Journal of Molecular Liquids最新文献

Improving the efficiency of renewable energy sources can lead to obtaining electrical energy in an environmentally-friendly way. Therefore, the development of nanofluids for use in parabolic trough collectors in concentrated solar energy (CSP-PTC) is a research line of interest. Thus, in this work, nanofluids based on Ag nanoparticles and a polydimethylsiloxane (PDMS) type fluid used in CSP-PTC technology were prepared. The use of this fluid in this technology and the preparation of nanofluids based on it has not been studied widely, and the evaluation of the use of nanofluids from this type fluid is of great interest. Thus, the physical stability and the properties of interest measured, that are density, surface tension, viscosity, isobaric specific heat and thermal conductivity, were characterized. The nanofluids prepared presented interesting thermal properties. An increase of up to 4.5 % in the isobaric specific heat and up to 24 % in thermal conductivity were observed with respect to the base fluid, without a significant increase in viscosity. Thus, an increase in the heat transfer coefficient of up to 16 % was obtained. These results are really promising for the use of the nanofluids prepared in CSP-PTC technology. Finally, the moderate increase in isobaric specific heat and the significant increase in thermal conductivity is explained by the weak Van der Waals force interaction observed between the Ag surfaces and the PDMS molecules.

To the best of our knowledge, the detailed evaluation of the interaction of gentamicin with chitosan nanoparticles in the absence and presence of Sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactant followed by the evaluation of structural, dynamical, and thermodynamic properties was carried out for the first time which helped to understand the relative drug retention and release time in the model drug delivery system. Gentamicin being an unstable drug molecule demonstrated low efficacy against brucellosis as well as considerable toxicity, thus requiring frequent dosing in different forms including a single dose and combination with other antibiotics; however, no satisfactory result was observed. Chitosan is biodegradable and biocompatible which could help overcome drug delivery issues enabling the drug to reach the target site. Our study is based on the investigation of the chitosan-drug systems without and with the surfactant for the evaluation of the structural, dynamical, and transport properties using a combined approach consisting of density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The DFT results showed that increasing the size of the chain consisting of D-glucosamine facilitated its interaction with the drug molecule thus signifying the role of polymer for the drug accommodation. Furthermore, MD simulation results exhibited the interaction of chitosan nanoparticles with the drug molecules via H-bonding and hydrophobic contacts which were enhanced after the addition of the surfactant. The dynamics and thermodynamic data corroborated the structural properties of the drug-nanoparticle interaction which confirmed the perturbation of the simulation system after the addition of the surfactant. The investigation of another two simulation systems based on the polymer constituents, D-glucosamine pointed towards the significance of the polymerization which eventually resulted in nanoparticles thus providing a platform for drug adsorption. The gentamicin-chitosan nanoparticles were further characterized via transport properties in terms of drug diffusion coefficients which served to consider its use in the context of target drug delivery to treat brucellosis.

Traditional demulsifiers are commonly produced using raw materials like ethylene oxide and propylene oxide, which deplete significant petroleum resources and involve hazardous and complex manufacturing processes. In this investigation, a hydrophobically modified chitosan (HMC) was synthesized by grafting dodecyl diethanolamine onto natural chitosan to facilitate the separation of O/W emulsions. Characterization of HMC was conducted using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy (¹H NMR) and scanning electron microscopy (SEM). The demulsification efficacy of HMC was assessed through a bottle test in an O/W emulsion containing 0.2 % crude oil. Results showed that at a HMC dosage of 40 mg/L, the light transmission (W_T) and oil removal efficiency (W_R) of the resulted water phase were 93.4 ± 0.8 % and 99.8 ± 0.1 %, respectively. Furthermore, the competitive adsorption between natural surfactants and HMC at the interface was investigated using interfacial tension (IFT), three-phase contact angle (CA), droplet coalescence time (CTA), and interfacial film substitution. A potential demulsifying mechanism was also proposed, emphasizing HMC’s hydrophilic core and dispersed hydrophobic alkyl chains that enable rapid diffusion to the oil–water interface, replacing interfacial active components to induce demulsification by destabilizing the composite film. The advantages of HMC demulsifier over commercial demulsifiers lie in its superior environmental benefits, diverse range of sources, higher efficiency, and outstanding demulsification performance.

In order to improve the salt resistance and shear resistance of partially hydrolyzed polyacrylamide-based oil displacement agents (they are all anionic polyelectrolytes), this paper proposes the preparation of branched low hydrophobic monomer content sodium alginate grafted hydrophobically modified partially hydrolyzed polyacrylamide P(AM-SA-MO8) using acrylamide (AM), sodium alginate (SA), and non-ionic hydrophobic monomer (MO8) as main raw materials through the method of adiabatic polymerization followed by hydrolysis. The polymerization conditions of P(AM-SA-MO8) were optimized, and the solution properties and oil displacement performance of P(AM-SA-MO8) and P(AM-MO8) (copolymer of AM and MO8) were compared. It was found that the viscosity, resistance to Ca²⁺/Mg²⁺, shear resistance, resistance factor (RF), residual resistance factor (RRF), and enhanced oil recovery performance of P(AM-SA-MO8) solution were better than those of P(AM-MO8). Especially in seawater, at 75 ℃, the viscosity of 1500 mg/L P(AM-SA-MO8) solution was 6.5 mpa.s, RF was 6.08, RRF was 2.28, and the enhanced oil recovery was 26.28 % with a injection rate of 4.9 ft/day.

A detailed comparison of the corrosion behaviour of Al–O (1 1 1) surfaces on 7A46 aluminium alloy in 1.0 M hydrochloric acid and sulfuric acid solutions was conducted using electrochemical, surface analysis, and density function theory calculations. The results show that the corrosion current density is around 80.62 μA.cm⁻² in HCl solution and 104.21 μA.cm⁻² in H₂SO₄ solution. Uncovered defects in the oxide film on the alloy surface can contribute to local erosion and degradation during the corrosion process. In addition, the amounts of charge transferred from the surface of the alloy to Cl⁻ and O²⁻ were 0.811 and 0.178e, respectively, suggesting the formation of an Al–O bond on the surface, which expedites the corrosion process in the HCl solution. In contrast to HCl, the O atoms on the surface of the aluminium alloy obtained 2.032 e and 1.611 e electrons from Al on the Al–O (1 1 1) surfaces and S atoms in H₂SO₄ solution, respectively, indicating a strong adsorption affinity for SO₄²⁻. Both Cl–Al and S–Al bonds form covalent bonds. It is worth mentioning that the resonance peaks in the HCl adsorption system was between −6 eV and 2 eV, whereas that in the H₂SO₄ adsorption system show a more pronounced shift to the right (−10 eV to 0 eV), suggesting heightened system activity and increased electronic interactions among the atoms in H₂SO₄ adsorption system. This research contributes to a comprehensive understanding of the surface corrosion behaviour of aluminium alloys, providing valuable insights for the design and application of aluminium alloys across diverse environmental contexts.

Aiming to address the issues of limited suitability of conventional chemical oil displacement materials for formation conditions and the serious emulsification of oil and water in the produced liquid, the innovative nano oil-displacing system with CO₂-responsive behavior has been developed. This system integrates oil displacement and emulsion breaking. The efficacy of the CO₂-response system in creating stable emulsions with a high capacity to decrease interfacial tension has been demonstrated. The interfacial responsive behavior of all active components, including Janus nanoparticles, sodium oleate, gums, and asphaltenes, in the emulsion system was analyzed in terms of interfacial rheology and adsorption. Additionally, the prepared system demonstrated a rapid response to CO₂, effectively breaking the emulsion within 5 min. Furthermore, the oil recovery enhancing mechanism of the CO₂-response system was investigated using a microscopic visualization model. The system was proved to be efficient in initiating the residual oil within pore channels. Considering the combined effectiveness of the CO₂-response system in terms of efficient oil displacement and rapid response, it offers valuable insights for advancing the chemical flooding technology of in enhanced oil recovery.

The development of methods for detection and differentiation of chemically similar saccharide molecules is a challenging task. This study describes a simple approach for saccharide differentiation based on saccharide induced micelle formation of a reverse poloxamine surfactant, T90R4. The differential response is derived from the different kosmotropic effect of each type of saccharide, which is not only dependent on the number of hydroxyl groups present in the saccharides, but is also sensitive to their stereochemistry. This results in different propensities of the saccharides for inducing micellization of T90R4, which in turn is reflected by variations in the emission spectrum of a solubilised fluorescence probe, 7-hydroxy-4-methylcoumarin (7H4MC). The effect of temperature on the emission spectrum of 7H4MC is also found to be uniquely dependent on the nature of the saccharides. These effects work in tandem to generate a supramolecular platform for fluorescence pattern based recognition of multiple saccharides.

Scientists are becoming interested in nanomedicine as a potential new approach to cancer detection and therapy in the twenty-first century. This paper presents the first investigation of the anticancer and antibacterial properties of selenium (Se) and zinc oxide (ZnO) nanoparticles obtained from Rheum ribes plant extract by a green synthesis method. Morphological and spectroscopic characterization of the synthesized nanoparticles was performed using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis), which is a useful and straightforward technique for the preliminary characterisation of nanoparticles, dynamic light scattering (DLS) and X-ray diffraction (XRD) analysis. The size of the nanoparticles was determined to be 33 nm for Se-Nps and 32.8 nm for ZnO-Nps. The anticancer activity was assessed by the use of MTT, annexin V, caspase 3/7, and confocal microscopy imaging techniques. ZnO-Nps and Se-Nps were found to have significant antibacterial activity with MIC values for Escherichia coli (0.7 μg/mL, 0.63 μg/mL), and Staphylococcus aureus (1.56 μg/mL and 1.1 μg/mL). Furthermore, the antibacterial activity and the mechanism of action of the nanoparticles on E. coli and S. aureus bacteria were evaluated using microdilution and disc diffusion methods. In addition, the antiproliferative properties of ZnO-Np and Se-Np significantly suppressed the growth of A549 cells during a 24-hour incubation period (IC₅₀ 18.89 μg/mL ve 23.88 μg/mL). The results of the anti-cancer and anti-bacterial activity of the present study suggest that certain concentrations of Se-Np and ZnO-Np could be useful for pharmacological applications in cancer treatment and for coating surfaces for sterilization of medical equipment in healthcare settings, particularly in intensive care units.

Titanium-based lithium ion sieve adsorbents (HTOs) are considered among the most promising materials for lithium extraction from aqueous sources. In this study, four surfactants—sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), hydroxypropyl cellulose (HPC), and tannic acid (TA)—were used to surface-etch HTOs, preparing adsorbents with enhanced hydrophilicity at the nanoscale. Correlation studies between the hydrophilicity of the HTO-X and their adsorption performance revealed that all HTO-X had lower contact angles than the unetched counterparts, indicating improved adsorption capacities. Notably, TA plays a synergistic role of “killing two birds with one stone”. The TA-etched HTO-T adsorbent exhibited the lowest contact angle (8.8°) and the highest specific surface area (62.10 m²/g). In a LiCl solution, HTO-T’s adsorption capacity for Li⁺ reached 33.61 mg/g, a 26 % increase over the unetched HTO adsorbent (26.56 mg/g). Simultaneously, HTO-T significantly reduces the adsorption time and enhances the adsorption efficiency during the surface diffusion phase. Additionally, HTO-T demonstrated remarkable selectivity for lithium ions, with separation factors α(Li/Na), α(Li/K), α(Li/Mg), and α(Li/Ca) of 397.13, 181.55, 1288.47, and 1345.19, respectively, showcasing an excellent separation effect. The adsorption mechanism indicates that Li⁺ adsorption by HTO-T primarily occurs through the disruption of O–H bonds and the formation of new O-Li bonds. This research presents an efficient strategy for the development of HTOs, demonstrating HTO-T as a potential adsorbent for lithium recovery from brine sources.

Supramolecular deep eutectic solvents (SUPRADESs) as green designer solvents can be applied to facilitate key steps of separation, extraction, catalysis, and drug transport processes. However, so far, the details concerning the formation mechanism of SUPRADESs are still not clear, thus hindering full development. The present study is dedicated to the theoretical exploration of the structural properties of co-formers that can form SUPRADESs with cyclodextrins (CDs) to design better-performing task-specific SUPRADESs and further structural modifications. Firstly, a series of aliphatic organic acids (AOAs) with similar structures were screened for forming the SUPRADESs. The structure-property relationship showed that co-formers with a higher hydrogen-bond donating ability were found to favor the propensity to form SUPRADESs. Based on this finding, an empirical rule originating from molecular surface electrostatic potential (ESP) descriptors was proposed that can preliminarily predict the formation possibility of SUPRADESs. Density functional theory (DFT) calculations in conjunction with molecular dynamics (MD) simulations further demonstrated that the formation of SUPRADESs mainly depends on the net hydrogen donating ability of co-formers, which is affected by the electron-withdrawing substituent, the carbon chain length, and the molecular self-association degree. Overall, this study provides important guidance to develop novel and green functional SUPRADESs, which will greatly simplify the SUPRADES manufacturing process and reduce the time cost.