Metal Negative Ions Research Articles

Ionized acrylamide-based copolymer / terpolymer hydrogels for recovery of positive and negative heavy metal ions.

In this study, we explored the effective capture of both cations and anions onto a single adsorbent. Acrylamide (AAm) served as the polymer backbone, onto which co-monomers sodium p-styrenesulfonate (SS) and N,N-dimethylaminopropyl acrylamide (DMAPAA) were grafted, creating ionized polymer hydrogel adsorbents. These adsorbents were engineered for the synergistic separation and recovery of heavy metal cations and anions from concentrated solutions, focusing specifically on industrially significant ions such as Ni2+-, Cu2+, Zn2+ and (Cr2O7)2-. The adsorption and desorption behaviors of the AAm terpolymer hydrogels were investigated across various pH solutions, considering the competition and concentrations of these specific metal ions. Moreover, the study delved into the effects of the internal pH environment within the hydrogel adsorbents, determining its impact on the type of metal adsorbed and the adsorption capacity. Our findings indicated that the adsorption of cations was enhanced with a higher proportion of SS relative to DMAPAA in the hydrogel. In contrast, significant anion capture occurred when the concentration of DMAPAA exceeded that of SS. However, equal ratios of SS and DMAPAA led to a noticeable reduction in the adsorption of both types of substrates, attributed to the counteractive nature of these co-monomers. To enhance the adsorption efficiency, it may be necessary to consider methods for micro-scale separation of the two types of monomers. Additionally, the adsorption capacity was observed to be directly proportional to the swelling capacity of the hydrogels. For complete desorption and separation of the cations and anions from the adsorbent, the application of concentrated NaOH solutions followed by HNO3 was found to be essential. Given the varying concentrations of cation and anion pollutants, often present in heavy metal factory effluents, it is crucial to fine-tune the ratios of DMAPAA and SS during the synthesis process. This adjustment ensures optimized efficiency in the decontamination and recovery of these significant heavy metal ions.

Construction of Multishelled Binary Metal Oxides via Coabsorption of Positive and Negative Ions as a Superior Cathode for Sodium-Ion Batteries.

Multishelled binary metal oxide, which can exert a synergetic effect of different oxides, is a promising electrochemical electrode material. However, it is challenging to synthesize this kind of binary metal oxide due to the severe hydrolysis and/or precipitation reactions of the precursors between cations and anions of different metals. Herein, by using citric acid as a chelating agent to inhibit hydrolysis and precipitation, a series of multishelled binary metal oxide hollow spheres (Fe2(MoO4)3, NiMoO4, MnMoO4, CoWO4, MnWO4, etc.) were obtained via coabsorption of negative and positive metal ions. In addition, the chelation between a metal ion and citric acid is systematically validated by NMR, MS, Raman, and UV-vis. In particular, multishelled Fe2(MoO4)3 hollow spheres show excellent electrochemical performance as cathode material for sodium-ion batteries benefited from their structural superiorities. Especially, the quintuple-shelled Fe2(MoO4)3 hollow sphere shows the highest specific capacity (99.03 mAh g-1) among all Fe2(MoO4)3 hollow spheres, excellent stability (85.6 mAh g-1 was retained after 100 cycles at a current density of 2.2 C), and outstanding rate capability (67.4 mAh g-1 can be obtained at a current density of 10 C). This general approach can be extended to the synthesis of other multishelled multielement metal oxides and greatly enrich the diversity of hollow multishelled structures.

Thermodynamic Calculation of the Characteristics of Metal Thermionic Emission

The thermodynamic equilibria of the “Fermi–Dirac gas–Maxwell gas–Boltzmann gas” and “metal–saturated vapor” systems are considered (with allowance for charged particles). It is shown that the work function of a metal at 0 K is equal to the Mulliken electronegativity of its atoms. For the latter case, it is proposed to take into account the relationship between the work-function thermal coefficient and the thermodynamic functions of positive and negative metal ions.

Negative ions in liquid helium

The structure of negative ions in liquid 4He is analyzed. The possibility of cluster or bubble formation around impurity ions of both signs is discussed. It is shown that in superfluid helium, bubbles form around negative alkaline earth metal ions and clusters form around halogen ions. The nature of "fast" and "exotic" negative ions is also discussed. It is assumed that "fast" ions are negative ions of helium excimer molecules localized inside bubbles. "Exotic" ions are stable negative impurity ions, which are always present in small amounts in gas discharge plasmas. Bubbles or clusters with radii smaller the radius of electron bubbles develop around these ions.

Promoting a core electron to fill a d-shell in negative ions: Shape versus Feshbach resonances and a novel threshold law

Two new results emerging from inner-shell photodetachment of transition metal negative ions are obtained, following studies in Pt−. First, the d-wave form of the Wigner threshold law is observed for the first time in single-photon measurements. Second, single-vacancy valence shells are filled with a core electron. While this should result in stabilization of the core excited state, producing Feshbach resonances, we find that stabilization does not occur for some core excitations, dramatically demonstrating the importance of core-valence interactions.

Shape resonances in inner-shell photodetachment of transition metal negative ions

Inner-shell photodetachment of transition metal negative ions was studied using photoion spectroscopy. We focused on shape resonances, their behavior, and their decay mechanisms produced by np → (nd+ϵd) (n = 3, 4, 5) photoexcitation for Fe, Ru, Ni, Pd, and Pt transition metal negative ions.

Role of ion-ion recombination in population of triplet resonance levels of cadmium and mercury

In this paper, we present the results of the experimental study of the spectral line emission of cadmium and mercury atoms in the pulsed discharge afterglow in gas mixtures containing vapors of bromides of these metals, hydrogen, and helium buffer gas. It was shown that the population of triplet resonance levels is controlled by recombination of positive metal ions and negative bromine ions.

Negative ions in non-polar liquids

The structure and mobility of positive and negative ions in non-polar liquids are analyzed. The possibility of clusters and bubbles creation around ions of both signs is discussed. It is demonstrated that complexes formed around negative metal and halogen ions in superfluid helium have qualitatively different structures, although the measured values of the mobility were similar. In the case of Ba−and Ga− ions, which have low electron affinities, a bubble is formed around the ion; this bubble is similar to an electron bubble. In the case of Cl−, F−, and I− ions, which have high electron affinities, a cluster is formed near the ion; this cluster is similar to the well-studied cluster at the He+ ion.

Electrical and optical study of ITO films on glass and polymer substrates prepared by DC magnetron sputtering type negative metal ion beam deposition

Transparent, conducting indium tin oxide (ITO) films were deposited without intentional substrate heating on glass and polyethersulfone (PES) substrates by a magnetron sputter type negative metal ion source (MSNIS). The effect of substrate type on optical transmittance, electrical resistivity, surface morphology and roughness of the ITO film was analyzed. ITO/glass substrates show a higher optical transmittance (89%) and lower resistivity (4 × 10 −4 Ω cm) than ITO/PES (78%, 6 × 10 −4 Ω cm). X-ray diffraction (XRD) spectra indicate polycrystalline ITO films deposited on glass and amorphous ITO films on PES. Atomic force microscopy (AFM) images also indicate that ITO/glass has a lower surface roughness than ITO/PES. The values of figure of merit ( T 10/ R sh) for ITO/glass ( ϕ TC = 7.7 × 10 −3 Ω −1) are higher than ITO/PES ( ϕ TC = 1.3 × 10 −3 Ω −1), indicating that ITO/glass achieved the best performance in this study.

The luminescence and optoelectrical properties of ITO films prepared by a sputter type negative metal ion deposition

Transparent conducting indium tin oxide (ITO) thin films were prepared on glass substrates by a magnetron sputter type negative ion source which requires cesium (Cs) vapor injection for surface negative ionization on the ITO target surface. Although the film was prepared at 70°C, it attained high optical transmittance, 88% and low resistivity, 2.03×10−4Ωcm, at an optimized Cs partial pressure of PCs=1.7×10−3Pa. The as-deposited ITO films have a poly-crystalline structure with (211), (222), (400), (411) and (440) reflections.Also, ITO films prepared at PCs=1.7×10−3Pa were post-deposition vacuum annealed at 300°C for 30min. The films had a resistivity of 1.8×10−4Ωcm and a transparency of 89.2%. The post-deposition vacuum annealed ITO film was used as an anode for a transparent organic light emitting diode (TOLED). A maximum luminance of 19,000cd/m2 was obtained.

Properties of ITO on PES film in dependence on the coatingconditions and vacuum annealing temperatures

【Transparent conducting indium tin oxide (ITO) films were deposited onto the Polyethersulfone (PES) substrate by using a magnetron sputter type negative metal ion source. In order to investigate the influence of cesium (Cs) partial pressure during deposition and annealing temperature on the optoelectrical properties of ITO/PES film the films were deposited under different Cs partial pressures and post deposition annealed under different annealing temperature from $100^{\circ}C$ to $170^{\circ}C$ for 20 min at $3\;{\times}\;10^{-1}$ Pa. Optoeleetrical properties of ITO films deposited without intentional substrate heating was influenced strongly by the Cs partial pressure and the Cs partial pressure of $1.5\;{\times}\;10^{-3}$ Pa was characterized as an optimal Cs flow condition. By increasing post-deposition vacuum annealing temperature both optical transmission in visible light region and electrical conductivity of ITO films were increased. Atomic force microscopy (AFM) micrographs showed that the surface roughness also varied with post-deposition vacuum annealing temperature.】

Tin nanoclusters obtained in potassium chloride by thermal annealing

AbstractTin nanoclusters were obtained in potassium chloride crystals following the electrolytic coloration of KCl:Sn2+ and KCl: Sn2++Ca2+ crystals and thermal annealing at various temperatures and times. Electrolytic coloration of KCl:Sn2+ crystals produces electronic centers inside of samples, presumably negative metal ions of tin. Optical absorption measurements were performed on as grown sample, colored and thermal annealed samples. The behavior of the samples with Sn colloids was compared with theoretical predictions according to Mie's theory. Tin nanoclusters in KCl exhibit an absorption band with a peak at 215 nm. The structure of the nanoclusters was studied by optical absorption and transmission electron microscopy means. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Measurements of partial cross sections and photoelectron angular distributions for the photodetachment ofFe−andCu−at visible photon wavelengths

Photodetachment cross sections and the angular distributions of photoelectrons produced by the single-photon detachment of the transition metal negative ions ${\mathrm{Fe}}^{\ensuremath{-}}$ and ${\mathrm{Cu}}^{\ensuremath{-}}$ have been measured at four discrete photon wavelengths ranging from 457.9 to $647.1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ $(2.71--1.92\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ using a crossed-beams laser photodetachment electron spectrometry (LPES) apparatus. Photodetachment cross sections were determined by comparing the photoelectron yields from the photodetachment of ${\mathrm{Fe}}^{\ensuremath{-}}$ to those of ${\mathrm{Cu}}^{\ensuremath{-}}$ and ${\mathrm{C}}^{\ensuremath{-}}$, which have known absolute photodetachment cross sections. Using the measured photodetachment cross sections, radiative electron attachment cross sections were calculated using the principle of detailed balance. Angular distributions were determined by measurements of laboratory frame, angle-, and energy-resolved photoelectrons as a function of the angle between the linear laser polarization vector and the momentum vector of the collected photoelectrons. Values of the asymmetry parameter have been determined by nonlinear least-squares fits to these angular distributions. The measured asymmetry parameters are compared to predictions of photodetachment models including Cooper and Zare's dipole approximation theory [J. Cooper and R. N. Zare, J. Chem. Phys. 48, 942 (1968)], and the angular momentum transfer theory developed by Fano and Dill [Phys. Rev. A 6, 185 (1972)].

Pulsed population inversion in recombination of positive metal ions with negative oxygen ion

We discuss the ion-ion recombination of positive metal ions and negative oxygen ion in a pulsed gas discharge for realization of the pulsed inversion population mechanism. The metal atom energy levels most populated in this process are estimated. The energy level diagrams with probable transitions for several metal atoms are presented.

Effect of Post Deposition Annealing Temperature on the Optoelectrical Property of ITO Thin Films Prepared by Magnetron Sputter Type Negative Metal Ion Source

Transparent conducting indium tin oxide (ITO) thin films were deposited on glass substrates by magnetron sputter type negative metal ion source (MSNIS) using ITO target and then the effect of post deposition annealing temperature on the optoelectrical property of ITO film has been investigated. The resistivity and optical transmittance of ITO films that prepared at 70°C (without intentional substrate heating) with optimized deposition condition reached at 6.2×10-4 cm and 80%, respectively. As increasing post deposition annealing temperature, a rapid decrease is observed in the resistivity. The lowest resistivity of 1.7×10-4 cm and the highest optical transmittance of 83% were obtained at the post annealing temperature of 300°C. From the XRD and SEM measurements, the increment of the optical transmittance and conductivity by post deposition annealing treatment is attributed to the enhanced crystallinity of the ITO film.

Low temperature deposition of ITO on organic films by using negative ion assisted dual magnetron sputtering system

In a magnetron sputter type negative metal ion deposition, the influence of positive bias voltage ( V b) on the surface morphology, electrical resistivity, optical transmittance, and microhardness of ITO prepared on organic polycarbonate films has been investigated. In this study, the V b increased from 0 to 250 V to attract secondary negative In and Sn metal ions, which were produced from ITO target by surface negative ionization with intense Cs ion bombardments. During deposition although reactive oxygen gas was not introduced into the chamber, by adjusting V b at 100 V, ITO films on polycarbonate substrate with resistivity as low as 6.1×10 −4 Ω cm and transmittance over 90% at 550 nm have been obtained without intentional substrate heating. AFM measurement also shows that surface roughness varied significantly with V b. However, too intense ion bombardment originated by high V b (>100 V) condition increased surface roughness and as a result deteriorated the electrical and optical property of ITO films.

New perturbed Pb −-aggregate centers in electrolytically colored KBr:Pb 2++(Ca, Ba) crystals

New luminescent centers with a large near-infrared emissions were obtained by unusual electrolytic coloration method (low temperature and high electric field) in the KBr:Pb 2+ crystals co-doped with alkali-earth ions (Ca 2+, Sr 2+, Ba 2+). These so-called Tx centers involve Pb −-negative metal ions and the presence of at least one alkali-earth ion, which enhances the photoluminescence properties of those centers. The formation of these new centers is due to the presence of F-centers created in the process of electrolytical coloration. The photoluminescence properties, together with the magnetic circular dichroism spectra, prove the existence of at least one paramagnetic luminescent center.

Delta layer formation of silver nanoparticles in thin silicon dioxide film by negative ion implantation

Two formation methods of nanoparticles distributed at a certain depth in a delta layer by negative ion implantation were investigated. Such delta layer formation of isolated metal nanoparticles is desired in a very thin gate oxide film, with thickness of less than 10 nm for the development of a single electron device using nanoparticles as very small capacitance for Coulomb blockade. We have tried two methods by metal negative ion implantation in a thermally grown SiO 2 film on Si substrate and postannealing for (1) a delta layer formation of gold nanoparticles in the surface region of SiO 2 film, and for (2) a delta layer formation of silver nanoparticles in the bottom region of SiO 2 film. In the former with gold negative ion implantation with a low energy, the depth distribution of nanoparticles formed at annealing at less than 900 °C depended on depth deviation of implanted atoms. The almost delta layer of Au nanoparticles with diameters of 4–8 nm was obtained just under the surface by Au negative ion implantation at 1 keV and annealing at 900 °C. In the latter with silver negative ion implantation at 10 keV, 1×10 15 ions/cm 2, 25-nm-thick SiO 2/Si, and annealing at 700 °C, Ag nanoparticles with a diameter of 6–8 nm were aligned at the same depth in a delta layer in the bottom region of the SiO 2 at a distance of 2 nm from the boundary.

High-fluence implantation of negative metal ions into polymers for surface modification and nanoparticle formation

Negative ion implantation has been applied to polymers in order to modify the surface and to fabricate nanoparticles. Metal nanoparticles in the vicinity of a polymeric surface are promising for biomedical applications as well as nonlinear optical applications. Substrates of polymethyl methacrylate (PMMA) were implanted with Ag − and Cu − of 60 keV at 3 μA/cm 2 up to 3×10 17 ions/cm 2. Optical absorption spectra of the implanted PMMA were measured in a photon range from 0.5 to 4.5 eV. A peak of surface plasmon resonance (SPR) emerges in the absorption spectra above about 1×10 17 ions/cm 2, both for the Ag − and Cu − cases. A coexisting absorption slope, due mostly to defects, increases but tends to saturate with ion fluence. The SPR peak of Ag-implanted PMMA is much broader than that of the Cu-implanted one. Corresponding to the SPR spectra, metal nanoparticles are observed by cross-sectional TEM. With increasing ion fluence, the Ag nanoparticles spread out towards the surface, in contrast to the localized Cu nanoparticles. The results demonstrate that metal nanoparticle fabrication in polymers is capable by using appropriate low-energy ions and provides a variety of spatial distributions dependent on ion species and fluence. In particular, Ag − ion implantation fabricates surface-exposed/gradient nanoparticles, which are suitable for biomedical applications such as anti-microbial effects.

Characterization of the Sn Doped In2O3 Film Prepared by DC Magnetron Sputter Type Negative Metal Ion Beam Deposition

Transparent conducting indium tin oxide (ITO) films were prepared on a glass substrate by DC magnetron sputter type negative ion source from a target of a mixture of In2O3 (90%) and SnO2 (10%). In order to investigate the influence of cesium (Cs) partial pressure (PCs) on the optoelectronic property of ITO films, the PCs was varied from 1×10-3 to 2.2×10-3 Pa. The O2/Ar flow rate, working pressure, power density, and substrate temperature were kept constant at 3.6%, 9×10-2 Pa, 2.5 Wcm-2 and 70°C, respectively. By optimizing the PCs at 1.7×10-3 Pa, transparent (transmission ∼81% at 550 nm) and conducting (resistivity ∼4.3×10-4 Ωcm) ITO films were prepared. Atomic force microscopy (AFM) images showed that the surface morphology also varied significantly with PCs and that the lowest surface rms roughness was 0.6 nm measured at PCs=1.7×10-3 Pa. XPS measurement showed that the Cs concentration in the ITO films was less than 0.2 at%.