Basic Medium Research Articles

Synthesis, Characterization and Analytical Study of New Azo Compounds for using as acid-base indictors

A diazotization method was used to synthesize new azo compounds, to which phenol was subsequently added to diazonium salt solution in basic medium at temperatures ranging from 0 to 5 °C and compounds were characterized by FT-IR, 1H-NMR, and 13C-NMR spectroscopy. The potential of the compounds as acid-base indicators was tested by determining their ionization and protonation constants at different pH levels (1 to 14) using a DMSO solution of the synthesized compounds. UV-Vis spectra shown as maximum wavelength (380-390 nm) observed at pH 1-7 occurs, indicating the cationic formula (protonated form of compound H2 and H4), another peak (470-530 nm) appears at pH 8-13, indicating the ionic formula (deprotonated form of compound H2 and H4), where for compound H5 observed at 560 nm at pH 1-7. Another peak appears 505 nm at pH 8-13 attributable to absorption the ionic formula (deprotonated form of compounds H5). Molecules H2, H4, and H5 showed distinct color changes when shifted to acidic and basic conditions. Furthermore, these compounds showed exceptional accuracy in drawing conclusions about the phenomenon.

Preparation and Characterization of Acid and Base Modified Fish Scales of Labeo Rohita and Their Application as an Adsorbent

The study is carried out to investigate the removal efficiency of the textile dye Congo Red (CR) on fish scales (FS) of Labeo rohita. Huge fish scales are dumped as waste from the fish markets and are not converted into valuable products. That is why a fish scale of widespread fish in Bangladesh Labeo rohita has been selected as an adsorbent in removing Congo red from an aqueous solution. In the present study, the effect of different parameters such as adsorption dosage, contact time, concentration of dye, and pH on the removal of CR were investigated. The maximum dye removal efficiency (88.53 %) was observed for 3g/100 mL of adsorbent at an initial concentration of 1×10-4 M and pH 8.80 after 60 minutes. Modification of the surface of the fish scales was carried out by using HCl and KOH. The surface of the adsorbents was characterized by FTIR spectroscopy. After 60 minutes of contact time, the percentage of adsorption for the acid and base-modified FS was 54.81% and 90.51% respectively. The higher intense FTIR spectra of the base-modified FS denoted the better efficiency of the adsorbent at the basic medium. The adsorption kinetics of CR on FS is studied by following the pseudo-first-order and pseudo-second-order kinetic model. Experimental results showed that fish scales of Labeo rohita have satisfying color removal efficiency and might be a better alternative to other adsorbents to detoxify industrial wastewater. A mechanism of adsorption of CR on FS has been proposed.

DIAGNOSTICS OF THE DEVELOPMENT OF INFORMATION AND DIGITAL COMPETENCE OF FUTURE OFFICERS

Formulation of the problem. Today the problem of developing information and digital competence (IDC) of future officers in the context of non-formal education and the problem of designing a diagnostic apparatus to measure such development is relevant. The paper aims to develop a diagnostic apparatus (criteria and indicators) to measure the development of information and digital competence of future officers Methods. To achieve this goal, we used the analysis and generalization of scientific sources, structural and logical analysis to identify and substantiate the indicators of the development of the IDC of future officers, as well as content analysis and comparative analysis to characterize the levels of development of the IDC of future officers. Results. To assess the levels of development of the IDC of future officers, the criteria (motivational and value, cognitive and activity) and the relevant indicators (the presence of motives, value attitudes for self-development, knowledge about IT & DT in general and in the industry, the ability to use DT and IT to solve professional problems) have been determined. The qualitative assessment of the indicators made it possible to characterize the levels of development of future officers' IDC. Each level (low, medium, and high) reflects a different degree of IDC development, and, accordingly, a different degree of development of motives, knowledge, and skills to use IT and DT in professional activities. A low level may be sufficient for basic tasks, but medium and high levels are critical for managing complex operations and adapting to the performance of professional duties. Conclusions. This diagnostic apparatus has been developed, and levels of development of future officers' information and digital competence have determined the ability to use modern technologies to perform official duties effectively. With the help of the diagnostic apparatus, it becomes possible to test the effectiveness of pedagogical models of future officers' IDC development.

Application of Anionic Hydrogels from Date Palm Waste for Dye Adsorption in Wastewater Treatment.

This work aimed to develop an anionic cellulose nanofiber (CNF) bio-adsorbent from date palm tree waste and to investigate its removal efficiency compared to cationic methylene blue dye from contaminated water. Date palm pulp was first prepared from date palm leaves through acid hydrolysis using H2SO4, followed by hydrolysis in a basic medium using KOH, in which the process completely removed the components of hemicellulose, lignin, and silica. To obtain anionic CNF, the resulting pulp was further treated with H2SO4, followed by centrifugation. Biogel formation of the CNF suspension was promoted by sonication, where its removal efficiency of methylene blue dye was studied as a function of dye concentration, temperature, contact time, and pH value. In this work, we investigated two isotherms, i.e., Langmuir and Freundlich. The Langmuir model's consistency with the experimental data suggests that the adsorption of methylene blue dye onto CNF is monolayer and surface-limited. The reported maximum removal efficiency of 5 mg/g at 60 °C indicates the optimal temperature for adsorption in this specific case. Additionally, a pseudo-second-order model and Elovich model were also utilized to obtain a better understanding of the adsorption mechanism, in which we found not just physical adsorption but also an indication of a chemical reaction occurring between methylene blue dye and CNF. According to the results, that pseudo-second-order model's consistency with the experimental data suggests that the adsorption of methylene blue (MB) onto CNF is rate-limiting step involving chemisorption between the two. The study reveals that CNF adsorbents derived from renewable natural waste sources such as date palm leaves can be effective in removing cationic contaminants such as methylene blue dye.

Eutectogel adhesives with underwater-enhanced adhesion to hydrophilic surfaces and strong adhesion in harsh environments

It has been a challenge to achieve strong adhesion strength for gel adhesives in water. In this study, a novel eutectogel adhesive is synthesized via one-step photoinitiated polymerization of N-vinylpyrrolidone (NVP) in deep eutectic solvent (DES). The abundant hydrogen bonding interactions and the hydrophilic polyvinylpyrrolidone network structure endow the eutectogel with excellent adhesion to both hydrophilic and hydrophobic surfaces in air and underwater. Moreover, for hydrophilic substrates, the underwater adhesion strength of the eutectogel adhesives is 1.3 times larger than that in air, demonstrating an underwater-enhanced adhesion effect. In contrast, for hydrophobic substrates, the underwater adhesion strength is lower than in air. Furthermore, strong adhesion performance is maintained even in boiling water, strong acidic medium, strong basic medium, and organic solvents. The experimental and simulation results have unveiled the underwater adhesion enhancement mechanism of the eutectogel. It is believed that the designed eutectogel will show great promise in the development of the next-generation of gel adhesives with underwater adhesion capabilities and high environmental adaptability.

Synthesis, Characterization and Molecular Docking Study of New 1,3,4-Thiadiazole Derivatives

In this study, a series of 5-(5-{(Z)-[(4-R1)methylidene]amino}-1,3,4-thiadiazol-2-yl)benzene-1,2,3-triol (L1-3), and 4-(5-{(Z)-[(4-R1)methylidene]amino}-1,3,4-thiadiazol-2-yl)benzene-1,2-diol (L4-6) compounds were synthesized, where R1 = 4-Nitro, 4-bromo, 4-chloro. The reaction between benzoic acid derivatives and hydrazinecarbothioamide in the basic medium gave the intended products with high yield and purity. The preparation of the compounds was confirmed by spectroscopic measurements in addition to physical properties. The biological properties of the prepared compounds were studied by molecular docking. The binding interaction between the new synthesized derivatives of 1,3,4-thiadiazole and the target, ADP-sugar pyrophosphatase, was studied. One of these 1,3,4-thiadiazole derivatives, 5-(5-{(Z)-[(4-nitrophenyl)methylidene]amino}-1,3,4-thiadiazol-2-yl)benzene-1,2,3-triol (L3) showed a high binding and coordination with its target. Molecular docking showed a docking score = −8.9 kcal/mol and MM-GBSA = −31.5 kcal/mol. The molecular docking estimation for the (L3) compound exhibited that four hydrogen bonds were created with NUDT5 Gene.

Palladium nanoparticles incorporated biogenic modified graphitic carbon nitride as an electrocatalyst for methanol oxidation reaction

This research explores palladium (Pd) nanoparticles supported on graphitic carbonitride (g-C3N4) as a cost-effective and CO tolerant catalyst towards electrocatalytic methanol oxidation reaction (MOR). The study delves into the green synthesis strategy, employing phytochemicals as reducing, capping and stabilizing agents. This approach aligns with environmentally friendly practices, steering away from hazardous chemicals and solvents commonly used in traditional synthesis methods. The synthesis involves the dispersion of Pd nanoparticles supported on graphitic carbon nitride (g-C3N4) modified by banana leaf extract [PdNPs@g-C3N4-BLE]. The obtained nanocatalyst is characterized using various spectroscopic and microscopic techniques. Further, the synthesized PdNPs@g-C3N4-BLE is utilized as electrocatalyst for methanol oxidation reaction (MOR) in basic medium (1 M KOH). PdNPs@g-C3N4-BLE shows satisfactory activity towards MOR with an onset potential of 0.834 V and current density of 6.795 mA/cm2 at 1.0 V.

Golden Guardians: Advanced pH Sensors with Built‐in Antimicrobial Defense

AbstractGold nanoclusters (Au NCs) capped with a small biomolecule, namely (+)‐norephedrine, (Au@Nore) display exceptional performance as fluorescent pH sensors. They display high emission quantum yield (ΦPL of ≈33% in strongly basic media); absence of nanocluster (NC) aggregation and/or induced rigidification of the organic shell; a linear dependency of their emission on the pH in the 8.2–9.5 range; and reversible pH sensing. In addition, excitation at 310 nm, where both the NC and the ligand absorb, enables ratiometric sensing. Studies on the fungus Candida albicans and bacterium Bacillus subtilis demonstrate that while Au@Nore do not cause any impact on the growth of the fungus, it inhibited the growth of the Bacillus, showing the lowest cell viability of 18% at the highest pH values via a mechanism of action involving the disruption of the bacterial wall.

Evaluation of chicken embryo extract and egg yolk extract as alternatives to basic cell culture medium supplement

BackgroundFetal calf serum (FCS), an existing cell culture supplement, is effective but has several drawbacks, including being expensive, requiring a lengthy process of production, and requiring a hard currency. With this in mind, we planned to evaluate chick embryo extract and egg yolk extracts in cell culture as alternatives to fetal calf serum (FCS).MethodsSpecific pathogen-free eggs were purchased from the National Veterinary Institute, Bishoftu, Ethiopia, and incubated in a humidified incubator at 37 °C for 11 days. Egg yolk extract (EYE) and chick embryo extract (CEE) were collected after the egg was opened with caution not to destroy the yolk sack or the chick embryo itself. Chick fibroblasts and Vero cells were cultured in minimum essential medium (MEM) supplemented with egg yolk extract or chick embryo extract at ratios of 0:10, 1:9, 2.5:7.5, and 5:5% fetal calf serum.ResultsFibroblast cell attachment was better in media supplemented with 5% CEE and 5% FCS. The confluency was also greater than 50% at this concentration. Vero cells cultured with 5% CEE and 5% FCS also exhibited very good cell attachment and a confluency of up to 70%. Viability and confluency were also observed at 5%:5% ratios of 50 and 70%, respectively.ConclusionThis investigation evaluated these two extracts as cell culture supplements and revealed promising results as alternatives to fetal calf serum. The limitation of this study is that it only used two cell types and additional cell lines, and different ratios should be tested. With the above findings, further research using different cell lines, ratios and conditions is warranted.

Osmotic energy harvesting using acrylic acid hydrogel PET membrane

In this study, we investigated the osmotic energy harvesting using a cation-selective membrane. The cation-selective membrane was synthesized by the incorporation of acrylic acid hydrogel in a porous support membrane. FTIR analysis and SEM images confirmed the presence of the acrylic acid hydrogel rods inside the porous support material. The exposure of the acrylic acid hydrogel PET (AP) membrane to a concentration gradient culminated in the generation of electric power. The AP membrane was evaluated in regard to the following parameters: EDiff, Io, Pmax and t+. The maximum power obtained with the membrane was 1.10 μW at the 40-fold concentration gradient (test area∽ 100 mm2). Increasing the concentration gradient increased the power output. However, a decrease in power output was observed after a certain value of the concentration gradient. An enhancement in power output was noted as the fraction of acrylic acid within the membrane was augmented. Additionally, the cation transference number also increased owing to a high charge density and a reduction in the mesh size. The AP membrane was also investigated in acidic and basic media. The time-dependent study revealed the superior chemical stability of the AP membrane.

Isomerization, Protonation, and Hydrolysis Properties of Naphthalimide-Containing Spiropyran in Aqueous Media.

Synthesis of spiropyrans exhibiting ring-opening/closing isomerization driven by external stimuli is a challenging subject for the development of molecular sensors. A napthalimide-containing spiropyran (1) promotes rapid isomerization between the spirocyclic (SP) form and ring-opened merocyanine (MC) form by the change in solvent polarity even under the dark condition at room temperature. In this work, the effect of water on the isomerization behavior of 1 was studied. The addition of water caused an MC-water H-bonding interaction and shifted the resonance MC structure to the zwitterionic form with a lower ground-state energy. The stabilized MC form promoted spontaneous SP → MC isomerization and increased the equilibrium MC concentration. The effect of pH on the behavior of 1 was also studied. In acidic-neutral media, protonation/deprotonation of the naphthalimide moiety led to rapid and reversible changes in the absorption spectra. In contrast, strongly basic media (pH > 12) promoted irreversible base-catalyzed hydrolysis of the alkene moiety.

Unidirectional photoisomerisation in a dual channel proton transfer molecule rhodamine B based Schiff Base: A ratiometric pH sensor

In this article we have presented the synthesis, characterisation and spectral study of a newly designed fluorophore, (E)-2-((3-(benzo[d]oxazol-2-yl)-5-bromo-2-hydroxybenzylidene)amino)-3′,6′-bis(diethylamino)spiro [isoindoline-1,9′-xanthen]-3-one (RHHBO) which has two possible six member intramolecular hydrogen bonded networks capable for dual channels proton transfer reaction − one towards the N atom of oxazole moiety and the other towards the N atom of rhodamine moity. Details steady state and time resolved spectral analysis of RHHBO and a comparison of spectral features of control compounds 2-(2-hydroxyphenyl)benzoxazole (HBO), (E)-4-bromo-2-(hydrazonomethyl)phenol (HBN) and (E)-2-((5-bromo-2-hydroxybenzylidene)amino)-3′,6′-bis(diethylamino)spiro[isoindoline-1,9′-xanthen]-3-one (RH) having only single proton transfer site reveal that excited state intramolecular proton transfer (ESIPT) in RHHBO occurs towards the rhodamine side but not towards the oxazole side. Interestingly, RHHBO shows different fluorescence colour in acidic and basic medium and hence can be used ratiometric emission based pH sensor.

Carbon nitride effect on La2NiO4 and La2CuO4 structural, morphological and photocatalytic properties

The sol-gel method was used to prepare La2NiO4, La2CuO4, and La2NiO4/g-C3N4 and La2CuO4/g-C3N4 nanoparticles. The structural and surface morphology of prepared nanoparticles were evaluated by scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. FT-IR analysis confirmed the presence of metal-oxygen bonds (M-O). The bandgap from the Tauc plot was studied by UV–Vis spectroscopy. Synthesized materials were used as photocatalysts to degrade methylene blue dye as a function of medium pH (2–12). The photocatalyst potential was compared for La2NiO4/g-C3N4 and La2CuO4/g-C3N4 and maximum photocatalytic activity was observed in the basic medium. The enhanced photocatalytic activity is due to effective charge transfer between VB and CB in the presence of g-C3N4 which resultantly enhanced the formation of reactive species (•OH and -•O2) that are responsible for the degradation of methylene blue dye. Hence, it is concluded that fabricated nanoparticles could be employed for the removal of toxic pollutants from industrial effluents.

A Comparative Study of Ni-Based Catalysts Prepared by Various Sol-Gel Routes.

The use of heterogeneous catalysts to increase the development of green chemistry is a rapidly growing area of research to save industry money. In this paper, mesoporous SiO2-Al2O3 mixed oxide supports with various Si/Al ratios were prepared using two different sol-gel routes: hydrolytic sol-gel (HSG) and non-hydrolytic sol-gel (NHSG). The HSG route was investigated in both acidic and basic media, while the NHSG was explored in the presence of ethanol and diisopropyl ether as oxygen donors. The resulting SiO2-Al2O3 mixed oxide supports were characterized using EDX, N2 physisorption, powder XRD, 29Si, 27Al MAS-NMR and NH3-TPD. The mesoporous SiO2-Al2O3 supports prepared by NHSG seemed to be more regularly distributed and also more acidic. Consequently, a simple one-step NHSG (ether and alcohol routes) was selected to prepare mesoporous and acidic SiO2-Al2O3-NiO mixed oxide catalysts, which were then evaluated in ethylene oligomerization. The samples prepared by the NHSG ether route showed better activity than those prepared by the NHSG alcohol route in the oligomerization of ethylene at 150 °C.

Transition‐Metal‐Free Chemo‐Selective C−C/C−N Bond Formation Reaction for the Highly Efficient Synthesis of Pyrazoles, Pyrazolo fused Pyrimidines and Pyridines

AbstractPyrazoles and pyrazolo fused pyrimidines and pyridines are well known for their applications in various fields like pharmaceuticals, agrochemicals and materials sciences. Keeping this in mind herein, we have developed the transition‐metal‐free approach for the chemo‐selective synthesis of the pyrazole and its derivatives from acetopheneones. The selectivity of the reaction can easily be tuned by shifting reaction from acidic to basic medium for the synthesis of pyrazolo‐pyrirmidines and pyrazolo‐pyridines respectively. The reaction shows excellent functional group tolerance in the form of −F, −Cl, −Br, −NMe2, −OH, −OMe, and −B(OH)2 in good yields.

Development of a Suitable Method for the Synthesis of New Thiadiazoles Using Hydrazonoyl Halides

Background: Hydrazonoyl halides and methylhydrazinecarbodithioate have been generally utilized in the synthesis of heterocycles. Methods: This study describes a new and simple method to prepare new thiadiazoles from the reaction of N-(naphthalen-1-yl)-2-oxopropanehydrazonoyl chloride or ethyl 2-chloro-2-(2-(naphthalen-1-yl)hydrazono)acetate with methylhydrazinecarbodithioate in the presence of basic medium under reflux. In this study, the synthetic schemes are designed to show the chemical reactions. Elements analysis, Fourier Transform Infrared Spectroscopy (FT-IR), Mass Spectrom-etry (MS), and Nuclear Magnetic Resonance (NMR) are used to identify and characterize the final compounds. Results: There are two ways to synthesize the final thiadiazoles molecules. The first can be through nucleophile substitution of thiolate of methylhydrazonecarbodithioate to the chlorinated carbon of hydrazonoyl. Hydrochloric acid is then removed to provide an S-alkylated intermediate. Methanethiol is eliminated from this intermediate by an in situ intra-molecular cyclocondensation process to give the final products. The subsequent [3+2] cy-cloaddition involving 1,3-dipolar cycloadditions of nitrilimines to C=S is succeeded by the re-moval of methanethiol. Conclusion: This approach utilizes affordable, readily accessible reagents and simple reaction conditions to produce new thiadiazole derivatives with satisfactory yields.

Novel Triton X-114 coated Fe3O4 magnetic nanoparticle adsorbent for Cd(II) and Co(II) ions preconcentration in honey samples using magnetic solid-phase extraction: Determination by ICP-OES

This work focuses on creating and studying the effectiveness of Fe3O4 nanoparticles coated with (3-aminopropyl)triethoxysilane (APTES) and polyethylene glycol tert-octylphenyl ether (TX-114), respectively, as adsorbent. Fe3O4@APTES@TX-114 adsorbent extracts heavy metal cations Cd2+ and Co2+ using a magnetic solid phase extraction technique. The synthesized magnetic nanoparticles (MNPs) were characterized by Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Fourier Transform Infrared Spectroscopy (FT-IR), and Thermogravimetric Analysis (TGA). After this stage, Cd2+ and Co2+ determinations were made with the ICP-OES device. The optimum conditions for recovering Cd2+ and Co2+ cations were pH 7, an adsorbent dosage of 2 g/L, and a contact time of 120 min. While the method was compatible with Langmuir and Freundlich isotherm models, the pseudo-second-order kinetic equation was more compatible than the pseudo-first-order. Acidic and basic media were investigated for the desorption of Cd2+ and Co2+ ions from the adsorbent. At the same time, maximum recovery was achieved for both cations at a concentration of 1.5 mol/L HCl, but no significant recovery was obtained in the NaOH medium. The common ion study observed that Cd2+ and Co2+ cations were recovered over 95 % in the presence of many cations and anions at different concentrations. The relative standard deviation (RSD), limit of quantification (LOQ), limit of detection (LOD), and enrichment factor (EF) were calculated as 1.40 %, 2.963 µg/L, 0.889 µg/L, 20.99 for Cd2+ and 3.05 %, 1.88 µg/L, 0.564 µg/L, 109.41 for Co2+, respectively. The magnetic solid phase extraction method realized quantitative recovery of Cd2+ and Co2+ cations in different honey samples. It was found that the heavy metal contents in honey samples from the Sakarya region are below permissible levels.

Changing cellulose acetate deriving from cigarette filters to be used as catalyst in effluent treatment

Cigarette butts are a significant environmental issue, mainly when they are improperly discarded. However, this waste type is recyclable, since its structure is based on cellulose acetate, which is used in the industrial sector for absorbent and filtering purposes. The aim of the present study is to chemically change cellulose acetate deriving from cigarette filters by incorporating iron to it, in order to use it as catalyst in effluent treatment processes. Three different methods were used for iron immobilization purposes in basic, acidic and ferric media, for 7 days. The method showing the best iron adsorption, based on spectroscopic analyses, was the one wherein cigarette butts remained in contact with 0.1 mol/L ferric solution. Therefore, the group of cigarette butts resulting from this method was used in Fenton and photo-Fenton processes. Moreover, it recorded positive results for textile dye mix discoloration, as evidenced by spectral changes in the 350-700 nm range, which pointed out significant color change in the assessed sample. Although the current article results from a preliminary study, the herein collected data point towards the potential use of cigarette butts as alternative to treat effluents deriving from companies that use large amounts of dye.

Cu‐promoted Access to 1,4‐Diazine‐fused Isoindoles Through Concomitant Csp3‐N and Csp2‐N Bonds Formation Starting from Constrained N,O‐acetals

Scarce dihydro‐1,4‐diazinoisoindole framework bearing two points of diversity was prepared through interesting cascade process based on concomitant Csp3‐N and Csp2‐N bonds formation. This approach consists on amidation in basic medium of tosyl group by nucleophilic substitution followed by Cu‐mediated Goldberg reaction in same operation. The required β‐bromoenamide bearing a tosyl group was obtained by tosylation of fused brominated N,O‐acetals for the first time in acidic medium using submolar amounts of PTSA. The obtained piperazines act as a powerful reaction intersection as illustrated by the formation of N‐heterocyclic system via the intramolecular interception of enamide function.

ZnAl2O4 decorated on graphitic carbon nitride (g-CN) composite as efficient electrocatalyst for water oxidation in alkaline medium

The main purpose of this research is to form highly effective and novel electrocatalysts for water splitting procedure, a pivotal step in the generation of sustainable energy. Cost-effective metal oxides exhibited superior benefits compared to alternative materials when used for oxygen evolution reactions (OER) in alkaline electrolyte. Our study focuses on the preparation of ZnAl2O4@g-CN composite by utilizing hydrothermal approach for electrocatalytic water splitting. The electrocatalytic potential of prepared electrocatalyst was observed by a comprehensive series of tests. Numerous electrochemical approaches such as chronoamperometry and electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were implemented to analyze catalytic procedure and durability in basic medium. The electrocatalytic tests of ZnAl2O4@g-CN composite reveal a remarkable overpotential of 209 mV, enabling the attainment of current density (Cd) 10 mA/cm2. Additionally, the composite shows significantly lower Tafel value (36 mV/dec) and has remarkable durability for 30 h. These characteristics mutually designate that electrocatalyst is well-suited for OER procedure. Therefore, the fabricated composite exhibited excellent efficacy in OER procedure as well as for several other upcoming applications.