Concentration Of Sn2 Research Articles

The Effect of Bismuth and Tin on Methane and Acetate Production in a Microbial Electrosynthesis Cell Fed with Carbon Dioxide.

This study investigates the impacts of bismuth and tin on the production of CH4 and volatile fatty acids in a microbial electrosynthesis cell with a continuous CO2 supply. First, the impact of several transition metal ions (Ni2+, Fe2+, Cu2+, Sn2+, Mn2+, MoO42-, and Bi3+) on hydrogenotrophic and acetoclastic methanogenic microbial activity was evaluated in a series of batch bottle tests incubated with anaerobic sludge and a pre-defined concentration of dissolved transition metals. While Cu is considered a promising catalyst for the electrocatalytic conversion of CO2 to short chain fatty acids such as acetate, its presence as a Cu2+ ion was demonstrated to significantly inhibit the microbial production of CH4 and acetate. At the same time, CH4 production increased in the presence of Bi3+ (0.1 g L-1) and remained unchanged at the same concentration of Sn2+. Since Sn is of interest due to its catalytic properties in the electrochemical CO2 conversion, Bi and Sn were added to the cathode compartment of a laboratory-scale microbial electrosynthesis cell (MESC) to achieve an initial concentration of 0.1 g L-1. While an initial increase in CH4 (and acetate for Sn2+) production was observed after the first injection of the metal ions, after the second injection, CH4 production declined. Acetate accumulation was indicative of the reduced activity of acetoclastic methanogens, likely due to the high partial pressure of H2. The modification of a carbon-felt electrode by the electrodeposition of Sn metal on its surface prior to cathode inoculation with anaerobic sludge showed a doubling of CH4 production in the MESC and a lower concentration of acetate, while the electrodeposition of Bi resulted in a decreased CH4 production.

Speciation analysis of tin at the tin side of float glass by solvent extraction combined with a stepwise etching technique

In the float process for glass making, tin penetrates the glass surface that is in contact with the molten tin. A detailed understanding of the tin penetrating the surface is required to achieve a high-quality surface. In this paper, we describe and demonstrate a novel and quantitative wet chemical analysis method for determining the concentrations of total Sn and Sn4+ that penetrate the surface. This method consists of three steps: stepwise etching of a glass sample, separation of tin species, and determination of the total Sn and Sn4+ concentrations. The concentration of Sn2+ and the ratio of Sn2+ to total Sn (Sn redox) were calculated from the total Sn and Sn4+ concentrations. This method provides quantitative depth profiles of the total Sn, Sn4+, Sn2+, and the Sn redox. When the total Sn concentration (as SnO2) is greater than 0.2 mass%, this method has the finest depth resolution, 0.1 μm, as compared with other techniques. Moreover, it can be implemented in the laboratory because it requires only commonly used apparatus and equipment. Thus, the proposed method can be used to obtain detailed information about tin penetrating the float glass, and thereby strongly contributes to the float process for producing high-quality glass.

Preparation of chemical-resistant atomically ordered Sn-Ni alloy films by electroless plating

A ternary Ni-Sn-B alloy film was successfully deposited on an iron plate through electroless plating. The Sn content and film thickness strongly depended on the concentration of Sn2+ ions in the plating bath. The prepared Ni-Sn-B alloy films were characterized by X-ray diffraction (XRD) and X-ray fluorescence analyses and X-ray photoelectron spectroscopy. The XRD results confirmed the crystal structure of the Ni-Sn-B alloy. When the Sn2+ concentration was between 0.03 and 0.07 mol L−1, an atomically ordered phase of Ni-Sn-B was formed. To estimate the chemical resistance, the prepared Ni-Sn-B alloy films were immersed in NaOH or H2O2 for 10 days, and only a small decrease in film thickness was observed after immersion. The results suggested that the atomically ordered phase of the Ni-Sn-B alloy contributed to chemical resistance.

Structural, magnetic, thermal and optical properties of Sn2+ cation doped magnetite nanoparticles

Tin doped nanomagnetites, SnxFe3-xO4, were synthesized with various concentrations of Sn2+ ion (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) by co-precipitation method. XRD, VSM, TG-DTA, SEM-EDX and UV–Vis were used to characterize and study the structural, magnetic, thermal, and optical properties of SnxFe3-xO4 nanoparticles. XRD confirmed the presence of cubic structure and spinel phase of tin doped magnetites. The d-spacing, lattice parameter, density, crystallite size and cation distribution were derived from the XRD analysis. The M − H curves exhibited changes in saturation magnetization (Ms), coercive field (Hc), remanent magnetization (Mr) and susceptibility (χ), with increasing concentration of non-magnetic Sn2+ ions. Differential thermal analysis was used to study the thermal stability of SnxFe3-xO4 nanoparticles. The SEM images revealed the surface morphology of the nanoparticles and the EDX spectra showed an increase in the Sn content and a corresponding decrease in the Fe content for the tin doped samples. The optical bandgap was found to be centered at 3.9 eV for the synthesized materials. This systematic study may be the first comprehensive report on synthesis and characterization of tin doped magnetites.

Inhibition of Anodic Dissolution of Steel by Sn2+ in Perchloric Acid Solution

The inhibition effect of Sn2+ on the anodic dissolution of Fe-0.05C steel was investigated electrochemically in a solution of 0.2 M HClO4. Anodic currents were suppressed in the presence of Sn2+, and the suppression behavior depended on the concentration of Sn2+ and the electrode potentials. The experimental condition for the current suppression is explained by the theory of underpotential deposition (UPD). X-ray photoelectron spectroscopy (XPS) depth analysis revealed the deposition of metallic Sn on the steel, while inductively coupled plasma-mass spectrometry (ICP-MS) analysis demonstrated that the Sn layer thickness was monolayer-level. This strongly suggests that the anodic dissolution of iron was suppressed by the UPD of Sn. The proposed mechanism for corrosion inhibition by Sn-UPD also explains the superior corrosion resistance of Sn-bearing steel under atmospheric environments.

Regeneration of Sn4+ from Sn2+ solution during electrowinning process using anion exchange membrane

ABSTRACTElectrowinning process to regenerate Sn4+ from Sn2+ in HCl solution using an electrowinning cell with anion exchange membrane was proposed to suggest a novel recycling process to recover Sn. During the tests, the effects of initial Sn2+ concentration on the regeneration of Sn4+ were investigated under the following condition; 7,000 mg/L, 10,000 mg/L, and 13,000 mg/L of Sn2+, 1 M HCl, 250 A/m2 of current density, graphite anode, titanium cathode, room temperature, and 2 h. Electro-deposited Sn on the cathode showed dendritic structure regardless of the Sn2+ concentration and no change of Sn concentration was observed in the anolyte. Leaching tests were performed using the anolyte, obtained from the electrowinning tests, to examine the amount of regenerated Sn4+ concentration during electrowinning process. Based on the results of Sn leaching tests, it was found that 84.44%, 81.03%, and 79.43% of Sn4+ were regenerated from 7,000 mg/L, 10,000 mg/L, 13,000 mg/L initial concentration of Sn2+ solution, respectively. Consequently, it was found that the regeneration of Sn4+ can occur during the electrowinning process at the same time with Sn recovery and Sn4+ can be reused as an oxidant to leach Sn successfully.

Ternary Zn–Mn–Sn alloy electrodeposition from an ionic liquid based on choline chloride

Zinc–manganese–tin (Zn–Mn–Sn) ternary alloys have been successfully prepared, for the first time, by electrochemical deposition from a choline chloride-based ionic liquid. The influence of electrolyte composition and electrodeposition potential on the ternary Zn–Mn–Sn alloy surface morphology, composition and corrosion resistance were investigated and contrasted with the characteristics of binary Zn–Mn and Zn–Sn electrodeposits. It was found that the composition of the plating bath and deposition potential have a significant influence on the alloy content, morphology and corrosion properties of the Zn–Mn–Sn alloys. The content of Sn in the ternary alloy increased with a decrease in electrodeposition potential and an increase in concentration of Sn2+ in the electrolyte. The corrosion studies showed that the Zn–Mn–Sn alloys have a synergistic property combining the barrier behaviour afforded by Sn and the strong passive behaviour of Mn, while the sacrificial characteristics are still preserved.

Different valence Sn doping – A simple way to detect oxygen concentration variation of ZnO quantum dots synthesized under ultrasonic irradiation

An ultrasonic method is employed to synthesize the Sn doped Zn0.95Sn0.05O quantum dots with green light emission. Sn2+ and Sn4+ ions are used to create different optical defects inside Zn0.95Sn0.05O quantum dots and the changing trend of oxygen concentration under different ultrasonic irradiation power are investigated. The photoluminescence spectra are employed to characterize the optical defects of Zn0.95Sn0.05O quantum dots. The UV–vis spectra are used to study the band gap of Zn0.95Sn0.05O quantum dots, which is influenced by their sizes. The results indicate that ultrasonic power would influence the size of Zn0.95Sn0.05O quantum dots as well as the type and quantity of defects in ZnO quantum dots. Changing trends in size of Sn2+ and Sn4+ doped Zn0.95Sn0.05O quantum dots are quite similar with each other, while the changing trends in optical defects types and concentration of Sn2+ and Sn4+ doped Zn0.95Sn0.05O quantum dots are different. The difference of the optical defects concentration changing between Sn2+ doped Zn0.95Sn0.05O quantum dots (VO defects) and Sn4+ doped Zn0.95Sn0.05O quantum dots (OZn and Oi defects) shows that the formation process of ZnO under ultrasonic irradiation wiped oxygen out.

Luminescence of Sn2+ Center in ZnO–B2O3 Glasses Melted in Air and Ar Conditions

Abstract The authors report on luminescence of SnO-doped 60ZnO–40B2O3 (SZB) glasses melted in air and Ar atmosphere. In photoluminescence (PL), excitation spectra consist of two excitation bands, and the lower excitation band, emerging at lower energy with increasing amount of SnO, affects the optical absorption edge. The present SZB glasses can exhibit light emission by irradiation of near UV light, which is different from the zinc phosphate glass system. X-ray induced scintillation spectra indicate that concentration of Sn2+ mainly affects the intensity. 119Sn Mössbauer spectra show that a certain amount of Sn2+ centers in the SZB glass was oxidized to Sn4+ even when melted under the inert atmosphere, which is one of the reasons for the low PL quantum efficiencies, approximately 60%. The 119Sn Mössbauer spectra also suggest site dispersion of Sn2+ centers, whose local coordination states affect the optical absorption and luminescent properties.

Highly sensitive and selective fluorescent detection of rare earth metal Sn(II) ion by organic fluorine Schiff base functionalized periodic mesoporous material in aqueous solution

Abstract A Schiff base 3-((4-aminophenyl)imino)-5-fluoroindolin-2-one (APIFI) functionalized mesoporous material (APIFI-SBA) has been first developed by covalent binding with epoxypropoxyl groups on the inner surface of siliceous wall. The obtained material has been characterized by small angle X-ray diffraction, nitrogen adsorption–desorption and Fourier transform infrared spectroscopy. The results indicate that the Schiff base molecule APIFI is successfully immobilized within the channels of mesoporous material with linked ligand. Moreover, the ordered porous structure of mesoporous host is still retained on the Schiff base functionalized mesoprous material. The material APIFI-SBA shows high sensitivity and selectivity of detecting Sn2+ ions in aqueous media. A good linearity between the fluorescence intensity of the material and the concentration of Sn2+ ion is constructed, which enables it as a fluorescent chemosensor for detecting Sn2+ ion in aqueous solution. In future, it is potential to be used as a novel chemosensor for a lot of practical applications in chemical, environmental and biological systems.

Electrodeposition of copper–tin film alloys for interconnect applications

The electrodeposition of copper–tin alloy thin films was studied as a potential application for on-chip interconnection, where Cu–Sn alloys may be less susceptible to failure caused by electro- and stress-migration than pure copper. Alloys with variable Sn content were plated from acidic copper sulfate electrolytes by polarizing copper deposition into the region where Sn deposition became possible. The effective polarization was demonstrated by means of several halogen–polyether pairs, with Br–EPE (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)) pair exhibiting the strongest polarization. Alloy content of Sn between 0 and 7at% was obtained above the reduction potential of Sn2+, which can be attributed to UPD mechanism. Higher Sn content of up to 20at% was achieved when Cu deposition was suppressed below the reduction potential of Sn2+ by the combination of Br− and EPE. A positive correlation between Sn content and concentration of Sn2+ in the electrolyte was observed. At low rotation speeds of a disk electrode (i.e. 25rpm versus 100rpm) the tin content in the alloy was higher, possibly due to stronger suppression of copper deposition at low rotation speeds. The relationship between Sn content and the applied current density was specific to the employed additive chemistry.

A Study of Bright Sn Electroplating Technology in Methanesulfonic Acid System

A bright tin coating was prepared by electrodeposition method in the electroplating system of methanesulfonic acid. The effects of methylsulfonic acid concentration, main salt concentration, current density and brightener on brightness of coating were investigated by orthogonal experiment. A plating process of bright tin was confirmed: concentration of methylsulfonic acid: concentration of Sn2+: current density: 2.5A/dm2, dosage of brightener: at the same time, current efficiency, throwing power, covering power and electrochemical behavior for the process were inspected systematically. And the coatings are characterized by X-ray diffraction analysis (XRD) and scanning electron microscope (SEM).

Design and characteristics of tin (II) optode based on immobilization of dithizone on a triacetylcellulose membrane and its application in canned foods

The characterization of an optical sensor membrane is described for the determination of tin (II) based on the immobilization of dithizone on a triacetylcellulose membrane. The membrane responds to tin (II) ions by changing color reversibly from green to red in buffer solution at pH 6 and wavelength 611 nm. This optode has a linear range of 0.3–6.33 μg cm−3 (2.52–53.32 μmol dm−3) of Sn2+ ions with a limit of detection of 0.15 μg cm−3 (1.26 μmol dm−3). The response time of the optode was about 8–10 min depending on the concentration of Sn2+ ions. The selectivity of the optode to tin (II) ions at pH 6 was good. The sensor can be readily regenerated by exposure with EDTA solution. The color is fully reversible, and the optical sensor could be fully regenerated. Experimental results showed that the optode could be used as an effective tool in analyzing the tin content in canned foods. Graphical Abstract text

The Polarographic Determination of Divalent Tin in Sodium Formate

Abstract Well-defined cathodic and anodic polarograms of stannous tin in sodium formate have been reported. The diffusion current is directly proportional to the concentration of stannous tin between 10−5 to 10−4m. The anodic half-wave potential of tin is shifted to positive values with the increase in the concentration of Sn2+, whereas the cathodic half-wave potential is constant. The anodic polarogram is highly irreversible. The cathodic polarogram is also irreversible. The irreversibility of the anodic polarogram is increased with the concentration of stannous formate. This is evidenced by a corresponding increase in the difference between E3⁄4 and E1⁄4. Above pH 5.0 the anodic polarogram merges with the cathodic polarogram,. thereby limiting the polarographic determination of Sn2+ to the pH value 3∼5. The E1⁄2 of the anodic polarogram shifts to negative potentials when the pH was increased, whereas that of the cathodic wave is constant. The polarogram with equal wave heights obtained in 1 molar sodium formate at pH 3.0 with 0.005% gelatin has been taken for the determination of tin.