Silver Ions In Water Research Articles

LIFs-Based Fluorescent Analysis of Silver Ions in Water Using AIEgen-Embedded PVA Hydrogel.

The detection and quantification analysis of silver ions is important to protect human health and improve the level of wastewater treatment. In this work, a polyvinyl alcohol (PVA) hydrogel-based sensing material based on an aggregation-induced emission strategy was developed and combined with a portable laser-induced fluorescence spectroscopy (LIFs) device for the direct detection and quantification of silver ions in water. Considering the requirements of environmental water analysis regarding portability, reliability, and convenience, this fluorescence turn-on strategy was optimized accordingly to ensure the accuracy and stability of the analysis in complex natural water environmental. This sensing method showed operational excellence and good sensitivity (down to 1 ppb) and may provide a stable and convenient strategy for the on-site, real-time analysis of environmental water samples.

Homogeneous electroanalysis coupled with colorimetry dual-mode sensing of silver ion in water based on target-inhibited peroxidase activity of Pt@ZIF-8 nanozyme

Electrochemical sensing is the commonly used method for the detection of heavy metal silver ion (Ag+), while the conventional electrochemical sensors generally require the existence of electrode modifications and even electrodeposition step coupled with a single-mode readout. Herein, by preparing ZIF-8 organometallic frame load with platinum nanoparticles (Pt@ZIF-8) as nanozyme and o-phenylenediamine (OPD) as colorless substance, taking advantage of the superior peroxidase activity of Pt@ZIF-8 that can catalyze the oxidation of OPD to product electroactive/yellow 2,3-diaminophenazinc and the target-inhibited effect towards nanozyme activity from Ag+, a homogeneous electroanalysis coupled with colorimetry (HEA-CM) dual-mode sensing platform was designed for the first time to detect Ag+. Furthermore, the colorimetric images were converted on a smartphone to digital signals for the quantitative analysis. The designed strategy could offer multiple advantages such as electrodeposition-free, modification-free and dual channel readout. After investigating the sensing mechanism and experimental parameters, the analytical performance of the designed strategy was evaluated, obtaining extremely low detection limit (0.034 nM), reliable recovery rate (99.61 %-101.6 %) and wide linearity. This work offered an effective method for the simple, sensitive, rapid, accurate and multiplexed determination of Ag+, and also opened a new pathway for the detection of other heavy metals based on HEA-CM dual-mode strategy.

Exploring the antibacterial potential of magnetite/Quince seed mucilage/Ag nanocomposite: Synthesis, characterization, and activity assessment

In this study, we present a novel core-shell antibacterial agent designed for water disinfection purposes. The nanocomposite is synthesized by combining quince seed mucilage (QSM) as the shell material and Fe3O4 as the core material. The integration of antibacterial silver nanoparticles (Ag NPs) onto the QSM shell effectively prevents agglomeration of the Ag NPs, resulting in a larger contact surface area with bacteria and consequently exhibiting enhanced antibacterial activity. The incorporation of magnetic Fe3O4 NPs with a saturation magnetization of 55.2 emu·g−1 as the core allows for easy retrieval of the nanocomposites from the medium using a strong magnetic field, enabling their reusability. The Fe3O4/QSM/Ag nanocomposite is extensively characterized using XRD, FT-IR, VSM, DLS, FE-SEM, and TEM techniques. The characterization results confirm the successful synthesis of the nanocomposites, with an average particle size of 73 nm and no contamination or impurities detected. The nanocomposites exhibit superparamagnetic properties, with a saturated magnetization of 22.69 emu·g−1, ensuring facile separation from water. The antibacterial activity of the synthesized nanocomposite is evaluated using the disk diffusion method against both Gram-positive and Gram-negative bacteria. The results reveal excellent antibacterial efficacy, with minimum inhibition concentrations (MIC) of 0.8 mg·mL−1 against E. coli and S. typhimurium. Furthermore, the measurement of released silver ions in water using ICP-OES indicates a low concentration of remaining silver ions in the medium, highlighting the controlled release of antimicrobial agents. Overall, this study provides valuable insights into the development of advanced antibacterial agents for water disinfection applications, offering potential solutions to combat microbial contamination effectively.

Oxygen stabilized W−Ag films for environmental antibacterial applications

Oxygen was added into sputter deposited tungsten films to reduce residual stress of the films, and silver with content up to 14.3 at.% was further added for antibacterial functionalization. The films were analyzed by SEM-EDX, XPS and XRD. Only X-ray diffraction peaks from β-W or W3O phase were detected for the films. Oxygen and silver existed mainly as solid solution atoms in the films. Silver addition decreased hardness (still ≥10.3 GPa) and elastic modulus of the films. The potentiodynamic polarization demonstrated lower corrosion current density of the WO film than that of the tungsten film, and silver changed corrosion behavior of the films. The Ag-depleted tungsten oxide layer on the film surface suppressed the release of silver ions in water. The WOAg films had good antibacterial activity with E.coli bacteria. The WOAg films would be useful in environmental and other antimicrobial applications.

Orange Pomace Facilitated Synthesis of Cu2O/ZnO Nanocomposites for Visual and Optical Sensing of Silver Ions in Water for Environmental Remediation

AbstractThe presence of silver ions at toxic concentrations in wastewater has provoked many scientists to design novel methods to detect silver ions in water. Employing agro‐waste to design nanomaterials has incited the use of orange pomace to design fruitful and biocompatible nanomaterials for endorsing sustainable and green methods. Herein, we report a sensitive and selective colorimetric detection of silver ions employing biogenically synthesized Cu2O/ZnO nanocomposites (NCs). The Cu2O/ZnO NCs were fabricated using orange pomace (OP) holistically acting as a stabilizing and reducing agent. Sensing ability of Cu2O/ZnO NCs synthesized via greener route for the presence of different metal ions such as Na+, Ca2+, Cd2+, Sr2+, Ag+, Ni2+, Fe2+, Pb2+, Mg2+, and K+ has been examined at room temperature. A naked eye colour change form slight yellowish to black was noticed in case of silver ions, this is confirmed by the shifting of maximum wavelength from 453 nm to 362 nm. Thus, in this work Cu2O/ZnO NCs was demonstrated as an extremely specific and selective colorimetric nanosensor for silver ions in water and showed a good linearity over the range of 20 μM–2 mM and a limit of detection (LOD) of 13.1 μM. The green fabrication of nanosensor for silver ions further maintain the sustainability of environment and encourage the researchers for greener fabrication of colorimetric sensors.

Potentiometric Titration Based on the Reference Electrode Equipped with Ionic Liquid Salt Bridge — 1. Precipitation Titration of Chloride with Silver Ions in Water

Potentiometric Titration Based on the Reference Electrode Equipped with Ionic Liquid Salt Bridge — 1. Precipitation Titration of Chloride with Silver Ions in Water

On–Off–On fluorescence sequential sensor for silver ions, thiamine and anti-counterfeiting application using mannitol derived carbon dots

We are reporting the synthesis of mannitol derived carbon dots (MCDs) and their application as silver ion and thiamine sensors. The synthesized MCDs were characterized by HR-TEM, FT-IR, UV–visible, fluorescence, XRD and Raman methods. The synthesized MCDs exhibit a blue emission at 444 nm and the quantum yield of the MCDs is 43.8%. The MCDs particle size was determined to be 3.09 nm with a mono-dispersed nature, using HR-TEM images. Next, we have used MCDs as a probe for the detection of silver ions and thiamine. Interestingly, the highly blue emitting MCDs fluorescence was quenched (ON–OFF) upon the addition of silver ions. On addition of thiamine into the same solution, the fluorescence was enhanced (OFF–ON) . Based on the emission intensity changes, we determined the concentrations of silver ions and thiamine. The limit of detection of silver ions and thiamine were calculated to be 0.5 nM and 0.57 nM (LOD = 3 S/m), individually. The MCDs show high selectively towards the detection silver ions and thiamine. To this end, we have applied this sensor method for the sensing of silver ions in water, silver antibiotic sulfadiazine cream and also thiamine in drugs and biological samples. Notably, we have developed a wax pencil, designed for on-site monitoring of silver ions and thiamine with a wax coated paper based kit. Further, we have successfully prepared an anti-counterfeiting fluorescent ink using mannitol derived carbon dots and a PEG solution. Our anti-counterfeiting fluorescent ink is a low cost material, easy to use and it can replace the commercially available fluorescent inks.

A Novel Ratiometric Fluorescent Probe for Ag+ Based on Arginine-Naphthalene Imide

A ratio fluorescent probe to detect Ag+ using arginine-naphthalene imide (AN) had been elaborately designed and synthesized. The structure of AN was characterized by 1HNMR and FTIR. The optical properties of AN were investigated by ultraviolet and fluorescence spectroscopy. The results indicated that the fluorescent intensity of AN was enhanced gradually with the increase of Ag+ concentration, which was hardly affected by other metal ions such as Bi3+, Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Hg2+, Pb2+, K+ and Na+. A good linear correlation was displayed between the concentration of Ag+ (ranging from 4.30 to 11.40 μmol L−1) and the fluorescence intensity (R2 = 0.9985). The detection limit was 0.1883 μmol L−1. The mechanism of the sensor may be based on the principle of intramolecular charge transfer. It was expected that this novel ratio sensor could be used for the detection of silver ions in water.

Changes of Parameters of Mixed Monolayers Based on Photosensitive Crown Ether in the Presence of Silver Ions

The use of the achievements attained in colloid chemistry and other fields of chemical sciences allows us to develop new nanoscale systems for chemosensorics. Mixed monolayers consisting of a new chemosensory amphiphilic dithia-18-crown-6, which contains a dye of 4-alkylpyridine series with polyvinyl stearate at the water–air interface, are obtained and studied. The influence of various concentrations of silver ions on these mixed monolayers is studied. A promising method for the detection of silver ions in water using the given nanoscale systems based on chemosensory amphiphilic dithia-18-crown-6 is proposed.

A facile synthesis of cysteine-based diketopiperazine from thiol-protected precursor.

l-Cysteine is one of the most promising biomass-based building blocks with great potential applications. Herein, we report a versatile synthetic route to produce cysteine-based 2,5-diketopiperazine (DKP) with good yield from the thiol-ene click reaction of l-cysteine and commercially available acrylates, followed by dimerization of the amino acid intermediates. The achieved DKP diastereomers were successfully separated and fully characterized by spectroscopic methods. Moreover, the chiroptical property of DKP in the presence of various metal ions was investigated by circular dichroism spectroscopy. The potential application of the optically active cysteine-based DKP as a chiral probe for detection of silver ion in water has been demonstrated.

Production of Silver Nanoparticles Using High Voltage Arc Discharge Method

Background: Silver is the most often studied and the most used substance in the form of nanoparticles. Currently, the production of silver nanoparticles (SNPs) reached the level of 320 tons per year. SNPs consisting of approximately 20–15000 silver atoms. SNPs are most commonly used as antimicrobial and antifungal agents in production of clothing, cosmetics, toys, paints, and in water filters. In the field of medicine, SNPs are used in dentistry, orthopedics, surgery, and in the production of medicines. Methods: During electric discharge between silver electrodes, plasma is produced under the effect of strong electric field with high temperature causing the removal of silver atoms from surface of the electrodes. In aqueous solutions, dissociation of water into oxygen and hydrogen atoms occurs. The interaction of active silver atoms with oxygen and hydrogen atoms and water particles causes the formation of stable nanoparticle colloid. Results: The arc discharge produces metallic silver nanoparticles and silver ions in water, tri-Sodium citrate dehydrate (TSC), and ethanol. The size distribution of obtained SNPs has maximum size between 7 and 20 nm. The properties of colloidal silver prepared with HVAD method are analyzed by UV-Vis spectroscopy, dynamic light scattering, and transmission electron microscopy. The stability of silver colloids is tested thermal treatment under high pressure. On the basis of AAS measurements of centrifuged colloids, silver ion to SNP ratio was estimated. Conclusions: Using HVAD method, one can produce SNPs quickly with silver concentration of approximately 15 ppm in various dispersant such as water, TSC solution, and ethanol. The aqueous solution contains 4.5% silver ions and the 3.3 μM TSC solution contains 0.5% silver ions. Keywords: Arc discharge, ionic silver, silver colloids, silver electrodes, silver nanoparticles, tri-Sodium citrate.

Trace monitoring of silver ions in food and water samples by flame atomic absorption spectrophotometry after preconcentration with solvent-assisted dispersive solid phase extraction

In this research, a new sample treatment technique termed solvent-assisted dispersive solid phase extraction (SADSPE) was developed. The new method was based on the dispersion of the sorbent into the sample to maximize the contact surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by injecting a mixture solution of the sorbent and disperser solvent into the aqueous sample. Thereby, a cloudy solution formed. The cloudy solution resulted from the dispersion of the fine particles of the sorbent in the bulk aqueous sample. After extraction, the cloudy solution was centrifuged and the enriched analytes in the sediment phase dissolved in ethanol and determined by FAAS. Under the optimized conditions, the detection limit for silver ions was 0.8 μg L(-1). The relative standard deviations for six separate extraction experiments for determination of 5 and 200 μg L(-1) of silver ions was 3.4 and 3.1 %. The preconcentration factor was found to be 61.7. SADSPE was successfully applied for trace determination of silver ions in water and food samples.

Biopolymer-reinforced synthetic granular nanocomposites for affordable point-of-use water purification

Creation of affordable materials for constant release of silver ions in water is one of the most promising ways to provide microbially safe drinking water for all. Combining the capacity of diverse nanocomposites to scavenge toxic species such as arsenic, lead, and other contaminants along with the above capability can result in affordable, all-inclusive drinking water purifiers that can function without electricity. The critical problem in achieving this is the synthesis of stable materials that can release silver ions continuously in the presence of complex species usually present in drinking water that deposit and cause scaling on nanomaterial surfaces. Here we show that such constant release materials can be synthesized in a simple and effective fashion in water itself without the use of electrical power. The nanocomposite exhibits river sand-like properties, such as higher shear strength in loose and wet forms. These materials have been used to develop an affordable water purifier to deliver clean drinking water at US $2.5/y per family. The ability to prepare nanostructured compositions at near ambient temperature has wide relevance for adsorption-based water purification.

Effect of gold alloying on stability of silver nanoparticles and control of silver ion release from vapor-deposited Ag–Au/polytetrafluoroethylene nanocomposites

In the present study, nanocomposites containing Ag–Au alloy nanoparticle ensembles with various compositions on polytetrafluoroethylene were prepared by physical vapor deposition. After a certain time of immersion of the samples in water, oxidation and dissolution of the Ag nanoparticles (AgNPs) occurred, and changes in the morphology, optical properties and composition of the nanocomposites were examined using transmission electron microscopy, ultraviolet-visible spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The composition-dependence and the time-dependence of the silver ion release were studied, and the concentration of the silver ions in water was detected using inductively coupled plasma mass spectrometry. The results indicate that with increasing gold fraction in the Au–Ag alloy nanoparticles, a strong improvement of the oxidation resistance of the AgNPs occurs. The dissolution of Ag is rapid at the first contact of the sample with water until a saturation state is reached. XPS synchrotron measurements with different excitation energies show that the depletion of Ag from the nanoparticles does not lead to the formation of a Au-rich shell and that the atomic mobility is high enough in the small nanoparticles of about 5 nm average size to equilibrate any concentration gradient.

Fluorescent detection of silver ions in water with organic nano-aggregates

A novel chemosensor, that has a bis-thiocarbamate scaffold appended to hydrophobic naphthoyl groups, displays fluorescence enhancement in the presence of Ag+ ions. The sensor behaves differently in aqueous and methanolic environments. In the aqueous media it forms organic nano-aggregates, which undergo further aggregation and grow in size in the presence of Ag+ ions. The detection limit of the sensor is 11 ppb for Ag+ ions, which is far within the US-EPA guidelines for drinking water.

Selective Separation/Preconcentration of Silver Ion in Water by Multiwalled Carbon Nanotubes Microcolumn as a Sorbent

AbstractThe present paper proposes the application of multiwalled carbon nanotubes (MWCNTs) as a solid adsorbent for selective separation/preconcentration of silver(I) in water samples prior to flame atomic absorption spectrometry. The procedure is based on the solid phase extraction of Ag(I)–2‐mercaptobenzothiazole chelate on MWCNTs. The elution step is carried out with 5 mL of 2 mol L−1 HNO3 in acetone solution at a flow rate of 1.0 mL min−1. The influences of the various analytical parameters including pH of the solution, eluent type, sample volume, flow rates of eluent, matrix ions were investigated for optimization of the presented procedure. Tests of addition/recovery for analyte ion in real samples were performed with satisfactory results. Preconcentration factor and limit of detection for Ag(I) were 160 and 0.21 µg L−1, respectively. The synthesized MWCNT exhibited excellent stability in eluent solution and its adsorption capacity was 5.4 mg of silver per gram of sorbent. The proposed method was successfully applied to trace silver determination in a variety of environmental water samples.

Preparation of Electrically Conductive Film from Silver Nanocolloid Synthesized by Reduction of Silver–Thiolate

Abstract We have developed a simple scheme for preparation of silver nanoparticle film. This scheme includes the reaction between octanethiol in the toluene and silver ion in water at toluene–water interface. The electric conductive films would be produced by sintering the coated films of the prepared silver nanoparticles below 200 °C.

Properties of silver-filled acrylate photopolymer layers prepared by a heterogeneous photocatalytic polymerisation reaction

Crosslinked, silver-filled acrylate photopolymer coatings on polyetheretherketone films were prepared without the aid of molecular photoinitiators by exploiting the photocatalytic activity of a silver-coated titanium dioxide pigment for the initiation of the polymerisation reaction. Because of the strong hydrophilic properties of the photopolymer the layers exhibit an efficient release of silver ions into water. The kinetics of the silver ion release from the coatings is governed by diffusion. The diffusion coefficient of silver ions in the acrylate photopolymer layer was estimated to be about 1 ⁎ 10− 13 cm2/s which is about eight orders of magnitude lower than the diffusion coefficient of silver ions in water. As expected from the results of the silver ion release tests the acrylate photopolymer layers exhibit an antimicrobial activity. 5 µm thick photopolymer films containing between 2.5 and 7.5 wt.% of the silver-coated titanium dioxide pigment (which corresponds to a silver content between 0.03 and about 0.1 wt.%) eliminate more than 90% of E. coli within 5 h. Within 24 h the bacteria are killed completely. Under the test conditions used only the release of silver ions and not the activity of the titanium dioxide is responsible for the antimicrobial efficacy of the photopolymer layers.

Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-Dimethylaminophenol

A new chromogenic reagent, 2-(2-quinolylazo)-5-Dimethylaminophenol (QADMAP) was synthesized, and a sensitive, selective, and rapid method was developed for the determination of the μg/L level of silver ions. The method is based on the rapid reaction of silver(I) with QADMAP and the solid phase extraction of the colored chelate using a C18 cartridge. The QADMAP reacts with Ag(I) in the presence of a citric acid-sodium hydroxide buffer solution (pH 5.0) and a sodium dodecyl sulfonate (SDS) medium to form a violet chelate of molar ratio 1 : 2 (silver to QADMAP). This chelate was enriched by solid phase extraction with C18 cartridge, and the retained chelate was eluted from the cartridge using ethanol (with 1% acetic acid). In the ethanol medium (with 1% acetic acid), the molar absorptivity of the chelate was 1.25 × 105 L mol−1 cm−1 at 584 nm. Beer’s law was obeyed in the range 0.01–0.6 μg/mL. The relative standard deviation for eleven replicate samples of 0.01 μg/mL was 1.86%. The detection limit is 0.02 μg/L in the original samples. The method was applied to the determination of μg/L levels of silver ions in water with good results.

Antibacterial activity of resin-containing triethylenetetramine side chains and/or thiol groups-metal complexes

Four chelating resins containing triethylenetetramine side chains and/or thiol groups were made from macroreticular 2,3-epithiopropyl methacrylate, styrene–divinylbenzene (DVB), or methyl methacrylate–DVB copolymer beads, and then the resins bearing metal ions such as Ag+, Cu2+, and Zn2+ were made. The antibacterial activity of the resins bearing metal ions against Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) was investigated. The resins containing thiol groups showed the higher adsorption capacity for silver ions than for other metal ions. The resins, which contain both triethylenetetramine side chains and thiol groups, bearing silver ions (RE-TTA-Ag) exhibited high antibacterial activity against bacteria, especially E. coli, without the residual silver ions in water after contacting with bacteria. The activity of the RE-TTA-Ag did not decrease even after reusing several time. © 1996 John Wiley & Sons, Inc.