Solutions Of Copper Salts Research Articles

Green Synthesis of Copper and Copper Oxide Nanoparticles From Brown Algae Turbinaria Species' Aqueous Extract and Its Antibacterial Properties.

Background Copper and copper oxide nanoparticlessynthesized by green methods have attracted considerable attention due to their environmentally friendly properties and potential applications. Green synthesis involves non-hazardous and sustainable techniques used in the production of a wide range of substances, including nanoparticles, pharmaceuticals, and chemicals. These methods often use different organisms, including bacteria, fungi, algae, and plants, each offering different advantages in terms of simplicity, cost-effectiveness, and environmental sustainability. The environmentally friendly nature of these green synthesis methods responds to the growing need for sustainable nanotechnologies. Brown algae have gained popularity due to their distinct morphological characteristics and diverse biochemical composition. This research focuses on the process of synthesizing copper and copper oxide nanoparticlesfrom the brown algae Turbinaria. It emphasizes the natural ability of the bioactive compounds contained in the algae extract to reduce and stabilize the nanoparticles. The green synthesis of copper and copper oxide nanoparticlesfrom brown algae has demonstrated a wide range of applications, including antibacterial activity. Materials and methods Fresh Turbinaria algae were collected from marine environments to ensure that they were free of contaminants. The algae underwent a purification process to remove impurities and were dried. An aqueous extract was prepared by pulverizing the dried algae and mixing them with distilled water. A copper salt solution utilizing copper nitrate was prepared. The algae extract was mixed with the copper salt solution. There are bioactive compounds in the algae extract that help reduce copper ions, which makes copper and copper oxide nanoparticles come together. The reaction mixture was incubated in a controlled environment to facilitate the growth and enhance the stability of the nanoparticles. To separate the nanoparticles from the reaction mixture, centrifugation was employed, or filtration was done with Whatman filter paper (Merck, Burlington, MA). The nanoparticles were dried to yield a stable powder. Results Copper and copper oxide nanoparticles derived from brown algae extract showed antibacterial effects against Streptococcus mutans,Klebsiella sp.,andStaphylococcus mutans. The scanning electron microscopy (SEM) analysis verified the irregular shape and elemental content of the synthesized copper and copper oxide nanoparticles. The X-ray diffraction (XRD) analysis indicated that the synthesized nanoparticles exhibited a crystallinity nature and were composed of a mixture of copper and copper oxide species, namely face-centered cubic and monoclinic structures. The transmission electron microscopy (TEM) images showed copper and copper oxide nanoparticles that were evenly distributed and had a rectangular shape. They exhibited substantial antimicrobial activity against both Gram-positive and Gram-negative bacteria. Conclusions This study enhances the field of green synthesis techniques by showcasing the adaptability of Turbinaria brown algae to synthesize copper and copper oxide nanoparticles. It underscores the potential advantages of these nanoparticles in terms of their antibacterial properties.

Liposomal form of 2-alkylthioimidazolone-based copper complexes for combined cancer therapy.

Aim: To develop an optimized approach for encapsulating a 2-alkylthioimidazolone-based copper coordination compound within liposomes, which could offertreatment of cancer and bacterial infectionsby reactive oxygen species generation toxicity mechanisms. Materials & methods: For drug-loaded liposome preparation, lipidsand drug mixturein organic solvents wasinjected into copper salt solution, forming a coordination compound simultaneouslyembedded in the lipid bilayer. In vitro tests were performed on MCF7 and MDA-MB-231 breast cancer cells. Results: Liposomes had a loading capacity of up to 1.75% (molar drug-to-lipid ratio). In vitro tests showed increased viability and accumulation of the liposomal formulation compared with free drugas well as lack of cytotoxicity in hepatocytes. Conclusion: This optimized technique for encapsulating large copper complexes in liposomes could be used to improve theirdelivery and better treat cancer and bacterial infections.

Breeding evaluation of the common buckwheat accessions (<i>Fagopyrum esculentum</i> Moench) obtained with the use of copper and zinc ions

Relevance. Employing new biotechnological methods in the breeding of buckwheat, including the screening of forms with tolerance to copper and zinc ions, might increase the adaptability of genotypes and allow the creation of promising starting material for further breeding.Methods. The research on common buckwheat with tolerance to copper and zinc ions and breeding evaluation of the obtained accessions were conducted at FSBSI «FSC of Agricultural Biotechnology of the Far East named after A.K. Chaiki» in 2020–2023. The research object was 10 accessions obtained from buckwheat varieties Kitavasesoba (Japan) and Izumrud (Russia) and hybrid Izumrud×Kitavasesoba, whose microshoots and seeds were exposed to copper and zinc ions. Released variety Izumrud was used as the standard. The method of cell and tissue culture in vitro as well as the germination of seeds in concentrated solutions of copper and zinc salts in vivo were employed.Results. In the conditions of the monsoon climate of Primorsky Krai, a three-year test of 10 buckwheat samples obtained under the influence of copper and zinc ions in culture in vitro and in vivo was carried out. As a result of the study, three samples were selected for further selection (No. 989, 1013, 783), which are characterized by a complex of economically valuable traits: high seed productivity (6.5–7.1 g), stress resistance, genetic flexibility, high mass of 1000 seeds (37.8–44.8 g), a combination of high mass of 1000 kernels (27.4–33.1 d) with low film content (23.3–25.5%), and two samples (No. 997, 1005) with an increased content of rutin in fruits (7.1–7.7 mg / 100 g).

A New Pyrrole-2-carboxaldehyde Functionalized Chitosan-Cu(II) Complex-based Chemosensor for Iodide Anion in Aqueous Media

Iodine is an essential ingredient in thyroid hormones of which both low and high intakes may cause thyroid disease. This study develops a Pyrrole-2-Carboxaldehyde functionalized chitosan-Cu(II) Complex [PCAFC-Cu(II)] chemosensor, for quick and easy detection of iodide ions from its aqueous solutions. PCAFC-Cu(II) complex was synthesized from a simple condensation reaction of chitosan (CS) and pyrrole-2-carboxaldehyde (PCA) along with an aqueous solution of copper(II) salt. The starting materials and the products were characterized by spectroscopic (FT-IR and UV-Visible), X-ray powder diffraction, and microscopic methods (Scanning Electron Microscopy). The PCAFC-Cu(II) colorimetric sensing of I- revealed a color change adduced to the formation of a hydrogen bond or deprotonation of the complex matrix. Colorimetric detection for I- ions was obtained with a detection limit (LoD) of 0.005 M and the complex has high specificity for I- ions detection from a solution consisting of several anions. The synthesized complex [PCAFC-Cu(II)] could serve as an on-site reagent for the qualitative detection of iodide ions.

In Situ Generation of Copper Nanoparticles in Heat-Treated Copper-Containing Masson’s Pine as a Preservative Process for Sawn Timber

Heat-treated wood has good dimensional stability, durability, and color, but its susceptibility to fungal growth affects its commercial value. In this study, lumber harvested from mature Masson’s pine (<i>Pinus massoniana</i> Lamb.) was vacuum impregnated with a basic copper salt solution (copper hydroxide, diethanolamine, and polyethylene glycol 200) prior to heat-treatment at 220°C for 3 h. Antifungal properties, surface chemistry, crystal structure and sugar contents were tested, compared with heat treatment alone. The results showed that the samples treated by heating without copper salt treatment showed poor suppression of fungal growth, the copper-impregnated heat-treated wood suppressed (100%) the growth of <i>Botryodiplodia theobromae</i> Pat., <i>Aspergillus niger</i> V. Tiegh., <i>Penicillium citrinum</i> Thom, and <i>Trichoderma viride</i> Pers. The combined results of X-ray photoelectron spectroscopy, X-ray diffraction and sugars analysis suggested that fungal inhibition by the heat-treated copper-bearing Masson’s pine was mainly due to the reduction of the metal salt by PEG200 at high temperature to generate copper nanoparticles. In addition, the reduced sugar content of the treated timber, and hence the nutrient substrate for spoilage microbes, reduced in the presence of the metal salts at high-temperature. This study has demonstrated an effective method of increasing low-grade wood’s utility and commercial value.

Dynamics of Adsorption of Copper Ions in Fixed-Bed Column and Mathematical Interpretation of the First Stage of the Process

The dynamics of the adsorption process in the fixed-bed column was experimentally studied on the example of the system natural zeolite - water solution of copper salt with low concentrations, which are characteristic for wastewater treatment processes from toxic contaminants. The initial curves of the adsorption process for the height of the sorbent layer of 5 and 7 cm were constructed. The equilibrium of such processes can be described by Henry's linear equation. The adsorption process in the layer consists of two stages, which are examined in the study. The first stage is the formation of concentration front and the second one – its moving. The sum of the time of the first and second stages is the total adsorption time, which is determined before breakthrough time. The first stage of adsorption is mathematically formulated by the differential equation of molecular diffusion with a boundary condition of the first type. The second stage is supplemented by the balance equation, which takes into account not only the change of concentration in time, but also in the vertical coordinate and determines the time of movement of concentration front to breakthrough time. A mathematical model of the adsorption process in a fixed-bed column has been developed. Experimental data and theoretical calculations were compared. The results of statistical calculation of research results showed a satisfactory convergence of experimental and theoretical data.

Highly active atomic Cu catalyst anchored on superlattice CoFe layered double hydroxide for efficient oxygen evolution electrocatalysis

Developing active, natural abundant and non-expensive electrocatalysts for large scale production and storage of clean hydrogen (H 2 ) fuel is a prerequisite to drive stable water splitting reaction. Herein, atomic Cu species loaded on hierarchical flower-like CoFe layered double hydroxides (LDHs) superlattice (denoted as Cu x /CoFe LDHs) were firstly fabricated by a facile co-precipitation method followed by a room temperature treatment to load the atomic Cu species from alkaline copper salt solution. The superlattice structure was proved by the high resolution transmission electron microscopy (HRTEM). Remarkably, benefiting from high level long ordering associated with vacant cation sites and defects, the unique superlattice structural features and the atomic Cu % loading onto the LDHs matrix, the obtained Cu x /CoFe LDHs electrocatalyst exhibited superior activity and stability for oxygen evolution reaction (OER). The loaded atomic Cu species improves the electronic structure and provides more exposed active sites due to synergetic electron coupling between Copper and the LDHs. These atomic species have outstanding potentials for achieving high selectivity and reactivity in electrocatalysis and heterocatalysis. Importantly, the efficient resulted Cu 4.76 /CoFe LDHs electrode in which the atomic Cu % loading ratio is 4.76% showed the best electrocatalytic activity which only required the much lower overpotential of 253 mV to reach 10 mA/cm 2 and a small Tafel slope of 63 mV/decade in 1 M KOH. This electrocatalyst possessed unique superior features to many other state-of-the-art earth-abundant electrocatalysts. This work paves a facile and novel method for enhancing the catalytic activity of CoFe LDHs based electrocatalyst, which may be extended to the synthesis of future electrocatalysts having highly active OER performance. • Novel synthesis of Cu x /CoFe LDHs electrocatalysts via co-precipitation followed by atomic Cu species loading. • 3D hierarchical porous flower-like morphologies offering more accessible channels and active sites. • Electrons transfer from M (Co or Fe) to Cu via M–O–Cu bonds. • The Cu 4.76 /CoFe LDHs electrode showed much lower overpotential and small Tafel slope. • The loaded atomic Cu species improves the electronic structure and provides more exposed active sites.

Improving the anti-mould property of Moso bamboo surface by using a bamboo green colour preservation approach

ABSTRACT Bamboo is prone to mould infection and discolouration. Traditional methods of preventing mould are to peel off the green and yellow layers, and then anti-mould treatment was performed. Though these methods were efficient, the original green colour of bamboo was removed and resulted in resources waste because of the removal of the green portions. This paper presented an anti-mould property method of Moso bamboo surface by using a green colour preservation process. The results revealed that the outer bamboo skin processed a certain anti-mould effect. Based on this result, the green colour preservation method involving the alkali solution and the copper salt solution treatment processes could improve the anti-mould property of the Moso bamboo surface as well as the green colour by removing the covering wax and opening the stoma. Compared with the control, the treated specimen’s mould growth was delayed by 11 days. The mould area was reduced by half, which exhibited a green colour with a low a* value of −14.91.

Some peculiarities of the kinetics of interaction of cationic hydrogels based on copolymers of vinyl esters of monoethanolamine and ethylene glycol with copper ions

Over the past few decades, formation of polymer hydrogels complexes with metal ions, including transition ones, attracts the steady attention of researchers. The relevance of such study is due to the fact that the kinetics of swelling and contraction of hydrogels in various media has been studied in many works, however, this question remains insufficiently studied. Cationic hydrogels based on copolymer of vinyl ethers of monoethanolamine (VEMEA) and ethylene glycol (VEEG) as the study subject in the present work have been used. The kinetics of interaction cationic hydrogels based on copolymer of vinyl ethers of monoethanolamine and ethylene glycol with copper ions in aqueous solutions has been studied. It was shown that swelling behavior such hydrogel in this process is characterized two stages. At the initial stages of the interaction of the gel with the copper salt solution, the interaction in question is determined mainly by the displacement of water from the swollen mesh, due to the difference in osmotic pressures inside and outside the sample. At this stage, the kinetics of the gel contraction is described by the same laws as for polyelectrolyte hydrogel in the alkali metal solution. At the second stage, the network charge density increases due to the formation of a complex, and the degree of the gel swelling begins to increase with time. On the basis of the results obtained, it can be assumed that in systems of this kind, metastable states with differences in character from truly equilibrium states, persisting for a long time, can be formed.

QUANTUM CHEMICAL SIMULATION OF THE INHIBITORY EFFECT OF AQUEOUS SOLUTIONS OF INORGANIC COPPER(II) SALTS ON THE COMBUSTION OF HYDROCARBONS

Introduction. The search for chemicals that would have an effective fire extinguishing effect and the development of new fire extinguishers based on them is an extremely important problem of fire safety. It is known from the literature that new aqueous fire extinguishing agents (AFEAs) based on dissolved inorganic salts of transition metals, in particular, copper(II) chloride salts, have a rather efficient inhibitory effect on the hydrocarbon flame. However, the mechanism of inhibition of hydrocarbon combustion by this class of substances is not completely ascertained. However, it is reliable information about the processes that take place in the flame after the bringing in there of the aerosol of the mentioned AFEA will allow a systematic search for more optimal chemical composition of dissolved inorganic salts of d-metals. Purpose. The purpose of the work is to reveal the peculiarities of the interaction of concentrated aqueous solutions of copper(II) chloride salts with chemically active flame particles.Methods. Quantum chemical calculations of the chemical activity of radicals that appear in the flame and the physicochemical processes that occur in the flame after the bringing on there of AFEA aerosol.Results. The mechanism of a fire-extinguishing effect of aqueous solutions of inorganic copper(II) salts on a hydrocarbon flame is investigated by a calculation method. The sequence of stages of chemical processes that occur in the flame during the inhibiting combustion of hydrocarbons by AFEAs—concentrated solutions of CuCl2 and K2[CuCl4]—and the thermal effects of all reactions that accompany each of these stepwise transformations were ascertained. The stages of the interaction of gaseous Cu2Cl4 molecules with ×OH and ×H radicals in flame with the formation of first a radical-molecular complex and then a molecular complex are decisive in the process of inhibition and display the processes of interruption of chain reactions, i.e. deactivation of radicals in a flame.Conclusion. Thus, using the method of quantum chemical calculations the mechanism of inhibition of hydrocarbon combustion by copper(II) salts was offered. The mechanism of this process is considered to be associative, the decisive elementary act of which is carried out according to the scheme of addition of active radicals of a flame (×OH particles) to gaseous molecules Cu2Cl4 with the formation of radical-molecular complex [{Cu(×OH)Cl2}2] and with its subsequent deactivation by ×H particles.

Enhanced photocatalytic activity of biogenically synthesized CuO nanostructures against xylenol orange and rhodamine B dyes

In the present article we report the Tamarindus indica L extract mediated biogenic green synthesis of CuO nanostructures. The synthesis consisted of reacting mixtures of copper salt solution and fruit extract at elevated temperatures. Heating under hydrothermal conditions for a very short duration (1 h) and under normal conditions for several hours were employed. The role of the heat treatment method on the growth of the nanostructures and their photocatalytic properties has been investigated. To the best of our knowledge, no one else has reported such a rapid synthesis of CuO nanostructures biogenically employing plant extracts. Moreover, no one else has reported the synthesis of CuO nanostructures such as nanosheets using fruit extracts of Tamarindus indica L. X-ray diffraction (XRD) and selected area electron diffraction (SAED) results reveal that the CuO nanostructures grow in the monoclinic and cubic phases. Morphological studies indicate the material grown under short duration (hydrothermal conditions) predominantly consists of nanosheets (~27 nm thick) while that grown with prolonged heating consists of granular nanoparticles (diameter ~ 19 nm), both agglomerated as spherical structures. Thermogravimetric results show good thermal stability of the nanostructures even at high temperatures. Optical properties indicate the material is visible light active and possesses an indirect energy band gap ~ 1.7 eV. Photoluminescence (PL) spectra of the nanostructures showed prominent emission at ~700 nm and a small amount of emission around 400 nm. The color coordinates of the nanoparticles determined from the PL data were located in the blue region of the Commission internationale de l'éclairage (CIE) diagram. Surface area analysis revealed mesoporous nature of the nanostructures. The nanosheets exhibit larger surface area (35.4 m2/g) than the granular nanoparticles (22.6 m2/g). The microspheres made of agglomerated nanosheets were used to carry out the photocatalytic degradation of rhodamine B (RhB) and xylenol orange (XO) dyes under UV–Visible light illumination. The nanosheets exhibited strong photocatalytic behavior and photodegraded 96% of RhB and 87% of XO in 150 and 90 min of light illumination, respectively. The photocatalyst showed good stability during the photocatalytic reactions. High activity and better stability of the nanosheets indicate the photocatalysts have potential ability to get commercialized.

Synthesis and Metal Phases Characterization of Mordenite Supported Copper Catalysts

Three catalysts were synthesized by the impregnation method using copper as an active metal and mordenite as a support material. The metal loading was set at 0, 4 and 8 %wt, respectively. The used copper salt solutions were collected as filtrate and analyzed by atomic absorption spectroscopy (AAS) to predict the metal content was successfully loaded onto mordenite. For a further step, catalysts are activated through the calcination and reduction process. The metal content was further confirmed by X-Ray Fluorescence (XRF) and the results were not much different compared to AAS analysis. It was obtained that copper metals were successfully impregnated on the catalyst as 3.74 %wt for Cu/MOR 4 and 5.52 %wt for Cu/MOR 8. Meanwhile, the catalysts were also characterized using X-ray diffraction (XRD) and then followed by match with a mordenite standard diffractogram. Further diffractogram analysis was carried out by the Le Bail method to get semi-quantitative data of metal phases on catalysts. Mordenite phase was consistently obtained as the main content of all catalysts, over 99%. The copper phase at Cu/MOR 4 catalyst was consisted of Cu, Cu(OH)2 and Cu2O. In contrast, Cu/MOR 8 catalysts showed no Cu(OH)2 phase on it, but Cu and Cu2O still found.

БИДАЙ ДƏНДЕРІН ПРАЙМИНГТЕУДІҢ МЫС ИОНДАРЫ БАР ОРТАДА ӨСКІНДЕРДІҢ ДАМУЫ МЕН ПРОЛИН МӨЛШЕРІНЕ ƏСЕРІ

In addition to antioxidants, compounds called osmoprotectants also play a special role in relieving the negative effects of oxidative stress that occurs in plants. These include glycinbetaine, proline, and mannitol. Among them, the biological role of proline is most common among plants. The results of this study are related to the development of pre- sowing processing (priming) of grains of various varieties of spring wheat to increase its resistance to heavy metals, yield and seed quality. The study is aimed not only at increasing seed germination, growth and development of their seedlings under heavy metal exposure, but also at determining the amount of proline in sprouted seeds after priming. It was carried out under the above-mentioned conditions of different concentrations of priming and copper salt solution and studied how Proline levels change in wheat sprouts. The obtained results show for the fi rst time that the relationship between antioxidants and osmoprotectants changes during oxidative stress caused by heavy metal. Key words: proline, pre-sowing priming, heavy metals, osmoprotectants.

Radiation–Chemical Reduction of Cu2+ Ions in an Aqueous Solution

Upon irradiation with accelerated electrons of aqueous solutions of copper salts containing methyl alcohol, the formation of a precipitate containing metallic copper and monovalent copper oxide Cu2O is observed in a mass ratio of 75.2 and 24.8%, respectively. The process of metal precipitation and its properties were studied. The radiation–chemical yield of the mass of the precipitated precipitate is (7.2 ± 0.2) × 10–3 g/kGy. The efficiency of the radiation method for the reduction of copper from aqueous solutions of its salts has been substantiated. The method can be promising for the production of precipitates of pure and amorphous metals, as well as for the treatment of water effluents containing toxic transition metals.

Обоснование использования лузги гречихи для получения функциональных пищевых красителей

The aim of the work was to substantiate the use of buckwheat husk for obtaining a functional food colorant melanin. The objects of the study were samples of buckwheat husk Fagopýrum esculéntum and isolated water-soluble melanin. The isolation of melanin was carried out by extraction of buckwheat husk with 4% NaOH at a hydraulic modulus of 1:20. The sorption capacity of the melanin extract was determined by its interaction with copper salt solutions in an alkaline medium. It has been established that a distinctive feature of buckwheat hulls is its low ash content, a rather high fiber content – 24.7–26.5%, and a sufficient content of pectin substances – 7.2–7.7% and melanin – 15.7–16.2%. The husk can be used for further processing in order to obtain the food coloring melanin. The experiment proved the ability of a melanin sample to bind copper ions: one gram of a 0.5% solution of buckwheat husk melanin extract bounded 966.6 mg/ml copper, and the antioxidant activity of one gram of melanin extract corresponds to the antioxidant activity of 0.056 g of rutin. Thus, water-soluble samples of melanin isolated from buckwheat hulls can be used as food coloring agents, as well as antioxidants and biosorbents, which makes it possible to recommend them as functional food ingredients in food.

Preparation and Structures of Carbon-Copper Oxide Nanofibers from Electrospun Polyacrylonitrile Composite

Carbon-copper oxide nanofibers have been prepared by heat treatment of polyacrylonitrile-copper salt nanofibers. In this study, fabrication of PAN-copper salt using two different methods - firstly, synthesis of PAN-copper salt solution using electrospinning (PAN-CuAc NF), and secondly, immersion of electrospun PAN nanofiber in the copper salt solution (PAN-c-CuAc NF). Those ways had a distinct effect on the structure of carbon-copper oxide nanofibers. The morphologies and structures of carbon-copper oxide nanofibers were observed by scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX), infrared spectroscopy (IR), X-ray diffraction (XRD), and Raman spectroscopy. The SEM image showed a randomly oriented nanofiber structure without bead formation, which average diameter of the nanofiber decreased with increasing process temperature. IR spectra and XRD patterns confirmed the formation of aromatic structures and graphite-like structures on carbon-copper oxide nanofiber. The Raman spectrum revealed that the intensity ratio (ID/IG) of carbonized nanofibers showed different values when the electrospun PAN composite nanofibers were synthesized using a different method, 1.59 for electrospun PAN nanofibers (CNF), 1.92 for carbonized PAN- CuAc nanofibers (C-copper oxide NF), and 0.60 for carbonized PAN-c-CuAc nanofibers (C-c-copper oxide NF).The presence of Cu element has been successfully detected in carbon-copper oxide nanofibers using EDX analysis.

Deposition and properties of mixed molybdenum sulfide (MoS2) and copper sulfide (CuxS) films on glass surface using elemental sulfur as a precursor

Mixed molybdenum sulfide (MoS2) and copper sulfide (CuxS) materials were synthesized on glass slides as a model substrate by successive ionic layer adsorption and reaction method using elemental sulfur as a sulfur source and solutions of copper (II/I) and molybdenum (IV) salts. X-ray diffraction data showed the presence of copper sulfides (anilite Cu7S4 and djurleite Cu31S16 phases), molybdenum disulfide and molybdenum oxide with adjustable crystalline phase composition dependent on the precursor exposure time and reaction temperature. Scanning electron microscopy images showed that the surface had a homogenous layer distribution at lower temperatures/short exposures and comprised of ~1 μm particles. X-ray photoelectron spectroscopy showed no oxidized sulfate (SO42−) compounds present on the sample surface while a thin MoO3 layer was found to cover the sample surface. Optical ultraviolet-visible spectroscopy showed mixed layers formed, containing optical properties of both MoS2 and CuxS. After annealing in an N2 atmosphere at 100 °C, the sample was composed primarily of MoS2 and copper sulfides in the crystalline phase with minimal residual S8. Usability of this mild mixed metal sulfide thin film preparation method on supports for sour natural gas catalyst synthesis is also discussed.

Preparation, characterization and application of polymeric thin films containing silver and copper nanoparticles with bactericidal activity

The aim of this work was to prepare and characterize self-assembled thin films (SATFs) of poly(allylamine hydrochloride) and poly(acrylic acid) containing silver (AgNPs) and copper nanoparticles (CuNPs) for their subsequent application in the disinfection of an industrial wastewater. The AgNPs and CuNPs were synthesized by direct irradiation of SATFs with ultraviolet light after immersion in silver and copper (II) salt solutions. At the end of the self-assembly procedure, the SATFs were thoroughly characterized by different instrumental techniques, including glow discharge optical emission spectroscopy (GD-OES), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), and transmission electron microscopy (TEM). In general, the GD-OES spectra confirmed the incorporation/formation of AgNPs and CuNPs/copper (II) oxide in the SATFs. Moreover, it was observed through the FESEM and TEM analyses that a change in the salt concentration promoted a variation in the nanoparticle size incorporated into the SATFs (10−250 nm for AgNPs, and 10−170 nm for CuNPs). The disinfection process of the industrial wastewater with the SATFs reduced the total count of coliforms by 91 and 100 % compared to the raw industrial wastewater (untreated), being the SATF prepared with a concentration of 0.1098 mmol Ag+ L−1 the most efficient material. Finally, the SATFs developed in this work present great potential for a possible application in the tertiary treatment of industrial wastewater due to ease of application, reduced environmental impact, and satisfactory inhibitory action.

Features of Preparation of the Methanol Synthesis Component of a Bifunctional Dimethyl Ether Synthesis Catalyst

The production of dimethyl ether from synthesis gas involves the use of bifunctional catalysts, which mediate the synthesis and dehydration of methanol. The effect is provided by the presence of a methanol synthesis component and a dehydration component in the catalyst; the components can be synthesized independently. The published data on the synthesis of a CuО/ZnО/Al2О3 methanol synthesis catalyst by precipitation from a nitrate solution are conflicting; therefore, it is relevant to study the effect of the procedure and conditions for the precipitation of copper, zinc, and aluminum nitrate solutions with sodium carbonate on the activity of the above catalyst. Data on the phase composition of the precipitates after a heat treatment and the activity of the synthesized catalysts in methanol synthesis suggest that the presence of nitrate groups in the precipitates leads to a decrease in catalytic activity. A method to prepare a methanol synthesis catalyst at room temperature by introducing a solution of copper, zinc, and aluminum salts into a sodium carbonate solution (reverse coprecipitation) is proposed. This method provides the level of activity of the resulting samples directly in methanol synthesis that is close to the level of activity of a commercial methanol synthesis catalyst. Dimethyl ether synthesis in the presence of bifunctional catalysts, in which the methanol synthesis component is prepared by different methods and the dehydration component is commercial gamma-Al2O3, is studied. In the presence of the synthesized samples, the methanol selectivity is almost identical; however, the productivities with respect to oxygenates and dimethyl ether are significantly different.

Plant mediated synthesis of copper nanoparticles by using Camelia sinensis leaves extract and their applications in dye degradation

In the present study, we have developed a green, facile, eco-friendly and cost-effective approach for the synthesis of copper nanoparticles (CuNPs) from copper salt (CuCl) solution by using Camelia sinensis leaf extract. The biomolecules present in C. sinensis leaves extract were responsible for the reduction and stabilization of CuNPs. The synthesized nanoparticles were characterized by using FT-IR, SEM, TEM and EDX analysis. FT-IR analysis was used to ratify the presence of biomolecules in C. sinensis leaves extract, while SEM and TEM analysis showed that the synthesized nanoparticles are in agglomerated form and having an average size of 60 ± 6 nm. The percentage weight of synthesized nanoparticles was measured through EDX analysis. Moreover, the photocatalytic degradation of synthesized CuNPs was also evaluated by using bromophenol blue (BPB) dye under sunlight irradiation. The maximum photo-degradation of BPB dye was up to 83.7%. UV-Vis spectral analysis of CuNPs proved them as an efficient photocatalyst in dye degradation.