Search Results (21)

The development of highly effective natural-based adsorbents to face the increasing rates of CO₂ production and their delivery to the atmosphere are a big concern nowadays. For such purposes, synthetic and natural zeolites were modified via an ion exchange procedure to enhance the CO₂ uptake. Samples were characterized by SEM, EDS, TGA and nitrogen adsorption at 77 K, showing the correct incorporation of the new metals; in addition, the CO₂ adsorption isotherms were determined using a gas analyser. During the first stage, the role of the compensation cations for CO₂ adsorption was assessed by modifying a pure ZSM-5 synthetic zeolite with different metal precursors present in salt solutions via an ion exchange procedure. Then, five samples were studied; the samples modified with bivalent cation precursors (Zn²⁺ and Cu²⁺) presented a higher adsorption uptake than those modified with a monovalent cation (Na⁺ and K⁺). Specifically, the substitution of the compensation cations for Cu²⁺ increased the CO₂ capture uptake without affecting the surface properties of the zeolite. The results depict the prevalence of π-cation interactions enhanced by the field gradient induced by divalent cations and their lower ionic radii, if compared to monovalent ones. Subsequently, a natural zeolite was modified considering the best results of the previous phase. This Surface Response Methodology was implemented considering 11 samples by varying the concentration of the copper precursor and the time of the ion exchange procedure. A quantitative quadratic model to predict the adsorption uptake with an R² of 0.92 was obtained. The results depicted the optimal conditions to modify the used natural zeolite for CO₂ capture. The modification procedure implemented increased the CO₂ adsorption capacity of the natural zeolite more than 20%, reaching an adsorption capacity of 75.8 mg CO₂/g zeolite. Full article

Coccidiosis is a major economic threat in poultry, and with anticoccidials being phased out, cost-effective alternatives like copper (Cu) supplementation are of interest. This study investigated whether in-feed monovalent Cu (100 ppm) could mitigate the effects of a mild Eimeria challenge in broilers. A total of 216 broiler chicks were randomly assigned to three treatments (six replicates, 12 birds/replicate): unchallenged control (NC), challenged control (PC), and challenged + Cu-supplemented. Birds were fed starter (days 1–10), grower (days 10–21), and finisher (days 21–35) diets. On day 14, all birds except the NC group were orally challenged with 5000 oocysts each of Eimeria acervulina and E. maxima. Feces were collected (days 17–28) for oocyst count, and growth performance, lesion scores (day 21), carcass traits and bone morphology (day 35), gut morphology (days 21 and 35), gizzard weight (days 21 and 35), and cecal bacterial load (days 21 and 35) were evaluated. The mild challenge was confirmed by the observed differences in lesion scores on day 21 (p < 0.05), fecal oocyst counts from days 17–28 (p < 0.05), and overall mortality (p > 0.05) between challenged and unchallenged groups. Copper supplementation tended to improve FCR during the grower phase (1.403 vs. 1.469; p = 0.057) and significantly reduced oocyst excretion on days 23–25 (p < 0.001) compared to the PC treatment. Although performance benefits were limited, Cu reduced oocyst shedding, indicating potential anticoccidial effects. However, further studies are needed to confirm the consistency of this effect across different doses of Cu in poultry production. Full article

Background: Fibroblast activation protein (FAP)-targeted theranostic radiopharmaceuticals have shown desired tumor-to-background organ selectivity due to the ubiquitous presence of FAP within the tumor microenvironment. However, suboptimal tumor retention and fast clearance have hindered their use to deliver effective cancer therapies. With well-documented FAP-targeting moieties and linkers appending them to optimal chelators, the development of copper radiopharmaceuticals has attracted considerable interest, given the fact that an ideal theranostic pair of copper radionuclides (⁶⁴Cu: t_1/2 = 12.7 h; 17.4% β⁺; E_β⁺_max = 653 keV and ⁶⁷Cu: t_1/2 = 2.58 d; 100% β⁻; E_β⁻_max = 562 keV) are available. Herein, we report our design, synthesis, and comparative evaluation of monovalent and divalent FAP-targeted theranostic conjugates constructed from our previously reported bifunctional chelator scaffold (BFS) based on 1,4,8,11-tetraaza-bicyclo [6.6.2]hexadecane-4,11-diacetic acid (CB-TE2A), which forms the most stable complex with Cu(II). Methods: After synthesis and characterization, the monovalent and divalent conjugates were radiolabeled with ⁶⁴Cu for in vitro cell assays, followed by in vivo positron emission tomography (PET) imaging evaluation in relevant mouse models. Results: Both ⁶⁴Cu-labeled conjugates showed high in vitro stability and anticipated FAP-mediated cell binding and internalization. The divalent one showed significantly higher FAP-specific tumor uptake than its monovalent counterpart. Conclusions: Our results demonstrate that the BFS-based multivalent approach can be practically used to generate FAP-targeted radiotheranostic agents for effective cancer diagnosis and treatment. Full article

The effects of nickel content in nickel-bearing pyrite on photocatalytic properties, light absorption properties, and oxidative decomposition of thiosulfate were studied. The leaching experiments show that the consumption of thiosulfate in the Cu²⁺-ethylenediamine (en)-S₂O₃²⁻ system increases with an increase in nickel content in nickel-bearing pyrite. The consumption of Cu(en)₂²⁺ initially increases and then decreases with an increase in leaching time. There is a clear correlation between the change trend in its consumption and the doping amount of nickel in pyrite. The XPS results show that in the Cu²⁺-ethylenediamine (en)-S₂O₃²⁻ leaching gold system (temperature 25 °C, time 35 h, solution: 0.1 mol/L S₂O₃²⁻, 5 mmol/L Cu(en)₂²⁺, 200 mL solution), the nickel of pyrite-containing nickel can be transferred to the leaching solution and becomes nickel ion. In this leaching system, Cu(II), which was originally complexed with en, is reduced to Cu(I) in a short time. The consumption of Cu(en)₂²⁺ increased rapidly in the 5 h period and then decreased gradually after 5 h. The results showed that the presence of free Ni²⁺ in the solution facilitated the conversion of bivalent copper ions to monovalent copper ions. Free Ni²⁺ ions can compete with Cu²⁺ ions for en ligands. When ethylenediamine complexes with Ni²⁺, the decomposition of Cu(en)₂²⁺ into Cu(en)⁺ and en occurs more rapidly. And the en, which was originally to be oxidized with Cu(en)⁺ to form Cu(en)₂²⁺, forms Ni(en)₂²⁺. As a result, the concentration of Cu(en)₂²⁺ continues to decrease in a short period of time. Full article

The application of low-pressure nanofiltration (NF) was investigated for three different applications: water reuse from acid mine drainage (AMD), surface water containing natural organic matter (NOM) and agricultural reuse of microfiltered biologically treated sewage effluent (MF-BTSE). AMD contains many valuable rare earth elements (REEs) and copper (Cu) that can be recovered with fresh water. The NF90 membrane was investigated for recovery of fresh water from synthetic AMD. A steady permeate flux of 15.5 ± 0.2 L/m²h was achieved for pretreated AMD with over 98% solute rejection. NF90 achieved a high dissolved organic carbon (DOC) rejection of 95% from surface water containing NOM where 80% of the organic fraction was hydrophilic, mainly humics. The NF process maintained a high permeate flux of 52 LMH at 4 bars. The MF-BTSE was treated by NTR-729HF for agricultural reuse. NTR-729HF membranes were capable of rejecting DOC and inorganics such as sulfates and divalent ions (SO₄²⁻, Ca²⁺ and Mg²⁺) from MF-BTSE, with less than 20% rejection of monovalent (Na⁺ and Cl⁻) ions. The sodium adsorption ratio (SAR) was significantly reduced from 39 to 14 after treatment through NTR-729HF at 4 bar. The resulting water was found to be suitable to irrigate salt-sensitive crops. Full article

Ciprofloxacin (CIP), a broad-spectrum fluoroquinolone antibiotic, is commonly used in aquaculture to prevent and treat bacterial infections in aquatic animals. For this reason, aquatic environments contain CIP and its derivatives, which lead to the development of drug-resistant bacteria. In the present study, copper nanoparticles were prepared using Garcinia mangostana extract (GME-CuNPs) as a reducing agent and evaluated for their CIP removal efficiency (CRE). The results demonstrate that within 20 min, GME-CuNPs at 25 mM possess a CRE of 92.02 ± 0.09% from CIP-containing aqueous media with pH 6–7. The CRE is influenced by both monovalent and divalent salts. A high salt concentration significantly reduces the CRE. Contaminants in fish wastewater can reduce the CRE, but phenolics, flavonoids, tannins, and ammonia do not affect the CRE. Our results reveal that the CRE is controlled by electrostatic attraction between the negatively charged GME-CuNPs and the cationic species of CIP. The CRE is reduced by wastewater with a pH higher than 8.0, in which the CIP molecules have a negative charge, resulting in a repulsive force due to the negative charge of GME-CuNPs. In fish wastewater with a pH lower than 7.0, GME-CuNPs show the potential to achieve a CRE above 80%. Therefore, pH adjustment to a range of 6–7 in fish wastewater before treatment is deemed imperative. It is concluded that the newly developed GME-CuNPs possess excellent activity in CIP elimination from actual fish wastewater samples. Our findings suggest that GME-CuNPs can be a promising tool to effectively eliminate antibiotics from the environment. Full article

Organic–inorganic halocuprates based on monovalent copper are promising luminescent compounds for optoelectronic applications; however, their relaxation processes in the excited electronic state are severely underexplored. In this contribution, we prepare thin films of bis(tetraethylammonium) di-µ-bromo-dibromodicuprate(I) [N(C₂H₅)₄]₂[Cu₂Br₄], abbreviated (TEA)₂Cu₂Br₄, which features a “molecular salt” structure containing discrete [Cu₂Br₄]²⁻ anions. This compound, which has an absorption peak at 283 nm, displays a blue, strongly Stokes-shifted emission with a peak at 467 nm. Transient photoluminescence (PL) experiments using broadband emission detection and time-correlated single-photon counting (TCSPC) both find an excited-state lifetime of 57 μs at 296 K. UV–Vis transient absorption experiments at 296 K covering time scales from femto- to microseconds provide evidence for the formation of the T₁ state through intersystem crossing from S₁ with a time constant of 184 ps. The triplet state subsequently decays to S₀ predominantly by phosphorescence. In addition, the time constants for carrier–optical phonon scattering (1.8 ps) and acoustic phonon relaxation (8.3 ns and 465 ns) of (TEA)₂Cu₂Br₄ are provided. Full article

The two most common oxidation states of copper in biochemistry are Cu(II) and Cu(I), and while Cu(II) lends itself to spectroscopic interrogation, Cu(I) is silent in most techniques. Ag(I) and Cu(I) are both closed-shell d¹⁰ monovalent ions, and to some extent share ligand and coordination geometry preferences. Therefore, Ag(I) may be applied to explore Cu(I) binding sites in biomolecules. Here, we review applications of ¹¹¹Ag perturbed angular correlation (PAC) of γ-ray spectroscopy aimed to elucidate the chemistry of Cu(I) in biological systems. Examples span from small blue copper proteins such as plastocyanin and azurin (electron transport) over hemocyanin (oxygen transport) to CueR and BxmR (metal-ion-sensing proteins). Finally, possible future applications are discussed. ¹¹¹Ag is a radionuclide which undergoes β-decay to ¹¹¹Cd, and it is a γ-γ cascade of the ¹¹¹Cd daughter nucleus, which is used in PAC measurements. ¹¹¹Ag PAC spectroscopy may provide information on the coordination environment of Ag(I) and on the structural relaxation occurring upon the essentially instantaneous change from Ag(I) to Cd(II). Full article

Copper (Cu)-based antimicrobial compounds (CBACs) have been widely used to control phytopathogens for nearly fourteen decades. Since the first commercialized Bordeaux mixture was introduced, CBACs have been gradually developed from highly to slightly soluble reagents and from inorganic to synthetic organic, with nanomaterials being a recent development. Traditionally, slightly soluble CBACs form a physical film on the surface of plant tissues, separating the micro-organisms from the host, then release divalent or monovalent copper ions (Cu²⁺ or Cu⁺) to construct a secondary layer of protection which inhibits the growth of pathogens. Recent progress has demonstrated that the release of a low concentration of Cu²⁺ may elicit immune responses in plants. This supports a triple-tiered protection role of CBACs: break contact, inhibit microorganisms, and stimulate host immunity. This spatial defense system, which is integrated both inside and outside the plant cell, provides long-lasting and broad-spectrum protection, even against emergent copper-resistant strains. Here, we review recent findings and highlight the perspectives underlying mitigation strategies for the sustainable utilization of CBACs. Full article

In this paper, a 2-mercaptobenzimidazole-copper nanoparticles (MBI-CuNPs) fluorescent probe with high performance based on 2-mercaptobenzimidazole functionalized copper nanoparticles was synthesized by a hydrothermal method and used for cysteine (Cys) detection in serum. The MBI-CuNPs probe exhibits strong fluorescence emission at 415 nm under the excitation at 200 nm, which is attributed to the metal-ligand charge transfer (MLCT) transition through the coordination of an MBI ligand and monovalent copper. Furthermore, the MBI-CuNPs probe has a high quenching fluorescence response to Cys, and shows a good linearity relationship with Cys in 0.05–65 µM, with a detection limit of 52 nM. Moreover, the MBI-CuNPs probe could eliminate the interference of biological mercaptan Hcy and GSH with a similar structure and reaction properties, due to the strong electron-donating ability of Cys, which can quench the fluorescence of the MBI-CuNPs probe. The MBI-CuNPs probe was applied to the analysis of Cys in real serum, and the absolute recovery rate was as high as 90.23–97.00%. Such a fluorescent probe with high sensitivity and selectivity has potential applications for the early prevention of various diseases caused by abnormal Cys levels. Full article

An elevated level of circulating homocysteine (Hcy) has been regarded as an independent risk factor for cardiovascular disease; however, the clinical benefit of Hcy lowering-therapy is not satisfying. To explore potential unrevealed mechanisms, we investigated the roles of Ca²⁺ influx through TRPC channels and regulation by Hcy–copper complexes. Using primary cultured human aortic endothelial cells and HEK-293 T-REx cells with inducible TRPC gene expression, we found that Hcy increased the Ca²⁺ influx in vascular endothelial cells through the activation of TRPC4 and TRPC5. The activity of TRPC4 and TRPC5 was regulated by extracellular divalent copper (Cu²⁺) and Hcy. Hcy prevented channel activation by divalent copper, but monovalent copper (Cu⁺) had no effect on the TRPC channels. The glutamic acids (E542/E543) and the cysteine residue (C554) in the extracellular pore region of the TRPC4 channel mediated the effect of Hcy–copper complexes. The interaction of Hcy–copper significantly regulated endothelial proliferation, migration, and angiogenesis. Our results suggest that Hcy–copper complexes function as a new pair of endogenous regulators for TRPC channel activity. This finding gives a new understanding of the pathogenesis of hyperhomocysteinemia and may explain the unsatisfying clinical outcome of Hcy-lowering therapy and the potential benefit of copper-chelating therapy. Full article

Mine water usually contains heavy metals and other inorganic and organic pollutants that contaminate water bodies. Reverse osmosis (RO) techniques are capable of producing purified water that meets discharge regulations. However, the problem of RO concentrate disposal and utilization is still not solved. The well-known zero liquid discharge (ZLD) process provides total concentrate utilization at the power industries but seems unreasonably expensive for the treatment of large amounts of mine water due to required chemical softening and the evaporation of concentrate. In the present article, a new approach to increase the recovery of reverse osmosis and to avoid high operational costs is demonstrated and discussed. The new technique involves radical RO concentrate flow reduction and withdrawal, together with dewatered sludge. The idea to “hide” concentrate in dewatered sludge is proposed and demonstrated during experiments. The article demonstrates results of the conducted experimental program aimed at reduction of volumes of all liquid wastes produced during mine water treatment using a new approach to concentrate it with a cascade of nanofiltration membranes and to reach a TDS value of 110–120 g per liter. The obtained concentrate is mixed with the wet sludge, which is further dewatered and withdrawn together with the dewatered sludge. Experiments are conducted that demonstrate a reduction in calcium in the concentrate due to deposition of calcium carbonate on the “seed crystals” in the circulation mode. Another distinguishing feature of the new technique is the separation of concentrate into two streams containing high concentrations of monovalent ions (sodium and ammonium chlorides) and divalent ions (calcium, magnesium and copper sulphates). Flow diagrams of the processes are presented to demonstrate the water treatment technique used to produce deionized water and two types of sludges: sludge after clarification and sludge after calcium carbonate deposition. Full article

The charge distribution study of metal atoms in CuCr_0.99Ln_0.01S₂ (Ln = Pr–Tb) solid solutions was carried out using X-ray photoelectron spectroscopy (XPS). The analysis of the binding energy of S2p, Cu2p, Cr2p, Ln3d and Ln4d levels allows one to determine the oxidation state of atoms. Copper atoms were found to be monovalent. Chromium and lanthanide atoms were found to be in the trivalent state. Sulfur atoms were found to be in the divalent state. Cationic substitution was found to occur via an isovalent mechanism of Cr³⁺ to Ln³⁺. The obtained results were used for the interpretation of the Seebeck coefficient increase for CuCr_0.99Ln_0.01S₂ solid solutions in contrast to the initial CuCrS₂ matrix. The largest Seebeck coefficient values of 142 and 148 µV/K were observed at 500 K for CuCr_0.99Sm_0.01S₂ and CuCr_0.99Pr_0.01S₂, respectively. The obtained values are 1.4 times greater in comparison with those for the initial matrix (105 µV/K). Full article

Organic–inorganic perovskite solar cells (PSCs) have delivered the highest power conversion efficiency (PCE) of 25.7% currently, but they are unfortunately limited by several key issues, such as inferior humid and thermal stability, significantly retarding their widespread application. To tackle the instability issue, all-inorganic PSCs have attracted increasing interest due to superior structural, humid and high-temperature stability to their organic–inorganic counterparts. Nevertheless, all-inorganic PSCs with typical CsPbIBr₂ perovskite as light absorbers suffer from much inferior PCEs to those of organic–inorganic PSCs. Functional doping is regarded as a simple and useful strategy to improve the PCEs of CsPbIBr₂-based all-inorganic PSCs. Herein, we report a monovalent copper cation (Cu⁺)-doping strategy to boost the performance of CsPbIBr₂-based PSCs by increasing the grain sizes and improving the CsPbIBr₂ film quality, reducing the defect density, inhibiting the carrier recombination and constructing proper energy level alignment. Consequently, the device with optimized Cu⁺-doping concentration generates a much better PCE of 9.11% than the pristine cell (7.24%). Moreover, the Cu⁺ doping also remarkably enhances the humid and thermal durability of CsPbIBr₂-based PSCs with suppressed hysteresis. The current study provides a simple and useful strategy to enhance the PCE and the durability of CsPbIBr₂-based PSCs, which can promote the practical application of perovskite photovoltaics. Full article

This paper presents a technology for applying copper and silver films to cotton fabrics by combining photochemical and chemical methods for the reduction of the compounds of these metals. The resulting metal-containing films have inherent electrical conductivity of metals. All the main processes described in the work were carried out by means of the compounds being sorbed by the surface of the fabric when they were wetted in appropriate solutions. The aim of the work was to study the application of electrically conductive composite copper films on cotton fabrics. The tasks to achieve this aim were to perform scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis to confirm that as a result of the experiment, CuCl with a semiconductor ability was formed on the surface of the sample. The driving force behind the photochemical reduction of copper and silver halides on cotton surfaces is that, as a result of the photooxidation of cellulose molecules in the fabric, copper monochloride is first formed on the cotton surface. Subsequently, the process of obtaining silver particles based on semiconductor silver chloride obtained as a result of the transformation of copper monochloride was carried out. The physicochemical and photochemical processes leading to the formation of monovalent copper chloride, which provides sufficient adhesion to the substrate, are considered. It is shown that in this case, the oxidation of monovalent copper also occurs with the formation of soluble salts that are easily removed by washing. Since the proposed technology does not require special equipment, and the chemical reagents used are not scarce, it can be used to apply bactericidal silver films to various household items and medical applications in ordinary laundries or at home. This article examines an affordable and simple technology for producing metal films on a cotton surface due to the presence of disadvantages (time duration, high temperature, scarce reagents, special installations, etc.) of a number of well-known methods in the production of chemical coatings. Full article