Influence Of Copper Ions Research Articles

Manganese-Doped Carbon Quantum Dots (CQDs) Prepared from Bovine Bone Powder and Their Application for the Fluorescent Determination of Chlorpyrifos

Employing a one-step hydrothermal method with bovine bone powder as the carbon source, Mn-doped fluorescent carbon quantum dots were synthesized. Experimental investigations were conducted on their morphology, structure, composition, and optical properties. The experiments were carried out at 280 °C, pH 7.0, and a reaction period of 12 h. A rapid residual method for organophosphorus pesticides (OPs) was developed based on the fluorescence quenching of quantum dots. A linear correlation between fluorescence quenching and OP concentration was established. Chlorpyrifos was chosen as the analyte for method evaluation. The findings showed that the fluorescence intensity of the Mn-BQDs decreased with the copper ion concentration. Furthermore, the influence of copper ions on the fluorescence quenching of carbon quantum dots varied with pH. At pH 7, copper ions exhibited optimal quenching with a detection limit of 5.8 × 10−4 mg/L. This method offers simplicity in operation and environmental friendliness, rendering it well-suited for the swift on-site screening of OPs.

Influence of Copper Ions on the Structural, Mechanical, Radiation Shielding and Dielectric Properties of Borate Zinc-Fluoride Glasses

Influence of Copper Ions on the Structural, Mechanical, Radiation Shielding and Dielectric Properties of Borate Zinc-Fluoride Glasses

The influence of copper ions on the transport and relaxation properties of hydrated eumelanin.

Eumelanin, the human skin pigment, is a poly-indolequinone material possessing a unique combination of physical and chemical properties. For numerous applications, the conductivity of eumelanin is of paramount importance. However, its hydration dependent conductivity is not well studied using transport-relaxation methods. Furthermore, there is no such work taking into account the simultaneous control of humidity as well as metal ion concentration. Here we present the first such study of the transport and relaxation characteristics of synthetic eumelanin doped with various Cu ion concentrations while controlling the humidity with a frequency range of 10-3 Hz-1 MHz. We found that Cu ions do not cause the appearance of additional relaxation processes, but partially slow down those present in neat eumelanin. In addition, considering previously published work, the key relaxation process observed in doped and undoped materials is associated with the moisture-induced synthesis of uncharged semiquinones and a corresponding increase in the overall aromaticity of the material.

Diatomite Dynamic Membrane Fouling Behaviour during Dewatering of Chlorella pyrenoidosa in Aquaculture Wastewater.

Combined microalgal and membrane filtration could effectively treat aquaculture wastewater; however, the membrane fouling induced by extracellular organic matter (EOM) during the dewatering process is an issue. This study investigated diatomite dynamic membrane (DDM) fouling behaviour during the dewatering of Chlorella pyrenoidosa under the influence of copper ions. The results indicate that copper ion heavy metals in aquaculture wastewater significantly affected purification and algae dewatering by DDM. Aquaculture wastewater with a high copper concentration (1 and 0.5 mg/L) could induce serious DDM fluxes and cake layer filtration resistance (Rc), whereas fewer filtration fluxes were induced when aquaculture wastewater had a low copper concentration, particularly that of 0.1 mg/L, at which the Rc was lowest and the concentration effect was highest. Macromolecular organics of EOM, such as biopolymers, polysaccharides, and proteins, were responsible for DDM fouling and accumulated mostly in the slime layer, whereas only a small amount of them accumulated in the diatomite layer. The DDM rejected more protein-like organics of EOM in the slime layer when dewatering algae at low copper concentrations (<0.1 mg/L); however, when using the DDM to dewater algae at high copper concentrations, more polysaccharides of EOM were rejected (0.5 < Cu2+ < 5 mg/L). This result has significant ramifications for aquaculture wastewater treatment as well as algae separation and concentration by the DDM.

Insight into the evolution of microbial community and antibiotic resistance genes in anammox process induced by copper after recovery from oxytetracycline stress

The influence of copper ion (Cu2+) on anaerobic ammonium oxidation (anammox) performance and microbial community structures after oxytetracycline (OTC) stress recovery were assessed. Experimental results demonstrated that anammox performance were stressed by 1.0 mg L−1 Cu2+ and inhibitions were reversible with total nitrogen removal rate higher than 3.08 ± 0.2 kg N m−3 d−1. The residual OTC in the anammox sludge could combine with Cu2+ introduced and thereby retarded inhibition on performance in the presence of 2.0 mg L−1 Cu2+. Moreover, the positive relation of dominant bacterium Ca. Anammoxoglobus with the abundance of functional genes and parts of antibiotic resistance genes were observed, suggesting that regain of performance was the results of the gradual domestication of latent resistant species after inhibition. This investigation reveals new insights into resistance of anammox performance for Cu2+ and OTC.

Exosomes secreted by macrophages upon copper ion stimulation can promote angiogenesis

Copper, a frequently used additive of implant materials, can alter macrophage phenotype thus directing the fate of the implants. Exosomes, secreted by mammalian cells, can target to recipient cells and mediate their functions. However, whether exosomes derived from macrophages upon copper ion stimulation can modulate angiogenesis, a key index for implant osseointegration, is still unclear. Herein, the influence of copper ions on macrophage-derived exosome secretion, ingestion behavior by endothelial cells, and angiogenic-induction ability is investigated. The results show copper ions (0–100 μM) have little influence on the secretion of macrophage-derived exosomes. Endothelial cells can uptake the exosomes from all the groups in a time-dependent manner. The exosomes have little influence on endothelial adhesion and proliferation, but can upregulate angiogenic ability of endothelial cells in vitro and in vivo, which may be related to trafficking of integrin β1. The results provide insight into the effect of copper ions on immunomodulatory mechanism of macrophages, which is important for implant design from the perspective of material compositions.

Effects of Long-Term exposure to Heavy Metals upon Rhizosphere Bacteria from Baia Mare Area (Maramureş County, Romania)

The aim of this study was to investigate the extent of heavy metal (HM) pollution and its effect on microorganisms from rhizosphere soil in Baia Mare area (Maramureş County, Romania). Two sites with different contamination degrees were included in the study: one with a long history of mining activities and one within a drinking water safeguard zone. Rhizosphere soil samples were characterized with respect to physico-chemical parameters and the Cd, Cu, Pb and Zn contents. Native bacteria were investigated for HM tolerance and biofilm formation under toxic exposure by the microdilution assay. The most resistant strains were identified and the minimum inhibitory concentrations for HMs were determined. Cd, Cu, Pb and Zn exceeded the intervention threshold in Bozânta tailings site, while Pb content exceeded the intervention level within the area of the drinking water treatment plant. Cd showed a very high potential ecological risk in Bozânta area. The long-term exposure to HMs contributed to the selection of HM-tolerant and weakly adherent strains. Biofouling was significantly reduced under the influence of copper ions. Arthrobacter, Rhodococcus and Acidovorax strains with exceptional resistant profiles were isolated from the tailings site, indicating the important role of native microorganisms in rhizosphere ecosystems of contaminated sites.

Synthesis, spectral characteristics and microbiological activity of benzanthrone derivatives and their Cu(II) complexes

Two benzanthrone derivatives with an amide group (B1 and B2) attached to the C-3 atom have been synthesized and characterized by different spectral methods. The basic photophysical characteristics were investigated in organic solvents of different polarity. A batochromic shift was observed in the transition from non-polar to polar media. The influence of copper ions on the intensity of fluorescence emission was investigated and a stable copper complex with compound B2 was isolated. Its chemical structure was characterized by electronic spectroscopy, IR and EPR spectroscopy. The stoichiometry of the isolated complex was found to be at a 1: 1 ligand-copper ratio. The microbiological activity of the newly synthesized compounds against gram positive and gram negative bacteria and yeast was examined. The copper complex enhanced the antibacterial activity compared to that of the ligand.

Resistance of seedlings of native and alien species of the genus Bidens (Asteraceae) from different geographic populations to the action of heavy metals

One approach to assessing the competitiveness of invasive species is a comparative analysis of the morphological, physiological, and reproductive traits of this species with native species of the same genus. The invasive species Bidens frondosa L. from the Asteraceae family, included in the list of the 50 most common and most aggressive invasive species in Europe, occupies the same ecological niche as the native species B. tripartita L., and displaces it from natural habitats. There is an obvious and growing interest in the sustainability of B. tripartita and B. frondosa in extreme conditions of existence, one of which is the action of heavy metals. Our research was performed in laboratory conditions with seedlings that developed from seeds collected from populations of the Upper and Middle Volga region. The seeds were germinated in Ni2+ and Cu2+ solutions at various concentrations. At the end of the experiment, morphometric parameters were measured and the index of tolerance was determined. Seedlings from different populations under the influence of nickel ions developed at concentrations of 1–50 mg/l, under the influence of copper ions – at 1–100 mg/l. The nickel and copper ions had the greatest toxic effect on the growth and development of the root system – at 25 mg/l and above, the main root was completely necrotic, while the action of copper ions simultaneously increased the number of adventitious roots. The tolerance index (“root test”) under the action of nickel ions was higher among the seedlings from the population of the Middle Volga region, while under the action of copper ions there were no significant differences among the seedlings from different populations. However, it decreased with the action of both heavy metals at a concentration of 10 mg/l. High concentrations of both metals significantly reduced the length of the hypocotyl, cotyledon, and the true leaf. It was also found that copper ions are more toxic for the root system (main root and adventitious roots), nickel ions – for above-ground organs (hypocotyl, cotyledons, and true leaves). We noted differences between the populations to the action of nickel and copper. From the population of the Upper Volga region, the seedlings of B. frondosa were more stable. For seedlings from the population of the Middle Volga, a smaller toxic effect was confirmed for B. tripartita. It can be assumed that the resistance of B. frondosa to the action of heavy metals as a stress factor in the Upper Volga region is one of the reasons for the suppression of B. tripartita by the invasive species.

Fate and UF fouling behavior of algal extracellular and intracellular organic matter under the influence of copper ions

Copper ion plays an important role in the outbreak of algal blooms. The aim of this research was to investigate the fate and fouling behavior of algal extracellular organic matter (EOM) and intracellular organic matter (IOM) under different copper concentrations during ultrafiltration (UF). Under the lowest copper concentration of 0.01 μmol/L, both the EOM and IOM caused the largest decrease in filtration flux, followed by EOM under high copper concentrations of 0.3 μmol/L and 0.1 μmol/L; less membrane fouling was induced by IOM under a copper concentration of 0.3 μmol/L than under a copper concentration of 0.1 μmol/L. More reversible fouling (Rre) was induced by EOM/IOM at the lowest copper concentration of 0.01 μmol/L than under the other two copper concentrations, whereas more membrane fouling was induced by EOM than by IOM under the different copper concentrations. Fluorescence excitation-emission matrices-parallel factor analysis (PARAFAC) indicated that fouling by the protein-like components in EOM was more irreversible under 0.01 μmol/L copper than under 0.1 μmol/L and 0.3 μmol/L copper. However, the fouling by this component was more reversible in the IOM solutions than in the EOM solutions. The amount of macromolecular biopolymers was highly correlated with the total and reversible membrane fouling during the EOM/IOM filtration, whereas a weaker correlation (r2) between the humic-like organics and membrane fouling was determined by Pearson's correlation matrix analysis. High-performance size exclusion chromatography (HPSEC) combined with peak-fitting prediction was suggested to be more suitable for membrane fouling implication in algal water treatment.

In vitro growth and indoleacetic acid production by Mesorhizobium loti SEMIA806 and SEMIA816 under the influence of copper ions

The indoleacetic acid produced by symbiotic bacteria is an important phytohormone signaling microbe-plant interaction, being therefore essential for rhizoremediation. In this study, the effect of different concentrations of copper ions on the bacterial growth and indoleacetic acid production was investigated in two strains of Mesorhizobium loti in in vitro conditions, aiming to determine critical concentrations of this heavy metal for rhizoremediation of contaminated soils using this bacterium. The experiment consisted on a control culture without copper and three treatments supplemented with 10 mg.L-1, 20 mg.L-1 or 50 mg.L-1 of CuSO4. For both strains, the growth stopped after 48h and no significant difference was observed across treatments. The production of indoleacetic acid by the control treatment without copper was significantly higher in comparison to the copper- containing treatments. Mesorhizobium loti SEMIA806 and SEMIA816 are resistant to up to 50 mg.L-1 of CuSO4 in the culture medium, presenting effective growth. The synthesis of indoleacetic acid was strongly reduced but not excluded by ions copper in the medium. So, it is expected that environmental copper found in the soil up to the concentration of 50 mg.L-1 will not preclude the symbiotic interaction between M. loti and leguminous host plant in rhizoremediation enterprises.

Influence of copper ions on structural and non-linear optical properties in manganese ferrite nanomaterials

A series of Mn1-xCuxFe2O4 (x = 0, 0.15, 0.30, 0.45, 0.60 and 1) particles were prepared using chemical co-precipitation method with metal nitrates as precursor materials. Samples were synthesized under various annealing temperatures and 800 °C was found to be the optimal temperature for phase formation. Powder XRD analyses confirm the formation of spinel manganese ferrites along with the α-Fe2O3 phase which got reduced with increase in copper concentration. Samples were characterized using spectroscopic and microscopic techniques. UV-Diffuse reflectance spectroscopy was employed to calculate the band gap which varied between 1.51 eV and 1.83 eV. HR-SEM images reveal the spherical nature of the particles. Ferromagnetic nature of these materials was confirmed from vibrating sample magnetometer (VSM) measurements. Z-scan technique was employed to measure the non-linear optical properties. The non-linear refraction, non-linear absorption and non-linear susceptibility are found to be of the order of 10−8 cm2/W, 10−4 cm/W and 10−6 esu respectively. The samples showed a defocusing effect which was utilized to explain the optical limiting behavior at the same wavelength using the continuous-wave laser beam. The results show that these materials have potential for exploitation towards device applications like optical limiting and switching.

Removal of Methyl Red, a cationic dye, Acid Blue 113, an anionic dye, from wastewaters using chitin and chitosan: influence of copper ions

Removal of Methyl Red, a cationic dye, Acid Blue 113, an anionic dye, from wastewaters using chitin and chitosan: influence of copper ions

Raman spectroscopy for the control of soil contamination by copper ions

The experimental results of changes in the plant optical characteristics depending on the concentration of copper ions in the soil were presented by a method of Raman spectroscopy. Raman spectral features of plant tissue growing under the influence of copper ions in the soil that excess the MPC were obtained. The basic changes were registered at Raman bands 1325 cm-1, 1527 cm-1 and 1547 cm-1 that responsible for the stretching vibrations of chlorophyll a and b, carotene and chlorophyll a. The optical coefficient based on the dependence of the copper ion concentration from the optical parameters of plants was introduced. When the concentration of copper ions in the soil of 3 MPC observed increase optical coefficient values on the first day of experiments.

The influence of copper ion on thermooxidative destruction characteristics of polyglucaneurethane based on xanthan and caprolactame blocked polyisocyanate

The influence of copper ion on thermooxidative destruction characteristics of polyglucaneurethane based on xanthan and caprolactame blocked polyisocyanate

Protective ability of cerium-containing conversion films on aluminium

The options for electroless deposition of conversion films of lanthanum group metal oxides, in particular cerium, as an alternative to chromate conversion films (containing Cr6+) have been studied on aluminium. The main task of the study was to establish the influence of copper ions as a component of electrolytes for conversion treatment on the processes of formation and on the corrosion protective ability of cerium oxide films.It has been ascertained that the electrochemical activation of the aluminium surface in the presence of Cu2+ in the electrolyte, leads to formation of oxide layers richer in cerium and possessing a better protective ability.The presence of active cathodic sections of electroless, contact-deposited Cu has been shown to promote the corrosion activity of the system, due to the possibility of the appearance of micro-galvanic couples Al/Cu. A model experiment has been carried out to establish the inclination of the system to pitting corrosion. It has been shown that at the studied concentration of Cu2+ in the electrolyte the character of the corrosion does not change observably but there is a catalysing effect of the copper ions in the working electrolyte. The copper islands on the Al surface also have a catalysing effect, which is dominating in the processes of cerium oxide film formation. The chemical state and the composition of the conversion films have been defined by XPS measurements.

Influence of Copper Ions on Mechanical Properties of PVA-Based Nanofiber Textiles

The nanofiber textiles are utilized in the textile industry, as a treatment of exposed surfaces, they find their use in medicine and in future they might be used in civil engineering as vapor barriers. For some applications it is advantageous to use the textiles with special, e.g. antibacterial, treatment by means of silver or copper ions. This paper is focused on the determination of mechanical properties of PVA-based nanofiber textiles produced by electro-spinning. The polymer solution used for electrospinning contained copper in the form of ions. The results of the tensile testing were compared with the results for the reference sample without any additives. The results indicate that the addition copper ions cause an increase of the strength and stiffness.

Influence of copper ions on thermoluminescence characteristics of CaF2–B2O3–P2O5 glass system

Thermoluminescence (TL) characteristics of γ−ray irradiated calcium fluoro borophosphate glasses doped with different concentrations of CuO (0.2–1mol%) have been studied in the temperature range 30–300°C. The γ−ray dose is varied from 0.25kGy to 10kGy. The glow curves of these glasses have exhibited a dosimetric peak at about 200°C and a high temperature peak at about 300°C. The glasses doped with 0.2mol% of CuO have exhibited maximum TL light output. The increase of dopant concentration beyond 0.2mol% caused the inhibition of TL emission drastically with shifting of peak positions towards higher temperatures. The probable mechanism responsible for quenching of TL emission in these glasses has been explained based on the variations in the valence state of copper ions with the aid of optical absorption spectra. The dose response of 0.2mol% CuO doped borophosphate glass samples showed linear behavior within the dose range of 0.25 to 4kGy. Samples containing higher concentrations of CuO (>0.2mol%) were found to be not suitable for radiation dosimetry within 10kGy dose.

Influence of copper ions in transformer oil properties and adsorption treatment

The dissolution of copper with trace acid, oxygen, moisture, nitrogen compounds, and corrosive sulfur in oil formed copper ions. A transformer oil with 7.0 mg/kg copper ion was treated via the adsorption method. The efficiency of adsorbent was raised with the increase of addition amount and temperature. In the adsorption process, the copper ions, interfacial tension, water content, acid value, volume resistivity, and dielectric loss tangent tan δ of oil were tested, and the relationship between copper ions and electrical properties was investigated. In 140 h, the copper ions decreased to 0.5 mg/kg, the dielectric loss tangent from 2.19% to 0.07%, and the volume resistivity from 0.67×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> Ωcm to 7.05×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> Ωcm. Moreover, the antioxidant content, oxidation stability, and transformer insulation resistance before and after the adsorption treatment were analyzed. The adsorption treatment was effective in elevating the transformer insulation resistance from about one to ten thousand.

Influence of copper ions and calcium ions on adsorption of CMC on chlorite

The effects of copper ions and calcium ions on the depression of chlorite using CMC (carboxymethyl cellulose) as a depressant were studied through flotation tests, adsorption measurements, ζ potential tests and co-precipitation experiments. The results show that the electrostatic repulsion between the CMC molecules and the chlorite surfaces hinders the approach of the CMC to the chlorite while the presence of copper ions and calcium ions enhances the adsorption density of CMC. The action mechanisms of these two types of ions are different. Calcium ions can not adsorb onto the mineral surfaces, but they can interact with the CMC molecules, thus reducing the charge of the CMC and enhancing adsorption density. Copper ions can adsorb onto the mineral surfaces, which facilitates the CMC adsorption through acid/base interaction. The enhanced adsorption density is also attributed to the decreased electrostatic repulsion between the CMC and mineral surfaces as copper ions reduce the surface charge of both the mineral surfaces and the CMC molecules.