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Copper nanoparticles (CuNPs) have attracted attention due to their low cost and high specific surface area. In this work, a simple and inexpensive two-step synthesis method was proposed to prepare highly stable and well-dispersed spherical CuNPs in solution with a particle size of approximately 37 nm. Synthesis of CuNPs was carried on in the presence of complexing agent trisodium citrate (TSC), while for the chemical reduction step, sodium borohydride (NaBH4) was used. Taking into account the potential of this type of nanoparticles, their synthesis and characterization represent a current and relevant topic in the field. The ability to control the size, shape and properties of CuNPs by adjusting the synthesis parameters (pH, precursor:stabilizer:reductant ratio, homogenization time, temperature) offers extraordinary flexibility in the development of these materials. The combination of characterization techniques such as SEM, EDX, UV–Vis, Raman, FT-IR and AFM provides a thorough understanding of the structure and properties of CuNPs, allowing the modulation of the properties of the obtained nanoparticles in the desired direction. Based on the studies, the copper reduction mechanism was proposed. For the theoretical verification of the size of the experimentally obtained spherical CuNPs, Mie theory was applied. A stability study of the synthesized CuNPs in optimal conditions was performed using UV–Vis analysis at specific time intervals (1, 3, 30 and 60 days), the sample being kept in the dark, inside a drawer at 25 °C. The CuNPs obtained after setting the optimal synthesis parameters (Cu(II):TSC: B H 4 + = 1:1:0.2, pH = 5, homogenization time 60 min and temperature 25 °C) were then tested to highlight their antibacterial effect on some reference bacterial strains. The obtained CuNPs demonstrated very good antimicrobial efficacy compared to traditional antimicrobials, for both Gram-negative and Gram-positive bacteria. This may reduce the development of antimicrobial resistance, an urgent medical issue. After evaluating the cytotoxic effects of CuNPs on the SKBR3 cancer cell line, a significant decrease in cell proliferation was observed at the 0.5 mg/mL concentration, with a reduction of 89% after 60 h of cultivation. Higher concentrations of CuNPs induced a more rapid cytotoxic effect, leading to an accelerated decline in cell viability. [ABSTRACT FROM AUTHOR]

The alumina, in the form of α-Al2O3 tabular balls, considered in this study is a high-purity form of aluminum oxide that has been fired at high temperatures (well above 1900 °C), virtually removing porosity. However, the purity and inertness of the surface of the Al2O3 tabular balls minimize the catalytic activity, which is why lithium doping was tried. Thus, the target of this study was the effect of doping with lithium ions in some tabular balls of Al2O3 (the crystalline structure is corundum) on the improvement of the catalytic properties of alumina. This study examined the impact of a lithium catalyst on the combustion of various fuels within a porous inert medium (PIM) burner. This study specifically compared low calorific gaseous fuel (e.g., biogas) combustion in a PIM burner with and without the lithium catalyst. The experimental setup comprised a gas preparation unit for mixing CNG and CO2 to simulate biogas and a PIM burner. The PIM burner comprised Al2O3 spheres (13 mm diameter, 45% porosity) in a random packing configuration. Three fuels, varying in composition and lower heating value (LHV ranging from 20.771 to 27.695 MJ/m3), were combusted at air ratios ranging from 1.67 to 1.79. The results indicated that the catalyst increased peak combustion temperatures by 23.2 °C to 51.4 °C, depending on the fuel type and air ratio. Significantly higher carbon monoxide (CO) concentrations were observed without the catalyst, particularly with fuel type F1, while nitrous oxide (NOx) levels remained consistently low. Upstream flame propagation was observed in the presence of the catalyst. These findings demonstrate the potential of lithium catalysts to enhance combustion stability and reduce emissions in porous media combustion burners. Following these studies, it can be stated that Li(I) has the role of promoter of the catalytic process. [ABSTRACT FROM AUTHOR]

The European Union regards gallium as a crucial element. Because of that, the retrieval of gallium ions from secondary sources through diverse methodologies is of the utmost significance in an actual economical context. The primary goal of this study was to explore the viability of MgFe2O4 spinel as an adsorbent material for Ga(III) ions recovery from aqueous solutions. A spinel adsorbent material was synthesised by using the sol–gel synthesis method. After preparation, the obtained spinel was subjected to a thermal treatment, which resulted in modifications of its crystalline structure and morphology, in concordance with the calcination temperatures. Specifically, two distinct temperatures of 260 and 650 °C were utilised in the process, which was conducted in air. The second objective was represented by the physicochemical characterisation of the newly prepared adsorbent material by using various analytical techniques, e.g., Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and magnetic measurements. The optimal conditions for Ga(III) adsorption were established (S:L ratio, solution pH, contact time, temperature, initial Ga(III) concentration). Simultaneously, the obtained experimental data were modelled to prove the fact that the pseudo-second-order model explained the studied kinetics process and established its mechanism. Intraparticle diffusion was also studied to highlight the rate-determined step during the Ga(III) adsorption process. The equilibrium of the process was also studied, establishing that the Sips isotherm fitted the experimental data best, with a correlation coefficient R2~1, indicating that the studied adsorption process was homogeneous, the maximum adsorption capacity of spinel being 24.7 mg Ga (III)/g MgFe2O4. Thermodynamic parameters, involving ΔG°, ΔH° and ΔS°, were also calculated; negative values of ΔG° indicated that the adsorption was spontaneous. ΔH° proved to be endothermic, and the calculated ΔS° values being positive confirmed the fact that the process was spontaneous. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop new materials with adsorbent properties that can be used for the adsorption recovery of Au(III) from aqueous solutions. To achieve this result, it is necessary to obtain inexpensive adsorbent materials in a granular form. Concomitantly, these materials must have a high adsorption capacity and selectivity. Other desired properties of these materials include a higher physical resistance, insolubility in water, and materials that can be regenerated or reused. Among the methods applied for the separation, purification, and preconcentration of platinum-group metal ions, adsorption is recognised as one of the most promising methods because of its simplicity, high efficiency, and wide availability. The studies were carried out using three supports: cellulose (CE), chitosan (Chi), and diatomea earth (Diat). These supports were functionalised by impregnation with extractants, using the ultrasound method. The extractants are environmentally friendly and relatively cheap amino acids, which contain in their structure pendant groups with nitrogen and sulphur heteroatoms (aspartic acid—Asp, l-glutamic acid—Glu, valine—Val, DL-cysteine—Cys, or serine—Ser). After preliminary testing from 75 synthesised materials, CE-Cys was chosen for the further recovery of Au(III) ions from aqueous solutions. To highlight the morphology and the functionalisation of the material, we physicochemically characterised the obtained material. Therefore, the analysis of the specific surface and porosity showed that the CE-Cys material has a specific surface of 4.6 m2/g, with a porosity of about 3 nm. The FT-IR analysis showed the presence, at a wavelength of 3340 cm−1, of the specific NH bond vibration for cysteine. At the same time, pHpZc was determined to be 2.8. The kinetic, thermodynamic, and equilibrium studies showed that the pseudo-second-order kinetic model best describes the adsorption process of Au(III) ions on the CE-Cys material. A maximum adsorption capacity of 12.18 mg per gram of the adsorbent material was achieved. It was established that the CE-Cys material can be reused five times with a good recovery degree. [ABSTRACT FROM AUTHOR]

Pollution is a major problem updated in every corner of the world. The sources of pollution are diverse, from the natural pollution to the anthropogenic pollution. Anthropogenic pollution has a significant impact. Industrial activity, with all its fields, represents one of the most important sources of anthropic pollution. Also, the mining activities can be a source of pollution worth considering. Even if the mining activity has been completed, the possibility of pollution exists. Mining activity is the major source of industrial waste. At present, the mining units can fall into three categories: active mining, where the activity continues; in conservation mining, where the closing and greening program has not yet been applied; closed mining, which are in the Closing and Greening Program. The most affected environmental factors can be the sources of water, soil, but also air.

The need to develop advanced wastewater treatment techniques and their use has become a priority, the main goal being the efficient removal of pollutants, especially those of organic origin. This study presents the photo-degradation of a pharmaceutical wastewater containing Kabi cytarabine, using ultraviolet (UV) radiation, and a synthesized catalyst, a composite based on bismuth and iron oxides (BFO). The size of the bandgap was determined by UV spectroscopy, having a value of 2.27 eV. The specific surface was determined using the BET method, having a value of 0.7 m2 g−1. The material studied for the photo-degradation of cytarabine presents a remarkable photo-degradation efficiency of 97.9% for an initial concentration 0f 10 mg/L cytarabine Kabi when 0.15 g of material was used, during 120 min of interaction with UV radiation at 3 cm from the irradiation source. The material withstands five photo-degradation cycles with good results. At the same time, through this study, it was possible to establish that pyrimidine derivatives could be able to combat infections caused by Escherichia coli and Candida parapsilosis. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating various fruit samples using atomic absorption spectrometry method, the content in mineral elements, macroelements (Na, K, Ca, Mg) and microelements (Cr, Cu, Mn, Fe, Cd , Pb, Zn, Co and Ni). Fruit samples were taken from supermarkets (imported products) and agricultural markets (domestic products) in the city of Timisoara, Romania. The results obtained by chemical analysis were evaluated statistically based on method of main components analyzed. Major influence in the group had evidence if macroelements potassium and sodium, iron and manganese where microelements. The results were compared with results obtained by other researchers in the world. The results fall within the legal limits set by law.

The aim of this paper is to provide a simple and efficient photoassisted approach to synthesize silver nanoparticles, and to elucidate the role of the key factors (synthesis parameters, such as the concentration of TSC, irradiation time, and UV intensity) that play a major role in the photochemical synthesis of silver nanoparticles using TSC, both as a reducing and stabilizing agent. Concomitantly, we aim to provide an easy way to evaluate the particle size based on Mie theory. One of the key advantages of this method is that the synthesis can be "activated" whenever or wherever silver nanoparticles are needed, by premixing the reactants and irradiating the final solution with UV radiation. UV irradiance was determined by using Keitz's theory. This argument has been verified by premixing the reagents and deposited them in an enclosed space (away from sunlight) at 25 °C, then checking them for three days. Nothing happened, unless the sample was directly irradiated by UV light. Further, obtained materials were monitored for 390 days and characterized using scanning electron microscopy, UV-VIS, and transmission electron microscopy. [ABSTRACT FROM AUTHOR]

In the present work, two novel aminophosphinic acid ligands grafted on poly(styrene-1%divinylbenzene) (St-%DVB) have been synthesized by reacting polymer precursors bearing primary amino groups with benzaldehyde (or propionaldehyde) and phenylphosphinic acid by the 'one-pot' Kabatachnik-Fields reaction. The resins functionalized with aminophosphinic pendant groups were characterized by means of Fourier transform infrared spectroscopy (FTIR), thermal analysis, energy dispersive X-ray microanalysis (EDX), and Scanning electron microscopy (SEM) imaging. Its adsorption capacity for divalent metal ions such as Cu(II) and Ni(II) were investigated. The adsorption procedure of Cu(II) and Ni(II) ions on polymer-grafted aminophosphinic acid ligands was carried out by batch experiments. The result also shows that the adsorption process was best described by a pseudo-second-order kinetic equation and by the Langmuir adsorption isotherm. The best maximum adsorption capacity was obtained for resin with aminobenzylphosphinic acid groups [1.46 mg Cu(II)/g and 1.36 mg Ni(II)/g]. POLYM. ENG. SCI., 53:1117-1124, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION In recent years, public awareness has increased on the long-term toxic effects of water containing dissolved metal ions. Many industries such as textile industry, oil refining, metal plating facilities, [...]