Cadmium Nitrate Solution Research Articles

The structural, electrical and optical properties of CdS thin films as a function of pH

Cadmium sulfide (CdS) thin films have been deposited on glass substrates at 30 °C for 36 h using chemical bath deposition technique. The deposition was carried out in the pH range of 10–12 using aqueous solution of cadmium nitrate and thioacetamide salts. Structure of these films was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Elemental analyses of the films were studied by energy dispersive X-ray analysis (EDX). The optical and electrical properties of the prepared films were analyzed by absorbance spectra and Hall effects measurements, respectively. Influence of the pH on the structural, optical and electrical properties of CdS films was investigated. After all investigations, it was concluded that the pH value of 10 is suitable for producing CdS films by chemical bath deposition technique and the examined properties (good crystallinity and low resistivity) of this film show its feasibility for technological purposes, especially for solar cells.

High temperature powder diffraction study of (Zn,Cd)S and ZnxCd1−xS nanopowders

Nanocrystalline powders of cubic (Zn,Cd)S and ZnxCd1−xS were synthesized by the chemical precipitate method from the aqueous solution of sodium sulphide, zinc nitrate and cadmium nitrate at 277 K without any capping agent. High temperature X-ray diffraction (HTXRD) has been performed to test the stability of the nanopowders. We observed, ZnS is more structurally stable than CdS even at high temperature. The systematic shift in peak position towards the higher angles revealed the changes in the lattice parameter of ZnS and ZnxCd1−xS with an increase in the temperature. The environmental impact on ZnS during HTXRD has also been observed. We observed a significant change in the particle size as the temperature increases. Results of the high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAD) are in accordance with the XRD data.

RESERVE MOBILIZATION DISORDER IN GERMINATING SEEDS OF VICIA FABA L. EXPOSED TO CADMIUM

The experiment was performed to study the germination of Vicia faba L. under the influence of cadmium (Cd) stress. Seeds were germinated for ten days by soaking in distilled water or cadmium nitrate solution. Germination rate, embryo radicle growth and water, Cd, and amino acid and sugar contents in cotyledons were investigated. Nutrient concentrations were also determined in the germination medium to quantify the solute leakage. Results showed that Cd-induced delay in seed germination can be associated to disturbance due to a failure in sugars and amino acids freeing. Such nutrients were lost in the imbibition medium at the expense of suitable mobilization to the growing embryonic axis. To explore the mechanism of cadmium toxicity, the solute leakage provides an indication of the way in which Cd might affect the germinative metabolism.

Energy dispersive X-ray fluorescence determination of cadmium in uranium matrix using Cd Kα line excited by continuum

An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90 µg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700 µg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5 mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd Kα intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1 σ) and the results deviated from the expected values by < 4% on average.

Novel Fabrication of CdS Hollow Spheres Induced by Self-assembled Process

Micro-size CdS spheres of hollow shape were fabricated through the self-assembly of high density arrow-like nanorods. The synthesis of the CdS hollow spheres were accomplished in an aqueous solution of cadmium nitrate and triblock copolymer (Pluronic P123) at low temperature (80 °C) through the slow release of S 2- ions from thioacetamide. Morphology of the fabricated CdS hollow spheres was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results indicate that the arrow-like CdS nanorods are simultaneously grown and attached each other to form the building units that become the spheres with hollow inside as a self-assembled process. The CdS spheres have a diameter of 2∼3 μm and consist of the nanorods with a length of ∼800 nm. The nanocrystal building blocks have a hexagonal CdS structure.

Ionic Conductivity of Selected 2:1 Electrolytes in Dilute Solutions of Mixed Aqueous–Organic Solvents at 298.15 K

Equivalent conductivities of dilute solutions of calcium nitrate, cadmium nitrate, zinc nitrate, and calcium chloride (c < 0.0021 eq·dm−3) were measured in binary aqueous mixtures containing up to 70 wt % cosolvent (methanol, ethanol, and acetone) at 298.15 K ± 0.1. Data were treated by the Fuoss−Edelson equation, and its parameters, the limiting equivalent conductivity, Λ0, and the primary association constants, K1A, were evaluated. Variations in Walden products and K1A were interpreted in terms of ionic properties as well as solvent structure and dielectric constant.

Formation of CdO films from chemically deposited Cd(OH) 2 films as a precursor

Formation of cadmium hydroxide at room temperature onto glass substrates from an aqueous alkaline cadmium nitrate solution using a simple soft chemical method and its conversion to cadmium oxide (CdO) by thermal annealing treatment has been studied in this paper. The as-deposited film was given thermal annealing treatment in oxygen atmosphere at 450 °C for 2 h for conversion into cadmium oxide. The structural, surface morphological and optical studies were performed for as-deposited and the annealed films. The structural analyses revealed that as-deposited films consists of mixture of Cd(OH) 2 and CdO, while annealed films exhibited crystalline CdO. From surface morphological studies, conversion of clusters to grains after annealing was observed. The band gap energy was changed from 3.21 to 2.58 eV after annealing treatment. The determination of elementals on surface composition of the core–shell nanoparticles of annealed films was carried out using X-ray photoelectron spectroscopy (XPS).

Effect of film thickness on liquefied petroleum gas (LPG) sensing properties of SILAR deposited CdO thin films

Nanocrystalline cadmium oxide (CdO) thin films of different thicknesses were deposited on a glass substrate by a simple chemical method (successive ionic layer adsorption and reaction, SILAR) based on alternate dipping of the substrate in an alkaline cadmium nitrate solution and double-distilled water containing 1% H 2O 2, followed by air heat treatment at 723 K for 5 h. The cadmium oxide thin films were used as sensing layers for liquefied petroleum (LPG) resistive gas sensors. These samples were structurally and morphologically characterized using X-ray diffraction and SEM techniques, respectively. The dependence of LPG sensing properties on the thickness of CdO thin film was investigated. Maximum gas response achieved was 18.75% for the film of thickness 1.5 μm at a fixed gas concentration of 0.08 vol% at 698 K.

The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems.

Cadmium-induced genotoxicity, cytotoxicity and lipid peroxidation in Allium sativum and Vicia faba

Cadmium (Cd) is one of the most toxic environmental pollutants affecting cytogenetically the various organisms. The cytogenetic damage in root tip cells exposed to cadmium nitrate (CdNO3) solutions at four different concentrations (1, 10, 100 and 200 microM) was evaluated with biological tests based on micronucleus (MN) assay in two plant species, Allium sativum and Vicia faba. Additionally to the cytogenetic analysis, lipid peroxidation analyses were performed in both A.sativum and V.faba roots. Cd enhanced the MN frequency in both A.sativum and V.faba root tip cells, but no dose-dependent. Induction of MN is not depending on CdNO3 concentrations. Besides, high concentrations of Cd decreased the mitotic index and caused the delay in mitosis stages in both plants, mainly in V.faba. On the other hand, lipid peroxidation was significantly enhanced with external Cd in V.faba. The results clearly indicate that high concentrations of cadmium induce the lipid peroxidation resulting in oxidative stress that may contribute to the genotoxicity and cytotoxicity of Cd ions.

Isentropic Compressibility, Shear Relaxation Time, and Raman Spectra of Aqueous Calcium Nitrate and Cadmium Nitrate Solutions

Speed of sound, viscosity and Raman spectra of aqueous calcium nitrate and cadmium nitrate solutions were measured as functions of molality and temperature. The isentropic compressibility isotherms for both systems cross over in a narrow molality region. In comparison with Ca(NO3)2(aq) solutions, Cd(NO3)2(aq) solutions have lower isentropic compressibilities due to a lower charge to radius ratio. The observed Raman spectral changes in the ν3 (≈1400 cm−1) and ν4 (≈700 cm−1) modes with an increase in molality suggest that the symmetry of NO3− changes from D3h to C2v, and solvent-separated and/or solvent-shared ion pairs are formed in both systems. The results from plotting electrical conductivity versus shear relaxation time also imply that the influence of the solvent-separated and/or solvent-shared ion pairs begins ≈2.0 mol-kg−1 for these systems. The larger Δν values for the ν3 mode for Cd(NO3)2(aq) solutions indicate stronger solvent-separated and/or solvent-shared ion pairs formation in comparison to Ca(NO3)2(aq) solutions.

Comparative Analysis of the Solubility of Alkali Metal Chlorides in Cadmium and Zinc Nitrate Solutions at 25°C

Maximum solubilities of salts MCl (M = Li, Na, K, Cs) in cadmium and zinc nitrate solutions of various concentrations were measured. The effect of the structure of the solution on the mutual solubility was demonstrated.

Structure of Aqueous Electrolyte Solutions by X-ray Diffraction

Cadmium nitrate and cesium chloride solutions were studied in a wide concentration range by the X-ray diffraction method. The structure of aqueous solutions of the electrolytes is similar to the structure of solid phases that crystallize from them.

Reason for Different Solubility of Alkali Metal Chlorides in Cadmium Nitrate Solution

An idea that concentrated solutions of salts forming several crystal hydrates can be considered as systems of mixed solvents was developed within the framework of a phenomenological model of solution structure for the systems Cd(NO3)2-MCl-H2O (M = Li, Na, K, Cs). It was supposed that LiCl and CsCl preferentially interact with a solvent like Cd(NO3)2 nanohydrate, whereas NaCl and KCl, with a solvent like Cd(NO3)2 tetrahydrate.

Studies on the interaction between Cd 2+ ions and DNA

Cadmium is a potent carcinogen in rodents and has recently been accepted by the International Agency for Research on Cancer as a category 1 (human) carcinogen, but the molecular mechanism of its action remains largely unclear. It has however been suggested that cadmium-induced carcinogenesis may involve either direct or indirect interaction of Cd 2+ with DNA. Cd 2+ is believed to bind covalently with N7 centres of adenine and guanine. At low concentrations (≤50 mM), Cd 2+ is found to react with plasmid DNA to produce a mixture of Form I and Form II bands whereas at higher concentrations (≥100 mM), Cd 2+ causes extensive damage to DNA at a pH 5.8 solution of cadmium nitrate. Within the range 0–100 mM (when pH is adjusted to 7.4 by adding NaOH) an increase in concentration of Cd 2+ is found to cause a decrease in the gel mobility rate of plasmid and an increase in the intensity of the Form II band. When plasmid DNA is digested with BamH1, only the Form III band is observed both in the presence and absence of Cd 2+. However, the mobility of the band is found to decrease with the increase in the concentration of Cd 2+. When the enzyme Ssp1 which cuts plasmid DNA at the AT sites is used instead of BamH1, two bands are observed in the presence of cadmium as against one band in the absence of cadmium. These results suggest that Cd 2+ binds covalently with DNA (possibly at G, A and T centres) and can form intrastrand bifunctional AT adducts but not the GG adducts. It may also be that neither GG nor AT adducts are formed and yet Ssp1 digestion is prevented because of a structural modification introduced in adenine by its interaction with Cd 2+. In the presence of antioxidants such as cysteine, glutathione and ascorbate (especially cysteine and ascorbate), DNA damage is found to be greater than expected for the combined effects of the antioxidant and Cd 2+. The increased DNA damage is believed to be due to the formation of reactive oxygen species (ROS).

Features of Component Interaction in Concentrated Solutions of Multicomponent Systems

Classical complex formation processes in the multicomponent systems Cd(NO3)2-MCl-H2O (M = Li, Cs) occur at preeutectic concentrations of salts. At posteutectic concentrations of salts the formation of cadmium chloride complexes is of structurally enforced nature and depends on the type of the cybotactic group dominating in the solution. The example of the system Cd(NO3)2-LiCl-H2O was used to show that the law of mass action does not apply to systems in which structurally enforced processes occur. Differences in the solubility of MCl (M = Li, Cs, Na) in concentrated solutions of cadmium nitrate are proposed to explain in terms of differences in interactions of cybotactic groups formed by cadmium nitrate and the corresponding chloride.

Solubility Product of the Cadmium Phosphate Cd5H2(PO4)4·4H2O at 37 °C

The solubility product of Cd5H2(PO4)4·4H2O at 37 °C has been determined by mixing dilute solutions of cadmium nitrate and ammonium phosphate and measuring cadmium and phosphate concentrations as well as the pH values of the saturated solutions. Using the definition Ksp = a(Cd2+)5a(HPO42-)4/a(H+)2, the value pKsp = (30.9 ± 0.3) was found. Necessary values of stability constants of cadmium phosphate complexes in solution were estimated from literature values determined at high ionic strength with the aid of mean ion activity coefficients from independent sources.

Dépollution par méthode électrocinétique d'un matériau argileux dopé au cadmium. essai pilote

Electrokinetic treatment is a remediation technique for fine-grained soils. The feasibility and efficiency of transporting cadmium with this treatment are investigated at pilot scale in a 3.25 t clayey medium specimen spiked with cadmium nitrate solution and at an electrode spacing of 100 cm. Sulfuric acid is added to catholyte to neutralize the hydroxides generated at the cathode. A constant current density of 0.3 mA-cm −2 is applied. The test is conducted with cadmium at a concentration of 882 mg·kg −1 of dried matter. Cadmium was transported toward the catholyte and plated on the cathode. After 3 259 h of processing and an energy expenditure of 159 kWh·m −3, 98.5 % of the cadmium was removed.

The removal of cadmium and lead from aqueous solution by ion exchange with NaY zeolite

Lead and cadmium removal from aqueous solution by batch ion exchange with a solid NaY zeolite has been studied under competitive and non-competitive conditions. The extent of heavy metal (HM) removal is found to be inlependent of the nature of the anion, and equilibrium exchange isotherms are presented for NaY treatment of lead and cadmium nitrate and chloride solutions at 293 K. An increase in solution phase HM concentration lowers the affinity of the zeolite for the in-going HM ion, but lead was preferred to the indigenous sodium ion over the entire range of initial metal concentration to zeolite weight ratios (0.3–13 × 10−2 mol dm−3 gz−1) that were studied. Lead removal was much greater than that of cadmium under identical experimental conditions and NaY exchange efficiency is shown to increase in the order Ni2+ < Cu2+ < Cd2+ < Pb2+. Exchange selectivity is discussed in terms of metal ion hydration and siting within the zeolite framework. A Pb/Cd/NaY ternary exchange isotherm was constructed from 38 pairs of experimental points, and is treated quantitatively in terms of ternary and pseudo-binary separation factors. Treatment of the lead/cadmium solutions resulted in a greater depletion (by a factor of 2) of the lead component.

Preparation of Fine Particles of ZnS-CdS Solid Solution by the Spray-Pyrolysis

Ultrasonic spray-pyrolysis method was applied to the preparation of fine particles of solid solution in the system ZnS-CdS. An aqueous solution of zinc nitrate, cadmium nitrate and thiourea was used as a starting solution. Morphology and crystallinity of the produced particles were examined as a function of preparation conditions and their composition. Spherical particles of a hexagonal phase were obtained by the pyrolysis at around 700°C. The size of the obtained particles was distributed in the range from 0.3 to 1.5μm; each particle was found to consist of much finer crystallites. Lattice constants of the particles varied linearly with the composition, showing that solid solution particles were formed in the whole composition range of ZnS-CdS.