Cd Incorporation Research Articles

Steric, Synergetic, Energetic Studies on the Impact of the Type of the Hybridized Polymers (Chitosan and β-Cyclodextrin) on the Adsorption Properties of Zeolite-A for Congo Red Dye.

Zeolite-A was synthesized successfully from kaolinite and hybridized with two species of biopolymers (chitosan (CH/Z) and β-cyclodextrin (CD/Z)). The obtained hybridized forms were assessed as potential adsorbents of Congo red synthetic dye (CR) with enhanced affinities and elimination capacities. The synthesized CD/Z and CH/Z hybrids demonstrated uptake capacities of 223.6 and 208.7 mg/g, which are significantly higher than single-phase zeolite-A (140.3 mg/g). The integrated polymers change the surface area, surface reactivity, and number of free active receptors that are already present. The classic isotherm investigations validate Langmuir equilibrium behavior for ZA and Freundlich properties for CD/Z and CH/Z. The steric parameters validate a strong increase in the existing active receptors after the incorporation of CD (CD/Z) to be 98.1 mg/g as compared to 83 mg/g for CH/Z and 60.6 mg/g for ZA, which illustrate the detected uptake behaviors. Moreover, the CR dye was adsorbed as several molecules per single site, reflecting the vertical uptake of these molecules by multimolecular mechanisms. The energetic assessment, considering both Gaussian energies and adsorption energies (<40 kJ/mol), validates the dominant impact of the physical mechanism during the sequestration of CR (dipole binding interactions (2-29 kJ/mol) and hydrogen bonds (<30 kJ/mol)), in addition to the considerable effect of ion exchange processes. Based on the thermodynamic parameters, the CR molecules were adsorbed by exothermic and spontaneous reactions.

Ca-oxalate crystals are involved in cadmium storage in a high Cd accumulating cultivar of cacao

Cadmium (Cd) concentrations in cacao often exceed food limits. A better understanding of the molecular mechanisms of Cd accumulation in cacao trees is necessary to advance Cd mitigation strategies. This study explores Cd distribution and speciation (i.e., chemical form) within the vegetative organs of a high Cd accumulating cacao cultivar growing in soil with background Cd concentrations (0.28 mg Cd kg−1) by synchrotron radiation-based micro- and nano-X-ray fluorescence imaging and X-ray absorption spectroscopy on duplicate samples of roots, young branches, mature branches, and leaves. In both the roots and branches, the incorporation of Cd in Ca-oxalate crystals with binding to oxygen-ligands was identified as a major mechanism of Cd regulation. The Ca-oxalate crystals were more abundant in the branches than in the roots. We suggest that the incorporation of Cd into the Ca-oxalate crystals may limit the transfer of Cd to other organs like the leaves and beans. The roots also featured Cd-sulfur species in dilated cells of the wood, probably for the retention of Cd in the roots by strong binding with Cd to thiol-containing ligands. A Cd hotspot in large, secreting channels of the branches suggested that mucilage may play a role in the transport of Cd within cacao trees. The leaves had local Cd enrichments in the parenchymatous tissues and displayed a higher Cd concentration in the mesophyll compared to the epidermis. These insights in Cd distribution and speciation underscore that Theobroma cacao L. develops original Cd detoxification strategies, strongly different from non-tolerant species such as cereals.

Robust Bi-anchoring carbon dot/BiOCl sheet heterojunction photocatalysts toward superior photocatalytic activity.

BiOCl has attracted much attention due to its robust layered structure, excellent photocatalytic activity and nontoxicity. However, its practical application is hindered by its narrowband UV photoresponse and rapid recombination of photocarriers. Herein, zero-dimensional Bi-anchoring carbon quantum dot (Bi-CD)/two-dimensional BiOCl heterojunction (Bi-CD/BiOCl) photocatalysts are designed and synthesized by a facile hydrothermal method. Under 190-1100 nm broadband light irradiation, the optimized Bi-CD/BiOCl sample exhibits a superb rhodamine B (RhB) degradation rate of nearly 100%, which is 2.3 (1.7) times that of pristine BiOCl (CD/BiOCl). Additionally, the optimized sample exhibits an RhB degradation rate of up to 88.1% even under direct outdoor light and robust durability in water solution. Experimental results combined with DFT calculations reveal that the superior photocatalytic activity arises from the synergetic effects of broader light absorption due to the incorporation of CD, extra hot electron excitation by the localized surface plasmon resonance (LSPR) effect of metallic Bi, and enhanced electron transfer across the heterojunction interface as well as the existence of more oxygen vacancy traps in BiOCl. This work gives insights into the structure and photocatalytic properties of Bi-CD/BiOCl and provides a new strategy for the design and fabrication of robust high-performance photocatalysts under wide spectrum light irradiation.

Electrochemically deposited nanostructured Cd-doped SnS thin films: Structural and optical characterizations

This paper investigates the impact of Cd-doping on the structural and optical properties of electrochemically deposited SnS thin films. The synthesized samples underwent characterization through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, Fourier transform infrared spectrometer (FTIR), and UV–vis spectroscopy. According to the XRD analysis, the undoped SnS material exhibited a crystallite size (D) of 20 nm. However, as the Cd-doping concentration increased, the D initially increased and then decreased. The substitutional incorporation of Cd into SnS lattice was confirmed by XRD results. The inclusion of Cd-dopant into SnS lattice was validated through EDX analysis. SEM images demonstrated that appropriate Cd-doping into the SnS lattice can enhance crystalline nucleation, growth, and morphology. The absorption spectra of Cd 2–4 samples were higher than that of Cd 1, primary due to their increased film thickness and altered morphology type. The Cd 2 and Cd 3 samples exhibited higher R % values than Cd 1, associated with their superior crystalline quality. The deposited SnS samples exhibited a very high absorption coefficient (α) ranging from 10 to 25 × 104 cm−1, making them suitable as an absorber layer. The refractive index (n) value of the Cd 2 sample at wavelengths of 400–1000 nm surpassed all other samples due to its larger crystallite size. The Eg for undoped SnS was 1.57 eV, which initially decreased to 1.30 eV and then increased to 1.81 eV after Cd-doping. The Raman analysis confirmed the successful formation of the SnS phase in all samples. Based on the obtained results, it can be concluded that the Cd-dopant improves the structural and optical characterizations of SnS thin films.

The effect of the isoelectronic traps on the luminescence properties of Zn1-XCdXO thin films

In this report, Zn1-xCdxO ceramic thin films were deposited by the sol-gel method on an n-type Si (100) substrate. The structure, morphology, and luminescence properties of the thin films were studied. To elucidate the structure and the optical properties of Zn1-xCdxO thin films, our study focuses on the roles of changing the content of the doped Cd and the annealing temperature in Cd-doped ZnO thin films. The Cd doping behavior was investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL). The research concentrates on the effects of doping concentration, annealing temperature, and isoelectronic trapping on the crystallization quality and luminescence properties of the thin films. On the basis of the different electronegativity of the doping elements, Cd substitution for Zn forms isoelectronic traps, which influence the intensity of luminescence and change the luminous peaks. By raising the annealing temperature further, the intensity of each diffraction peak of ZnO is gradually increasing, improving the quantity of Cd entering the ZnO crystal lattice. The PL spectra display that the ZnO thin films only appear in yellow-green emission bands, which appear redshift through the incorporation of Cd. With the increase in Cd doping amount, the yellow light luminous center keeps moving in the low energy direction. When the Cd doping amount reaches 20 %, the luminescence intensity reaches its maximum, which holds great promise for its application in light devices.

First principal observation documenting the three-dimensional uptake of cadmium and spatial distribution of cadmium hydroxyapatite mineral in bone char

The 3-D matrix scale ion-exchange mechanism was explored for high-capacity cadmium (Cd) removal using bone chars (BC) chunks (1–2 mm) made at 500 °C (500BC) and 700 °C (700BC) in aqueous solutions. The Cd incorporation into the carbonated hydroxyapatite (CHAp) mineral of BC was examined using a set of synchrotron-based techniques. The Cd removal from solution and incorporation into mineral lattice were higher in 500BC than 700BC, and the diffusion depth was modulated by the initial Cd concentration and charring temperature. A higher carbonate level of BC, more pre-leached Ca sites, and external phosphorus input enhanced Cd removal. The 500BC showed a higher CO32-/PO43- ratio and specific surface area (SSA) than the 700BC, providing more vacant sites by dissolution of Ca2+. In situ observations revealed the refilling of sub-micron pore space in the mineral matrix because of Cd incorporation.The X-ray nanodiffraction (XND) analyses revealed that Cd was mainly removed from water by incorporation into the mineral lattice of 500BC via ion exchange, rather than surface sorption and precipitation, and the mineral phase was transformed from hydroxyapatite (HAp) to cadmium hydroxyapatite (Cd-HAp). The Rietveld's refinement of X-ray diffraction (XRD) data resolved up to 91% of the crystal displacement of Ca2+ by Cd2+. The specific phase and stoichiometry of the new Cd-HAp mineral was dependent on the level of ion exchange. This mechanistic study confirmed that 3-D ion exchange was the most important path for heavy metal removal from aqueous solution and immobilization in BC mineral matrix, and put forward a novel and sustainable remediation strategy for Cd removal in wastewater and soil clean-up.

Comparative study of Cd addition effects on precipitation in different aluminium alloys

This work demonstrates that Cd microadditions can enhance the precipitation of age-hardening precipitates in 2xxx and 6xxx alloys as well as the dispersoid precipitation in 3xxx alloys, but have a minimal effect on the precipitation in 7xxx alloys. Experimental and theoretical methods are utilised to investigate the nucleation and precipitation of precipitates/dispersoids in Cd-containing Al alloys. The enhanced precipitation of θ′ and α-dispersoids in 2xxx and 3xxx alloys, respectively, are proposed to result from the heterogeneous nucleation on earlier-formed Cd-rich nanoparticles, while the enhanced precipitation of β′′ in 6xxx alloys is attributed to the increased number density of effective Mg-Si co-clusters due to the Cd incorporation. This investigation provides theoretical basis for the design of precipitation-strengthened Al alloys via microalloying.

Partitioning and transformation behavior of Cd(II) and As(V) during As(V)-Cd(II)-Fe(III) coprecipitation: Effect of aging under aerobic conditions at pH 5 and 11 relevant to tailings and acid waste

Aerobic coprecipitation and subsequent aging of the As(V)-Cd(II)-Fe(III) system are ubiquitous processes in engineered settings, natural shallow water, surficial soils, and mine tailings. Herein, we have investigated the partitioning of As(V) and Cd(II) coupled with the solid evolution during As(V)-Cd(II)-Fe(III) coprecipitation and subsequent aging process under aerobic conditions at different pH (5 and 11) and Fe(III)/As(V) ratios (10 and 40) with various Cd(II) concentrations at 90 °C. X-ray diffraction and transmission electron microscopy results reveal that ferrihydrite is the dominant phase in the initial coprecipitates, regardless of pH and the coexisting As(V) and Cd(II). Low pH and high Fe(III)/As(V) ratios favor the transformation of initial ferrihydrite to hematite during the aging process, which can further promote the incorporation of ferrihydrite-bound As(V) and Cd(II) into stable hematite. Chemical analyses indicate that the partitioning fractions of adsorbed/extractable and solid-incorporated As(V) and Cd(II) are controlled by pH, Fe(III)/As(V) ratio, and aging time during ferrihydrite transformation. High Fe(III)/As(V) ratios facilitate the incorporation of the extractable Cd(II) into the aging intermediates, whereas the As(V) partitioning is less affected by the initial Cd(II) concentration. The crystallization rates of ferrihydrite at high Fe(III)/As(V) ratios or low pH are higher than those at low Fe(III)/As(V) ratios or high pH. Furthermore, increased Cd(II) concentrations significantly reduce the crystallization rates of the initial ferrihydrite. These findings have shed new light on the mobility and transformation behavior of toxic As(V) and Cd(II) in the As(V)-Cd(II)-Fe(III) coexisting environment under aerobic conditions and are useful for developing novel As(V)-Cd(II)-compound contaminant management strategies for metallurgical waste residues and water treatment sludges.

A comparative analysis of ZnCdTe and ZnCdTeO semiconductor alloys as competent materials for optoelectronic applications

In this paper, we report the comparative study of some parameters of II–VI ternary alloy ZnCdTe and II–VI–O dilute oxide ZnCdTeO. The purpose of this comparative study is to establish both the ternary and quaternary alloys as superior materials for optoelectronic and solar cell applications in which the quaternary materials show more superiority than the ternary material. In this purpose, we take the data from the experiments previously done and published in renowned journals and books. The parameters of these alloys are mainly being calculated using Vegard’s law and interpolation method of those collected data. It was certainly demonstrated that the incorporation of O atoms produces a high bandgap ([Formula: see text]) reduction in host ZnCdTe (Zn[Formula: see text]CdxTe) in comparison to the bandgap reduction in host ZnTe material with Cd incorporation. The bandgap of ZnCdTeO (Zn[Formula: see text]CdxTe[Formula: see text]Oy) was found to be reduced to 1.1357 at [Formula: see text] and the spin–orbit splitting energy ([Formula: see text]) value of ZnCdTeO was calculated to be 1.175[Formula: see text]eV for Cd concentration of 0.5[Formula: see text]mole and O concentration of 0.1[Formula: see text]mole both of which showed excellent results with the prospect of optoelectronic and solar cell applications. The constant rise in the spin–orbit curve signifies a very less internal carrier recombination which decreases the leakage current and augments the efficiency of solar cell. The lattice constants and strain calculation values give very good results and confirm the stability of the materials. Besides, the calculated band offsets values show that for ZnCdTeO, there is higher bandgap reduction than that of ZnCdTe. Moreover, ZnCdTeO covers a wide range of wavelength in the visible region starting from violet region at 393[Formula: see text]nm upto red region at 601[Formula: see text]nm. Both ZnCdTe and ZnCdTeO are found to have excellent applications in optoelectronic and solar cell devices though quaternary ZnCdTeO proves much supremacy over ternary ZnCdTe in all aspects of the properties.

Efficient catalytic decomposition of N2O over Cd-doped NiO in the presence of O2

A series of Cd-doped NiO catalysts were prepared and tested in the N2O catalytic decomposition reaction. In comparison with NiO, it was found that the Cd0.04Ni catalyst showed higher N2O decomposition activity in the temperature range of 300–450 °C with or without O2, and lower activation energy (77.8 kJ mol−1). The incorporation of Cd into the NiO lattice was verified by X-ray diffraction (XRD) patterns and Raman spectra. This led to the distortion of the original NiO structure and weakened the Ni-O bond. X-ray photoelectron spectroscopy (XPS) results showed that compared with NiO and CdO, Cd0.04Ni possessed higher Ni2+ and Cd(n+1)+ contents, which might have been induced by the electron transfer behavior between CdO and NiO. A possible mechanism for active site regeneration and O2 desorption over Cd0.04Ni was proposed. The Cd0.04Ni catalyst also exhibited good resistance to NO and O2.

The fate of Cd during the replacement of Cd-bearing calcite by calcium phosphate minerals

Carbonate-bound speciation is a critical sink of potentially toxic elements (PTEs) like cadmium (Cd) in soil and sediment. In a phosphate-rich environment, carbonate minerals could be replaced by phosphate minerals such as dicalcium phosphate dihydrate (DCPD, also known as brushite), octacalcium phosphate (OCP), and hydroxylapatite (HAP). Currently, it is unclear the migration and fate of PTEs during the replacement of PTEs-bearing carbonates by HAP and related intermediate minerals. Therefore, we synthesized Cd-bearing calcite by the coprecipitation method and converted it to DCPD, OCP, and HAP to investigate the redistribution and fate of Cd. The results showed that Cd incorporation in calcite significantly inhibited their replacement by DCPD and OCP, respectively. 1.26% of Cd in calcite was released into the solution when DCPD replaced calcite, and subsequently, most of the released Cd was recaptured by OCP. Significantly, the released Cd was below 0.05‰ when all the solid converted to HAP. These results suggested that with the application of phosphate fertilizer in alkaline soil, the secondary calcium phosphate minerals could control the environmental behavior of Cd.

Trace element compositions of galena in an MVT deposit from the Sichuan-Yunnan-Guizhou metallogenic province, SW China: Constraints from LA-ICP-MS spot analysis and elemental mapping

Galena trace element signatures and element partitioning between associated sulfides are poorly constrained, especially in Mississippi Valley-type (MVT) Zn-Pb deposits. This study reports laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analysis data of different stages of galena as well as elemental mapping results of typical sulfide assemblages in the Daliangzi Zn-Pb deposit, one of the largest MVT deposits in the Sichuan-Yunnan-Guizhou (SYG) metallogenic province, SW China. The galena is generally enriched in Sb and Ag, with minor Cd, Cu, and As, but depleted in Bi. Antimony was generally incorporated into galena lattice via Sb3+ + Ag+ ↔ 2Pb2+, and the substitution of 2Sb3+ + □ (vacancy) ↔ 3Pb2+ also occurred at high Sb content level (>1200 ppm). Direct substitution is the main way for Cd incorporation, while Cu and As may exist via coupled substitution. Micro-inclusions also play important roles in the incorporation of Sb, As, and Cu in some cases. The elemental distribution maps show that Sb, Ag, and Tl are dominantly incorporated into galena, while Cd, Fe, Mn, Cu, As, Ga, and Ge are primarily concentrated in sphalerite. However, when present tennantite-tetrahedrite will become the preferential host phase of Sb, Ag, Cu, and As. This elemental partitioning verifies that the preferential host sulfide for trace elements is controlled by intrinsic factors (e.g., oxidation state and ion radius) rather than external factors (e.g., metal sources, pressure, temperature, and redox conditions). External factors, such as temperature, may be vital for the partitioning of a given element (e.g., Cd) between priority and subordinate hosts. Additionally, the galena trace element characteristics are found to vary significantly with the ore genetic types, which appears to imply the applicability of galena geochemistry in the ore type discrimination.

Complex impedance, dielectric constant, electric modulus, and conductivity analysis of Cd doped ZnO nanostructures at high temperatures

Cd-doped zinc oxide (ZnO) nanostructures with a standard formulation Z n ( 1 − x ) C d x O (x = 0%, 3%, 6%, and 10%) were fabricated by a co-precipitation technique. The structural and morphological analyses were studied using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The Study of x-ray diffraction investigation indorses the existence of a wurtzite structure with a P 6 3 mc space group in all the samples. Impedance spectroscopy, dielectric measurements, and electrical conductivity at different temperatures of 300–460 K with a frequency range from 20 Hz to 2 MHz were performed using an impedance LCR meter. The complex impedance spectrum ( Z ´ ´ v s Z ´ ) for all samples were fitted with a parallel bulk resistance ( R b ) and capacitance ( C b ) combination circuit. The results of the dielectric measurements indicate that the parameters ε ´ , ε ´ ´ , and tanδ are reduced with the increasing frequency and increase with temperature. The complex electric modulus plots ( M ´ , M ´ ´ ) with frequency have explained the non-Debye type of relaxations mechanism due to interfacial and depolarization. The variation of ac ( σ a c ) conductivity with Cd concentration indicates a gradual increase because the impedance values with Cd-doped decrease. It is confirmed that the activation energies decrease with the doping of Cd concentration. Moreover, ac conductivity was then investigated by Jonscher's power law. Finally, the temperature-dependent exponent s fitted well with the correlated barrier hopping (CHB) conduction. • Cd-doped ZnO nanoparticles with different concentrations were fabricated by the co-precipitation method. • XRD studies revealed the incorporation of Cd into ZnO lattice. • Nyquist plots suggested the negative temperature coefficient of resistance behaviour. • The influence of Cd-doping on the electrical behaviour of ZnO was reported.

Defect Engineering for Efficient Cu2ZnSnS4 Solar Cells via Moisture‐Assisted Post‐Deposition Annealing

AbstractSulfide kesterite Cu2ZnSnS4 (CZTS) solar cells, containing earth‐abundant and environmentally benign constituents, are regarded as promising candidates for thin‐film photovoltaic technologies. CZTS device performance, however, is currently limited by severe nonradiative recombination caused by abundant deep‐level defects. Herein, an effective defect engineering approach for high bandgap CZTS solar cells using a newly introduced moisture‐assisted post‐deposition annealing treatment is reported. This treatment modifies the local chemical composition within the heterojunction and CZTS grain boundaries and enhances the incorporation of Cd within the CZTS layer during CdS deposition. Cd not only accumulates at the grain boundaries, but it also presents in grain interiors where it occupies Cu lattice sites. The overall modification of the local chemical environment suppresses deep level defects and activates relatively shallow acceptor CuZn antisites and Cu vacancies, giving rise to remarkably improved device performance. This work opens a new direction for defect engineering of kesterite materials, which may also be applicable to other thin film semiconductors.

Rapid synthesis and theoretical analysis of CH3NH3Pb1-xCdxBr3 perovskite quantum dots for backlight LEDs: A step towards enhanced stability

Colloidal CH 3 NH 3 Pb 1-x Cd x Br 3 perovskite quantum dots (PQDs) have shown potential for the development of new solar cell and light-emitting diodes due to their enhanced optoelectronic properties. Here, we have reported a potential ligand-assisted room temperature rapid synthesis method for partial cation exchange in colloidal CH 3 NH 3 Pb 1-x Cd x Br 3 PQDs, where exchange of Pb 2+ takes place for various similar cations, which result in doped CH 3 NH 3 Pb 1-x Cd x Br 3 maintaining its original PQDs shape and structure. There was lattice contraction was observed into the Cd doped perovskite. A blue shift in optical spectra was observed due to partial Pb 2+ exchange in place of Cd 2+ , however high photoluminescence quantum yields, sharp absorption features, and narrow emission of the original CH 3 NH 3 Pb 1-x Cd x Br 3 PQDs remained the nearly same. XPS study confirmed the incorporation of Cd 2+ ions in the place of Pb 2+ . Theoretical analysis was also performed to study the different structural and optical aspects of the doped perovskite samples. Furthermore, a prototype perovskite QDs based white LEDs was fabricated that have a higher color gamut. The current work presents a new possibility to develop stable PQDs with enhancing optoelectronic properties. • Rapid perovskite quantum dot synthesis within 30 min. • Cd incorporation enhanced the stability and performance of PQDs. • Theoretical and experimental investigation of Cd: MAPbBr 3 PQDs. • High color purity, PLQY, and intense PQDs enhanced thin films. • Backlight LEDs with high color gamut.

Structural and Optoelectronic Characterization of Synthesized Undoped CZTS and Cd-doped CZTS Thin Films

Copper zinc tin sulfide (CZTS) thin films with different doping ratios of Cadmium (Cd) were successfully fabricated using the sol-gel method by dip-coating technique. The surface morphology, the crystal structure properties as well the optical properties of undoped CZTS thin film and Cd- doped CZTS thin films were investigated using scanning electron microscopy (SEM), x-ray diffraction (XRD), and UV-Vis spectrophotometer. SEM micrographs demonstrated that the size and morphology of the particles improve due to increasing the Cd concentration in CZTS thin films. In addition, the XRD patterns exhibited the crystalline nature for CZTS thin films with kesterite crystal structure and showed improvement in some crystal structure properties such as crystal size and volume of unit cell with the incorporation of Cd into CZTS thin films. Moreover, optical bandgap energy

Transcriptomics and transmission ultrastructural examination reveals the nephrotoxicity of cadmium in laying hens.

The objective of this study was to reveal the effects of cadmium (Cd) on ultrastructural changes, oxidative stress, and transcriptome expression in the kidneys of laying hens. Seventy-two healthy Hy-Line brown laying hens at 41weeks old were randomly allocated to four treatment groups with six replicates. The control group received a basal diet without additional Cd incorporation, and the other three treatment groups received diets supplemented with 15, 30, or 60mg Cd /kg of feed. After 6weeks of exposure, the results show that administration of 60mg/kg Cd significantly reduced (P < 0.05) eggshell thickness. With an increase in the Cd concentration in feed, the concentrations of renal Zn and Fe also had changed. Renal histopathology and ultrastructure also showed aggravated damage to glomeruli and renal tubules and the deformation of nuclei and mitochondria in all Cd treatment groups. With an increase in Cd in feed, the activity of glutathione peroxide (GPX) and catalase (CAT) was significantly reduced (P < 0.05), while the activity of total antioxidant capacity (T -AOC) was decreased (P < 0.05) only in the 60mg/kg Cd group. RNA-seq analysis revealed that 410 genes displayed differential expression (≥ 1.5-fold) in the 60mg/kg supplementation group, compared to the control group. GO and KEGG pathway analysis results showed that Cd affected many genes involved in mitochondria and ion transport. In conclusion, this study elaborates the mechanisms underlying renal toxicity caused by Cd, which might provide target candidate genes for alleviating Cd poisoning in laying hens.

Enhanced blue-shift of the optical band gap in Cd-doped ZnO nanoparticles

Nanoparticles of ZnO prepared through an inexpensive chemical route were doped with controlled quantities of Cd in wt%. The samples were found to be polycrystalline in nature which is confirmed by XRD. They also matched with their respective Powder Diffraction Data files. Morphological and compositional studies were conducted using FESEM to confirm the grain size, texture and doping. Frequency dependent impedance spectroscopy demonstrated that the ac conductivity increases with frequency but decreases with increasing cadmium concentration. Analysis on the samples shows that the absorbance does not significantly change with doping which is further established from the bandgap calculations using the reflectance graphs. Contrary to the common observation, the optical band gap of Cd-doped ZnO is blue-shifted from 3.47 to 3.56 eV as the doping weight percentage is increased to 3 %. This can also confirmed in FTIR analysis as signatures of new peaks in doped samples are obtained. From FTIR spectra it has been observed that the vibrational modes of the doped samples are around 473 cm-1and 475 cm−1. It also confirms a new peak which is due to defects created by incorporation of Cd in the host lattice.

Characterization of landfill deposited sediment from dredging process during different maturation stages

A long-term monitoring of deposited sediment in the environment is considered in order to examine the mechanism of incorporation of Cu and Cd into mineral fractions and to investigate their bioavailability during landfill maturation. Using the sequential extraction technique (Community Bureau of Reference, BCR), the dominant presence of Cu and Cd in the oxidation and residual fraction was determined, which suggests a low risk of bioavailability of these metals in the environment. The maturation of the deposited sediment indicates that the Cu and Cd content decreases over time in the exchangeable fraction and increases in the oxidation fraction. X-ray techniques XRF and EDS indicated a prevalence of silicates in the tested samples, which suggests the possibility of presence of silicate compounds that can bind metals and thus convert them into less mobile forms in the sediment. By imaging the samples with a scanning electron microscope SEM, the formation of heterogeneous structures over time was determined, which confirms the formation of new minerals and the potential possibility of incorporating copper and cadmium in them. In order to determine the mineral forms and dominant compounds in the examined sediment samples, X-ray diffraction analysis was applied, and the transformation pathways were explained.

Improvement of hetero-interface engineering by partial substitution of Zn in Cu2ZnSnS4-based solar cells

This paper investigates the effects of partial substitution of zinc (Zn) in pure sulfide kesterite (Cu2ZnSnS4) by cadmium (Cd) and manganese (Mn) incorporation. Thin films of Cu2ZnSnS4 (CZTS), Cu2Zn1–xCdxSnS4 (CCZTS) and Cu2Zn1–xMnxSnS4(CMZTS) were produced chemically. A comparison of pure CZTS with CCZTS and CMZTS was performed to study the influence of Cd and Mn incorporation on the morphology, structure, optical and electronic properties of the films. The results show an improvement of the morphology and an adjustment of the band gap and valence band position by partial substitution of Zn with Cd and Mn. In addition, for the first time, the band alignment at the absorber/buffer hetero-interface is studied with partial Zn substitution. Band alignments at the absorber/buffer hetero-interface were estimated by XPS and UV/Visible measurements. The results show a cliff-like CBO for CZTS/CdS heterojunction, a spike-like CBO for CCZTS/CdS and a near flat-band CBO for CMZTS/CdS heterojunction.