[en] Short communication

[en] Graphical abstract: - Highlights: • Confirmation of the perfect additivity of micropores independently of the geometry of arrays. • Study of assisted transfer of cadmium ions by 8-HQ at water/1,2-DCE. • Validation by cyclic and square wave voltammetry measurements for high and low concentrations. • Quantification of Cd(II) ions until 11 ppb in very simple conditions. • Highlighting of the very interesting use of arrays in a classical liquid-liquid microinterface device. - Abstract: For the first time, experimental measurements confirm the real additivity of the currents with micropore arrays, independently of the geometry (square, circular or in crosswise), from one single micropore until 256 micropores, in the case of the assisted transfer of cadmium ions by 8-hydroxyquinolinol (8-HQ). This result was obtained for measurements made by cyclic voltammetry at high concentration of cadmium ions (10⁻⁴ M). At lower concentrations (until 10⁻⁶ M), measurements performed by square wave voltammetry confirm also this additivity until 64 micropores. A calibration curve performed with a 64 micropores array allows us, in very simple conditions, the quantification of cadmium ions until 11 ppb (100 nM), which is lower than to the imposed limit for this specie in various fields, and in industrial effluents, in particular. The gain of sensitivity is close to 170 compared to measurements performed with one single micropore, illustrating the real interest of these arrays

[en] The results of experimental studies on the saturation mechanisms in He--Cd laser discharge are presented. It is concluded that the saturation effects may be explained in terms of the influence of the discharge parameters on the helium triplet metastable density. (auth)

[en] Liu et al. published the use of 6-((anthracen-9-yl) methyleneamino)−2H-chromen-2-one for visualization of copper or cadmium ions by fluorescence microscopy and cited this method by our previous paper. The fluorescence dye 6-((anthracen-9-yl) methyleneamino)−2H-chromen-2-one mentioned by the authors is not specific for Cu or Cd ions, we never tested it for this aim and some photos presented by the authors indicate even double method mistake as explained below.

[en] In this paper we present the results of the variation of secondary Mg⁺ ion yield as a function of Cd⁺ ion current, focussed on the Mg target, at different fixed values of bombarding ion energies. We then try to explain qualitatively the phenomena observed and formulate underlying mechanism. (orig./RK)

[en] Samples of the BICDVOX system, formulated as Bi₄Cd_xV_2−xO_{11−(3x/2)−δ} in the Cd substitution range 0 ≤ x ≤ 0.25 were synthesized using the standard solid state reaction.The correlation between phase stability and oxide ion performance were investigated by variable temperature XRPD, DSC and AC impedance spectroscopy. The substitution of V⁵⁺ by Cd²⁺ exhibited different phase transitions upon varying composition. For compositions with x ≤ 0.05, two successive transitions; α↔β↔γ are evident, while the β↔γ transition exists in the composition range 0.05 < x < 0.175. However, some temperature dependent phenomena confirmed the exixtence of the γ′↔γ transition, coupled with the tetragonal symmetry stabilization for x ≥ 0.175. The maximum oxide ion conductivity at lower temperatures was observed for x = 0.20. It has also been found that the slow V⁴⁺ → V⁵⁺ re–oxidation results in increased defect trapping effects in the system at higher temperatures. -- Highlights: ► γ-Stabilized BICDVOX at lower dopant concentrations. ► Good oxide-ion conductivity at lower temperatures. ► High temperature-vanadium reduction with lower dopant concentrations.

[en] The interaction type of metal ion with the adsorbent surface in adsorption operation was evaluated in this study. The binary metal ions in solution was mixed with the sand then shaken in 100 rpm. The kinetics adsorption capacity was than measured with the pseudo order model to evaluate the interaction type from the r² indicator. The result found that the Cd ions with r² = 0.9656 and r² = 0.9989 for first and second order respectively, for black sand and r² = 0.9070 and r² = 0.999 for first and second order respectively, for white sand. It was indicated that the interaction type of metal ions on sand surface was occurred together as physical and chemical interaction. (paper)

[en] The behavior of cadmium labeled with ¹⁰⁹Cd in different depth horizons of arable and forest soils were studied under static (batch) conditions in three interconnected processes, which consist of sorption, desorption and extraction. In the sorption, Cd²⁺ was applied in the aqueous calcium nitrate solution. Both untreated soils and peroxide treated soils were used in order to remove organic matter from some of the soil samples used in parallel. The influence of the V/m ratio on the sorption coefficients was investigated in preliminary experiments with untreated soils. Contrary to the usually short-term sorption, a long-term sorption of cadmium was investigated in untreated and treated soil horizons, which lasted more than fortnight. Kinetic studies of sorption were carried out and cadmium concentration dependence in aqueous phase of the second order kinetic constants was observed. For evaluation of sorption and desorption processes Freundlich isotherms were used. It was found that the Freundlich adsorption intensity coefficient is more time dependent than the absorption capacity coefficient, and the sorption itself consists of rapid and slow processes according to the soil constituents. Desorption and extraction processes revealed the possibility of cadmium recovery from various soil horizons. Based on the obtained results two- or three-stage theory of cadmium retention in soils was proposed. Some new insight into the role of organic matter in the sorption/desorption process of cadmium is also presented. (author)

[en] The relationship between the ion exchange reaction in a column and temperature was examined in the system cadmium-ion exchanger resin Lewatin S 1080. Cadmium was bound by 0.02 M NHO₃ and then eluted by 2.0 M HCl. Working temperature was gradually increased from 273 to 333 K. Cadmium concentrations were determined by atomic absorption spectrometry. Thermostated columns were of our own construction. The distillation plate theory was applied for the same ion eluated at different temperatures. It was necessary to determine graphically the following parameters: c_ex, c_max, V_max, and the width of elution band. These parameters obtained for elution curves were related to temperature. The elution curves were found to be temperature specific. Deviations from Gauss normal distribution are larger at higher temperatures. This value can be determined from the segment of the elution curve with the ordinate c_max/e. Consequently, we suggest the width of elution curve to be a measure of elution conditions at higher temperatures. (author). 19 refs, 1 fig., 1 tab

[en] Cadmium-contaminated wastewater has attracted increasing concerns due to its non-biodegradable properties and high toxicity. To explore eco-friendly and economically feasible strategies, the screened Alcaligenes faecalis K2 were employed for the biomineralization and recovery of Cd²⁺ from wastewater while producing considerable secretory organo-biominerals (SOBs) as bioadsorbents. At 75 mg/L Cd²⁺ exposure, 85.5% of Cd²⁺ was removed by K2, 43.0% of which was fixed in the granular SOBs. SOBs were convenient for separating from the solution. The adsorption capacity of granular sorbent made from SOBs was verified to be greater than 77.1 mg/g. Practically, 89.5% of 75 mg/L of Cd²⁺ could be stably removed while ereK2 continuously generated SOBs in a moving-bed biofilm reactor (MBBR). To sum up, the production of bioadsorbents can be achieved by K2, while removing Cd with live microorganisms, which was conducive to making full use of materials and improving Cd removal efficiency.