Cadmium In Solution Research Articles

A Study on Vertical Transport of Zinc and Cadmium in Some Alluvial Soils of West Bengal, India

A study on vertical transport of aqueous Zinc (Zn) and Cadmium (Cd) in soil system has been carried out at the soil science laboratory of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India. Aqueous solution of Zn and Cd are vertically leached down through the soils collected from Pundibari (Agroecological zone 15.1, climate: sub-humid) and Malda (Agroecoloogical zone 15.1, climate: sub-tropical humid) in a double-chambered glass column. The similar procedure has been repeated for the soils collected from both places separately mixing with farm yard manure. The formation of the Breakthrough Curves (BTCs) for Zinc in Pundibari soils at 0.97 pore volume (Pv), while at 0.85 (Pv) in soil treated with FYM. The BTCs for Malda was at 0.49 (Pv), and that in soils treated with FYM was at 0.36 (Pv), while the BTCs for Cadmium at 0.96 (Pv) for Pundibari soil and that at 0.83 (Pv) for soil treated with FYM were observed. The order of time of dilution in both the cases using Zinc and Cadmium solution in the leachate followed as: Malda (Soil+FYM) > Pundibari (Soil+FYM) > Malda (Soil) > Pundibari (Soil) respectively. The capacity of soil mixed with FYM was found to be an effective sink for metals like Zinc and Cadmium and thus moderating the toxic effects of Zn and Cd in soils.

Eco-efficient cadmium(II) removal from water using alcohol distillate waste: A study of life cycle assessment

This study investigates the use of exhausted grape pomace, a byproduct of alcohol distillation, as a biosorbent for use in removing cadmium(II) from wastewater, in line with principles of a circular economy. Cadmium in water presents substantial environmental and health risks. Conventional treatment methods are often costly and environmentally damaging. This research proposes the use of agro-industrial waste as a sustainable and economical alternative. The biosorption process was optimized with Box-Behnken Design and Response Surface Methodology an adjusting factor such as the cadmium concentration, biosorbent dosage, solution pH, and stirring time. The findings reveal that cadmium(II) removal improves with increased stirring time, reaching a 99 % removal rate at 134 min. Optimal conditions include a biosorbent dosage of 2.4 g, pH 4.7, and initial cadmium concentration of 55 mg/L. The biosorption process also increased the solution’s pH, ensuring compliance with wastewater discharge regulations. Two optimization scenarios were evaluated. One achieved a 99.99 % removal efficiency for maximum cadmium reduction, The second focused on cost-effectiveness and environmental impact, attaining 77.35 % removal. This scenario highlights reduced the environmental impact, thereby supporting the role of exhausted grape pomace as a viable and eco-friendly option for wastewater treatment. Life cycle analysis, using CML-IA mid-point and ReCiPe end-point indicators, further underscores the sustainability of this approach, affirming the potential of grape pomace to contribute to circular, resource-efficient wastewater management.

Reduction in Olfactory Discomfort in Inhabited Premises from Areas with Mofettas through Cellulosic Derivative-Polypropylene Hollow Fiber Composite Membranes.

Hydrogen sulfide is present in active or extinct volcanic areas (mofettas). The habitable premises in these areas are affected by the presence of hydrogen sulfide, which, even in low concentrations, gives off a bad to unbearable smell. If the living spaces considered are closed enclosures, then a system can be designed to reduce the concentration of hydrogen sulfide. This paper presents a membrane-based way to reduce the hydrogen sulfide concentration to acceptable limits using a cellulosic derivative-propylene hollow fiber-based composite membrane module. The cellulosic derivatives considered were: carboxymethyl-cellulose (NaCMC), P1; cellulose acetate (CA), P2; methyl 2-hydroxyethyl-cellulose (MHEC), P3; and hydroxyethyl-cellulose (HEC), P4. In the permeation module, hydrogen sulfide is captured with a solution of cadmium that forms cadmium sulfide, usable as a luminescent substance. The composite membranes were characterized by SEM, EDAX, FTIR, FTIR 2D maps, thermal analysis (TG and DSC), and from the perspective of hydrogen sulfide air removal performance. To determine the process performances, the variables were as follows: the nature of the cellulosic derivative-polypropylene hollow fiber composite membrane, the concentration of hydrogen sulfide in the polluted air, the flow rate of polluted air, and the pH of the cadmium nitrate solution. The pertraction efficiency was highest for the sodium carboxymethyl-cellulose (NaCMC)-polypropylene hollow fiber membrane, with a hydrogen sulfide concentration in the polluted air of 20 ppm, a polluted air flow rate (QH2S) of 50 L/min, and a pH of 2 and 4. The hydrogen sulfide flux rates, for membrane P1, fall between 0.25 × 10-7 mol·m2·s-1 for the values of QH2S = 150 L/min, CH2S = 20 ppm, and pH = 2 and 0.67 × 10-7 mol·m-2·s-1 for the values of QH2S = 50 L/min, CH2S = 60 ppm, and pH = 2. The paper proposes a simple air purification system containing hydrogen sulfide, using a module with composite cellulosic derivative-polypropylene hollow fiber membranes.

Geotechnical performance of black cotton clay in the presence of lead and cadmium solutions for geoenvironmental application

ABSTRACT The usage of bentonites and sand–bentonite mixtures as liners has become prevalent due to their low permeability. However, these materials are scarce and prohibitively expensive in India. Black cotton clay (BCC) was chosen as an alternative clay liner for this research due to its abundance in India and its mineralogical composition. Since heavy metals accumulation in municipal landfills is a rising issue with devastating effects on the ecosystem and human health, in this investigation, two heavy metals (lead and cadmium) were intended as permeants at three different concentrations (100, 500, and 1000 ppm) to imitate the impact of heavy metal leachate on BCC. The essential index and engineering properties of BCC were evaluated and compared under these two permeants from the liner perspective. Experimental results revealed that the free swell index, Atterberg limits, swelling and swelling pressures were reduced for a rise in concentration irrespective of metal type. However, this reduction was more with cadmium permeants compared to lead. The measured swelling data was compared with predicted swelling data using a rectangular hyperbola model, and a good correlation was achieved. The hydraulic conductivity (k) and unconfined compressive strength (UCS) values were increased for a rise in concentration with both metal permeants. At 1000 ppm concentration, the k values were raised to 3.5 and 6.7 times, and UCS values were enhanced by 8.3 and 5.5% for lead and cadmium permeants, respectively. At high concentrations, field emission scanning electron microscopy (FESEM) results showed the formation of huge voids and aggregation.

Adsorption of Cd2+ by Lactobacillus plantarum Immobilized on Distiller's Grains Biochar: Mechanism and Action.

Immobilized microbial technology has recently emerged as a prominent research focus for the remediation of heavy metal pollution because of its superior treatment efficiency, ease of operation, environmental friendliness, and cost-effectiveness. This study investigated the adsorption characteristics and mechanisms of Cd2+ solutions by Lactobacillus plantarum adsorbed immobilized on distiller's grains biochar (XIM) and Lactobacillus plantarum-encapsulated immobilized on distiller's grains biochar (BIM). The findings reveal that the maximum adsorption capacity and efficiency were achieved at a pH solution of 6.0. Specifically, at an adsorption equilibrium concentration of cadmium at 60 mg/L, XIM and BIM had adsorption capacities of 8.40 ± 0.30 mg/g and 12.23 ± 0.05 mg/g, respectively. BIM demonstrated noticeably greater adsorption capacities than XIM at various cadmium solution concentrations. A combination of isothermal adsorption modeling, kinetic modeling, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffractometer (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses showed that cadmium adsorption by XIM primarily involved physical adsorption and pore retention. In contrast, the adsorption mechanism of BIM was mainly attributed to the formation of Cd(CN)2 crystals.

Associations of Cadmium Exposure with Peripheral Blood Cell Subtype Counts and Indices in Cadmium-Poisoned Mice.

This research was designed to investigate the effects of cadmium on blood cell injury in cadmium-poisoned mice. Twenty mice were randomly divided into two groups: control group and model group. The control group was intraperitoneally injected with normal saline every day and the model group was intraperitoneally injected with 1.4mg/kg cadmium solution every day. The experimental period was 28days. The blood of the mice was collected for detection and hematological analysis. The results demonstrated that cadmium increased the number of white blood cells and the number of neutrophils in mice. Cadmium reduced the number of eosinophils, the number of basophils, the number of monocytes, the amount of lymphocytes, the number of red blood cells, the hemoglobin concentration, mean corpusular volume, mean corpusular hemoglobin, mean corpusular hemoglobin concentration, and the number of platelets in mice. In summary, cadmium caused some damage to white blood cells, red blood cells, and platelets in mice, but the direction of damage to different cells was inconsistent. The possible reason for this result is that cadmium damages the generation of blood cells, and the body takes corresponding defense measures.

Arsenate and cadmium ions removal from multicomponent solutions of ionic polymers using mesoporous activated biocarbons

Activated biocarbons (AC) obtained in the process of simultaneous pyrolysis and activation of lemon balm (LB) and mint (MT) herbs with H3PO4 were used to purify aqueous solutions of cadmium, arsenate, polyethylenimine (PEI) and poly(acrylic acid) (PAA). The metals show high toxicity in the whole range of their concentrations, whereas the polymers are cytotoxic at high concentrations.The efficiency of As(V) removal from an aqueous solution depends on the pH value, while the Cd(II) adsorption on the activated biocarbons surface is independent on this parameter. The maximum adsorbed amounts are 135.8 mg/g for Cd(II) and 109.6 mg/g for As(V), respectively. The removal of metals ions and polymers from binary systems is lower in comparison to the one-component solutions. This is a consequence of the formation of polymer-metal complexes, that tend to remain in the solution. Additionally, the surface charge density, zeta potential, the size of activated biocarbons aggregates in the aqueous suspensions and the influence of toxic metal ions on the determination of the concentration of polymers in water samples was investigated. The obtained results proved that the PEI concentration can be effectively determined in the presence of metal ions, whereas the procedure of PAA determination requires additional validation.

Efficient and eco-friendly cadmium ion recycling: Ultrasonic enhancement of aluminum powder replacement for low-temperature industrial applications

Replacing cadmium ions in cadmium-containing solutions with aluminum powder is beneficial for cadmium resource recycling and environmental protection. However, the conventional aluminum powder replacement method requires harsh temperatures and prolonged conditions. In this study, the effect and mechanism of ultrasound on the replacement of cadmium with aluminum powder were investigated at low temperatures. Ultrasound has been proven to promote the etching of alumina films through the use of TEM and XPS, providing mechanistic support for the superiority of the new process. A degree of Cd replacement as high as 95.08 % is achieved at a low temperature (60 ℃) and in a short time (20 min) when using ultrasonicated aluminum powder replacement, which is 42.17 % higher than that of conventional aluminum powder. Compared with conventional aluminum powder replacement conditions with the same effect, the introduction of ultrasound can reduce the temperature by 30℃ and shorten the replacement time by 2/3, which has significant advantages in reaction efficiency and safety. The strengthening mechanism of ultrasound on the replacement effect of aluminum powder at low temperatures is revealed through detailed discussions on the corrosion of alumina films, agglomeration of aluminum powder, and adhesion of replacement products to the surface of aluminum powder, dissolved oxygen in the solution, and redissolution of cadmium. Therefore, a new approach for replacing aluminum powder in solutions with high Cd2+ concentrations at low temperatures is proposed in this work, which is expected to solve the existing harsh and dangerous problems of industrial aluminum powder replacement.

Adsorption Properties of Natural Zeolite Supported by Chitosan on Cd(II) in Micropolluted Irrigation Water.

This study utilized a 1% chitosan solution (dissolved in 2% acetic acid), with a chitosan-to-zeolite mass ratio of 0.005, to successfully prepare chitosan-loaded natural zeolite. The performance of chitosan-modified natural zeolite in the removal of low-concentration cadmium ions in the presence of micropollutants was investigated. The adsorbent was characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) techniques. The impact of modified adsorbent dosage, pH value, contact time, temperature, and initial concentration on adsorption performance was discussed. Additionally, the adsorption kinetics, isotherms, and thermodynamics of cadmium on chitosan-modified zeolites were analyzed. The results indicated that the modified zeolite exhibited a dispersed and porous structure with increased surface area, average pore size, and total pore volume. Under the conditions of 25 °C, pH 6, a dosage of 8 g/L, and a 60 min adsorption reaction time, chitosan-loaded natural zeolite (CNZ) achieved a removal efficiency of over 94.51% for a 100 μg/L cadmium solution (in a 100 mL volume). The adsorption process followed the Langmuir model, suggesting monolayer adsorption. The adsorption kinetics followed a pseudo-second-order equation, indicating an exothermic process with an increase in entropy. Chitosan-loaded natural zeolite demonstrated improved adsorption capacity and effectively removed cadmium from water contaminated with micropollutants.

A dual functional turn off florescence sensor using metal–organic framework for sensitive detection of aluminum(III) in aqueous solution

AbstractAluminum, classified as one of the toxic heavy metals, has a recommended daily consumption limit of 3–10 mg, as specified by the World Health Organization (WHO). Herein, the selective and sensitive aluminum(III) fluorescence sensor based on TMU‐16 metal–organic frameworks (MOFs) in aqueous medium, is reported. A sensing pathway was found via the cation exchange between aluminum(III) and zinc(II) ions, and caused selectivity and sensitivity detection of aluminum(III) with a 5–100 ppm linear range and 1.99 ppm limit of detection (LOD).This sensor offers the advantage of accurately determining the concentration range of aluminum(III) ions. At low concentrations, only fluorescence quenching was observed, while at higher concentrations, fluorescence emission not only undergoes quenching but also exhibits a blue shift in wavelength. Notably, the sensor demonstrates no interference from cation solutions of mercury(II), zinc(II), nickel(II), lead(II), cobalt(II), cadmium(II), silver(I), chromium(III), and iron(III).Another significant feature of this sensor is its selectivity toward copper(II) and aluminum(III) ions, due to quenching fluorescence in the presence of copper(II) ion. The results presented the sensor's selectivity toward copper(II) at low concentrations and aluminum(III) at high concentrations.

Single and joint toxic effects of waterborne exposure to copper and cadmium on Coregonus ussuriensis Berg.

Heavy metal contamination severely affects the aquatic environment and organisms. Copper (Cu) and cadmium (Cd) are two of the most common heavy metal contaminants that impair the survival, development, and reproduction of aquatic organisms. With the growth of agriculture and industry, there is a possibility of heavy metal pollution in Coregonus ussuriensis Berg's water source. However, there are no published studies on the toxicity to C. ussuriensis. Acute toxicity experiments in C. ussuriensis revealed the 96-h median lethal concentrations of copper and cadmium to be 0.492 mg·L-1 (95% confidence interval: 0.452-0.529) and 1.548 mg·L-1 (95% confidence interval: 1.434-1.657), respectively, and safe concentrations of 4.92 µg·L-1 and 15.48 µg·L-1, respectively. C. ussuriensis was then treated for 96 h with Cu (20% of 96 h LC50), Cd (20% of 96 h LC50), and a combination of Cu and Cd (20% of Cu 96 h LC50 + 20% of Cd 96 h LC50). The histological damage caused by the three different exposure modes to the liver and gills of C. ussuriensis was verified using hematoxylin and eosin staining. All three exposure modes caused different degrees of vacuolization, nuclear consolidation, and necrosis in the liver tissue of C. ussuriensis and edema, hyperplasia, laminar fusion, and epithelial elevation in the gill tissue compared with the reference group. The severity of the damage increased with increasing exposure time. Anti-oxidant activity in the gill and liver tissues were measured using enzyme activity assay kits to reflect oxidative stress induced by copper and cadmium exposure alone and in combination. The enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) were substantially higher than those in the reference groups. However, the activities of the enzymes decreased with increasing exposure time. Malondialdehyde (MDA) activity significantly increased during exposure in relation to that in the reference group. Analysis of immune gene expression in C. ussuriensis gill and liver tissues was executed using real-time inverse transcript polymerase chain response (RT-PCR). The expression levels of the pro-inflammatory cytokines interleukin one beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were positively correlated with exposure time and were significantly upregulated with increasing exposure time. Metallothionein (MT) gene expression levels were significantly upregulated in the short term after exposure compared to the reference group but decreased with increasing exposure time. Our results indicate that exposure to aqueous copper and cadmium solutions, either alone or in combination, causes histopathological damage, oxidative stress, and immunotoxicity in C. ussuriensis gill and liver tissue. This study investigated the toxic effects of copper and cadmium on C. ussuriensis to facilitate the monitoring of heavy metals in water sources for healthy aquaculture.

Alleviating the toxic effects of Cd and Co on the seed germination and seedling biochemistry of wheat (Triticum aestivum L.) using Azolla pinnata

One of the most significant environmental challenges in the twenty-first century is heavy metal pollution. The potential use of fresh Azolla pinnata to alleviate the toxic effects of Cd and Co on the germination measurements of wheat seeds (Triticum aestivum L.) and the biochemistry of seedlings was studied. Two concentrations (80 and 100 mg L−1 solutions) of CdNO3 and CoCl2 were used before and after treatment with A. pinnata. The highest removal efficiency (RE) by A. pinnata was obtained on the fifth day, with a Cd RE = 55.9 and 49.9% at 80 and 100 mg L−1, respectively. Cadmium and cobalt solutions reduced the germination percentage, and the measured variables of wheat seeds meanwhile increased the radicle phytotoxicity. In contrast, the presence of A. pinnata in the germination medium increased all the measured variables and decreased radicle phytotoxicity. At 80 and 100 mg L−1, Cd significantly reduced the fresh and dry biomass, and height of wheat seedlings after 21 days of cultivation compared to Co. Cadmium and high concentrations of cobalt increased the contents of H2O2, proline, MDA, phenolic, and flavonoid compounds. The application of treated Cd and Co solutions by A. pinnata showed a decrease in H2O2, proline, phenolic, and flavonoid compounds levels accompanied by a reduction in catalase and peroxidase activities compared to the control. This study showed the positive role of A. pinnata in alleviating the metal impacts, particularly Cd, on the seedling growth of wheat and its germination.

Features of technological synthesis and properties of ZnO-Cd based materials for photocatalytic applications. Review

In this review, the current state of ZnO-Cd based materials for photocatalytic applications is summarized. Relevant technological synthesis methods such as pulsed laser deposition, magnetron sputtering, electrodeposition, sol-gel, metalorganic chemical vapor deposition, evaporating, spray pyrolysis, reflux are considered, and recent developments in effective and reproducible synthesis technology of nano- and microstructured zinc oxide, doped with cadmium and solid solutions of Zn1‑xCdxO for photodecomposition of organic pollutant molecules are discussed. The synthesis technology and level of Cd doping has a significant effect on the structure and morphology of zinc oxide and, as a result, on the optical and photocatalytic properties. The figures of merit, the theoretical limitations and rational control of the concentration of the cadmium alloying impurity is necessary to create a material with balanced optical properties and photocatalytic activity. Lastly, the importance of doping ZnO by isovalent Cd impurity significantly improves its photocatalytic properties due to a narrowing of the band gap, a decrease in the rate of recombination of electron-hole pairs, which increases the efficiency of spatial charge separation, the formation of active oxide radicals and an increase in the specific surface area. Thus, ZnO-Cd based materials are the most promising photocatalytic materials for organic pollutants.

Longevity of coal waste for controlling cadmium-contaminated groundwater considering groundwater velocity.

Coal waste composed of naturally occurring minerals is applicable as a reactive medium to permeable reactive barriers due to its reactivity to heavy metals. In this study, we evaluated the longevity of coal waste as PRB media to control heavy metal-contaminated groundwater considering variable groundwater velocity. Breakthrough experiments were conducted using coal waste-filled column by injecting artificial groundwater, 10mg/L of cadmium solution. The artificial groundwater was fed to the column at different flow rates to mimic a wide range of porewater velocities in the saturated zone. The reaction between cadmium breakthrough curves was analyzed using a two-site nonequilibrium sorption model. The cadmium breakthrough curves showed a significant retardation, which increased with decreasing porewater velocity. The greater the retardation, the longer the longevity of coal waste could be expected. The greater retardation under a slower velocity environment was due to the higher fraction of equilibrium reaction. The nonequilibrium reaction parameters could be functionalized with respect to the porewater velocity. The simulation of contaminant transport using the reaction parameters could be used as a method to evaluate the longevity of the pollution-blocking material in an underground environment.

V–Cd nanoparticle-formed alloys: fabrication, phase composition and structure

The results of the study of targeted sputtering and deposition of ultrafine vanadium and cadmium particles on substrates that are not heated and shifted with respect to the substrate plasma currents are revealed. As a result of the conducted studies, coatings were obtained in the range with a concentration of cadmium from 9.6 to 88.6 at.%. The critical size of vanadium particles capable of forming alloys with cadmium is 0.6 nm. The concentration limit for the presence of solid solutions of cadmium in vanadium is the cadmium content of ~37 at.%, at a higher cadmium content the film coating is represented by a mixture of cadmium phases and a solid solution of cadmium in vanadium. The dependence of the lattice parameter of α-vanadium on the content of cadmium in it corresponds to the expression: а [nm] = 8·10–4СCd + 0.3707, where СCd is the concentration of cadmium, at.%. On the surface of the sample in the region of solid solutions (31.6 at.% Cd), the presence of threadlike crystals of cadmium was found, the reason for the appearance of which is the lattice pressure of the matrix metal. Annealing of films rich in cadmium (69.5 at.%) in vacuum is accompanied by cracking of the coating and the formation of pores. The latter can be used as a method for obtaining porous vanadium.

Absorption of Cadmium and its Effect on the Growth of Halfsib Family of Three Cocoa Clones Seedling

The issue of cadmium in cocoa beans has become one of the primary considerations in setting quality criteria in chocolate-consuming countries. Using rootstock genotypes that are tolerant to cadmium uptake can provide data on the absorption of cadmium into shoots for recovery. This study examined cocoa plants’ growth and physiological response to cadmium (Cd) accumulation. The research was carried out using polybags in the Greenhouse of the Indonesian Coffee and Cocoa Research Center using a half-sib family of cocoa aged 4 months after sowing. The study was designed using a completely randomized split-plot design with 3 replications. The parent plots were the half-sib families of Sulawesi 1, Sulawesi 2, and Scavina 6. The subplots were added with cadmium solution at 0 (control), 2, 4, and 8 ppm. The results showed that adding cadmium up to 8 ppm did not affect the growth and biomass of cocoa seedlings; however, it had a negative effect on plant physiological processes of the net assimilation rate and relative growth rate. Cadmium content in the tissue increased with increasing cadmium concentration in the growing medium. The accumulation of cadmium in roots was higher than that of shoots. Absorption of cadmium in the root tissue of Sulawesi 1 was higher than that of Scavina 6 and Sulawesi 2; genetic factors did not affect cadmium uptake in the shoots. There was a positive correlation between root dry weight and cadmium concentration in the tissue; the higher the dry weight of the root tissue, the higher the cadmium uptake in plants.

Inhibitory Effect of Cadmium on the Growth of Mung Bean (Vigna radiata (L.) R. Wilczek) and the Removal by Chelating Agent

This research studied the effect of cadmium (Cd) on the growth of mung bean (Vigna radiata (L.) R. Wilczek). The mung bean was cultured in a Hoagland solution containing different concentrations of Cd (0, 0.1, 0.3 and 0.5 mg/L) for 5 days. The result showed a significant decrease in the lengths of the roots and shoots of mung bean that was grown in cadmium solution. This effect was proportional to the concentrations of Cd. To assess cell death in the root of mung bean, Evan’ s blue staining technique was used in this study. The results showed that the concentrations of Evan's blue dye taken up by Cd-exposed mung beans at 0.1, 0.3, and 0.5 mg/L were 1.5612 ± 0.5417, 6.8641 ± 1.7447, and 8.0850 ± 2.6336 mg/L, respectively. A concentration-dependent increase of dead cellswas found in the Cd-treated group, mostly at the root cap zone. With respect to this result, the level of dead cells that was stained with Evan’s blue dye could be used as a biomarker to indicate cadmium contamination in water. Furthermore, the effects of chelating agents (EDTA) on cadmium removal were also studied. The results showed the possibility of using EDTA as a cadmium treatment agent and promoted plant growth in cadmium contamination areas.

Optimization of Biosorbent on Cd(II) Metal Biosorption Using Duck Eggshell Waste

Every year the production of duck eggs in Indonesia has increased, this case leads to an increase in the waste of duck eggshells. Duck eggshell waste has components that can be utilized into a biosorbent. To improve the quality of the biosorbent, can be done with an activation method and immobilization method. The purpose of this study was to determine the effectiveness of biosorbents made from duck eggshell waste in absorbing Cd(II) metal. In this study, duck eggshells were activated with physical activation by heating in a furnace at a temperature of 900oC for 2 hours. Independent variables of this study are biosorbent mass, contact time and concentration of cadmium solution. Critical values for Cd levels optimization conditions are accomplished when the biosorbent mass 1.45 grams, contact time 100 minutes and Cd solution concentration 86 ppm with a percentage decrease in Cd levels in the amount of 89%.

Screening and Optimization of Conditions for the Adsorption of Cd2+ in Serpentine by Using Response Surface Methodology

In order to explore the optimal conditions for the adsorption of Cd2+ in serpentine, this paper studied the adsorption of simulated cadmium solutions with serpentine as an adsorbent. On the basis of a single factor experiment, four factors including the amount of serpentine, initial pH, the initial concentration of solutions, and adsorption time were selected as the influencing factors, and the adsorption quantity and adsorption rate of serpentine to Cd2+ were double response values using the Box-Behnken design. Response surface analyses were used to study the effects of four factors on the adsorption quantity and adsorption rate of serpentine on cadmium, and the interaction between various factors. The results showed that the optimum adsorption conditions were as follows: the amount of serpentine was 1%, the initial pH was 5.5, the initial solution concentration was 40.83 mg·L-1, and the adsorption time was 26.78 h. Under these conditions, the theoretical adsorption quantity and adsorption rate of serpentine to Cd2+ were 3.99 mg·g-1 and 95.24%, respectively. At the same time, after three repeated experiments, the actual adsorption quantity and adsorption rate of serpentine to Cd2+ were 3.91 mg·g-1 and 94.68%, respectively, and the theoretical value was similar to the actual value. Therefore, it was proved that the experimental design of the regression model is reliable, and it is feasible to use the response surface method to optimize the adsorption conditions of serpentine on Cd2+.

Study on Thermoelectric Property of Te Wire-Based Organic-Inorganic Hybrid Thermoelectric Composites through Electrochemical Process

Energy demand and importance are increasing with the industrial development and the development of high technology in modern society. However, the global supply of energy is facing problems such as fossil energy depletion and environmental pollution, and research and interest in alternative energy are increasing. Among them, research on thermoelectricity is being actively conducted. The thermoelectric characteristics are represented by the Seebeck coefficient, electrical conductivity, and thermal conductivity at the operating temperature. This is expressed as a thermoelectric performance index (ZT). ZT appears in proportion to the electrical conductivity and Seebeck coefficient, and inversely proportional to the thermal conductivity. Thermoelectric materials are divided into inorganic thermoelectric materials and organic thermoelectric materials, both of which have advantages and disadvantages. The inorganic thermoelectric material has high thermoelectric performance, but it is highly toxic and has low electrical conductivity. On the other hand, organic thermoelectric materials have lower performance than inorganic materials they are easy to obtain and have high electrical conductivity. In this study, organic-inorganic hybrid thermoelectric material was studied by combining the advantages of each material.In this study, Te nanowires (NWs) were synthesized at 50 Co by galvanic replacement reaction. We used Si (1 0 0) wafer as substrate of NWs. The substrate was degreased with acetone and ethanol. The solution of cadmium(1M), hydrofluoric acid (HF 51.0%, 4.5M) and tellurium dioxide (TeO2, 2mM). After the reaction, the synthesized Te NWs were washed with deionized water and IPA. The prepared Te NWs reacted with solution (silver nitrate in ethylene glycol) for topotactic reaction. After the reaction, the wires are washed several times with ethanol. The hybrid TE was fabricated by coating PEDOT:PSS on Ag-Te NWs with different ethylene glycol (EG) doping.A composite thermoelectric material was manufactured using Te (inorganic thermoelectric material) and PEDOT:PSS (organic thermoelectric material). Ag-topotactic reaction was conducted to increase the electrical conductivity of NWs. As the EG doping concentration of PEDOT increased, the electrical conductivity because the layer of PEDOT:PSS became thinner and didn’t fill the gap of NWS sufficiently. In conclusion, the Te NWs coated with PEDOT:PSS with 10% EG doping showed the best electrical conductivity and power factor. The more details will be presented. Figure 1