Silver Content Research Articles

Systemic Metal Ion Concentrations in Patients With Hip and Knee Megaprostheses: A Prospective Cohort Study.

Local tissue and serum metal ions have been shown to be elevated in some metal-on-metal and metal-on-polyethylene joint replacements. Local elevations have been linked to adverse local tissue reactions in some patients, and systemic elevation has been less commonly implicated cardiac and neurologic issues. Using a prospective study design, we aimed to identify the changes in serum metal ion levels after hip or knee megaprosthesis reconstruction. Furthermore, we will evaluate the occurrence of adverse effects and complications, possibly linked to metal ion elevation. Fourteen consecutive patients receiving a Modular Universal Tumor Revision System megaprosthesis were enrolled. Blood samples were collected preoperatively and postoperatively to determine the serum ion concentrations of aluminum, chromium, cobalt, and silver. To evaluate the safety of the megaprostheses and the subsequently possible related (elevated) serum metal ion concentrations, all adverse effects and complications were registered until last outpatient clinic visit at the time of this study. Compared to the preoperative median serum concentrations, the postoperative median serum concentrations of chromium, silver, and cobalt increased 11-fold, 62-fold, and 64-fold, respectively. The median serum concentration of aluminum increased with 16%. Elevations were primarily noted in patients with knee prostheses. Eight patients had no adverse effects or complications during the period between preoperative and postoperative blood sampling. One adverse effect directly related to the serum metal ion concentrations, namely argyria, was observed. This study documents significantly elevated concentrations of the metal ions, but only one adverse effect directly related to the metal ion concentrations was observed. Future studies are needed to further assess the impact of elevated metal ion levels after megaprostheses, specifically knee implants, which are metal-on-metal.

Impact of silver nanoparticle concentration in alginate microcapsules on their effects on morphological changes in periodontitis

Objective: to evaluate the effects of alginate microcapsules on morphological changes in periodontitis depending on silver nanoparticle concentration in them. Materials and Methods. The study was conducted on 30 rats distributed among three groups of 10 animals: the comparison group comprising animals with an experimental model of periodontitis and two experimental groups including animals with 5-week periodontitis, which were subjected to applications of the gel containing microcapsules with high (0.25 M, Group 1) and low (0.1 M, Group 2) concentrations of silver on the surface of their gums. To assess morphological changes, the mandible was sampled for subsequent examination. Results. In animals with periodontitis, changes in the supporting structure of the tooth took place, including defibration and perivascular edema in periodontal ligament of the tooth, and bone resorption via its replacement with connective tissue. The application of a gel containing microcapsules with silver nanoparticles led to a partial reduction of such disorders: particularly, it reduced bone resorption and its replacement with connective tissue. Destructive changes in periodontal tissues caused by gel with a high content of silver nanoparticles (0.25 M) were less pronounced than those caused by capsules with a low content of silver (0.1 M). Conclusion. Gels containing microcapsules with silver nanoparticles contributed to the reduction of destructive changes in the supporting structure of the tooth in periodontitis. The severity of the effects of the gel increased with an increase in the content of silver nanoparticles in alginate microcapsules.

Preparation of activated carbon fibers (ACF) impregnated with metallic silver particles from cotton-woven wastes and its performance as an antibacterial agent

Although activated carbon has been the subject of numerous research applications in water treatment, purification, catalysis, etc., its production is mainly focused on granular and powder presentations due to the commonly used raw materials (e.g., wood, phenolic resin, etc.). Herein, we report an easily established methodology for preparing activated carbon fibers (ACF) using cotton-woven wastes as raw material under chemical activation with H3PO4. We tested different experimental conditions between the activating agent and the cotton fabrics using a randomized-block experimental design with the specific surface area of the activated fibers as the response variable. A highly microporous structure was obtained with an average specific surface area of 1060 m2/g and pore size of 17 Å. The fibers were later impregnated with metallic silver particles using an immersion process in AgNO3 solutions followed by drying and a thermal decomposition to promote the nucleation and precipitation of non-regular shaped silver particles with sizes on the micro and nanoscale within the fiber’s porous. The novel material showed a strong antibacterial effect and a complete inhibition of bacterial culture growth with silver contents as low as 200 ppm. • Cotton-woven wastes are suitable precursors for activated carbon fibers production. • Esterification of cellulose-based raw materials is the activation mechanism. • Production of activated carbon fibers with a specific surface area up to 1200 m 2 /g. • Considerably dimension and structural stability reduction from the original fiber. • High antibacterial activity due to the presence of metallic silver microparticles.

The effect of strontium content on physicochemical and osteogenic property of Sr/Ag-containing TiO2 microporous coatings.

Strontium (Sr) is the most common element introduced into TiO2 coatings to strengthen the osteogenic property of titanium implants. However, the optimal Sr content and its effect on osteogenic and physicochemical properties of the coatings need to be clarified. In the current study, TiO2 microporous coatings with different contents of Sr (9.64-21.25 wt %) and silver (Ag) (0.38-0.75 wt %) were prepared via micro-arc oxidation technique. Sr contents did not change physicochemical properties of the coatings, including surface microstructure, micropore size and distribution, phase composition, roughness and hydrophilicity. Meanwhile, higher Sr contents (18.23-21.25 wt %) improved cytocompatibility, proliferation and alkaline phosphatase (ALP) activity of preosteoblasts, even the coatings underwent 30 days' PBS immersion. Furthermore, higher Sr contents facilitated preosteoblast growth and spreading, which are essential for their proliferation and osteogenic differentiation. Therefore, it is promising to incorporate higher Sr content (18.23-21.25 wt %) within TiO2 microporous coatings to improve their osteogenic capability.

A promising hydroxyapatite whisker with long-term and high-efficiency antibacterial performance and its potential application in implant

• The synergistic effect of nano-zinc oxide and silver ions can realize broad-spectrum antibacterial. • The silver ions in the hydroxyapatite whiskers will gradually dissolve as the whiskers degrade, realizing long-term antibacterial effects. Osteomyelitis remains one of the most challenging diseases for orthopedic doctors despite the advancement of therapeutic techniques. Biomaterials with antibacterial activities are beneficial to prevent infection post implantation. The aim of this study was to evaluate the antibacterial effects of three biomaterials including pure- hydroxyapatite (HA), Ag-HA and Ag-HA/ZnO. The prepared materials were analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM), cell adhesion and long-service antibacterial ability. The results showed that with the increase of silver content, the growth of whiskers was inhibited and the aspect ratio became smaller. Nano-zinc oxide is evenly attached on the surface of the whiskers. Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) were used for antibacterial tests. The results showed that Ag-HA and Ag-HA/ZnO had good antibacterial ability against E. coli and S. aureus . Thus, the low amount of Ag-HA has a potential of minimizing the risk of bacterial contamination, without compromising the bioactivity, and is expected to display greater biological efficacy in terms of osseointegration. Ag + and ZnO particles have a synergistic effect and can effectively kill most bacteria. At the same time, with the degradation of hydroxyapatite, Ag + is slowly released, which can play a long-term antibacterial effect.

Optimizing Silver Extraction Potential from Waste X-Ray Films Using Acid and Alkaline Leaching Agents

Abstract In this study, the silver extraction potential from waste x-ray films using sodium hydroxide and nitric acid was studied. Sodium hydroxide and nitric acid of different concentrations were used as stripping solutions to determine the optimum leaching concentration. Optimum leaching time and leaching temperature were also investigated by varying the time and temperatures, respectively. The stripped solutions were analysed for silver concentration using Flame Atomic Absorption Spectrophotometer. Results obtained revealed that, for sodium hydroxide stripping, 26.6 mg kg−1 of silver ion was obtained at an optimum leaching concentration, time and temperature of 1.5 M, 900 minutes and 30 °C. For nitric acid stripping, a maximum concentration of 9830.6 mg kg−1 was obtained at optimum concentration, time and temperature of 4 M, 1,440 minutes and 30 °C. The result revealed that the concentration of leaching agent was a significant factor affecting silver recovery, with nitric acid possessing a much higher recovery rate compared to sodium hydroxide.

Золото из аллювиальных отложений Пуйвинского района (Приполярный Урал)

In the Puyva region, located in the southeastern part of the Subpolar Urals, several gold-bearing placers and placer occurrences are known; however, information on gold itself is not complete enough, which makes the research relevant. The study of stream gold from the alluvium of the Khartes, Sertynya, Oika, Dorozhny, and Borovoy areas, has revealed that the gold is predominantly small; the particle shape is lamellar, thickened-lumpy, and complex. Gold roundness is medium; the portion of unrounded and well-rounded particles is insignificant. Silver is almost always present in gold, copper is less often noted. In some samples, electrum of a high silver content is found along with gold. Single gold particles have narrow, discontinuous high-fineness rims due to the removal of silver under exogenous conditions. Placer gold is gold of close wash-down; its original sources are probably represented by hydrothermal gold-sulfide-quartz veins localized in rocks of different composition and age.

The in vitro effects of selected substances and nanomaterials against Diaporthe eres, Diplodia seriata and Eutypa lata

AbstractGrapevine trunk pathogens (GTPs) cause serious damage to grapevines and have significant economic impacts. There is no effective protection against grapevine trunk diseases. Newly designed AgSe nanoparticles (NPs) and CuSe NPs, single‐element Ag NPs, Cu NPs, Se NPs and selected chemicals or chemical agents such as sodium arsenite, 8‐hydroxyquinoline, silver nitrate, colloidal silver, Altron Silver fertilizer and silver thiosulfate complex (NH4)3/Ag(S2O3)2 were tested in vitro against two serious GTPs Diaporthe eres, Eutypa lata and Diplodia seriata isolated from walnut. The most significant inhibition of fungal growth was observed for silver nitrate and AgSe NPs, which showed the highest level of half the maximum effective EC50 concentration with the lowest concentrations. In the case of silver nitrate at a concentration of 1000 mg L−1, 79% inhibition of mycelial growth was observed for the pathogen E. lata, 48% for D. seriata and 54% for D. eres. AgSe NPs, in which the concentration of silver is 2588 mg L−1 and that of selenium is 902 mg L−1, showed 68% inhibition of mycelial growth in the pathogen E. lata, 54% in D. seriata and 58% in D. eres.

Selective Sorption of Silver Ions from Aqueous Solutions Using Poly(N-thiocarbamoyl‑ 3-aminopropylsilsesquioxane)

The accumulation of electronic waste (e-waste) on the ground leads to environmental pollution with toxic metal ions, which subsequently harms all living organisms. Many countries still use hydrometallurgical or manual methods to extract silver ions from e-waste. These methods are unsustainable and highly toxic; therefore, it becomes necessary to introduce new environmentally compatible methods for separating valuable components from objects of various compositions. This article proposes an environmentally compatible method for the extraction of silver ions from multicomponent systems using poly(N-thiocarbamoyl‑3-aminopropylsilsesquioxane). The sorbent surface was studied by Fourier-transform infrared spectroscopy using an attenuated total internal reflection accessory. The concentration of grafted thiourea groups is 1.39 mmol/g according to elemental analysis. It has been determined that this sorbent is capable of quantitatively extracting silver ions in the pH range from 0 to 6 at a concentration of silver ions in the initial solution of 1·10–4 mol/dm3; the static sorption capacity for silver ions under experimental conditions reaches 1.22 mmol/g. When sorption is carried out in dynamic mode, the value of the dynamic capacity before breakthrough is 0.046 mmol/g, and the value of the total dynamic capacity for silver ions is 0.132 mmol/g. The highest desorption (71–78 %) is achieved using sulfuric acid solutions with a thiourea concentration gradient.

Prenatal exposure to silver is associated with an elevated risk for neural tube defects: a case-control study.

Exposure to copper, silver, and titanium has been reported to be associated with a variety of adverse effects on humans, but it is little focused on the fetus. We investigated the associations between prenatal exposure to the three metals (copper, silver, and titanium) and risk for fetal neural tube defects (NTDs). Placental samples from 408 women with pregnancies affected by NTDs and 593 women with normal pregnancies were collected from 2003 to 2016 in Pingding, Xiyang, Shouyang, Taigu, and Zezhou counties of China. Multilevel mixed-effects logistic regression and Bayesian kernel machine regression (BKMR) were used to evaluate the single and joint effects of the metals on NTDs. Silver was associated with an increased risk for NTDs in a dose-response fashion in single-metal logistic regression, with adjusted odds ratios (95% confidence intervals) of 1.78 (1.04-3.06) and 1.92 (1.11-3.32) in the second and third tertiles, respectively, compared to the lowest tertile. BKMR revealed toxic effects of silver on NTDs and the association appeared to be linear. No interaction of silver with any of the other two metals was observed. Besides, silver concentration was positively correlated with maternal certain dietary intakes. Placental high silver concentrations are associated with an elevated risk for NTDs. Maternal diet may be a source of silver exposure.

Catalytic reduction of nitrophenols using Gnetum montanum extract capped silver nanoparticles

The conversion of harmful pollutants into useful substances is one of the effective measures to reduce environmental pollution. Silver nanoparticles (AgNPs) represent an important role in this issue by serving in the development of powerful catalysts. In this study, we applied a simple and eco-friendly approach for the preparation of AgNPs using the aqueous extract of Gnetum montanum (GM) as a bioreductant and stabilizer. The suitable temperature, reaction time, and silver ion concentration for the GM-AgNPs synthesis were established at 100 °C, 75 min, and 2.5 mM, respectively. The mechanism of GM-AgNPs formation was discussed. The morphology studies revealed that GM-AgNPs were formed in a spherical shape with a mean size of 20 nm. The FTIR analysis elucidated the role of phytochemicals from GM extract in Ag+ reduction, capping, and stabilization of AgNPs, while the EDX spectra provided strong signals for the existence of Ag in the prepared material. The phytosynthesized GM-AgNPs were applied as a catalyst in reducing 3-nitrophenols and 4-nitrophenol by NaBH4. The reduction reaction for both pollutants was completed within 15 min. The pseudo-first-order rate constant for 4-nitrophenol was found to be 3.2×10−3 s−1, which was higher than that of 3-nitrophenol (2.0×10−3 s−1). The present study demonstrated the great potentiality of GM-AgNPs to serve as a high-performance catalyst for reduction of nitrophenols in water.

Mercury, silver and selenium in serum before and after removal of amalgam restorations: results from a prospective cohort study in Norway

Objective A prospective cohort study on changes of health complaints after removal of amalgam restorations was carried out at the request of the Norwegian Directorate of Health. The aim was to provide and evaluate experimental treatment to patients with health complaints attributed to dental amalgam fillings. Methods Patients (n = 32) with medically unexplained physical symptoms (MUPS), which were attributed to dental amalgam restorations had all their amalgam restorations removed and replaced with other dental restorative materials. Samples of blood were collected before and 1 year after removal of the fillings, and concentration of inorganic mercury (I-Hg), methylmercury (MeHg), silver (Ag) and selenium (Se) in serum was determined by inductively coupled plasma–sector field mass spectrometry. The comparison groups (one with MUPS but without attribution to amalgam [n = 28] and one group of healthy individuals [n = 19]) received no treatment. The participants responded to questionnaires at baseline and at follow-up after 1 and 5 years. Results Concentration of I-Hg and Ag in serum decreased significantly after removal of all amalgam restorations. Concentration of MeHg and Se in serum were not changed. Intensity of health complaints was significantly reduced after amalgam removal, but there were no statistically significant correlations between exposure indicators and health complaints. Conclusions Removal of all amalgam restorations is followed by a decrease of concentration of I-Hg and Ag in serum. The results support the hypothesis that exposure to amalgam fillings causes an increase of the daily dose of both I-Hg and Ag. Even though intensity of health complaints decreased after removal of all amalgam restorations there was no clear evidence of a direct relationship between exposure and health complaints. Trial registration: The project is registered at Clinicaltrials.gov (NCT01682278).

Silver Photochemical reactivity under electronic irradiation of Zinc-Phosphate and Sodium Gallo-Phosphate glasses

In the present work, the effect of electron irradiations on silver-containing phosphate glasses using a 2.5 MeV electron beam has been explored by Electron Spin Resonance (ESR) and luminescence spectroscopy. The process involved in the interaction of electron beam with both the silver-containing and silver-free phosphate glass matrix and the formation of colored centers is discussed. This allowed an understanding of the initial phenomena of electron deposition and charge trapping that supports the photosensitivity of these glasses by identifying the point defects and the Ag species. The effect of the silver concentration and the structure of the glass depending on the integrated dose have been investigated. The in-situ cathodoluminescence measurements give additional valuable information about the cascade of chemical reactions in the formation of new silver species, namely from the initial silver ions to the molecular silver clusters.

Ag-Modified ZnO for Degradation of Oxytetracycline Antibiotic and Reactive Red Azo Dye.

It is known that low electron-hole separation efficiency is the major disadvantage influencing low photoactivity of the UV-active ZnO photocatalyst. To solve this drawback, the excellent fabrication technique has been used to disperse silver metal on ZnO surface. In this study, an addition of silver content up to 15 wt% was carried out. The 5Ag-ZnO sample, comprising 5 wt% of silver metal, displayed a hexagonal wurtzite structure, and a band gap of 3.00 eV, with high sunlight-active photocatalytic performance of 99-100% and low photo-corrosion problem. The complete degradation of oxytetracycline (OTC) antibiotic and reactive red dye 141 (RR141) dye under natural sunlight was achieved. The highest rate constant of 0.061 min-1 was detected. The enhancement of the performance is mainly due to lowering of the electron-hole recombination rate. Dispersion of silver on ZnO causes the generation of the Schottky barrier at the interface between Ag and ZnO, so that improvement of quantum efficiency and enhancement of the resultant photoactivity could be expected. Furthermore, good distribution of metallic silver also causes a red shift in absorption of light toward the visible spectrum. This is strongly attributed to the surface plasmon resonance effect, which occurred after successful decoration of the noble metal on ZnO. The photocatalyst, with great structural stability, still maintains high photocatalytic efficiency even after five times of use, implying its excellent cycling ability. The present finding offers a new road to generate a silver decorated ZnO photocatalyst for the complete removal of dye and antibiotics contaminated in the environment.

Development of Antimicrobial Paper Coatings Containing Bacteriophages and Silver Nanoparticles for Control of Foodborne Pathogens.

In this study, a novel antimicrobial formula that incorporates Listeria bacteriophage P100 and silver nanoparticles into an alginate matrix was successfully developed. Paper coated with the antimicrobial formula inhibited the growth of Listeria monocytogenes. The effects of alginate concentration on the formation of silver nanoparticles, silver concentration on the infectivity of phages, and of low alginate concentrations on the sustained release of silver and phages were explored. The highest antimicrobial activity of the alginate-silver coating was achieved with an alginate concentration of 1%. Adding phage P100 (109 PFU/mL) into the alginate-silver coating led to a synergic effect that resulted in a 5-log reduction in L. monocytogenes. A bioactive paper was then developed by coating a base paper with the antimicrobial formula at different coating weights, followed by infrared drying. The higher coating weight was a crucial factor for the maintenance of phage infectivity throughout the coating and drying processes. Phages incorporated into the alginate matrix remained functional even after high-temperature infrared drying. Taken together, an optimized coating matrix is critical in improving the antimicrobial performance of bioactive paper as well as maintaining phage infectivity during the paper manufacturing process.

Kinetic investigation of invigorated photocatalytic performance of phytogenically prepared Ag@TiO2 composites

The research work presented in this report focuses on a facile phytogenic process for fabrication of Ag@TiO2 nanocomposites with varying silver content (0.5 wt% to 7 wt%) using the extract of fennel (foeniculum vulgare) seeds. The polyphenolics found in seeds reduce the Ag + ions into Ag0 (AgNPs) and stabilize them on the periphery of TiO2 nanopowder to make a strong schottky junction between the two. The phytogenic nanocomposites (NCs) were characterized employing a range of spectroscopic and microscopic techniques. X-Ray diffraction (XRD) studies were carried out to determine structure of crystalline nanomaterials. Optical studies were examined using UV–Visible diffuse reflectance spectroscopy (UV-DRS) and Photoluminescence spectroscopy (PL). In UV-DRS, an absorption band near 450 nm was observed, verifying formation and deposition of AgNPs on TiO2 surface. Fourier transform infra-red (FTIR) studies were carried out to investigate the various interactions between different elements. Further, morphology of nanomaterials was analyzed using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). Furthermore, X-Ray photoelectron spectroscopy (XPS) and Energy dispersive X-Ray spectroscopy (EDX) studies were executed to examine the elemental configuration and chemical state of the nanocomposites. In addition, the efficacy of phytogenic nanocomposites was explored for sunlight assisted photocatalytic decomposition of rhodamine-B (Rh-B) dye. Amongst prepared NCs, the 3 wt% Ag@TiO2 NCs exhibited outstanding photocatalytic activity. About 98.63% of Rh-B degraded in just 90 min of sunlight irradiation. Moreover, the apparent rate constants were also calculated for the photocatalytic degradation process and it has been observed that 3 wt% Ag@TiO2 NCs have 4.07 times higher photo-efficacy, compared to bare TiO2 (P-25). This invigorated photo-efficacy of phytogenically prepared Ag@TiO2 NCs was resultant from development of efficient and stable schottky contact between Ag metal and TiO2 surface.

Preparation and Investigation of Spherical Powder Made from Corrosion-Resistant 316L Steel with the Addition of 0.2% and 0.5% Ag.

The paper describes the production and study of spherical powder made from corrosion-resistant 316L steel with the addition of 0.2% and 0.5% Ag. The study of granulometric composition, morphology, fluidity and bulk density, phase composition, microhardness and impurity composition of the spherical powders was carried out. The study showed compliance of the spherical powders with the requirements for powders used for additive manufacturing. The fluidity of the powders was 17.9 s, and the bulk density was 3.76 g/cm3. The particles have a spherical shape with a minimum number of defects and an austenitic-ferritic structure. The study of the phase composition of ingots, wires and powders showed that the ingot structure of all samples consists of austenite. According to the results of studies of the phase composition of the wire, there is a decrease in γ-Fe and an increase in α-Fe and σ-NiCr in going from wire No. 1 to wire No. 3. According to the results of studies of the phase composition of the powder particles, there are three phases, γ-Fe, α-Fe, and Fe3O4. The study of microhardness showed a decrease in HV depending on the increase in silver. The hardness of the powder is lower than that of the ingot by 16-24% due to the presence of a ferritic phase in the powder. As a result of plasma spraying, an increase in residual oxygen is observed, which is associated with the oxidation of the melt during plasma dispersion. The amount of nitrogen and sulfur does not change, while the amount of carbon and hydrogen decreases, and the impurities content corresponds to the standards for corrosion-resistant steel. Qualitative and quantitative analysis of the silver content in the samples indicates that it was not affected by the stages involved in obtaining the spherical powder.

Biosynthesis of silver nanoparticles by Lentinus crinitus: characterization and antimicrobial activity

Silver nanoparticles (AgNP) obtained from biological synthesis can be widely used in industrial and medical fields because of their observed antimicrobial activity. The objective of this study was to analyze the biosynthesis of AgNPs by the fungus Lentinus crinitus (L.) Fr., and to evaluate the potential of these nanoparticles as antimicrobial agents. The antimicrobial activity of AgNPs was evaluated by agar diffusion, and broth microdilution methods to determine the minimum inhibitory concentration (CMI) against Staphylococcus aureus, Escherichia coli, Candida albicans and Candida tropicalis. AgNPs were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma emission spectrometry (ICP) and transmission electron microscopy (TEM). The UV-Vis spectra of the reaction mixture showed a SPR band with peak absorbance at 423 nm, confirming the presence of AgNPs. The synthesized AgNPs demonstrated antagonistic action against C. tropicalis (1.88 µg. mL-1), C. albicans (30.09 µg. mL-1), E. coli and S. aureus (7.52 µg. mL- 1). The AgNPs mediated by L. crinitus are mostly spherical, triangular and rod-shaped (mean diameter 8.82 nm). The concentration of silver in their crystalline structure is 120.37 µg / mL, and protein residues as possible stabilizers. The Lentinus crinitus mushroom isolated from substrates of the Amazon biome is a promising bio-resource for the biological synthesis of AgNPs with relevant antimicrobial properties and demonstrating a great potential for its application in pharmaceutical and food industries.

Photocatalytic degradation of phenol under visible light using electrospun Ag/TiO2 as a 2D nano-powder: Optimizing calcination temperature and promoter content

• Electrospun Ag/TiO 2 nanofiber (2D nano powder) was tested for phenol degradation. • Calcination temperature of 450℃ is the best one with a Rutile fraction of 23.8%. • An optimum value of thr Ag promoter is 5% in these photocatalytic experiments. • Adding 5% Ag to the TiO 2 nanofiber decrease the band gap from 3.27 to 3.03 nm. • Nanofibers as 2D nano-powder can be separated easily because of micrometric length. Phenol is one of the toxic materials, and releasing it into the water can be quite irritating and harmful to the health of organisms and the environment. In this study, phenol degradation was investigated using Ag/TiO 2 electrospun nanofiber photocatalyst as a 2D nano-powder. Nanofibers have 2 dimensions in the range of nanometers but their length of them are in the range of micrometers. The micrometer size is an advantage for the separation of the photocatalyst from the suspension. Though, nanometer size is suitable for increasing the available surface for the light. The effect of silver content (0.5–15%) as a promoter and the calcination temperature (300–900 °C) was studied on the degradation of phenol over the synthesized nanofiber-based photocatalyst. Photocatalysts were characterized by various techniques including N 2 -physisorption, XRD, SEM, EDX, TEM, FTIR, TGA/DSC, TPO, and DRS. The results have indicated that 5% of Ag content on TiO 2 is the best promoter loading in these experiments. Furthermore, the calcination temperature of 450 °C is found to be the optimum value with an optimum rutile fraction of 23.8%. Maximum phenol degradation was 82.65% at pH = 7, catalyst dosage of 1.5 g/L, and phenol concentration of 5 ppm under a low power visible light (18 W).

Silver Nanoparticles' Therapeutic Antibacterial, Antiproliferative, and Toxicological Effects.

Silver nanoparticles, among others, have broad-spectrum antimicrobial properties. Silver nanoparticles have suppressed dangerous microorganisms in medical and agricultural settings in several studies. Chemicals are harmful to humans and the environment, raising awareness of bioactive synthetic methods. These methods produce nanoparticles with better physicochemical qualities, stability, and toxicity. Biogenic nanoparticles can be made from bacterial and fungal byproducts that reduce and stabilize. Encapsulating these nanoparticles with biomolecules from the producing organisms may boost stability and biological activity. Nanoparticles' quick, clean, cheap, and ecological biologic manufacturing technique increases biocompatibility. Silver nanoparticles affect fish, algae, cell-based in vitro procedures, and microbes. Even though most of these studies were done quickly in well-regulated labs with much higher silver ion concentrations than in real life. Many silver types undergo long-term chemical transformation at extremely low levels (ng/L to g/L) in aquatic ecosystems. Thus, silver nanoparticles' environmental and health hazards need additional investigation. Recently detected antimicrobial silver at 10102 μg/mL. Multiple processes make silver nanoparticles dangerous. Basic (Ag0) and monovalent (Ag+) silver are most poisonous. Silver framework free ions affect silver toxicity. ROS damage DNA when elemental or zero-valent silver penetrates tissues. Packaged foods, contaminated water, swimming pools, antifouling, nasal and throat medicines, and other pharmaceuticals include silver nanoparticles. Consumption accumulates silver ions in subcutaneous fat. Prolonged exposure causes argyria-blue-gray skin. Silver inhibits Na+ and Cl absorption, disrupting electrolytes. Airborne silver nanoparticles may influence chronic pulmonary disease patients. Silver ions oxidize enzyme thiols, hindering electron transport and DNA replication. Ag+ rapidly damages DNA and RNA. Silver nanoparticle breakdown into silver ions creates germ-killing ROS. Silver nanoparticles are more hazardous than silver ions in the same atmosphere.