Sulfate Solution Research Articles

An assessment of the durability of untreated and water repellent-treated cultural heritage stone (Döğer tuff-Turkey) by salt mist and salt crystallization tests

Salt mist and salt crystallization tests were conducted to determine the resistance of the untreated and water-repellent-treated Döğer tuff samples to salt damage. The Döğer tuffs are of volcanic origin and consist of porous pyroclastic rocks. A series of characterization studies were performed to determine the physicochemical and chemical properties (XRF), mineralogical-petrographic characteristics (polarizing optical microscopy, XRD, and SEM), and pore-size distribution (MIP) of the Döğer tuff prior to the aging tests. Following the aging experiments, the changes in weight, ultrasound pulse velocity, uniaxial compressive strength, and variations in pore size distribution were examined in the tested tuffs. In addition, SEM studies were conducted to analyze the microstructures. The untreated tuff samples were more severely affected by salt crystallization. The increases in dry weight for untreated and water-repellent-treated Döğer tuff samples were 0.27% and 0.13% after 60 cycles of salt mist exposure and 7.2% and 3.76% after salt crystallization cycles using a sodium chloride solution, respectively. Both conditions resulted from the accumulation of NaCl crystals on the tuff surface and within the pores. Salt crystal formation in a sodium sulfate solution led to dry weight change of 2.02% and 0.29% in the untreated and water-repellent-treated samples, respectively. The uniaxial compressive strength of the untreated tuff samples decreased by 36.71% in the presence of sodium chloride solution and by 72.58% in the presence of sodium sulfate solution. The ultrasound pulse velocity values decreased in all tuff samples after the salt crystallization test. However, the Döğer tuff samples were still distinguishable after both tests and their physical integrity remained intact.

Theoretical and practical investigation of ion-ion association in electrolyte solutions.

In this study, we present a new equation of state for electrolyte solutions, integrating the statistical associating fluid theory for variable range interactions utilizing the generic Mie form and binding Debye-Hückel theories. This equation of state underscores the pivotal role of ion-ion association in determining the properties of electrolyte solutions. We propose a unified framework that simultaneously examines the thermodynamic properties of electrolyte solutions and their electrical conductivity, given the profound impact of ion pairing on this transport property. Using this equation of state, we predict the liquid density, mean ionic activity coefficient, and osmotic coefficient for binary NaCl, Na2SO4, and MgSO4 aqueous solutions at 298.15K. Additionally, we evaluate the molar conductivity of these systems by considering the fraction of free ions derived from our equation of state in conjunction with two advanced electrical conductivity models. Our results reveal that, while ion-ion association has a minimal influence on the modification of the predicted properties of sodium chloride solutions, their impact on sodium and magnesium sulfate solutions is considerably more noticeable.

Mechanism analysis and mixing characterization of variable-speed mechanical mixing enhancement

Abstract In response to the observed phenomenon of poor fluid mixing within the reactor, this study proposes a novel mixing method to enhance fluid mixing efficiency. In this study, numerical simulation and purification tests were carried out for the purification of zinc sulfate solution. Numerical simulations were conducted to compare the effects of variable-speed stirring and uniform-speed stirring on mixing efficiency, considering both momentum transfer process and mass transfer process. The purification test further demonstrated a significant improvement in the reaction rate under variable-speed stirring, as evidenced by the analysis of purification efficiency and microscopic morphology. It was elaborated that the enhancement mechanism of variable-speed stirring involved disrupting the periodic order structure in the tank, leading to the generation of a multi-scale vortex that increased stirring kinetic energy to form a shear force. This force contributed to reducing the velocity slip between the impurity ions and zinc particles, consequently decreasing reaction time and enhancing purification rate. The results indicated that sinusoidal stirring yielded the most effective mixing. When implemented in practical production settings, it enhanced dimensionless mixing efficiency by 24.83 % compared to the homogeneous stirring system. Additionally, it reduced reaction time by 15.47 % and decreased mixing energy per unit volume by 32.38 %, while simultaneously lowering energy consumption by 24.77 %.

Dissolution and Regeneration of Cellulose and Chitosan in Molten Salt Hydrate

The energy and environmental problems caused by current fossil resources are becoming more and more serious, and the development of renewable and sustainable materials has become a research hotspot. Chitosan and cellulose, as the two most abundant biomasses in nature, have the advantages of being non-toxic, harmless, and environmentally friendly. However, due to their high crystallinity, it is difficult to dissolve in water and common organic solvents. Molten salt hydrate has been discovered as a cost-effective and non-derivative solvent system for dissolving biomass. In this paper, the dissolution and regeneration of microcrystalline cellulose and chitosan in the molten salt system to prepare gel materials is investigated using lithium bromide molten salt as an example. First dissolve cellulose and chitosan, the total mass is unchanged according to the mixing ratio of the two are divided into multiple groups, dissolved in a mass fraction of 60% lithium bromide solution at 140°C into a hydrogel, gradient regeneration in water-ethanol-tert-butanol, to produce aerogel composites, the molten salt rotary evaporation back to use. Characterization tests show that the material has uniform distribution of nanoscale pores, pore size of about 50nm, porosity of 97.53%, strain 50% range can withstand up to 0.4MPa. 6mm thickness of the sample can be insulated at 150°C for up to 2h or more, the degree of adsorption of 2500mg/L copper sulfate solution reaches 22115.4mg/g. It has excellent thermal insulation and adsorption performance and has a wide range of application prospects in environmental protection, biomedical and other fields.

Fractal Characteristics and Microstructure of Coal with Impact of Starch-Polymerized Aluminum Sulfate Fracturing Fluids

The degree of irregularity and complexity of the pore structure are comprehensively reflected in the fractal dimension. The porosity of coal was determined by its fractal dimension, where a larger dimension indicates a lower porosity. Fractal theory and the Frenkel–Halsey–Hill (FHH) model were applied to explore the variation rules of concentration on functional groups and pore structure in this study. Combined with infrared spectroscopy (FTIR) and low-temperature nitrogen adsorption, a starch-polymerized aluminum sulfate composite fracturing fluid was prepared, which plays an important role in methane adsorption and permeability of coal samples. The test results showed that, compared with the original coal, the pore volume and specific surface area of each group of coal samples were reduced, the average pore diameter was initially enlarged and then declined, and fractal dimension D1 dropped by 5.4% to 15.4%, while fractal dimension D2 gained 1.2% to 7.9%. Moreover, the nitrogen adsorption of each group of coal samples was obviously lower than the original coal, and the concentration of starch-polymerized aluminum sulfate solution existed at a critical optimal concentration for the modification of the coal samples, and the nitrogen adsorption reached a minimum value of 0.6814 cm3/g at a concentration of 10%. The novel composite solution prepared by the combination of starch and flocculant in this paper enhanced the permeability of the coal seam, which is of great significance in improving the efficiency of coalbed methane mining.

Validation of High-Performance Liquid Chromatography method for the determination of doxorubicin in proliposomal drug delivery system formulation

The objective of this study develop a novel proliposome formulation containing Doxorubicin (Dox) and was to validate sensitive and selective reversed-phase high-performance liquid chromatographic (HPLC) method for the evaluation of Dox concentrations of proliposome formulation. The samples were chromatographed on C18 column (Zorbax Eclipse Plus 5µm 4.6 x 250 mm) using a mobile phase with Sodium Lauryl Sulphate solution:Acetonitrile (%50:%50) and detected 254 nm. Linearity was confirmed in the concentration range 10.0–75.0 µg/mL. Specificity, linearity, working range, LOD, LOQ, accuracy, precision, robustness and system suitability studies were done from HPLC validation parameters. Liposome formulation containing Dox was developed by pH gradient method then proliposome formulation was developed with lyophilisation technique. The developed HPLC method, the encapsulation capacity (EE%) was found to be 90%±0.5 and the drug loading capacity (DL%) was found to be 100.0%±0.3. In addition, in vitro release studies and stability study results were evaluated with validated HPLC method. It was observed that developed Dox-proliposome formulation increased Dox release at pH 5.5, pH 6.5 and pH 7.5 by 23.9%, 30.2% and 14.8%, respectively, compared to commercial product. The result of F2 test performed in pH 7.5 media was 51.4%. According to the results of the physicochemical tests performed within the stability studies, it was observed that there was no significant change at the end of 12 months. These results show that the HPLC method developed, and validation study performed are important and applicable in the development, characterization, in vitro release and stability studies of the novel proliposome formulation.

Integration of seeding-induced crystallization with microbubble aeration for membrane fouling and wetting control in vacuum membrane distillation

In this work, a bench-scale vacuum membrane distillation crystallization (VMDC) system coupled with microbubble aeration (MBA) was developed for treating high-salinity feed brine. Herein, the effect of seeding dose on membrane fouling and wetting control in the VMDC system was studied by using synthetic saturated calcium sulfate solution. The results showed that introducing gypsum seeds at a dose of 0.5 g/L effectively restricted membrane fouling and wetting. Subsequently, seeding-induced crystallization coupled with MBA was employed to investigate the control effect on membrane fouling and wetting during VMDC with simulated high-salinity feed brine treatment. As 0.5 g/L gypsum seeds were directly added at 7 h in the VMDC experiment while employing MBA, membrane fouling and wetting were effectively controlled. Finally, the mechanism behind the control of membrane fouling and wetting was elucidated during VMDC operation by integrating seeding-induced crystallization with MBA. This could be ascribed to the synergic effect of gypsum seeds and microbubbles in bulk solution. In brief, this work offers a promising approach to control membrane fouling and wetting during concentrating high-salinity wastewater by VMD.

Effective Method of Improving the Performance Properties of Wall Products On the Basis of the Gypsum Binder

The basis of the conducted research was the goal of modifying composite gypsum-containing binders for the manufacture of wall products with increased water resistance, strength, frost resistance, and durability by developing a hydrophobizing solution for processing products based on gypsum binder. The article presents the results of research on the modification of artificial gypsum stone with a developed hydrophobizing chemical solution based on calcium polysulfide and titanium dioxide. Comparative indicators of water absorption of original and solution-impregnated samples, which were exposed to the frontal influence of water, are given. The water absorption of the modified samples is within 9...21% and does not change after the frontal impact of rain. Indicators of chemical resistance of impregnated samples in solutions of magnesium sulfate, urea, acetic and oxalic acids, which are characteristic components for aggressive environments of livestock complexes, food and chemical industry, are presented. The test results of the samples showed that the developed chemical solution provides a chemical resistance factor of 0.7, that is, they are chemically stable in such environments. It is shown that, depending on the number of applied layers of the solution or the time of impregnation, hydrophobization gives high indicators of the softening coefficient of the products, which is in the range of 0.6...0.82. The research results showed that thanks to the developed hydrophobizing solution, the construction and technical characteristics of the artificial gypsum stone are significantly increased. Wall products made of this material have high operational characteristics, and it is advisable to use them both indoors and outdoors.

Experimental study on scale inhibition performance and fouling characteristics of spiral insert in heat transfer tube

In order to study the anti-scaling and descaling performance in the process of cooling crystallization, the effects of flow velocity and reciprocating displacement on fouling resistance and overall heat transfer coefficient under two spiral insert schemes are experimentally studied. The system studied in the experiment is a saturated sodium sulfate solution, which forms crystalline fouling during the experiment. The micro structure of the fouling layer is investigated to explain the variation of macroscopic thermal parameters. The average fouling thickness curve is obtained by heat transfer theory analysis. The results show that the maximum decrease of the asymptotic value of the fouling resistance of the fixed spiral insert is 63 % with the increase of the flow velocity. When the reciprocating displacement of the spiral insert increases to one pitch, the asymptotic value of the fouling resistance decreases by 83 %, and the overall heat transfer coefficient decreases by only 3 %. The particle size and porosity of fouling at different observation positions gradually increased, while the shape of fouling crystals changed from small to regular, and the degree of bonding changed from tight to loose. Statistics on the particle size of fouling particles show that the fouling particle size increases from 2-8 μm to more than 30 μm. For the fixed spiral inserts, the porosity of the fouling layer is up to 42 %, but the porosity of the middle layer increases rapidly with the flow velocity. With the change of flow velocity, the flow field characteristics in the tube are the main reason for changing the structure of the fouling layer. With the increase of reciprocating displacement, the collision effect of the spiral on the fouling layer is more comprehensive, and the interlayer bonding of the fouling layer is completely destroyed. In the field of industrial cooling crystallization, it can greatly improve the heat transfer efficiency of the inner wall crystallization process.

Investigating the sulfate resistance of mortars with multiple mineral admixtures in ammonium–magnesium sulfate solution

Sulfate resistance is evaluated in mortars containing sulfate-resistant cementitious materials (SRCMs) developed by mixing ground granulated blast furnace slag, fly ash, silica fume and desulfurisation gypsum. Compressive strength testing, X-ray diffraction analysis, differential thermal analysis and mercury intrusion porosimetry are carried out. Results show that the sulfate resistance of mortars mixed with SRCMs at a replacement percentage of 74 wt% is superior to that of mortars with 30 wt% fly ash when exposed to drying–wetting cycles in sodium sulfate solution, because adding SRCMs decreases the calcium hydroxide content, causing a reduction in gypsum formation. Moreover, reducing the water-to-binder ratio (W/B) from 0.50 to 0.35 increases the loss of compressive strength ratio (Lf) of mortars with SRCMs immersed in ammonium–magnesium sulfate complex solution. Specifically, the Lf values of mortars with W/B of 0.50 and 0.35 are 42.7% and 36.0% after 100 days of immersion, respectively. Furthermore, the main component of samples subjected to complex solution is identified as gypsum. In addition, both Lf and porosity exhibit a strong linear positive correlation with W/B. Finally, the findings confirm that optimising the composition of cementitious materials and lowering W/B could improve the sulfate resistance of concretes used for a sulfate-rich sewage environment.

A Study on Synthesis of para-menthane-3,8-diol (PMD) - A Safe Mosquito Repellent Active Ingredient

Active ingredient para-menthane-3,8-diol (PMD) is evaluated as effective in repelling insects in general and is recommended by the Centers for Disease Control and Prevention as an insect repellent, especially against mosquitoes worldwide. The present study attempted to evaluate the suitable conditions for the synthesis of PMD from two sources of materials that are pure (±)-citronellal (∼ 96%) and lemon eucalyptus (Eucalyptus citriodora) essential oil (∼ 60% citronellal) by treatment of sulfuric acid in a biphasic medium (H2O/essential oil). The one-factor-at-a-time method was used to determine the optimal conditions for the synthesis of PMD from pure (±)-citronellal. The effect of various factors such as oil-to-water ratio (citronellal to sulfuric acid aqueous solution), acid concentration (sulfuric acid), reaction temperature, and reaction time on the PMD yield and conversion of citronellal was investigated. The highest PMD yield (95.6%) with excellent conversion of citronellal (98.5%) was obtained at optimal conditions such as, oil to water ratio of 1:2, acid concentration of 0.75% (w/w), reaction temperature of 60°C, and reaction time of 6 h. These optimal conditions were applied to synthesize PMD from Eucalyptus citriodora essential oil. From 200 grams of essential oil and applied optimal conditions, PMD was obtained with a yield of 91.5%.

Study on Optimization of Deep Purification Process Design of Zinc Oxygen Pressure Acid Leaching Solution

According to the characteristics of high impurity content and complex composition of oxygen pressure leaching (OPL) solution of zinc sulfide concentrate, combined with the quality requirements of large plate electrowinning and automatic plate stripping, the advanced purification process of solution was designed. Through the deep purification process consisting of neutralization indium precipitation and low iron purification, high temperature antimony salt nickel and cobalt removal, copper slag chlorine removal, low temperature zinc powder replacement copper and cadmium removal, fine purification, calcium and magnesium removal, the contents of harmful impurities such as iron, indium, copper, cadmium, nickel, cobalt, fluorine and chlorine in the solution are strictly controlled to ensure that the quality of the deeply purified zinc sulfate solution is qualified and can meet the needs of continuous and stable production. The energy-saving effect of advanced purification process is obvious, and the average DC power consumption per ton of electric zinc is 2880kWh, reaching the advanced level of the same industry in China. The good effect of advanced purification process ensures the successful application of OPL and large plate zinc electrowinning, and improves the technology and equipment level of zinc smelting industry, which has important popularization and application value.

Deep purification of copper from zinc sulfate solution using controllable aging FeS nanoparticles through slow-release sulfide precipitation

The purification of impurity ions within zinc hydrometallurgical solutions significantly impacts the subsequent quality of zinc electrodeposition. Traditional methods for copper removal from zinc solutions suffer from issues like limited reactivity, high consumption, and elevated costs. To address these challenges, controllable aging of FeS nanoparticles was designed, employing temperature variations to facilitate comprehensive copper removal from neutral zinc leachates. The aging process imparts a crystalline structure to the FeS nanoparticles, enabling the slow release of sulfide ions. A temperature of 60°C is regarded as the optimal aging temperature, at which the resultant FeS nanoparticles exhibit an optimal sustained-release performance during the aging process. Temperature has been found to be a crucial factor influencing the sustained-release performance of FeS. Once the reaction temperature surpasses 60°C, the utilization efficiency of S ions in the sustained-release agent can reach over 95%, with a maximum of 98.5%. Under optimal conditions featuring a reaction temperature of 60°C, a reaction duration of 30 minutes, and a solution pH maintained at 1, the dosage aged FeS at the S/Cu (II) ratio of 1.2 times, nearly 100% copper removal rate can be achieved. The maximum removal rate for cadmium does not exceed 2.5%, and the residual copper concentration in the zinc leachate is below 0.2 mg/L. The precipitate obtained is high-purity copper sulfide residue, which contains virtually no zinc. Slow-release sulfidation can maximize the utilization efficiency of sulfide ions in the solution, reduce the occurrence of competing reactions, and minimize the intermixing of products. It offers advantages such as high selectivity and deep purification.

65 Testing the effects of rigid encapsulations on bovine primordial follicle quiescence versus growth

OBJECTIVES/GOALS: There is an interest in developing a bioprosthetic ovary for ovarian tissue transplantation. The properties of the ovarian extracellular matrix need to be better understood in order to replicate the human ovary. We tested the effects of an encapsulating hydrogel at different rigidities on bovine primordial follicle activation, growth, and survival. METHODS/STUDY POPULATION: Bovine primordial follicles were isolated from ovarian cortex. A mean of 9.9 follicles (range 3-24) were encapsulated per bead in either 1% or 5 % alginate across 4 experiments. The encapsulated follicles were subsequently crosslinked in a calcium sulfate solution. Follicles were then cultured for 8 days with light microscopy imaging taken every other day along with media exchanges. Follicles were then examined using immunofluorescence. Growth and survival curves were constructed and all statistical analyses were performed using Graph Pad Prism 9. RESULTS/ANTICIPATED RESULTS: A total of 372 follicles were encapsulated across 32 beads (16 in 1% alginate and 16 in 5% alginate). There were no differences in initial follicle size between the two conditions (33.53 µm vs. 32.45 µm, p=0.47). At the end of 8 days, there was no difference between follicle size (59.55 vs. 56.06, p=0.48). Additionally, there was no difference in survival between 1% and 5% alginate encapsulation (57.75% vs. 52.43%. p=0.40). Immunofluorescence is being performed on encapsulated follicles to confirm the presence of DDX4, a molecular marker of oocytes, after 8 days in culture. Additional encapsulated follicles have also been submitted for histologic sectioning and hematoxylin and eosin staining to better characterize the viability and health of these follicles after 8 days in culture. DISCUSSION/SIGNIFICANCE: There was no significant difference in growth or survival between primordial follicles cultured in 1% or 5% alginate gels. Immunofluorescent analysis confirmed the presence of viable follicles at the end of 8 days of culture. Future work needs to further explore how factors in the ovarian extracellular matrix impact follicle maintenance and growth.

Precipitation behavior of calcium sulfate in leach solution of ion-adsorption rare earth ore after reverse osmosis

Ion-adsorption rare earth ore (IAREO) is a crucial source of mid-heavy rare earths elements (M-HRE). Reverse osmosis technology is a promising technique for the pre-concentration of the leach solution from in-situ leaching of IAREO. However, calcium sulfate scaling is inevitably formed in sulfate system, causing decreases in the flux and life time of membrane. Herein, to simulate the precipitation behavior of calcium sulfate in the leach solution of IAREO during reverse osmosis, a series of experiments was conducted in binary and quaternary supersaturated calcium sulfate solution systems. Experimental data show that the concentration of Ca2+ decreases with the increase of the concentration of Mg2+, and increases with the increase of the concentration of RE3+ in both binary and quaternary systems. Whereas, the influence of Al3+ on the concentration of Ca2+ is different. This variation of the Ca2+ concentration is explained by thermodynamic analysis. The difference of association concentration for Mg2+, Al3+ and RE3+ with SO42− in binary or quaternary system is the main reason. Finally, the influence and mechanisms of antiscalant on the precipitation behavior of calcium sulfate are discussed. X-ray diffraction (XRD), Zeta potential and scanning electron microscopy (SEM) analyses reveal that polyacrylic acid (PAA) effectively inhibits the crystal growth of calcium sulfate, and the precipitation time of calcium sulfate is prolonged, indicating that PPA is a potential inhibitor for calcium sulfate scaling during the process of reverse osmosis.

Étude de l'adsorption des ions de Nickel sur des argiles naturelles locales dans les effluents hydrométallurgiques

This research focuses on the treatment of hydrometallurgical effluents, specifically studying the adsorption of metallic ions such as Nickel, Copper, Cobalt, Mercury, and lead on natural clays from the Democratic Republic of Congo (DRC). Twelve clay samples, six activated with a strong acid and six non-activated, were characterized using various techniques including X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, X-Ray Fluorescence, Transmission Electron Microscopy, and chemical dosage. The characterization revealed that the clays are mixed with several clayey minerals, enriched in aluminum silicate; contain absorption and water retention sites, and exhibit heterogeneities at the interfaces between grains and exchangeable ions. Activating the clays increased their cation exchange capacities, removed impurities, and increased pore size and specific area. Two aqueous solutions were used in the experiments: a laboratory-prepared nickel sulfate solution and a hydrometallurgical aqueous solution from a factory, both initially containing 15 mgL-1 of Ni2+ ions. Results showed that the adsorption of Ni2+ ions increased with the quantity of clay in the solution. The activated clays adsorbed more ions than non-activated clays at the same Ni2+ ion concentration. Additionally, adsorption was weaker in the hydrometallurgical solution compared to the nickel sulfate solution, suggesting competition from other metallic ions. The optimal adsorption occurred with chemically activated clays containing high Na+, Fe2+, and Al3+ ion content and low K+ ion content. The Hill-Langmuir model was used to describe the adsorption results, revealing that minimal quantities of activated clay were needed to adsorb a large quantity of Ni2+ ions in the solution, whereas large quantities of non-activated clays were insufficient. In conclusion, the research demonstrates the potential of natural clays from the DRC to adsorb metallic ions from hydrometallurgical effluents, providing insights for effective treatment methods in the future. The model revealed that the clay samples A2a clay, A6a and A3na have the very elevated reactional sites concentrations.

Optimization of simultaneous adsorption of nickel, copper, cadmium and zinc from sulfuric solutions using weakly acidic resins

In this research, the adsorption of nickel (Ni), copper (Cu), cadmium (Cd), and zinc (Zn) from real sulfuric leaching solution with weakly acidic resins has been studied using response surface methodology (RSM). The adsorption process on two weakly acidic resins has been investigated as a function of pH, time, temperature, and resin dosage. The experimental results indicate that the amino phosphoric acid resin removed Ni, Cu, Cd, and Zn from an acidic solution very efficiently. Based on the central composite design (CCD) on the RSM, the statistical criteria of correlation coefficient (R2) values of Ni, Cu, Cd, and Zn are 0.9418, 0.9753, 0.9657, and 0.9189, respectively. The adsorption process followed the pseudo-second-order kinetic model and the thermodynamic calculations indicated the chemical interaction between the resin surface and the metal ions. Enthalpy values greater than zero indicate that the adsorption reaction of the metals is endothermic. The optimal adsorption process was carried out at time of 20 min, temperature of 30 0C, pH of 5, and resin dosage of 4 g/L. In these conditions, the adsorption capacity of nickel, copper, cadmium, and zinc were obtained 13.408, 7.087, 4.357, and 15.040 mg/g, respectively.

Decontamination of Salmonella Enteritidis on Eggshell: Assessment of Efficiency of a Bacteriophage and Levulinic Acid-Sodium Dodecyl Sulfate

The majority of food infections caused by consumption of egg and egg products are caused by Salmonella enterica subspecies enterica serovar Enteritidis. In this study, the inhibitory effect against S. Enteritidis was determined by dipping the eggshell into Salmonella-specific bacteriophage SE-P47 and levulinic acid (LVA) plus sodium dodecyl sulfate (SDS) solutions (0.5% LVA+0.05% SDS, 1% LVA+0.05% SDS and 2% LVA+0.5% SDS) separately for 10 minutes. The treatments of phage and 2% LVA+0.5% SDS reduced S. Enteritidis below the detectable level on eggshell (at 2.76, 3.22, 4.48 and 5.30 log CFU/cm2 inoculum levels). After the treatment of 1% LVA+0.05% SDS, 1.94 and 0.89 log reductions were obtained at 4.48 and 5.30 log CFU/cm2 inoculum levels, respectively, while S. Enteritidis decreased below the detectable number at 2.76, 3.22 log CFU/cm2 inoculum levels. Although the lowest antibacterial activity was observed in the treatment of 0.5% LVA+%0.05 SDS, the decrease in the number of S. Enteritidis detected in all samples except 5.30 log CFU/cm2 inoculum level was found to be significant compared to the control sample. The results indicated that the combination of LVA and SDS, and especially SE-P47 phage alone had good potential efficacy for Salmonella decontamination on eggshell.

Effect of Order of Reagents Addition on Optical and Structural Properties of CdS Quantum Dot Prepared by Chemical Bath Deposition Technique

Cadmium sulfide quantum dots were synthesized and deposited on glass substrates by chemical bath deposition (CBD) technique using cadmium sulfate and thiourea solutions in the presence of a 4,4’-(1,2-ethanediyldinitrilo)bis-(2-pentanone) (EDDBP) tetradentate ligand as a complexing agent. The order of reagents addition was varied to deposit films that were characterized for their surface morphological, optical, structural, and solid-state properties using a scanning electron microscope (SEM), a UV-visible spectrophotometer, an X-ray diffractometer (XRD), and Brunauer-Emmet-Teller (BET) analyses. The optimal condition for film deposition using the normal sequence of reagents addition was found at pH 8-12 and 298-353 ± 1K and gave films of 2.40-321.06 nm thickness, while the variation in the order of reagents addition gave improvements in the film properties. The optical properties and the observed direct band gaps (1.75-3.16 eV) of the films suggest usage in electroluminescent and solar cell devices since they have a first-order transition. The XRD patterns of the quantum dots indicated hexagonal wurzite structures, while the BET confirmed their mesoporous and nanonature.

Supercapacitor Performance of MXene-Coated Carbon Nanofiber Electrodes

MXenes consisting of thin layers of transition metal carbides or nitrides are good candidates for electrode materials due to their excellent electrical conductivity and fast ion transfer. Electrospun carbon nanofibers are highly porous and electrically conductive, making them attractive for electrode materials. In this study, free-standing electrodes were prepared by the dip-coating of carbon nanofibers (CNFs) in the MXene (Ti3C2) colloidal solution, which was synthesized via the wet-etching of MAX (Ti3AlC2) phase, and their chemical structures were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. In addition, scanning and transmission electron microscopy were used to investigate the morphological and crystallographic features of MXene-coated CNFs. Surface area and pore volumes were investigated by nitrogen adsorption/desorption measurements. Supercapacitor performance was studied by assembling a 3-electrode system with 1M aqueous sodium sulfate solution as an electrolyte. MXene-coated CNFs exhibited a maximum specific capacitance of 514 F/g at 0.5 A/g, with energy and power densities of 71.4 Wh/kg at 0.5 A/g and 2.3 kW/kg at 5 A/g, respectively, which are relevantly higher compared to the pristine CNFs due to the pseudocapacitive behavior of MXenes. They also showed comparable cyclic stability during 5000 cycles with the CNFs. This result indicates that MXene-coated carbon nanofibers can be effective electrode materials for electrochemical energy storage.