Aqueous Sodium Hydroxide Solution Research Articles

Spatiotemporally resolved characterization for analyzing the interfacial behaviors of gelation in aqueous phase separation

Precipitating polymer in a completely aqueous environment is conceptualized as a process of aqueous phase separation (APS) and lends itself to the environmentally friendly fabrication of membranes. In an effort to effectively regulate the morphological formation in APS, it is of fundamental concern to elucidate how asymmetry can be developed in the absence of an unbalanced exchange of the ‘nonsolvent’ and solvent. Therefore, technical modifications were made by this study to essentially improve the in-situ characterization based on optical coherence tomography (OCT). In particular, a process of APS was modeled by passively contacting an acidic aqueous dope of chitosan with another aqueous solution of sodium hydroxide in a mini-coagulation bath, where the OCT scan was implemented in a high speed mode to capture the onset and evolution of gelation at the coagulant-dope interface with a temporal resolution of 6.25 ms. The quantitative analysis indicated that the gelation could be initiated at the interface in a period shorter than ∼10 ms and evolved in an oscillating way; a skin layer with a smaller critical size would be formed by damping the interfacial oscillations. This study not only sheds light on the APS-based fabrication of membranes, but also establishes a novel paradigm for in-situ characterizing the film formation via an OCT-based approach.

Aerated Concrete with Geopolymer Binder from Technogenic Waste

Aerated concrete is a material widely used in Vietnam due to several advantages over heavy concrete. This article presents some results of experimental studies of the properties of aerated concrete produced using geopolymer binder from industrial waste generated in large quantities in Vietnam. The raw materials used included thermal power plant fly ash, blast furnace slag, ceramic powder, aluminum powder and an activating alkaline solution consisting of aqueous solutions of sodium hydroxide and sodium metasilicate. Testing of aerated concrete samples of the developed compositions was carried out in accordance with current Russian and Vietnamese standards. Experimental results confirmed the possibility of producing aerated concrete with a geopolymer binder based on large-tonnage technogenic waste, with an average dry density of less than 1600 kg/m3 and a compressive strength at the age of hardening of 28 days of 18.8–27.9 MPa. At the same time, aerated concrete containing 0.456 kg/m3 of aluminum powder and 50% wt. showed the greatest strength. blast furnace slag in the composition of the geopolymer binder, with a ratio of activating alkaline solution and active mineral additives equal to 0.4.

Sustainable and renewable hydrogen production from recycled aluminum

The whole world has been suffering strong consequences related to climate change. The intense use of fossil fuels in the chemical and automotive industries have put the environment in jeopardy. Thus, the industry has achieved a point of no return and it is urgent the development of renewable and sustainable technologies. Hydrogen has been pointed as a key component of the new era in industry since it can be produced in a clean and sustainable way. Currently the development of hydrogen fuel cells technology has put the automotive sector ahead of the chemical industries in relation to studies regarding the hydrogen production. Chemical industries produce hydrogen with technologies reliant on fossil fuels while the automotive sector has been looking for renewable forms of hydrogen generation. Trains powered by hydrogen fuel cells are a reality in Europe, for instance. Hydrogen generation technological advances must match the pace of the development of fuel cells electrical vehicles in order to the environmental goals and widespread application of fuel cell systems to be achieved. The present study addresses the hydrogen generation from the spontaneous reaction between aluminum and aqueous solution of sodium hydroxide. Aluminum is a metal that presents high exergetic value and can be recycled several times without losing its thermo-mechanical properties. That makes the use of aluminum especially appealing. It will make hydrogen generation a cleaner and more affordable process. Our findings demonstrate that it is possible to predict the kinetic behavior of the reaction using data obtained by the conductometric method. Graphs of electrical conductivity vs time show that is possible to verify the order of the reaction. We will present concepts of kinetic, thermodynamic and transport phenomena of the reaction between solid recycled aluminum and sodium hydroxide in an aqueous solution. The knowledge acquired throughout this study will contribute to the development of a new reactor and as a consequence, a new renewable and sustainable industrial system of hydrogen generation.

Degradation behavior of polycarbonate during melt processing with an aqueous solution of sodium hydroxide

In this study, we aimed to enhance the reactivity of polycarbonate (PC) with the epoxy group of styrene-co-glycidyl methacrylate copolymer (SGMA) by introducing aqueous solutions of sodium hydroxide during the melt processing of PC. This approach led to the generation of hydroxyl groups at the ends of PC molecules, facilitating the formation of PC-SGMA copolymer. The effectiveness of this method in improving the compatibility of PC and styrene-acrylonitrile (SAN) blends was successfully confirmed through blending experiments with SAN and SGMA. Additionally, we investigated the impact of alkali-promoted hydrolysis on the rheological properties of PC, apart from the functionalization of PC end groups. Our findings revealed that an increase in the concentration of sodium hydroxide resulted in a decrease in the complex viscosity of PC. However, beyond a certain concentration level, the viscosity exhibited an upward trend. Furthermore, when constructing van Gurp-Palmen plots for the modified PC, we observed a significant deviation in curve shape compared to pure PC or water-modified PC. This observation suggests that changes in the microstructure occur during the degradation process due to the interaction between PC molecules and sodium ions.

Effect of adsorption-catalytic deformation and partial deactivation on the determination of the absolute activity of a liquid phase hydrogenation catalyst

Objectives. To take into account the change in the number of active sites during the adsorptioncatalytic deformation and deactivation of a catalyst surface by means of a catalytic poison when calculating the turnover frequency (TOF) of a hydrogenation catalyst.Methods. The activity was determined by a static method, using a titanium reactor having a volume of 400 mL, an experimental temperature controlled using a liquid thermostat with an accuracy of 0.5 K, with a paddle stirrer rotation speed of 3600 rpm and system hydrogen pressure equal to atmospheric. The consumption of hydrogen used to reduce the model compound was taken into account via the volumetric method. The heats of hydrogen adsorption were determined using a reaction calorimeter with an operating mode close to that of a chemical reactor. After measuring the specific surface area using low temperature nitrogen adsorption, the results were processed using Brunauer–Emmett–Teller theory approximations. Deactivation was carried out by introducing dosed amounts of catalytic poison into the system in titration mode.Results. A kinetic experiment for the reduction of a multiple carbon bond in a sodium maleate molecule using aqueous solutions of sodium hydroxide with additions of monohydric aliphatic alcohols as solvents under conditions of partial deactivation of the catalyst was carried out. The obtained values of heats of hydrogen adsorption on skeletal nickel in the course of the experiment are given. The described approach is used to calculate TOF values taking into account changes in the number of active surface sites during the course of a catalytic reaction and upon the introduction of a deactivating agent. A refined equation for the correct calculation of TOF is proposed along with its mathematical justification. The results of TOF calculations under various assumptions for a number of catalytic systems are shown.Conclusions. When calculating absolute activity values, a change in the number of active sites has a significant effect on the obtained values. The physical meaning of a number of constants in the proposed equation relates the activity of the catalyst to the distribution of hydrogen on its surface in terms of heats of adsorption.

Optical Asymmetry and Structural Complexity in Hierarchically Organized Chiral CuO Nanostructures: Insight into the Geometric and Crystallographic Effects on Cooperative Chirality.

Optical asymmetry and structural complexity across different length scales were realized in flower-shaped CuO nanostructures, prepared through refluxing an aqueous solution of copper acetate, sodium hydroxide, and D-tartaric acid, as well as in their toroid-like forms obtained on calcination at 600 °C. Atomic scale chirality in the flower morphology could be visualized as putative Boerdijk-Coexter-Bernal like tetrahelical fragments, while that in the toroid form could be identified as screw dislocation-driven helicity. The fraction of asymmetry in the nanostructures has been evaluated from their chiroptical responses based on Kuhn asymmetry factor (g) from circular dichroism (CD) spectroscopy in the entire UV-vis range. The origin of chirality in the two CuO nanostructures has been assigned to the helical arrangement of the Cu-O-Cu network in accordance with their microscopic and spectroscopic observations. Attempts have been made to interpret the crystallographic and geometric chiralities in the two CuO nanostructures based on the redshift and augmented intensity of the CD signal along with an increase in their corresponding anisotropic factor on calcination. Further, the diverse interaction of the toroid-shaped CuO nanostructures with enantiomeric tryptophan moieties has been illustrated from the measurement of their corresponding thermodynamic parameters.

Where do ferrate ions form? A dual dynamic voltammetry study

One of the most effective methods to produce ferrate ions (FeO42–) is electrochemical synthesis. During the transpassive anodic dissolution of iron, the formation of ferrate ions and the evolution of oxygen occur simultaneously, and only the sum of the currents generated by the two processes can be observed in the voltammetric curves. Products of the above process have been investigated in 45% (m/m) aqueous NaOH solutions by using the dual dynamic voltammetry (DDV)&rotating ring-disk electrode (RRDE) method (i.e., applying dynamic potential programs to the disk and the ring electrodes of the RRDE disk electrode and the RRDE ring electrode simultaneously) combined with spectrophotometric measurements. Fedisk/Ptring and Ptdisk/Ptring RRDE tips were used in the voltammetric experiments. The electrode potential regions where ferrate ions and oxygen are forming could effectively be identified. The results imply that, under the applied experimental conditions, the oxygen evolved at the disk cannot be reduced at the ring. This can be explained by the fact that elemental oxygen practically does not dissolve in concentrated aqueous sodium hydroxide solutions due to the “salting-out effect”. By using the dual voltammetric method, it was also possible to determine the optimal potential range for the electrochemical production of ferrate ions in terms of charging efficiency. The latter quantity has an important impact on the economics of practical applications. The approach proposed in this study proved to be very promising for the simultaneous detection of different dissolution products.

Synthesis and Molecular Docking Studies of New Pyrimidinone ring Containing 1,2,3-Triazole Derivatives

The current work describes the design, synthesis and molecular mocking studies of a series of new 1,4-disubstituted-1,2,3-triazole linked 2-pyrimidinone derivatives. Firstly, 4-(4-acetyl-5-methyl-1H-1,2,3-triazol-1-yl)benzene sulfonic acid 1 was synthesized as a key starting material. This compound was reacted with a series of aromatic aldehydes under-investigated conditions to give a new series of chalcones 2a-f. Reaction of compounds 2a-f with urea in the presence of an aqueous solution of sodium hydroxide led to the construct 2-pyrimidinone ring system to obtain a series of new compounds containing 1,2,3-triaozle ring and pyrimidinone ring 3a-f. The newly synthesized compounds 2a-f and 3a-f were characterized by FT-IR, 1H-NMR and 13C-NMR spectra. In-silico molecular docking simulations, compounds 3a-f and their precursors 2a-f were conducted on two selected proteins: 7dpp and 8cx9. The results revealed that all of the newly synthesized compounds 2a-f and 3a-f displayed have a good binding affinity with the target proteins and higher than values recorded for the selected three standard antiviral drugs.

Alkalization treatment engineering gas sensing selectivity improvement of ZnCo2O4 microspheres toward xylene

Improving the recognition ability of gas sensing materials toward target gases is one of the eternal themes of gas sensor research. Here, a feasible alkalization treatment strategy is proposed and is used to greatly improve gas sensing selectivity and response of oxide semiconductor based sensing materials. To be specific, ZnCo2O4 microspheres could be prepared through a solvothermal strategy with annealing, but do not exhibit gas sensing selectivity. When treated with 0.5 M sodium hydroxide aqueous solution, the alkalized ZnCo2O4 microspheres (ZCO-0.5) show significantly enhanced xylene gas sensing selectivity at 160 °C. Meanwhile, the ZCO-0.5 sensor also exhibits superior stability, repeatability and reliability toward xylene gas. The enhanced selectivity of xylene gas sensing originates from more exposed metal-oxygen bonds, OH functional groups, -O terminal groups and Co3+ ions on the surfaces of ZnCo2O4 microspheres introduced by the alkalization treatment of sodium hydroxide solution with appropriate concentration. The alkalization treatment method in this study could be applied to other oxide semiconductors to enhance their gas sensing selectivity and performances.

Rapid extraction and detection of five alkaloids in dried khat by solvent extraction-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

Khat is a common plant that grows primarily in Eastern Africa and the Arabian Peninsula. Cathinone, norpseudoephedrine, and norephedrine are the main psychoactive components of khat. Experimental studies have shown that red and green khat have similar cathinone contents, but green khat contains more norpseudoephedrine and norephedrine than red khat. Research indicates that Ethiopians believe that red khat has stronger psychoactive effects than green khat. Therefore, we speculated that other substances in red khat may enhance its psychoactive effects. Using the sampling method, we identified two other psychoactive components in khat: methcathinone and ethcathinone. At present, only a few studies on the extraction and detection of alkaloids from khat have been published in China, and no reports on the extraction and detection of methcathinone and ethcathinone from khat are available. In this study, we established an extraction and detection method for five alkaloids in dried khat using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF MS). To establish the extraction method, we optimized the extraction solvent and process. The amounts of dichloromethane and sodium hydroxide added during the purification step were also optimized. To establish the detection method, we optimized the chromatographic and MS conditions. The final extraction and detection method was as follows: Dried khat powder (0.1 g) was loaded into a polypropylene centrifuge tube, added with 1 mL of 0.05 mol/L hydrochloride aqueous solution, and vortex-oscillated for 3 min for extraction. The sample was centrifuged at 10000 r/min for 3 min. Next, 600 μL of the supernatant was placed in a centrifuge tube, added with 1 mL of dichloromethane, shaken for 1 min, and centrifuged at 10000 r/min for 3 min. Subsequently, 300 μL of the supernatant was placed in a centrifuge tube, added with 80 μL of 1 mol/L sodium hydroxide aqueous solution, shaken for 1 min, and added with 1 mL of acetonitrile. Vortex oscillation was performed for 2 min to extract the sample, after which solid sodium chloride (0.4 g) was added to the mixture, followed by shaking for 1 min to separate the acetonitrile and aqueous phases. The mixture was then centrifuged at 10000 r/min for 3 min. Finally, the supernatant was collected and diluted for further testing. The five target analytes were separated on a ZORBAX Eclipse Plus Phenyl-Hexyl column (100 mm×3.0 mm, 1.8 μm) via gradient elution using 0.1% acetic acid aqueous solution and acetonitrile as mobile phases with a flow rate of 0.3 mL/min and column temperature of 30 ℃. The analytes were identified using the targeted MS/MS method under positive electrospray ionization mode and quantified using the external standard method. The five alkaloids showed good correlations (all correlation coefficients (r2)≥0.9976) with their respective linear ranges. The limits of detection were between 0.08 and 0.75 μg/L, and the limits of quantification were between 0.25 and 2.50 μg/L. The average recoveries of the five alkaloids from two plants with different alkaloid contents were between 90.7% and 105.2%. The intra-sample precision ranged from 0.5% to 2.3%, the intra-day precision was between 1.0% and 2.5%, and the inter-day precision was between 1.3% and 3.3%. Using the developed method, we extracted and analyzed 15 khat samples, and detected five alkaloids. This method enables rapid sample pretreatment and has high sensitivity, good stability, and suitable accuracy. Based on the above results, we conclude that the proposed method meets the inspection and identification requirements for khat. Thus, it can provide a valuable reference for the physical and chemical identification of khat and support for further studies on its psychoactive components.

Alkali-activated cement manufactured by the alkaline activation of demolition and construction waste using brick and concrete wastes

This study examines the mechanical and materials science properties of a novel Alkali-activated cement (AAC) cured at room temperature and using construction and demolition waste (CDW), which was obtained from brick and concrete waste from a landfill in Medellín, Colombia. The cement was activated with an aqueous solution of sodium hydroxide and sodium silicate. Different mixtures were tested to determine the optimum amount of CDW and the proportion of alkaline activator. The formulations were characterized by compressive and flexural strength tests, X-ray diffraction, scanning electron microscopy, and water absorption tests. Results indicate that the mechanical properties of the developed cement are strongly influenced by both the type of activated residue and the activator ratio. The AAC with the best mechanical properties is the one based on brick waste, which has a mean compressive strength of 33 MPa.

Lignin extraction and fractionation from rice straw biorefinery residues

Crops straw contains many valuable natural compounds. Cellulose and hemicellulose in agricultural wastes have been widely used in biofuel production. However, the large-scale application of residue lignin from biorefinery is still an unsolved problem. Various impurities and heterogeneous lignin with a very complicated molecular weight distribution were generally found in the recovered raw solid products. In this study, brown solid residue from rice straw biorefinery was processed using membrane separation in combination with the soda-ethylene glycol (Soda-EG) process to extract high-purity lignin. At first, wet brown solid was mixed into an aqueous solution of sodium hydroxide and ethylene glycol for lignin fragmentation, depolymerization, and solubilization at elevated temperatures. Afterwards, microfiltration (MF) was applied to recover the dissolved lignin in the filtrate from the extracts. As high as 90% of the lignin in the brown solid could be recovered after acid precipitation of the filtrate. The highest lignin content in the precipitate product could be 90% (dry basis). The precipitate was re-dissolved at high pH aqueous solutions for further molecular weight fractionation by ultrafiltration (UF). The best rejection of high-molecular-weight (>1 × 105 g/mol) lignin was 77%, while low-molecular-weight (<3 × 103 g/mol) lignin was <13% with a MWCO of 10 kDa polysulfone UF membrane in a dead-end filtration system. The cross-flow operation with the same UF membrane showed that >80% lignin could be recovered from the retentate and the flux of permeate could be maintained after three operation-cleaning cycles. Overall, the combined MF-UF operation could be a viable method for obtaining high-value-added lignin products with a specific molecular weight range.

New insights in the treatment of real oilfield produced water: Feasibility of adsorption process with coconut husk activated charcoal

Naphthenic acids are water-soluble organic compounds (WSO), present in oilfield produced water (OPW), whose removal aims to comply with environmental legislation and ensure the correct disposal of OPW. In this study, the performance of the adsorptive process for the removal of WSO in synthetic (single- and multi-component) and real OPW was evaluated. It was observed that the lower the pH of the sample, the greater the adsorption capacity of WSO. Moreover, the kinetic parameters of adsorption followed the pseudo-second order model while the equilibrium parameters were represented by the isothermal BET (Brunauer, Emmett and Teller) model. In the desorption process followed the second-order model, and the aqueous solution of sodium hydroxide (0.3 and 0.1 M) showed the highest desorption efficiency (~70 %) in the synthetic and real systems, respectively. With this protocol, the adsorbent proved to be effective for the treatment of OPW, without significant loss of efficiency, for up to three consecutive cycles of adsorption-desorption. In addition, after treatment, the real effluent was classified within the legal parameters for offshore disposal, which enhances its industrial application.

Thermo-acoustic Parameters of Polymer Dextran with Aqueous Sodium Hydroxide: An Ultrasonic Study

Aims: This study aimed to investigate the molecular interactions of dextran as a solute with sodium hydroxide as a solvent. Background: The propagation of ultrasonic waves through solids and liquids offers vital information on the structure of solids and liquids. The molecular interaction in pure liquids and liquid solutions has also been explored using ultrasonic speed estimates. The ultrasonic speed in a fluid provides a cutting-edge, feasible, and trustworthy technique for examining the characteristics of the polymer, amino acid, carbohydrate, and vitamin arrangements, among other things. It is mainly connected to the binding capacities of particles or molecules and has been successfully used in comprehending the concept of molecular interaction in liquid solution. Ultrasonic velocity measurement allows for the precise evaluation of several relevant acoustical characteristics that are particularly sensitive to molecular interactions. Objective: The acoustic and thermodynamic characteristics were utilised to investigate different types of interactions, molecular motion, and different interaction modes and their effects, which were impacted by the size of the pure component and the mixes. The significance provides subjective data on the nature and quality of particle interactions between solute and solvent in liquid solutions. Acoustic characteristics are important for evaluating the effect of temperature and frequency on the polymer dextran's aqueous sodium hydroxide solvent interactions. The density (ρ), viscosity, and ultrasonic speed (η) at 303 K, 308K, 313 K, 318K and 323K have been measured in the systems of polymer dextran with aqueous sodium hydroxide solution by using a pycnometer, Ostwald viscometer, and ultrasonic interferometer at frequencies at 1MHz, 5MHz, 9MHz, 12MHz, respectively. The acoustic parameters, such as free volume, internal pressure, attenuation coefficient, Rao’s constant, and Wada’s constant, are determined using the experimental parameters, including density (ρ), viscosity (η), and ultrasonic speed (U). Methods: In this study, a pycnometer, an Ostwald's viscometer, and an ultrasonic interferometer to measure the density, viscosity, and ultrasonic velocity of the solution and compute the thermoacoustic parameters based on the measured parameters were used. Results: Ultrasonic wave propagation affects the physical characteristics of the medium, providing information about liquid and solution Conclusion: The effect of frequency and temperature on thermo-acoustic properties was studied. The aforementioned research has interpreted the nature of forces between molecules, such as hydrogen bonds, charge transfer complexes, and the breakdown of hydrogen bonds and complexes. Intermolecular forces are weak (electrostatic forces between charged particles having a permanent dipole and molecules with induced dipoles). The geometrical fitting of one molecule into another, owing to the variation in shape and size of the molecules, results in structural properties of the components. Other: In recent years, advances in ultrasonic methods have made them a potent instrument for assessing knowledge about the physical and chemical behaviour of liquid molecules. Due to its versatile pharmaceutical, biological, and contemporary uses, it has drawn analysts' attention to a new area of investigation. Consistent data on the physical and chemical characteristics of a wide range of liquid solutions are required.

Integrated capture and solar-driven utilization of CO2 from flue gas and air

Integrated capture and solar-driven utilization of CO2 from flue gas and air

SYNTHESIS AND POLYMERIZATION OF N,N-DI(β-CHLOR)ALLYLAMINO- ETHANIC ACID

Amino acids are chiral compounds that make up proteins and play an important role in biochemical processes in living organisms. They are widely used as building blocks in organic synthesis, components of asymmetric synthesis catalysts, separating agents, etc. To this end, we found that the interaction of 1 mol aminoethanic acid with 2 mol of (β-chlor)allyl chloride in an aqueous solution of sodium hydroxide leads to the formation of a new monomer – N,N-di(β-chlor)allylamino ethanic acid (BEA) with a yield of ~45%. When carrying out the polymerization of BEA in an aqueous solution in the presence of ammonium persulfate with an initiator concentration of 4·10-4–5·10-3 mol/l , water-soluble polymers with sufficiently high values of reduced viscosity ([η] = 0.16–0.18 dl/q) for the indicated amino acid were obtained. It was found that polymerization proceeds along the double bonds of diallyl groups according to the cyclolinear mechanism with a pyrrolidine structure

Kinetic Model of the Process of Polycondensation of Concentrated Phenols of Coal Tar with Formaldehyde

Phenolformaldehyde resins were obtained by polycondensation of concentrated phenols with formaldehyde in the presence of hydrochloric acid. Concentration of phenols is carried out by treating the phenolic fraction of coal tar with an aqueous solution of sodium hydroxide followed by neutralization of water-soluble phenolates with hydrochloric acid. The kinetic dependences of resin yield and softening temperature on the duration of the process at 333, 353, and 373 K were obtained. The order of the reaction was determined and the effective activation energy of this process was determined by a graphical method. In the interval 333-373 K for polycondensation reactions, the equation of the dependence of the resin yield on the temperature and duration of the process was obtained.

Design, Synthesis and Antimicrobial Activity of 1,3-Diazine Derivatives

Background: Pyrimidines have been shown to possess numerous biological activities, such as antimicrobial, anticancer, anticonvulsant, antiviral, and anti-inflammatory. Objective: Encouraged by these data, the synthesis of 2-((1H-benzo[d]imidazol-2-yl)methylthio)-4- amino-6-phenylpyrimidine-5-carbonitrile (3a-g) was performed. Methods: 4-amino-2-mercapto-6-phenylpyrimidine-5-carbonitrile was dissolved in an aqueous sodium hydroxide solution, and to this clear solution, 2-chloromethyl-1H-benzimidazole in methanol was added, and the reaction mixture was stirred under reflux to get the desired product. The structures of the newly synthesized compounds were confirmed by their physical, chemical, and spectral data. The synthesized derivatives were screened for their in vitro antibacterial activity against Gram-positive bacteria, Staphylococcus aureus and Bacillus subtilis, and Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, by using ciprofloxacin as a reference standard. While, their antifungal activity was evaluated against Aspergillus niger and Candida albicans using fluconazole as a reference drug. The docking study was performed to check the interactions of target compounds (3a-g) with homo sapiens DHFR (PDB: 1S3V), bacterial (S. aureus) DHFR (PDB: 2W9T), and DHPS (PDB: 1AD4) protein. The dock score and binding interactions were recorded. Result: The antimicrobial activity study indicated compounds with chloro (3b), fluoro (3f), and bromo (3g) substituents to show good antibacterial as well as antifungal activity. The docking study revealed that the same compounds, i.e., 3b, 3f, and 3g, showed good dock score and comparable interactions compared to the reference ligand (trimethoprim/sulfadiazine), which confirmed their selectivity. Conclusion: It can be presumed that the synthesized compounds have the capability for further promotion as novel antimicrobial agents.

Chemical Bath Deposition of α-GaOOH with Tunable Morphology on Silicon Using the pH Adjustment

The growth of GaOOH by chemical bath deposition has received great attention over the past years as a first step to form Ga2O3 with the α- or β-phases by combining a wet chemical route with thermal annealing in air. By using gallium nitrate and sodium hydroxide in aqueous solution, we show that the structural morphology of GaOOH deposits is thoroughly tunable in terms of both dimensions, density, and nature by varying the initial pH value from acidic to basic conditions. In the low-pH region associated with a low supersaturation level and where Ga3+ ions represent the dominant Ga(III) species, GaOOH microrods with a low aspect ratio and low density prevail. In the intermediate-pH region associated with a high supersaturation level and where GaOH2+ ions represent the dominant Ga(III) species, GaOOH prismatic nanorods with a high aspect ratio and high density are preferentially formed. In the high-pH region where Ga(OH)4- complexes are predominantly formed, the growth of partially crystallized GaOOH thin films with a typical thickness of about 1 μm proceeds. These findings show the correlation between the characteristics of the chemical bath and the resulting structural morphology of GaOOH deposits. They further open great perspectives to grow GaOOH and hence Ga2O3-based materials on silicon with a dedicated structural morphology using chemical bath deposition for engineering devices in the fields of gas sensing, solar-blind UV-C photodetection, and power electronics.

Ecofriendly synthesis of hydrated manganese oxide and its efficient adsorption of lead ions from water

Abstract Utilizing the waste liquid derived from graphene oxide synthesis as raw material, hydrated manganese oxide (HMO) was prepared by a chemical precipitation method with sodium hydroxide solution or aqueous ammonia solution. The HMO samples were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, Zeta potential analyzer, and scanning electron microscopy. The adsorption characteristics of the HMO samples were examined through lead ion adsorption from water. The effects of adsorption temperature, starting lead ion concentration, and adsorption time on the lead ion adsorption capacity were investigated. The relevant data agreed well with the pseudo-second-order kinetic model and the Langmuir isotherm model. Additionally, the maximum adsorption capacities of HMO-1 are 70.897 mg g−1, 76.660 mg g−1, and 79.424 mg g−1 for the lead ions at 298 K, 308 K, and 318 K, respectively. The lead ion adsorption mechanism of HMO has been explained. The findings indicate the as-synthesized HMO can be used as an efficient adsorbent material for eliminating lead ions from water.