Concentration Of AgCl Research Articles

Effect of potassium and silver ion-exchange on the strengthening effect and properties of aluminosilicate glass

In this work, the aluminosilicate glass was subjected to ion-exchange using the KNO3-AgCl mixed molten salt in order to strengthen the glass while imparting antimicrobial properties. The concentration distribution of K+ ions and Ag+ ions of the ion-exchanged glasses was characterized by EDS, the effects of ion-exchange temperature (460-500 °C), ion-exchange time (0.5-3 h) and AgCl concentration (0–2.5 wt%) in the mixed molten salt on the strengthening effect and properties of the glass were investigated. The results showed that Ag+-Na+ ion-exchange, K+-Na+ ion-exchange existed simultaneously, and Ag+-Na+ ion-exchange occurred preferentially. Due to the presence of metallic silver, the appearance of the Ag+ ion-exchanged glass was light yellow and its transmittance showed a decrease. The surface compressive stress trended up and then down with increasing temperature and time because of the stress relaxation effect. The Vickers hardness of ion-exchanged glass increased by 15%, and the densities and chemical stability were also increased. Ions leaching experiments showed that the Ag+ ions release concentration of silver-loaded glass in aqueous environment can reach the bactericidal level. It has been shown that ion-exchange of glass in KNO3-AgCl mixed molten salts allowed the glass to be strengthened and incorporated with antimicrobial active ions, its chemical stability was improved, too.

Extracellular β-d-fructofuranosidase from a novel Aspergillus sp. DHE1 with high potential for biotechnological applications: Purification and biochemical characterization

The current work focused on the purification and biochemical characterization of an extracellular β-d-fructofuranosidase from a novel fungus identified genetically using 18 S rRNA molecular sequencing, as Aspergillus sp. DHE1. The fungus was cultured under solid state fermentation using the Cotton (Gossypium herbaceum) seed waste as substrate. β-d-fructofuranosidase was purified through fractionation by ammonium sulphate salt, ion-exchange chromatography on DEAE-cellulose, and Sephadex G-100 gel filtration, yielding a 13.3-purification fold, 22.6% recovery and 192.9 U/mg protein specific activity. The apparent molecular mass of Aspergillus sp. DHE1 β-d-fructofuranosidase was 78 kDa as estimated on sodium dodecyl sulphate polyacrylamide gel electrophoresis. Optimal pH and temperature were observed at 6.0 and 50 °C, respectively, and the enzyme was quite thermostable at neutral/alkalophilic conditions, retaining 72% of its original activity after 1 h of incubation at 60 °C. The activity of the purified Aspergillus sp. DHE1 β-d-fructofuranosidase was stimulated by 1 mM of KCl (138.5%), NaCl (125.9%), CoCl2 (121.2%), and CaCl2 (112.3%), whereas the same concentration of AgCl, FeCl3, HgCl2, and CuCl2 inhibited the activity by 48.7%, 30.5%, 29.9%, and 26.2%, respectively. The kinetic studies using d-sucrose as the substrate were investigated using a Lineweaver-Burk plot, with Km and Vmax of 0.85 mM and 47.62 U/mL, respectively, indicating the high substrate affinity of β-d-fructofuranosidase. The ability of Aspergillus sp. DHE1 β-d-fructofuranosidase to tolerate ethanol suggests that it may have numerous uses in the food industry, including the production of alcoholic beverages.

Improved photoluminescence and spectroscopic features of Sm3+‒doped alkali borate glasses by embedding silver nanoparticles

Influence of Ag nanoparticles (NPs) on the improvement in photoluminescence and spectroscopic features of Sm3+‒doped alkali borate glass synthesized by the melt quenching process was systematically studied and analyzed. The increasing particle size of Ag NPs with the increase of AgCl concentration (0.1 – 0.5 mol%) causes the surface plasmon resonance peak to shift to a higher wavelength (red‒shift) side. Electron microscopic investigation confirmed the presence of silver NPs in the SmLAB‒1 glass sample with a median size of 4.57 nm. A significant enhancement in emission was noticed for 0.1 mol% AgCl concentration. Such improved emission was attributed to the enhanced local electric field by metallic NPs in the vicinity of Sm3+ ions and efficient energy transfer between Sm3+ ions and silver NPs. The Judd–Ofelt parameter, Ω2 decreased as the concentration of Ag NPs increases, indicating increased symmetry and ionicity between the trivalent samarium ions and their ligands. These prepared glass compositions could have applications in solid‒state devices such as LEDs and display applications.

Visible-Light Photocatalysts of ZrO2/AgCl:Eu3+ Nanoparticles

This paper reports the visible-light photocatalysts and luminescence quenching of ZrO2/AgCl:Eu3+ nanoparticles synthesized by the co-precipitation method as a function of AgCl concentration. XRD analysis indicated the presence of crystalline tetragonal ZrO2 and an AgCl phase. The synthesized ZrO2/AgCl:Eu3+ nanoparticles were observed to have a spherical morphology with diameters of ∼ 20 nm. The photocatalyst with 2.5% mole fractions of AgCl showed effective degradation of methylene blue under visible light with the decolorization percentage reaching ∼ 95% in 180 min. The red emission of Eu3+ in the ZrO2/AgCl:Eu3+ nanoparticles decreased with increasing AgCl mole fraction. Visible-light photocatalysts of ZrO2/AgCl:Eu3+ nanoparticles can be attributed to the presence of AgCl resulting in higher photoexcited charges separation, which can be confirmed by lower luminescence intensity.

Fundamental Data Acquisition toward Silver-Silver Chloride Reference Electrode

Cl2/Cl− reference system was established with quartz cell where Cl2 gas was trapped on a glassy carbon electrode surface allowing the thermodynamic equilibrium between Cl2 and Cl− ions. Based on the Cl2/Cl− reference, the equilibrium potential of Ag/AgCl reference electrode was evaluated at concentrations ranging from 0.00039 mole fraction AgCl to 1.0 mole fraction AgCl and temperatures from 723 K to 823 K. The measured values ranged from −0.877 V to −1.361 V and followed linear correlations against temperature and concentration. However, pure AgCl showed slight upward in comparison to other observed linear trends. Compared to the previously published data sets, this study provides a full spectrum of data yielding better understandings on Ag/AgCl reference, applicable for different experimental conditions. In addition, the activity coefficients of AgCl in LiCl-KCl salt were calculated using ideal Gibbs free energy at supercooled liquid standard state. The activity coefficients range from 0.0012 to 1.19, which did not conform to a linear relationship to AgCl concentration.

Physical and optical properties of zinc tellurite Glass embedded Silver Nanoparticles co-dopedwith Nd3+/Er3+ ions

A series of Silver Nanoparticles embedded in the system of zinc-tellurite glass co-doped Neodymium/Erbium ions with the composition of (69.5-2.5x)TeO2–30ZnCl2–xNd2O3–xEr2O3–(0.5+0.5x)AgCl concentration from 0.0 to 3.0 mol% (x=0, 1, 2 and 3) have successfully been synthesized by melt-quenching techniques. The amorphous nature of the glass was confirmed from x-ray diffraction technique. The decrease of refractive index from 2.446 to 2.429 is attributed to the generation of bridging oxygen atoms via the conversion of TeO3 into TeO4 units. Conversely the increase in refractive index to 2.436 is attributed to the generation of non-bridging oxygen atoms via the conversion of TeO4 into TeO3 units. From the absorption edge studies, the value of the optical band gap EIopt.. and Urbach energy (DE) have been evaluated. The value of EIopt. lies between 2.34 and 2.83eV for the indirect transition while the Urbach energy values lies between 0.005 to 1.33eV. The experimental results indicate that Nd3+/Er3+ rare earth ions co-doped in the system of zinc-tellurite glasses embaded silver nanoparticles are a good candidates for solid state laser as active medium.

Factor V Leiden G1691A mutation in patients with cerebral infarction

A series of Silver Nanoparticles embedded in Neodymium/Erbium ions co-doped in the system of zinc-tellurite nanocomposites with the composition of (69.5-2.x)TeO 2 – 30ZnCl 2 – xNd 2 O 3 – xEr 2 O 3 – (0.5+0.5x) AgCl concentration from 0.0 to 3.0 mol% (x=0, 1, 2 and 3) have successfully been synthesized by melt-quenching techniques.. The amorphous nature of the glass was confirmed from x-ray diffraction technique. From the absorption edge studies, the value of the optical band gap E opt. and Urbach energy (D E ) have been evaluated. The value of E opt. lies between 2.35 and 2.85eV for the indirect transition while the Urbach energy values lies between 0.005 to 1.295eV. The experimental results indicate that Nd 3+ /Er 3+ rare earth ions co-doped in the system of zinc-tellurite glasses embaded silver nanoparticles are a good candidates for solid state laser active medium

Functional link between ferroxidase activity of ceruloplasmin and protective effect of apo-lactoferrin: studying rats kept on a silver chloride diet.

Strongly pronounced argyrosis caused by adding AgCl to the feed of laboratory rats efficiently mimics the deficiency of ceruloplasmin (CP) ferroxidase activity. Bringing the concentration of AgCl in the feedstuff of lactating rats to 250mg% and keeping their progeny (Ag-rats) for 3months on the same silver-containing feed provided the serum iron content 1.4 times lower than that in the control group. Besides, the ferroxidase activity of CP dropped to zero. In CP purified from sera of Ag-rats two copper ions were substituted with two silver ions. Using rat models of both post-hemorrhagic and hemolytic anemia we showed that the deficiency of CP ferroxidase activity in Ag-rats affects the iron content in serum, though does not prevent the recovery of hemoglobin level accompanied by exhaustion of iron caches in liver and spleen. When apo-lactoferrin (apo-LF) was administered to Ag-rats suffering from either post-hemorrhagic or hemolytic anemia, both hemoglobin and serum iron were restored more rapidly than in the control animals. In independent experiments Ag-rats were compared with those fed on regular diet and the former displayed a prolonged 3-day stabilization of hypoxia-inducible factors 1 and 2 alpha (HIF-1a and HIF-2a) along with an increased serum concentration of erythropoietin. Introduction to Ag-rats of active CP separately or together with apo-LF reduced that effect to 1day only. It is concluded that saturation of apo-LF with iron, provided by active CP, can strongly affect its protective capacity.

Chlorine-Mediated Regeneration of Semiconducting AgCl(s) Following Light-Induced Ag0 Formation: Implications to Contaminant Degradation

AgCl(s) is a semiconductor that has been reported to photocatalytically degrade organic contaminants under visible light irradiation. On AgCl(s) irradiation, electrons are excited from the valence to the conduction band leaving holes in the valence band. While the photogenerated holes may degrade organic contaminants, photogenerated electrons in the conduction band reduce Ag(I) to form Ag(0) atoms which coalesce to form silver nanoparticles (AgNPs) that may aggregate further to form nonreactive Ag(0) assemblages. This continuous reduction of AgCl(s) to Ag(0) on irradiation results in a decrease in the concentration of AgCl(s), thereby reducing the rate of generation of holes and thus decreasing the efficacy of photoirradiated AgCl(s) as an oxidant. If this decrease in oxidizing ability is to be prevented, a pathway for continuous oxidation of Ag(0) to Ag(I) during the irradiation process is required in order to restore the activity of the AgCl(s) photocatalyst. The results of investigations described here...

Synthesis and characterization of β-Ag2Se and β-AgCuSe nanoparticles via facile precipitation route

β-Ag2Se and β-AgCuSe nanoparticles were synthesized using AgCl precursor instead of conventional AgNO3 by simple precipitation method. It was found that orthorhombic structures were obtained for both β-Ag2Se and β-AgCuSe nanoparticles. The result shows Ag2S as impurity while increasing the concentration of AgCl. Moreover, the microstructural images show polyhedral- and pebble-like particles. The band gap energy is increased for β-Ag2Se owing to small crystallite size. The AgCl precursor can effectively produce pure nanoparticles. Hence, it is interesting in terms of identification of potential precursor for synthesizing β-Ag2Se and β-AgCuSe nanoparticles.

Effect of AgCl on spectroscopic properties of erbium doped zinc tellurite glass

The Er3+ doped zinc tellurite glass containing Ag nanoparticles (NPs) were synthesized from high purity raw materials by melt quenching method and the influence of Ag NPs on the spectroscopic properties were investigated. The glasses are characterized using DTA, EDX, TEM, FTIR, UV–Vis–NIR and photoluminescence (PL) techniques. The DTA data reveal that the addition of silver chloride increased the thermal stability from 0.52 to 0.67 for samples without and with 2mol% AgCl respectively. The sharp peaks in EDX spectra show the presence of Ag nanocrystallites. The TEM micrograph shows the distribution of NPs is Gaussian and the average size is estimated ∼10nm. Seven absorption bands of erbium were evidenced in the UV–Vis–NIR measurements. Optical band gap and density were found to decrease with addition of AgCl concentration, while molar volume increased. The PL spectra exhibit four peaks corresponding to 2H11/2→4I15/2, 4S3/2→4I15/2, 4F9/2→4I15/2 and 4S3/2→4I13/2 transitions. An enhancement in the order of six times for 2mol% of dopant and a subsequent quench in luminescence spectra of co-doped zinc tellurite glasses were observed. Such enhancements were attributed to silver nanoparticles with average size of 10nm and absorption band centered at 552nm. The studied glasses provide enormous scope to achieve the materials suitable for nanophotonics, solid state lasers and color displays.

Silver Nanoparticles Enhanced Upconversion Luminescence in Er3+/Yb3+ Codoped Bismuth-Germanate Glasses

Surface plasmon resonance (SPR) of noble metal nanoparticles (NPs) fostered a new area of nanophotonics, especially in the selective photon absorption and scattering. The precipitation of Ag NPs in glass would enhance the emission efficiency. Here, we studied the effects of annealing temperature (resulted in the increased Ag NPs’ concentration) or AgCl concentration on the luminescence properties of Er3+/Yb3+ codoped bismuth-germanate glasses which were synthesized by a single-step melting–quenching technique. The SPR peak of Ag NPs appears around 600 nm, and the size of precipitated Ag NPs (spherical, hexagonal) ranges from 5 to 15 nm. With the precipitation of the Ag NPs, more intense green (527 nm, 548 nm) and red (661 nm) upconversion (UC) emission bands are observed up to 7.7, 10.1, and 6.5 folds in the glass containing 1 wt % AgCl annealed at 480 °C for 24 h, respectively. The Ag NPs embedded glasses showed significantly local field change that allowed for more bright UC emission by SPR.

Electrochemical properties of the Ag +|Ag and other reference electrodes in the LiCl–KCl eutectic melts

Thermochemical properties of the Ag +|Ag reference electrode were investigated by comparison with those of the Cl −|Cl 2 reference electrode in the LiCl–KCl eutectic melt at 673–873 K, and the influence of the AgCl concentration on the equilibrium potential was also studied. The potential difference between the Ag +|Ag electrode and the Cl −|Cl 2 reference electrode varied in nearly linear proportion to the concentration of AgCl ranging from 0.01 to 20 mol%. When the AgCl concentration in the inner solution of the Ag +|Ag electrode was 1.02 mol%, the equilibrium potential, E, of the Ag +|Ag electrode versus the Cl −|Cl 2 reference electrode at 673–873 K is described as following: E = −1.061 (±0.005) + 0.0000649 (±0.0000010) T, where T is the temperature in K. Since the density increased with an increase of the AgCl content, the mole number of electrolytes in a given volume increased. Accordingly, the standard redox potential, E A g + | Ag 0 , could be corrected by the equation: E A g + | Ag 0 = − 1.080 ( ± 0.005 ) + 0.000346 ( ± 0.000005 ) T . Furthermore, characteristics of other reference electrodes such as the Al 3+|Al and Li +|Li (Li–Al and Li–Sb alloys) electrodes were investigated. The standard redox potential, E A l 3 + | Al 0 , of the Al 3+|Al couple at 673–873 K is described as following: E A l 3 + | Al 0 = − 2.289 ( ± 0.005 ) + 0.000405 ( ± 0.000005 ) T . The equilibrium potential between the Li–Al (Li:Al = 42:58 in mol%) and the Cl −|Cl 2 reference electrode, E L i + | Li ( Li – Al ) and that between the Li–Sb (Li:Sb = 59:41 in mol%) alloys electrode and the Cl −|Cl 2 reference electrode, E L i + | Li ( Li – Sb ) , were obtained at the temperature range from 673 to 873 K ( E L i + | Li ( Li – Al ) = − 3.923 ( ± 0.005 ) + 0.000860 ( ± 0.000005 ) T and E L i + | Li ( Li – Sb ) = − 2.960 ( ± 0.005 ) + 0.000313 ( ± 0.000005 ) T .

Solubility of chlorargyrite (AgCl) in water vapor at elevated temperatures and pressures

The solubility of chlorargyrite (AgCl) in undersaturated water vapor was investigated at temperatures of 300 to 360 oC and pressures up to 180 bars. It was shown that the presence of water vapor increases the concentration of AgCl in the gas (vapor) phase by between 1.5 and 2 orders of magnitude. This phenomenon is attributed to the formation of hydrated gaseous particles. Silver chloride dissolved in water vapor without changing its stoichiometry (congruent dissolution, Ag:Cl = 1:1). On the basis of the experimental data obtained in this study, the process of chlorargyrite dissolution, and the formation of hydrated gaseous particles in water vapor can be described by the reaction: AgCl cryst. +3· H 2 O gas = AgCl·( H 2 O) 3 gas Considering that Ag is coordinated by three molecules of water and one molecule of chlorine in the AgCl · (H 2 O) 3 gas particle, it was assumed that the silver atom is in fourfold coordination. The properties of the AgCl · (H 2 O) 3 particle were refined using ab initio molecular orbital calculations, and the stable geometry of the particle was deduced to have C3 symmetry. The temperature dependence of the equilibrium constant for the reaction controlling the formation of AgCl · (H 2 O) 3 gas is described by the equation: logK ( P=1 bar) =(22.578±5.505)−(0.0255±0.0045)· TK−(11987.6±658.5)/ TK Preliminary calculations suggest that water vapor can transport significant quantities of silver, and that such transport may play an important role in mobilizing silver in natural hydrothermal systems.

The electrical and magnetic properties of molten mixtures

The electrical conductivity , thermopower S and magnetic susceptibility of liquid have been measured as a function of c. It is found that decreases monotonically on addition of AgCl to S and reaches a value typical of a molten salt when at which point a semiconductor to molten salt transition takes place. The thermopower is negative for c > 0.3 at which composition it changes sign. The magnetic susceptibility measurements show a steady increase with c, consistent with the changes in the ionic diamagnetism and a significant Pauli contribution from the electrons for the S rich compositions. The behaviour of the system is analysed and described in terms of a simple ionic band picture using a Kubo - Greenwood formalism in which the conductivity gap increases with increasing concentration of AgCl.

Are the stress proteins indicators of exposure or effect?

The stress-inducible proteins (SP) and particularly the heat-shock proteins (HSP) are general biological indicators of contamination. Their functions are becoming increasingly understood; some SP have been associated with classes of stressors, others with specific diseases. In this paper, evidence is presented that SP are synthesized in greater quantities in increasing concentrations of stressor. Both HSP 70 and HSP 90 were sensitive in Daphnia magna to concentration of AgCl and SDS. Evidence taken from the literature indicates that subsets of SP induced vary with specific stressors or classes of stressors. Thus, the SP may provide general and specific tests of exposure. As tests of effects (or toxicity), the SP are less well proven. There is correlational evidence based on studies of SP and organismal responses, but there is little direct evidence on SP levels and toxic effects.

Kinetics of nucleation in eutectic PbCl 2-AgCl system

Results of the space experiments show the shift of the eutectic point in the PbCl 2-AgCl system in the direction of the higher concentration of AgCl with an increase of the undercooling of the melt. In our paper we endeavour to explain this phenomenon on the basis of the study of nucleation kinetics in the system. Using the statistical methods of calculations of the probability of first critical nucleus creation in the system, a kinetic phase diagram is constructed, which corresponds to the experimental data. A molecular model (based on the energy of intermolecular binding) of the difference of chemical potential in liquid and solid phase is proposed in our work. This model describes the position of the eutectic point and the shape of the liquidus line in the equilibrium phase diagram very well.

On the third order elastic constants of AgCl-AgBr mixed system

Lowdin's many body effect is accounted to explain the violation of Cauchy's relation ( C 12= C 44) in silver halides. Lundqvists potential model with many body effect has been used to evaluate the third order elastic constants of AgCl and AgBr. A modified Lundqvist potential model is used to calculate the third order elastic constants for the simple AgCl- AgBr mixed system with varying concentration of AgCl and AgBr.