV-visible spectrophotometry, IR, SEM, and HPLC investigations. Within 15 minutes of adding sodium carbonate, an aqueous extract of dried Zingiber officinalis rhizome reduces silver nitrate. No further reduction and stabilizing chemicals are required for the entire process, showing a green synthesis. Escherichia coli and Staphylococcus aureus use biosynthesized “Zinger-AgNps” as a competent antibacterial agent. Zinger-AgNps were evaluated as its catalytic capability to reduce the model pollutant methylene blue. Both of them are displayed 2, 2-diphenyl-1-picrylhydrazyl-specific free radical scavenging activity (DPPH). Silver biological material nanoparticles are created by utilizing less hazardous and nontoxic reduction agents, such as ascorbic acid and sodium citrate. The antioxidant and lipid peroxidation inhibition properties of ginger prevent peroxidative damage, indicating the benefits of ginger in the prevention of microbial food spoilage, free-radical-induced damage and rancidity. The sodium citrate aggregation for silver nanoparticles, firm surface contact, and synthesized silver nanoparticles are used to study antibacterial efficacy and antioxidant activity.

Silver-chitosan (Ag-CH) nanocomposite hydrogel for remediation of aqueous medium

In this work, a low cost, in situ synthesized silver-chitosan (Ag-CH) nanocomposite hydrogel has been proposed for the detection and rapid removal of hexavalent chromium from water. Silver nanoparticles are enmeshed in a network of highly porous chitosan-based hydrogel matrix for the effective detection and removal hexavalent chromium. The in situ reduction of silver nitrate to silver nanoparticles within the chitosan blended polymer matrix ensures the high stability of AgNPs and the resulting Ag-CH nanocomposite acts as a colorimetric sensor for hexavalent chromium [Cr (VI)] with enhanced lower detection limit (LoD) of upto 0.1 ppb. Physico-chemical properties of the prepared Ag-CH nanocomposite hydrogel are studied using UV–Visible spectroscopy, FESEM and FTIR analysis. The Ag-CH nanocomposite shows high porosity and cross-linking, which makes it ideal as a biocompatible, low-cost and sustainable biosorbent material. The hydrogel has a high removal efficiency of 83 % for Cr (VI). The effortless regeneration of the nanocomposite hydrogel aids in its easy reusability. The biocompatibility, sustainability and reusability of the Ag-CH hydrogel confirms its effectiveness as a nanobiosorbent material and provides a potential solution for simultaneous sensing and remediation of heavy metal ions from aqueous matrices.

Electrical characteristics of (AgNPs-PVA)-based Schottky diode and its application as a low-voltage varistor devices

In this report, we studied the influence of silver nanoparticles (AgNPs) on the electrical conductivity of Polyvinyl Alcohol (PVA) as a semiconductor nanocomposites active layer. Here, the Schottky junction is constructed by mechanically pressing a copper (Cu) electrode onto a AgNPs-PVA nanocomposite, which shows rectification behavior at room temperature. The synthesis of silver nanoparticles (AgNPs) was achieved by the physical reduction of silver nitrate using an ultraviolet lamp. The nanocomposite films were created using a casting technique. An ultraviolet spectrophotometer (UV–vis), which displayed maximum absorbance at 430 nm, was used to confirm the synthesis of AgNPs and carry out the optical band gap. The charge carrier transport properties of AgNPs-PVA film were investigated by using impedance spectroscopy and I–V measurements. Then, AC impedance analysis was used to determine grain and grain boundary resistances; current-voltage analysis enabled the barrier height (Φ) to be determined. Moreover, the metal/semiconductor (Cu/AgNPs-PVA) Schottky barrier was confirmed as an equivalent circuit model via the Nyquist plot. Based on thermoionic emission theory, the characteristic I–V induced rectifying Schottky behavior can be understood. Moreover, the AgNPs-PVA nanocomposite exhibited hysteresis behavior under multiple repetitive measurements. For low voltage varistor devices, the nonlinear behavior may be completely utilized.