Ag Content Research Articles

Biomonitoring of Potentially Toxic Elements in Dyed Hairs and Its Correlation with Variables of Interest.

Hair is good bioindicator of exposure, due to its ability to store and retain trace elements for long periods of time. But it can be especially useful when hair dyes are used since they may contain potentially toxic salts in their composition. In this context, analytical methods for the determination of bismuth, cadmium, lead, and silver in scalp human hair by electrothermal atomic absorption spectrometry were successfully validated. A total of 60 samples obtained from women between 18 and 60 years were analyzed: 34 dyed hairs and 26 untreated hairs (control). Average results expressed in dry weight (dyed/control) for each element were 2.34/0.49 μg g-1 (silver), 0.142/0.139 μg g-1 (bismuth), 0.055/0.054 μg g-1 (cadmium), and 2.09/0.99 μg g-1 (lead), respectively. These results agreed with those previously reported for non-exposed populations. A statistically significant higher Ag concentration in dyed hairs was observed, suggesting the bioaccumulation of this element. The associations between metal concentration and variables of interest (age, education, smoking habit, dye brand, use of dietary supplements) were investigated. A strong Pearson correlation was found for the pair Ag/Pb (r = 0.494, p < 0.05). Also, strong associations between lead levels and all the selected variables were observed (p < 0.05), while strong associations between silver levels with age and dye brand and association between cadmium levels and smoking habit were found. Furthermore, several commercial hair dye brands were analyzed to verify compliance with cosmetic regulations. This constitutes the first study of such characteristics performed in Uruguay, with worldwide relevance.

Enhancing photocatalysis through annealing: Unveiling the role of physical properties in photocatalytic behavior

Using spray pyrolysis, silver-doped In2S3 thin films were deposited on pre-heated glass substrates, with varying doping concentrations. Subsequently, these films underwent vacuum annealing at 400 °C for a duration of 2 h. A comprehensive study of their structural, morphological, and optical properties was conducted, revealing homogeneous, compact, crack-free films with polycrystalline tetragonal-phase of In2S3. Among the set of the analyzed films the best parameter values, including crystallite size, dislocation density, micro-strain, grain size, and root mean square (RMS) roughness, were achieved when maintaining a Silver-to-indium (|Ag|/|In|) ratio of 4 % in the precursors for both as-deposited and annealed samples. The annealing process had a discernible impact on the grain size distribution, resulting in a significant increase in crystallite and grain size, along with RMS roughness, for most doped films. The optical analysis of these films unveiled their transparency in the visible and near-infrared regions, coupled with substantial absorption in the UV region. Higher Ag concentration in the as-deposited films led to an increased band gap energy in the annealed samples. The roughness peaked at |Ag|/|In| = 4 %, resulting in a noteworthy enhancement of photocatalytic activity, achieving 95 % photodegradation of a methylene blue aqueous solution. This underscores the critical role of surface properties in determining performance. Future research intends to explore other applications for these thin films, including potential usage in gas sensors, capitalizing these films' promising characteristics.

Tissue distribution, placental transfer and excretion of silver nanoparticles in pregnant rats after a single oral dose.

A quantitative assessment of silver nanoparticles (AgNPs) in fluids and some organs of pregnant rats as well as their fetal blood were carried out in this study. A single oral dose (1mg/kg) of AgNPs with a size range of 4-20 nm was administered to pregnant rats on the 19th of gestation. Five groups were euthanized after 10 min, 1, 6, 12, and 24 hr as well as the control group. Total Silver (Ag) contents were measured in bloods (maternal and fetal) and several organs using Inductive Coupled Plasma Optical Emission Spectroscopy (ICP-OES) followed by acid digestion. In maternal blood, AgNPs were found to increase time-dependently after 12 and 24 hr into 0.135 and 0.224 μg/ml, but it was slightly higher in fetal blood (0.32 and 0.31 μg/ml) after 10 min and 1 hr. In other samples: kidneys, liver, spleen, placenta, and uterus the data indicated that NPs were rapidly absorbed from the dosing site (gastrointestinal tract) as evidenced by the detection of Ag in the analyzed samples (fluids and tissues). On the other hand, the cumulative percentages of excretion level in urine was 8.25% which was higher than in feces (4.77%) after 24 hr. These findings indicate the ability of AgNPs to accumulate in pregnant rats and transfer to their fetus imposing adverse outcomes and male formation. Thus, further investigations must be followed for direct and/or indirect exposure to such NPs before decision for their practices.

Study on iodine adsorption capacity and adsorption mechanism of AgY

ABSTRACT To systematically study the methyl iodide (CH3I) adsorption performance and adsorption mechanism of Ag ion exchange NaY zeolite (AgY), AgY adsorbents with different Ag content were selected. 16.6% AgY was capable of storing 150 mg/g and 275 mg/g of CH3I when the penetrated CH3I reached 1‰ and 100% inlet concentration. TEM and EDS results presented a high relationship between Ag dispersion and CH3I adsorption capability. The formation of a stable AgI complex rationalized the CH3I adsorption mechanism on AgY. Compared to AgX, AgY was verified to possess a strong acid resistance by FT-IR, SEM and XRD. The effect of three key parameters (temperature, humidity and gas velocity) on CH3I adsorption was carefully investigated by orthogonal experiment design. The experimental results showed that AgY had better iodine removal performance at a high temperature, low humidity, and low flow rate. This work provides technical reference for further engineering applications of 16.6%AgY in spent fuel reprocessing plants.

(TiZrNbTaMo)N nanocomposite coatings embedded with silver nanoparticles: imparting mechanical, osteogenic and antibacterial traits to dental implants

Designing highly osteogenic and effective antibacterial biomaterials with a prolonged service life for oral implants remains an ongoing challenge. In this work, the multi-element (TiZrTaNbMo)N high entropy nitride (HEN), with different concentrations of Ag, was co-deposited onto surgical grade commercially pure titanium by a reactive sputter-deposition technique using a double cathode glow discharge plasma system. The effects of Ag concentration on the microstructure and mechanical properties of the HEN-Ag nanocomposite coatings were investigated by various testing methods. Potentiodynamic polarization measurements were used to evaluate the corrosion resistance of the coatings in simulated body fluid. The antibacterial activity of the HEN-Ag nanocomposite coatings against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) strains was examined based on the bacterial inhibitory zones and bacterial killing efficiency. The cytocompatibility and osteogenesis activity of the HEN nanocomposite coatings using MC3T3-E1 cells were evaluated by a CCK-8 assay and an alkaline phosphatase quantitative assay. These studies demonstrate that the Ag-free HEN coating was composed of a face-centered-cubic (FCC) nitride phase, which displays good mechanical properties, anti-corrosion performance and osteogenic function, but no antibacterial properties were observed. In contrast, the HEN0.9Ag0.1 coating, composed of amorphous/nanocrystalline high-entropy nitride embedded with silver nanoparticles ∼10 nm in diameter, displays good mechanical and anti-corrosion performance, together with the excellent cell compatibility and antibacterial performance, which offer potential for providing outstanding protective efficiency for dental implants. Although the HEN0.8Ag0.2 nanocomposite coating exhibited superior antibacterial efficacy, potential for in vitro cytotoxicity was identified.

Efficient catalytic reduction of dyes by single or agglomerated nano‑silver functionalized wood and hydrodynamic simulation of wood channels

Wood has a multi-scale pore structure, creating conditions for the development of new water purification materials. However, the adsorption capacity of wood for dyes is always limited, so this study combines the unique structure of wood with Ag nanoparticles (NPs) to achieve efficient catalytic reduction of dyes, harnessing the advantages of both. Ag/wood composite filtration materials with different Ag contents were prepared by hydrothermal method and vacuum impregnation. The results showed that with the increase of Ag content, the interaction between metal and wood channels and the degradation performance of Ag/wood composite materials exhibited a volcano-shaped trend. The contact area between Ag NPs and dye molecules plays a key role in the degradation of dye. The load phenomenon and internal flow state were discussed in detail by means of hydrodynamic simulation. Ag0.05/wood composite made silver nanoparticles and dye molecules reach a high balance and reduction degree. Therefore, Ag0.05/wood composites showed the highest catalytic reduction efficiency and great stability during the degradation of dyes, with a degradation efficiency of up to 96.9 %. The novelty of this study lies in the detailed description of the electron transfer process and mechanism of Ag NPs as a relay during MB degradation.

The ore genesis of the Shagou Ag-Pb-Zn deposit in the Southern North China Craton: Constraints from He-Ar-Pb isotopes and trace element compositions of sphalerite

Shagou is one of the largest Ag-Pb-Zn deposits with the highest grade of Ag (Ag 1754 t @284 g/t Ag, locally up to 20,000 g/t) in the Southern North China Craton. Four mineralization stages have been identified, with assemblages of: (I) quartz + siderite + pyrite, (II) quartz + dark-brown sphalerite + fine galena + silver minerals, (III) quartz + ankerite + light-brown sphalerite + coarse galena + silver minerals, and (IV) quartz + calcite (IV). Silver minerals were mainly deposited during stage III, in which polybasite and freibergite were the dominant Ag-bearing ore minerals. He-Ar isotope compositions suggest that the ore-forming fluids of the Shagou deposit were derived from a mix of crustal and mantle sources. In situ Pb isotope comparison with regional strata, magmatic rocks, and sulfides from nearby ore deposits indicate that Pb and other metals (e.g., Ag and Zn) of the Shagou deposit originated from both the Mesozoic granite, the surrounding Taihua Group and the Meso-Neoproterozoic marine sediments. LA-ICP-MS analyses revealed that the Ag content of the dark-brown sphalerite was one order of magnitude higher than that of the light-brown sphalerite, suggesting that fluid cooling coupled with decreases in logfO2 and logfS2 were the major factors that promoting extensive Ag deposition. Dark-brown and light-brown sphalerites were enriched in In (up to 474 ppm), consistent with magmatic-related deposits. The newly obtained data in this study, combined with previous results, support a magmatic-hydrothermal origin for the Shagou Ag-Pb-Zn deposit.

Antifungal Activity of Nontoxic Nanocomposite Based on Silver and Reduced Graphene Oxide against Dermatophytes and Candida spp.

Dermatomycoses are typical hair, skin, or nail infections caused mainly by dermatophytes and nondermatophytes: Trichophyton, Microsporum, Epidermophyton, and Candida. In addition to the esthetical impact, pain, and nail deformity, these mycoses can be a source of severe disease. The high cost of treatment, toxicity, and the emergence of resistant infectious agents justifies research into new drugs. This work evaluates the fungicidal activity of nanocomposites (NCs) based on reduced graphene oxide (rGO) loaded with silver (Ag) nanoparticles (rGO/Ag) against clinical isolates of dermatophytes and Candida species. This is an unprecedented study in which, for the first time, hybrid nanocompounds based on Ag/rGO were tested against Epidermophytom, Microsporum, and Trichophyton species (dermatophytes agents). In this paper, we synthesize rGO using different concentrations of Ag by hydrolysis of metal salt AgNO3 and follow the growth of nanocrystals on sheets of rGO provided by the NaBH4. The NCs were analyzed by X-ray diffraction analysis, and the NC morphology, silver distribution on the rGO surface, and crystalline information were investigated by transmission electron microscopy. Antifungal susceptibility assay was performed by the microdilution method based on modified Clinical and Laboratory Standards Institute (CLSI) protocol. Time-kill kinetics was conducted to monitor the effect of the composite to inhibit fungal cells or promote structural changes, avoiding germination. The toxicological evaluation of the NCs was born in an in vivo model based on Galleria mellonella (G. mellonella). Minimum inhibitory concentration (MIC) values of the rGO/Ag NCs ranged from 1.9 to 125 μg/mL. The best inhibitory activity was obtained for rGO/Ag12%, mainly against Candida spp. and Epidermophyton floccosum. In the presence of sorbitol, MIC values of rGO/Ag NCs were higher (ranging from 15.6 to 250 μg/mL), indicating the action mechanism on the cell wall. Both yeast and dermatophytes clinical isolates were inhibited at a minimum of 6 and 24 h, respectively, but after 2 and 12 h, they had initial antifungal interference. All hybrid formulations of rGO/Ag NCs were not toxic for G. mellonella. This study provides insights into an alternative therapeutic strategy for controlling dermatomycoses.

Metallogenetic process of Xunmei hydrothermal field (26°S), South Mid-Atlantic Ridge: Constraints from in-situ sulfur isotope and trace elements of sulfides

Seafloor hydrothermal sulfides at slow-spreading mid-ocean ridges (MORs) are of economic and scientific significance. The formation of newly discovered submarine hydrothermal sulfides on the South Mid-Atlantic Ridge (SMAR), particularly with respect to the fluid evolution, remains poorly understood. The Xunmei hydrothermal field is a typical volcanic dome-type hydrothermal field at 26°S on the SMAR. Based on the mineralogical zonation and assemblages, six distinct ore-forming stages were identified from low- to high-temperature stages with a seafloor weathering stage. The crystallinity of pyrite/marcasite and grain size of chalcopyrite increase gradually from the outer rim to the inner conduit of a sulfide chimney. The positive δ34SV-CDT values of pyrite/marcasite (2.1‰–8.2‰), chalcopyrite (2.5‰–5.6‰), and sphalerite (2.9‰–7.0‰) suggest 62%–91% of S was derived from the leaching of basement basalts, 9%–38% from reduction of seawater sulfate. In situ trace element data for sulfides show enrichments in Mn, Ag, Tl, and Pb in outer zones A and B, while enrichments in Se, In, and Sn in inner zones C and D, indicating an increase in precipitation temperature during chimney growth. Low pyrite Co contents, low Tl/Pb, low Sb/Pb, low Bi/Pb, high As, Ag, Cu, and Pb concentrations, suggesting that the pyrites precipitated from fluids that may have undergone supercritical phase separation during their ascent. High-temperature, Cl-depleted, vapor-rich hydrothermal fluids discharged into ambient cold seawater over multiple stages and probably evolved from low (<240 °C) to medium (∼ 263 °C) and high (∼ 317 °C) temperatures, reached a highest temperature of ∼335 °C, and then evolved to medium to low temperatures (∼ 270 °C to <240 °C) during the wanning of hydrothermal venting. The sulfur fugacity (fS2) likely evolved from a relatively low to high condition within the scope of intermediate sulfidation, and then decreased to low condition. The redox states (fO2) probably were strongly affected by seawater influx and evolved from relatively oxidized to original reduced conditions. The salinity decreased during chimney growth. Sulfide precipitation in the Xunmei hydrothermal field probably was the result of a combination of fluid-seawater mixing and phase separation. We propose a chimney growth and hydrothermal evolution models for the Xunmei hydrothermal field.

Amorphous silica-alumina modified with silver as an efficient catalyst for vapor-phase dehydration of 1,3-butanediol to 1,3-butadiene

Several silica-alumina modified with Ag were examined as catalysts in the dehydration of 1,3-butanediol to 1,3-butadiene (BD). Among several catalysts tested, an amorphous silica-alumina (SAL-3) modified with Ag operated in H2 flow gave the highest improvement in catalytic activity and stability. The improvement of catalytic activity and stability of this Ag/SAL-3 was due to the generation of reversible acid sites. Several parameters, such as reaction temperature, contact time, Ag content, and carrier gas, influenced the catalytic activity of the Ag/SAL-3 catalyst. The highest BD yield of 82.5 % was attained at 225 °C, while the highest BD productivity of 1.33 g gcat-1 h-1 with a BD selectivity of 68.9 % was achieved at 250 °C. The role of the Brønsted and Lewis acid sites was revealed by poisoning experiments of co-feeding 2,6- or 3,5-dimethylpyridine with 1,3-butanediol.

Femtosecond laser-induced production of ZnO@Ag nanocomposites for an improvement in photocatalytic efficiency in the degradation of organic pollutants

Green synthesis based nanoparticle production methods and water purification techniques were carried out using pulsed laser ablation and photocatalysis degradation techniques. The femtosecond laser ablation based ZnO and Ag nanoparticles were produced with different concentration ratios such as 2.0 wt%, 4.0 wt%, 6.0 wt%, 8.0 wt% and 10.0 wt% in ultra pure water to photocatalytic degradation of methylene blue dye contaminant. Following the production of nanoparticle and photocatalysis applications, FTIR, XRD and linear absorption spectra were recorded. HRTEM and FE-SEM microscopy was carried out to determine size and shape performance of nanoparticles. The crystal peak density of ZnO and its crystal size were decreased by doping Ag into ZnO nanoparticles. LSPR peak was formed due to plasmonic properties of Ag nanoparticles in ZnO. As Ag content is increased in ZnO, it has been observed that band gap of ZnO@Ag structure is decreased. The morphological structure of ZnO is partially composed of homogeneous particle mergers while ZnO@Ag can be formed from the growth of small particles on AgO clusters. The photocatalytic activity of composite photocatalysts was systematically investigated as a function of amount of Ag nanoparticles in samples. Experimental results showed that the optimal composite was Ag-ZnO composite containing 6.0 wt% Ag. This composite photocatalyst exhibited a 68.62% higher rate constant value in the degradation of methylene blue (MB) dye molecules under visible light compared to pure ZnO nanoparticles. The improved photocatalytic performance compared to pure ZnO nanoparticles was attributed to some increase in light absorption performance, more efficient charge separation due to the gradual band structure between plasmonic Ag nanoparticles and semiconductor ZnO nanoparticles. In addition, active radicals taking role in the degradation mechanism of MB were revealed by scavenger chemical experiments.

Chitosan-based synthesis of silver-doped tungsten oxide nanoparticles and assessment of its cytotoxicity and photocatalytic performance

In this project, pure tungsten oxide nanoparticles (WO3-NPs) and silver-doped tungsten oxide nanoparticles (Ag-doped WO3-NPs, 3, 5, and 7 % of Ag) were synthesized via the use of chitosan as the reducing and stabilizing agent in a sol–gel method. The optical and structural properties, size, and morphology of pure WO3-NPs and Ag-doped WO3-NPs were examined by UV–Vis, FT-IR, DRS, XRD, EDX, FESEM, ICP, and Raman studies. Accordingly, the XRD and FT-IR data approved the synthesis of pure and crystalline WO3-NPs and Ag-doped WO3-NPs. The evaluated cytotoxicity of nanomaterials on cancer B16F0 cell line through the MTT method exhibited their inhibitory impact on cancer cells with the IC50 of 287 and 209.6 µg/mL for WO3-NPs and Ag-doped WO3-NPs (7 %), respectively. The conducted photocatalytic tests under UV-C light irradiation indicated the effect of increasing the doping (Ag) concentration on intensifying the degradation percentage of methylene blue (MB) pigment after 260 min (83.7 % for WO3-NPs and 95.3 % for Ag-doped WO3-NPs (7 %)).

Long-term antibacterial activity of silver-containing hydroxyapatite coatings against Staphylococcus aureus in vitro and invivo

BackgroundThe potential of silver-containing hydroxyapatite (Ag-HA) coatings to prevent orthopaedic implant-associated infection was explored previously; however, the resistance of Ag-HA coatings to late-onset orthopaedic infections is unknown. This study aimed to evaluate the long-term Ag+ elution and antibacterial properties of the Ag-HA coatings through in vitro and in vivo experiments. MethodsAg-HA-coated disc specimens were immersed in fetal bovine serum (FBS) for six months. Ag concentration was measured over time using inductively coupled plasma-mass spectrometry to evaluate Ag release. The hydroxyapatite (HA)- or Ag-HA-coated disc specimens were immersed in FBS for 3 months to elute Ag+ for in vitro experiments. Methicillin-resistant Staphylococcus aureus (MRSA) suspensions were inoculated onto each disc; after 48 h, the number of colonies and the biofilm volume were measured. HA- or Ag-HA-coated disc specimens were inserted under the skin of Sprague-Dawley rats for three months for in vivo experiments. In in vivo experiment 1, specimens were inoculated with MRSA and the number of colonies was counted after 48 h. In in vivo experiment 2, the specimens were inoculated with bioluminescent S. aureus Xen36 cells, and bioluminescence was measured using an in vivo imaging system. ResultsThe Ag-HA-coated disc specimens continued to elute Ag+ after six months. The biofilm volume in the Ag-HA group was lower than in the HA group. In in vitro and in vivo experiment 1, the bacterial counts in the Ag-HA group were lower than those in the HA group. In in vivo experiment 2, the bioluminescence in the Ag-HA group was lower than that in the HA group on days 1–7 after inoculation. ConclusionsThe Ag-HA-coated discs continued to elute Ag+ for a long period and exhibited antibacterial activity and inhibition of biofilm formation against S. aureus. The Ag-HA coatings have the potential to reduce late-onset orthopaedic implant-associated infections.

Sulfide Mineralization of Carbonate–Silicate Veins in Early Proterozoic Metabasites of North Karelia: Mineral Assemblages, Mineral Forms of Silver, and Fluid Inclusions

The work presents the first data on sulfide mineralization in carbonate–silicate veins, which are widespread on the islands and coast of the White Sea (North Karelia), associating with Early Proterozoic metamorphosed gabbroid bodies. The veins with Fe–Cu sulfide mineralization up to ore occurrences are localized within metabasite bodies and along their contacts with host gneisses. During the study of the mineral composition of the veins, the main assemblages of sulfide minerals were identified: chalcopyrite –bornite ± chlorite ± selenides and Pb–Ag tellurides (B1); digenite–bornite ± selenides and Pb, Ag, and Pd tellurides (B2); pyrite–bornite ± chalcopyrite (B3); marcasite–pyrite–bornite–chalcopyrite (B4); and siegenite–chalcopyrite ± acanthite ± chlorargyrite. The development of sulfide associations, as well as quartz–chlorite aggregates, was related to the late stage of vein formation. Inductively coupled plasma and laser ablation mass spectrometry analyses showed that bornite from association B1 has the highest silver content (up to 675 ppm) and, in terms of Ag, Se, and Bi contents, is closest to bornite from low-temperature epithermal, skarn, and high-temperature vein deposits. In general, bornite is the main Ag carrier in the studied associations, while digenite containing up to 1000 ppm Ag, as well as discrete silver minerals (selenides, tellurides, acanthite, and chlorargyrite), occur in subordinate quantities. Fluid inclusions in quartz from sulfide associations, as well as from a sulfide-free carbonate–silicate vein, were studied by cryo- and thermometric methods. It is established that mineralization at the late stages of vein formation was related to heterogeneous CO2–H2O–NaCl metamorphic fluid. Carbon dioxide fluid inclusions were captured by vein quartz at temperature of 253–314°C and pressure of 2 ± 1 kbar. Water–salt inclusions were captured in a wider temperature range of 100–500°С. The highest temperature fluid inclusions with temperatures of homogenization 300°С are characteristic of quartz veinlets of the siegenite–chalcopyrite association with Ag sulfide and chlorargyrite.

Modification and development of optical, thermal, dielectric properties and antibacterial activity of PVA/SA blend by Ag/Se nanofillers: Nanocomposites for energy storage devices and food packaging applications

Silver nanoparticles (Ag NPs) were synthesized using Capsicum annuum extract, which is a cost-effective and green technique. At the same time, selenium nanoparticles (Se NPs) were prepared by sol-gel technique. Then, a series of PVA/SA blend samples filled with different contents of Ag–Se nanoparticles were prepared via the solution casting way. The nanocomposite films were investigated using different measurements. XRD scans of the nanocomposites displayed a decrease in the crystallinity of the PVA/SA blend with increasing the content of Ag–Se NPs as nanofillers in the PVA/SA matrix. FT-IR spectra indicated the complexation and positive interactions between the PVA/SA blend and Ag–Se NPs. The thermal stability of the polymeric samples was improved after the addition of the nanofiller (Ag–Se NPs), as shown by TGA scans. Moreover, the indirect/direct optical energy gap decreased from 3.96/5.28 to 2.73/3.59 eV with increasing concentrations of Ag–Se NPs, confirming the improvement in the optical properties of the filled polymeric samples, as indicated by UV/visible spectra. Dielectric studies revealed that the filling of Ag–Se NPs increases the defects and leads to a greater number of dipoles within the blend and, thus, an increase in the dielectric constant and dielectric loss of the nanocomposite samples. The antibacterial test showed that all filled samples had broad antibacterial activity against Gram-positive and Gram-negative bacteria compared to pure PVA/SA blend and that it was linearly related to the nanofillers concentrations in the polymeric matrix. Improvements in thermal, optical, and electrical properties make the present nanocomposite samples suitable for multiple functions in many applications, such as high-density energy storage and flexible electronic devices. In contrast, the enhancement in the antibacterial activity could indicate that these nanocomposites can also be used for antibacterial packaging and biomedical purposes.

Synergistic role of oxygen vacancy defect and plasmonics on modulating the photocatalytic activity of Ag/CuOx nanocomposites synthesized via solution plasma

Herein, an environmentally friendly green approach for the single-step synthesis of Ag/CuOx nanocomposite by generating plasma between two copper electrodes in an AgNO3 solution is reported. Morphological tunability of the CuOx nanoparticles from spindle to flower-like and then to wire-like is achieved by varying the concentration of the AgNO3 solution, which regulates toxic dye adsorption. Compositional analysis reveals the formation of oxygen vacancies, indicating the presence of sub-stoichiometric CuO due to the bombardment of plasma-generated species on the as-formed nanoparticle. The percentage of oxygen vacancies decreases with increasing the concentration of AgNO3 to fabricate the nanocomposites. At low Ag content in the Ag/CuOx nanocomposites, higher photocatalytic efficiency is observed than the bare CuOx nanoparticles, whereas for high Ag content, photocatalytic efficiency quenches. Electrochemical spectroscopy reveals an increase in the charge-transfer resistance with Ag content. A possible photo-degradation mechanism based on the trapping and transfer of photo-generated charge carriers between the defect-enriched CuOx and plasmonic Ag nanoparticles is presented. Charge carrier lifetime is investigated to support the photo-degradation mechanism. The effect of H2O2 on the photo-degradation by considering the band edge potential of CuOx nanoparticles is also discussed.

Differences in biomarker responses and chemical contamination among three flatfish species in the Bay of Seine (NE Atlantic)

To assess the potential of the sole as sentinel species for ecotoxicological monitoring, the present study compares contaminant levels and biological responses with two closely related flatfish species: the common dab and European flounder. Trace metals, organic contaminants and biomarkers were measured in the three flatfish species collected during the same oceanographic cruise in the Bay of Seine (France). Overall, sole showed lower concentrations of Hg, met-Hg, Cd, Zn and PBDE (lw), higher concentrations of Ag, Cu, PFOS (ww), PCBs, p,p’-DDE (lw) and OH-pyrene, a higher ability to metabolize PBDEs and higher genotoxic (Comet, Micronuclei) and neurotoxic (AChE inhibition) alterations. Sole was the species most frequently occurring in the bay and appeared sensitive to chemical contamination. We therefore recommend promoting the use of the common sole for ecotoxicological monitoring.

Synthesis of ultra-thin Cu/Ag bimetallic nanosheets assisted by polyvinylpyrrolidone as template

Bimetallic nanomaterials have rich electronic structures due to unique interfacial effects and synergistic effects. In this study, the polyhedron Cu nanoparticles were synthesized by the solvothermal method using polyvinylpyrrolidone (PVP) as a template. Then Ag precursor was added to obtain ultra-thin Cu/Ag bimetallic nanosheets at room temperature. SEM and TEM results showed that the as-prepared Cu/Ag samples changed from polyhedron to nanosheet structure with increased Ag content. When Cu: Ag = 1:1, the specific surface area of the sample reached 17.318 m 2/ g. 8.76 times the specific surface area of pure Cu. At the same time, electrochemical testing showed that the prepared bimetallic nanosheets had high onset voltage and half-peak voltage in alkaline media. Therefore, this work provides a new method for preparing ultra-thin bimetallic nanosheets, expanding their applications in fields such as electrocatalysis, sensors, optical detection, biomedicine, and fuel cells.

Enhancing the Photocatalytic Performance of Antibiotics Using a Z-Scheme Heterojunction of 0D ZnIn2S4 Quantum Dots and 3D Hierarchical Inverse Opal TiO2.

Limited light absorption and rapid photo-generated carriers' recombination pose significant challenges to the practical applications of photocatalysts. In this study, we employed an efficient approach by combining the slow-photon effect with Z-scheme charge transfer to enhance the photo-degradation performance of antibiotics. Specifically, we incorporated 0D ZnIn2S4 quantum dots (QDs) into a 3D hierarchical inverse opal (IO) TiO2 structure through a facile one-step process. This combination enhanced the visible light absorption and provided abundant active surfaces for efficient photo-degradation. Moreover, the ZnIn2S4 QDs formed an artificial Z-scheme system with IO-TiO2, facilitating the separation and migration of charge carriers. To achieve a better band alignment with IO-TiO2, we doped Ag into the ZnIn2S4 QDs (Ag: ZIS QDs) to adjust their energy levels. Through an investigation of the different Ag contents in the ZnIn2S4 QDs, we found that the optimal photo-degradation performance was achieved with Ag (2.0): ZIS QDs/IO-TiO2, exhibiting degradation rates 19.5 and 14.8 times higher than those of ZnIn2S4 QDs and IO-TiO2, respectively. This study provides significant insights for elevating the photocatalytic capabilities of IO-TiO2 and broadening its prospective applications.

Distribution of Ag, Au, Bi, Cu, and Mo in surface soils. Case study: Mitrovica region, Republic of Kosovo

ABSTRACT This article presents the results of a geochemical investigation of an anthropogenic group of metals (Ag, Au, Bi, Cu, and Mo) in the surface of the Mitrovica region, Republic of Kosovo. In order to determine their content and to evaluate the contamination level, 156 topsoil samples were collected in an area of 301.5 km2. The content of elements was determined by inductively coupled plasma-mass spectrometry. The results showed that the average content of Cu (42 mg/kg), Bi (1.5 mg/kg), Ag (0.44 mg/kg), and Au (2.7 μg/kg) exceeded their average content in European and world soils by 3.4 and 1.4 times; 3.0 and 7.5 times; 1.62 and 8.8 times and 2.7 and 1.8 times, respectively. The average Mo content (0.68 mg/kg) exceeded the average content in European soils by 1.09 times, while the average content in world soil was not exceeded. Copper levels exceeded the Dutch target value of 36 mg/kg in 152 km2 and the Dutch action value of 190 mg/kg in 6.2 km2 of the study area. The enrichment factor and geo-accumulation index values for the analysed elements indicate that their higher content is of anthropogenic origin, mainly due to lead and zinc mining and metallurgical activities in the study area. The quality of soils in the Mitrovica region varies from highly contaminated with copper and bismuth, with extremely high enrichment of Cu, Bi and Ag in the soils of the central zone (Zone I) and the urban soils of the cities of Zveçan and Mitrovica. Therefore, the establishment of a monitoring and treatment programme for contaminated soils in this zone would be necessary to protect human health .