Potential Of Cadmium Research Articles

Cadmium‐Doping Slows Trap Emptying in Ambient‐Air Blade‐Coated Formamidinium Lead Iodide Perovskite Solar Cells

AbstractFormamidinium lead iodide (FAPbI3) in its α‐phase is among the most desirable perovskite compositions for solar cells. However, because of its transition into the yellow δ‐phase at room temperature, it is a challenge to process it in ambient air by scalable fabrication methods. Here the introduction of a trace amount of cadmium (in the form of CdI2) to FAPbI3 is reported and found that it enhances the stability of the perovskite's black α‐phase polymorph, inhibits non‐radiative recombination events, leads to pin‐hole free compact surface morphology, and improves band energy alignment. The 0.6% Cd‐doped FAPbI3 solar cells show a champion efficiency of 22.7% for 0.049 cm2 and 16.4% for cm2‐scale pixels, which, to the best of the knowledge, are among the highest for air‐ambient fully blade‐coated pure FAPbI3 solar cells with an n‐i‐p architecture. Transient absorption microscopy measurements reveal that Cd doping reduces the number of trapped charges and increases their lifetimes, promoting charge accumulation and a higher photovoltage. The study sheds light on the potential of cadmium as a homovalent dopant for the stabilization and performance enhancement of FAPbI3 performance solar cells.

Modified embedded-atom method potential for cadmium

The second nearest-neighbor modified embedded atom method (2NN MEAM) is a semi-empirical simulation technique designed to calculate materials properties of metallic and covalent solids. It is a strong candidate for calculation of site occupation, defect association, and diffusion mechanisms in intermetallic compounds, which would provide a tool for interpreting experimental results and for predicting new, interesting measurements to perform. Potentials for 39 elements can be found in the literature, but cadmium, an important element for perturbed angular correlation spectroscopy (PAC), is absent. The purpose of this work was to develop a 2NN-MEAM potential for cadmium. Empirical parameters were determined through optimization of the potential’s ability to reproduce known physical properties of pure cadmium including cohesive energy, lattice parameters, elastic constants, structural enthalpy differences, surface enthalpy, vacancy formation energy, thermal expansion, and specific heat. Prospects for using this new potential with 2NN MEAM potentials for other elements to help interpret previous PAC studies of cadmium diffusion in intermetallic compounds will be discussed.

Study on Neuroendocrine Disrupting Potential of Cadmium in Rats and Evaluation of Role of Green Tea

Study on Neuroendocrine Disrupting Potential of Cadmium in Rats and Evaluation of Role of Green Tea

EDTA Supported Phytoextraction of Cd from Contaminated Soil by Four Different Ornamental Plant Species

ABSTRACTIn this study, some ornamental plant species such as Althaea rosea Cavan, Lonicera japonica Thunb, Salvia virgata Jacq. (Lamiaceae), and Dahlia hybrida growing in the natural vegetation of Black Sea Region (Turkey) were investigated for their phytoextraction potential of cadmium (Cd) from artificially contaminated soil of 10, 25, 50, and 100 mg/kg concentration under pot conditions. Effect of ethylenediaminetetracetic acid (EDTA) on this removal has also been studied. To evaluate the removal efficiency of the studied plants, the bioconcentration factor (BCF) and translocation factor (TF) values were also calculated. Higher BCF and TF values obtained from stems and leaves of A. rosea Cavan, L. japonica Thunb, and S. virgata Jacq. (Lamiaceae) show that those plants might be cultivated and used as hyperaccumulators in the removal of Cd from the contaminated soils. EDTA enhanced the Cd phytoextraction in plants; however, at the same time it resulted in a slight decrease in the dry matter.

Cadmium Removal Potential from Contaminated Soil by Tagetes erecta L. and Panicum maximum: Influence of Soil pH

ABSTRACTThe potential for cadmium (Cd) removal from contaminated soil by two species—marigold (Tagetes erecta L.) and Guinea grass (Panicum maximum)—was investigated in pot culture experiments in a greenhouse in triplicate. The concentration of Cd was varied from 50 to 200 mg kg−1 and the pH was varied from 5.0 to 7.5 to investigate the effect of pH on Cd uptake. The results showed that total biomass of Guinea grass was around nine and seven times higher than that of marigold for Cd treatments of 50 and 100 mg kg−1 at pH 5.0, respectively. Total cadmium uptake at Cd treatments of 50 and 100 mg kg−1 at pH 5.0 by Guinea grass was 19.28 ± 3.14 and 36.06 ± 4.28 mg kg−1, respectively, and for marigold was 15.66 ± 4.17 and 20.38 ± 3.24 mg kg−1, respectively. The total Cd uptake by Guinea grass was 1.23 and 1.77 higher than that of marigold at Cd treatments of 50 and 100 mg kg−1, respectively, at pH 5.0 due to higher biomass. The maximum Cd uptake by marigold and Guinea grass occurred at pH 5.0 at Cd treatment of 100 mg kg−1. The results clearly show that the two species behave very differently for Cd uptake. Guinea grass is easy to grow, drought tolerant and, due to its higher biomass, it can be used for remediation of Cd-contaminated soil.

Adsorption and Desorption Potential of Cadmium Using Green Algae: Equilibrium and Kinetic Studies

Microalgae has a diversity of species found in freshwater bodies but only a few have been explored for their biosorption potential as compared to macro algae (sea weed). Equilibrium and kinetic experiments were used to estimate sorption capacity and rate of reaction respectively. Chloroidium saccharophilum had the highest sorption capacity (qmax) of 200 mg/g and lower affinity (b) of 0.0095 L/g for removal of Cd. However, Stichococcus bacillaris was the best adsorbent for Cd as it had both a higher qmaxand higher b of 125 and 0.049 L/g. The Langmuir and Pseudo-second order models performed better than the Freundlich and First-order models with a regression coefficient (R2) > 0.9. Adsorption and desorption efficiency was achieved highest for Stichococcus bacillaris at 95.8% and 73.49% respectively.

Evaluation of the Potential of Cadmium and Dyes Removal by Chitosan Obtained from Zygomycetes

Background: Treatment process for heavy metal and dye removal is a worrying factor in environmental health because it can contribute to the formation of new contaminants. Objectives: To obtain and use chitosan from Zygomycetes for removal process of heavy metal (cadmium) and azodyes (Reactive Black and Remazol Red). Methods: Chitosan was obtained by Rhizopus arrhizus UCP 402 and Mucor javanicus UCP 69 following the described method of Synowiecki and Al-Khateeb (1997) and submitted to removal tests for 18 h, with different concentrations of Cadmium (0.5-4 mM), Reactive Black (B) and Remazol Red (1-1000 mg/L) in orbital shaker under 150 rpm at 28°C. Then, the samples were submitted to spectrophotometry and chitosan exposed to the contaminants were submitted to electronic microscopy analysis. Results: The efficiency of cadmium removal by Rhizopus arrhizus chitosan showed data of 92% (0.5 mM), 92.8% (1 mM), 75.9% (2 mM), 54% (3 mM) and 54.5% (4 mM) at pH 6.0. The efficiency of dyes removal by Mucor javanicus chitosan was about 100% (1 mg/L), 100% (10 mg/L), 100% (50 mg/L), 98% (100 mg/L), 55% (1000 mg/L) for Reactive Black (B) and 100% (1 mg/L), 100% (10 mg/L), 100% (50 mg/L), 98% (100 mg/L), 59% (1000 mg/L) for Remazol Red. Conclusion: Chitosan obtained by the strains was capable of removing cadmium and the reactive dyes: Reactive Black (B) and Remazol Red in all conditions tested.

Overexpression of bacterial γ-glutamylcysteine synthetase mediates changes in cadmium influx, allocation and detoxification in poplar.

Overexpression of bacterial γ-glutamylcysteine synthetase in the cytosol of Populus tremula × P. alba produces higher glutathione (GSH) concentrations in leaves, thereby indicating the potential for cadmium (Cd) phytoremediation. However, the net Cd(2+) influx in association with H(+) /Ca(2+) , Cd tolerance, and the underlying molecular and physiological mechanisms are uncharacterized in these poplars. We assessed net Cd(2+) influx, Cd tolerance and the transcriptional regulation of several genes involved in Cd(2+) transport and detoxification in wild-type and transgenic poplars. Poplars exhibited highest net Cd(2+) influxes into roots at pH 5.5 and 0.1 mM Ca(2+) . Transgenics had higher Cd(2+) uptake rates and elevated transcript levels of several genes involved in Cd(2+) transport and detoxification compared with wild-type poplars. Transgenics exhibited greater Cd accumulation in the aerial parts than wild-type plants in response to Cd(2+) exposure. Moreover, transgenic poplars had lower concentrations of O2 ˙(-) and H2 O2 ; higher concentrations of total thiols, GSH and oxidized GSH in roots and/or leaves; and stimulated foliar GSH reductase activity compared with wild-type plants. These results indicate that transgenics are more tolerant of 100 μM Cd(2+) than wild-type plants, probably due to the GSH-mediated induction of the transcription of genes involved in Cd(2+) transport and detoxification.

Incorporation of Cadmium into Clinker during the Co-Processing of Waste with Cement Kiln

The incorporation of cadmium into clinker during the co-processing of waste with cement kiln was investigated. Cadmium contained reagent was added to the cement raw meal to produce clinkers after clinkerization process. XRD analysis and SEM-EDS analysis were employed to indentify the major mineral phase of clinker and the cadmium contained mineral phase. Leaching test, sequential extraction procedures were employed to evaluate the leaching potential of cadmium in clinker. The results show the stabilization rate of cadmium during the clinkerization process is low. The incorporation ratio of cadmium in C2S is 0.32%~1.14%, the incorporation ability of cadmium in C2S is higher than C3S. The major mineral phases of clinker with the incorporation of cadmium were CH, C3S and C2S. The average leaching concentration of cadmium of clinker was 1.4 μg/L, which was higher than the blank samples. BCR Sequential extraction procedures analysis of the clinkers show exchangeable, water and acid-soluble fraction and residual fraction were very small, while the reducible phase of cadmium was up to 95.13%.

Cadmium uptake by the green alga <i>Chlorella emersonii</i>

Investigations were carried out on the uptake of the heavy metal cadmium (Cd) by the green alga Chlorella emersonii with the aid of an ion selective electrode. Cadmium uptake by Chlorella was very rapid with 70% of total uptake occurring during the first 10 seconds. Uptake of cadmium by Chlorella showed a direct relationship to the amount of metal present, suggesting ‘equilibrium conditions' being responsible for the amount of metal removed from solution rather than just number of binding sites available. Absence of metabolic involvement in the uptake process was observed as there was no difference on final uptake of cadmium whether cells were alive or dead. It is concluded that living or dead Chlorella biomass has a high biosorption potential for cadmium, and its rapid uptake makes it an attractive candidate in the current proposed application of biosorption technology for industrial waste treatment. KEY WORDS: Cadmium uptake, alga Chlorella, industrial waste treatment, biosorption technology, cell biomass. Global Jnl Pure & Applied Sciences Vol.10(2) 2004: 257-262

Differential responses of Australian wheat cultivars to cadmium concentration in wheat grain

Cadmium concentration in grain was studied for wheat cultivars grown nationally in the Interstate Wheat Variety (IWV) experiments (1988 and 1989) and cultivars grown in the Western Australian (WA) experiments (1990-1992). These experiments covered a range of differing soil and environmental conditions. The adaptation of these cultivars to changes in cadmium potential at a site was determined. Significant cultivar effects were identified, but these were less significant than the site effects. The Cd concentrations in grain exceeded the current Australian maximum permitted concentration (MPC) of 0.05 mg kg-1 at one site in the IWV experiments while the concentration exceeded the MPC at a larger proportion of sites in the WA experiments. Several trends in cultivar accumulation of Cd in grain were evident. Reeves and Kulin were found to have the highest Cd concentration at a number of sites for several years in both the IWV and WA experiments. The similar pedigrees of these two cultivars suggest that while wheat breeders were selecting for certain traits during the breeding selection process, they were inadvertently selecting for the ability to accumulate Cd. In the 1992 WA cultivar experiments, generally Aroona had the highest Cd concentration in grain. Aroona has different pedigree to Reeves and Kulin. Several of the cultivars that were low Cd accumulators also had similar pedigrees. This indicates that there is potential for selecting lines that are low Cd accumulators to be grown in areas where Cd accumulation in grain is a problem.

In vitro effects of cadmium, zinc and lead on calmodulin-dependent actions inOncorhynchus mykiss, Mytilus sp., andChlamydomonas reinhardtii

The potential of cadmium, zinc, and lead to interact with calmodulin (CaM) was investigated by examiningin vitro CaM-dependent protein phosphorylation in tissues from rainbow trout (Oncorhynchus mykiss) and sea mussel (Mytilus sp.) and CaM-dependent phosphodiesterase (PDE) activation by algal (Chlamydomonas reinhardtii) extracts. Cadmium, zinc, and lead proved effective in sustaining CaM-dependent protein phosphorylation in systems containing calcium, whereas only lead was capable of CaM activation in systems depleted of calcium. Cadmium lead to a small activation of CaM-dependent PDE activity by algal extracts, corresponding to ∼25% of that induced by calcium. Cadmium-induced PDE-activation could be attributed to the residual calcium present in the extract. The results indicate that metal-induced CaM activation is primarily mediated in the case of cadmium and zinc by resulting calcium/CaM complexes and in the case of lead by lead/CaM complexes.