Uranium recovery from UCF liquid waste by nanoporous MCM-41: breakthrough capacity and elution behavior studies

Adsorption and recovery of uranium by nanoporous MCM-41 from aqueous solutions (synthetic solution and uranium conversion facility liquid waste) were investigated by use of a fixed-bed column (1.2 cm diameter and 3.0 cm height). Adsorption was carried out at flow rates 0.2 and 0.5 mL min^?1, which correspond to retention times of 10 and 6 min. The maximum breakthrough capacity for uranium ions was achieved by use of nanoporous MCM-41 at the optimum pH of 3.6 and flow rate 0.2 mL min^?1 (61.95 μg g^?1). The Thomas and Yan models were applied to the experimental data, by use of linear regression, to determine the characteristics of the column for process design. The breakthrough curves calculated from the models were in good agreement with the experimental data. The elution behavior of uranium on nanoporous MCM-41 was studied with different eluents; the results showed that 0.1 M HCl is good eluent for uranium recovery. The regenerated column could be used in a multitude of adsorption–desorption cycles.     

Three Validated Methods for Simultaneous Determination of Ofloxacin and Dexamethasone in Binary Mixture

JPC – Journal of Planar Chromatography – Modern TLC - Three selective, precise, and accurate methods were developed and validated for the simultaneous determination of ofloxacin and...     

A heterogeneous and reusable nanopolymer-supported palladium catalyst for the copper- and phosphine-free Sonogashira coupling reaction under aerobic conditions in water

We report here the synthesis of a nanopolymer-supported palladium(II) complex catalyst, [PS-tet-Pd(II)] using a simple protocol. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR, and energy dispersive X-ray spectroscopy (EDS). PS-tet-Pd(II) proves to be a useful heterogeneous catalyst in the copper- and phosphine-free Sonogashira coupling reaction in water. The catalyst can be recovered from the reaction mixture by simple filtration and reused several times without any significant loss of catalytic activity.     

Fiber optical parametric amplifiers in optical communication systems

The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase‐insensitive amplifiers (PIAs) and phase‐sensitive amplifiers (PSAs) are considered. Low‐penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength‐ and time‐division multiplexed formats. High‐quality mid‐span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All‐optical amplitude regeneration of amplitude‐modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase‐modulated signals. A PSA with 1.1‐dB noise figure has been demonstrated, and preliminary wavelength‐division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength‐division multiplexed long‐haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long‐haul communication networks are discussed.

     

Lights and Shadows of DMSO as Solvent for Tin Halide Perovskites

In 2020 dimethyl sulfoxide (DMSO), the ever-present solvent for tin halide perovskites, was identified as an oxidant for Sn^II. Nonetheless, alternatives are lacking and few efforts have been devoted to replacing it. To understand this trend it is indispensable to learn the importance of DMSO on the development of tin halide perovskites. Its unique properties have allowed processing compact thin-films to be integrated into tin perovskite solar cells. Creative approaches for controlling the perovskite crystallization or increasing its stability to oxidation have been developed relying on DMSO-based inks. However, increasingly sophisticated strategies appear to lead the field to a plateau of power conversion efficiency in the range of 10–15 %. And, while DMSO-based formulations have performed in encouraging means so far, we should also start considering their potential limitations. In this concept article, we discuss the benefits and limitations of DMSO-based tin perovskite processing.     

Assessment of Lewis-Acidic Surface Sites Using Tetrahydrofuran as a Suitable and Smart Probe Molecule

Measuring the Lewis-acidic surface sites in catalysis is problematic when the material‘s surface area is very low (S_BET ≤1 m² ⋅ g⁻¹). For the first time, a quantitative assessment of total acidic surface sites of very small surface area catalysts (MoO₃ as pure and mixed with 5–30 % CdO (wt/wt), as well as CdO for comparison) was performed using a smart new probe molecule, tetrahydrofuran (THF). The results were nearly identical compared to using another commonly used probe molecule, pyridine. This audition is based on the limited values of the surface area of these samples that likely require a relatively moderate basic molecule as THF with pK_b=16.08, rather than strong basic molecules such as NH₃ (pK_b=4.75) or pyridine (pK_b=8.77). We propose mechanisms for the interaction of vapour phase molecules of THF with the Lewis-cationic Mo and Cd atoms of these catalysts. Besides, dehydration of isopropyl alcohol was used as a probe reaction to investigate the catalytic activity of these catalysts to further support our findings in the case of THF in a temperature range of 175–300 °C. A good agreement between the obtained data of sample MoO₃-10 % CdO, which is characterised by the highest surface area value, the population of Lewis-acidic sites and % selectivity of propylene at all the applied reaction temperatures was found.     

Synthesis and Assessment of Two Malonyl Dihydrazide Derivatives as Corrosion Inhibitors for Carbon Steel in Acidic Media: Experimental and Theoretical Studies

Despite the extensive use of carbon steel in all industrial sectors, particularly in the petroleum industry, its low corrosion resistance is an ongoing problem for these industries. In the current work, two malonyl dihydrazide derivatives, namely 2,2’-malonylbis (N-phenylhydrazine-1-carbothiamide (MBC) and N’1, N’3-bis(-2-hydroxybenzylidene) malonohydrazide (HBM), were examined as inhibitors for the carbon steel corrosion in 1.0 M HCl. Both MBC and HBM were characterised using thin-layer chromatography, elemental analysis, infrared spectroscopy, and nuclear magnetic resonance techniques. The corrosion tests were performed using mass loss measurements, polarisation curves, and electrochemical impedance spectroscopy. It is obtained from the mass loss studies that the optimal concentration for both inhibitors is 2.0 × 10⁻⁵ mol/L, and the inhibition efficiencies reached up to 90.7% and 84.5% for MBC and HBM, respectively. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP) indicate an increased impedance in the presence of both MBC and HBM and mixed-type inhibitors, respectively. Both inhibitors can mitigate corrosion in the range of 298–328 K. Values of free energy changes obtained from the Langmuir model suggest that the inhibitors suppress the corrosion process principally by chemisorption. The computational investigations were conducted to identify the factors connected with the anti-corrosive properties of the examined inhibitors.     

Phytochemical Profiling of Lavandula coronopifolia Poir. Aerial Parts Extract and Its Larvicidal,Antibacterial, and Antibiofilm Activity Against Pseudomonas aeruginosa

Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandula coronopifolia aerial parts extract using HPLC–MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC₅₀ = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17–38% at different Minimum Inhibitory Concentrations (MICs) (0.5–0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L. coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers.     

Enhancement of β-Glucan Biological Activity Using a Modified Acid-Base Extraction Method from Saccharomyces cerevisiae

Beta glucan (β-glucan) has promising bioactive properties. Consequently, the use of β-glucan as a food additive is favored with the dual-purpose potential of increasing the fiber content of food products and enhancing their health properties. Our aim was to evaluate the biological activity of β-glucan (antimicrobial, antitoxic, immunostimulatory, and anticancer) extracted from Saccharomyces cerevisiae using a modified acid-base extraction method. The results demonstrated that a modified acid-base extraction method gives a higher biological efficacy of β-glucan than in the water extraction method. Using 0.5 mg dry weight of acid-base extracted β-glucan (AB extracted) not only succeeded in removing 100% of aflatoxins, but also had a promising antimicrobial activity against multidrug-resistant bacteria, fungi, and yeast, with minimum inhibitory concentrations (MIC) of 0.39 and 0.19 mg/mL in the case of resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. In addition, AB extract exhibited a positive immunomodulatory effect, mediated through the high induction of TNFα, IL-6, IFN-γ, and IL-2. Moreover, AB extract showed a greater anticancer effect against A549, MDA-MB-232, and HepG-2 cells compared to WI-38 cells, at high concentrations. By studying the cell death mechanism using flow-cytometry, AB extract was shown to induce apoptotic cell death at higher concentrations, as in the case of MDA-MB-231 and HePG-2 cells. In conclusion, the use of a modified AB for β-glucan from Saccharomyces cerevisiae exerted a promising antimicrobial, immunomodulatory efficacy, and anti-cancer potential. Future research should focus on evaluating β-glucan in various biological systems and elucidating the underlying mechanism of action.     

Determination of Tedizolid Phosphate Using Graphene Nanocomposite Based Solid Contact Ion Selective Electrode; Green Profile Assessment by Eco-scale and GAPI Approach

Antibiotics determination plays a major role in minimizing antimicrobial resistance starting from quality control of pharmaceutical formulations to therapeutic drug monitoring. Green modified glassy carbon electrode has been developed for determination of tedizolid phosphate; new antibiotic prodrug; in presence of its active metabolite. The graphene transducer interlayer, dispersed with PVC, improved the electrode stability and standard potential reproducibility. Graphene hydrophobicity prevented the water layer formation between the sensing layers that decreased the potential drift down to 267 μV h⁻¹. Electrochemical impedance showed a low resistance value for graphene containing sensor due to its high electron transfer ability.