Solution Phases Liquid Research Articles

Water/oil interfacial photocatalysis of amphiphilic CdS/Bi2WO6 S-scheme heterojunctions for efficient production and spontaneous separation of H2O2 and value-added organics

The photocatalytic co-production of H2O2 and value-added organics in a suitable water/oil biphasic system offers an intriguing strategy to address the challenges encountered in a single liquid-phase solution, including the efficient separation of H2O2 and organic products as well as the mitigation of undesirable secondary reactions. For this, exploring amphiphilic photocatalysts with high performance is highly required. Herein, an amphiphilic CdS/Bi2WO6 S-scheme heterojunction photocatalyst is designedly synthesized through a two-step solvothermal process, aiming to achieve efficient interfacial photocatalytic reactions at the water/oil interface for simultaneous generation and selective separation of H2O2 and organic products. The CdS/Bi2WO6 heterojunction photocatalyst exhibits enhanced light absorption in UV–visible region, increased electron-hole separation efficiency, and powerful charge carriers with high redox abilities. Moreover, the formation of S-scheme heterojunction improves the catalyst stability by preventing CdS from photocorrosion. As a result, the production rate of H2O2 reaches up to 216.76 mmol g−1 h−1, accompanied by the generation of organic products (benzaldehyde: 104.91 mmol g−1 h−1, benzoic acid: 49.88 mmol g−1 h−1, and benzyl benzoate: 38.01 mmol g−1 h−1), in a water/benzyl-alcohol biphasic system under simulated sunlight irradiation. The photocatalytic mechanism is elucidated based on the results of comprehensive experiments and characterizations. This study highlights a rational construction of amphiphilic photocatalysts and their application in organic/water interfacial photocatalytic reactions.

High responsivity VIS-NIR photodetector based on (PEA)2PbI4/P3HT heterojunction

Two-dimensional (2D) Ruddlesden–Popper (RP) perovskite is an ideal platform for building high-performance photodetectors due to its unique structure, excellent stability, and tunable bandgap. However, 2D perovskite heterojunction photodetectors are still less reported. In this work, the photodetector based on (PEA)2PbI4/P3HT heterojunction was prepared by the liquid-phase solution method under air conditions, which showed a responsivity (R) of 8.38 A W−1 and a specific detectivity (D*) of 6.53 × 1011Jones under 808 nm light. In addition, the device has a transient response time of 79.57 μs/484 μs and a high stability performance that maintains more than 95% of the photocurrent under continuous cycling tests and shows good cyclic stability after 30 days without encapsulation. This work provides a promising strategy for extending 2D perovskite photodetectors in the VIS to NIR spectral range.

Effect of surfactant on dynamics and gas-liquid mass transfer for single carbon dioxide bubbles

In carbonation reaction, the impact of surfactants on the movement and mass transfer behavior of carbon dioxide bubbles were crucial for the production of high-quality silicon dioxide products. The study employed the Matlab image processing system to investigate the shapes, motion velocities, and rise path of single carbon dioxide bubbles within varying concentrations of cetyltrimethyl ammonium bromide (CTAB) solutions. This exploration aimed to elucidate the effect of CTAB on the movement and mass transfer coefficient (MTRC) of single carbon dioxide bubbles. Alterations in the CTAB solution concentration and bubble sizes significantly influenced the mass transfer and movement characteristics of single carbon dioxide bubbles. The conclusion was drawn through the computation of the MTRC of single carbon dioxide bubbles in deionized water and CTAB solutions: the addition of CTAB significantly reduced the mass transfer efficiency of carbon dioxide in deionized water, with the MTRC of CTAB solutions decreasing as the solution concentration increased. Utilizing the stagnant cap model, it can be concluded that CTAB's reduction of the MTRC of carbon dioxide was attributed to the high viscosity of the medium, low bubble velocity, stable flow conditions, and intensified adsorption degree of CTAB molecules at the gas-liquid interface. According to the significant periodic trajectories of single carbon dioxide bubbles in the stable range, the correlation between the trajectories of compressible bubbles in surfactant solution and mass transfer in liquid phase was established, and the previous method based on rigid sphere model was modified. The paper proposed the mechanism of CTAB's influence on single carbon dioxide bubbles, offering crucial theoretical insights into the industrial application of surfactants in the carbonation process for producing silicon dioxide.

RHEOLOGY AS A TOOL FOR TECHNOLOGICAL ADVANCEMENTS IN SELF-COMPACTING LIGHTWEIGHT CONCRETE MIXES

This paper outlines a methodology aimed at enhancing the technological performance of self-compacting concrete using lightweight expanded clay aggregate. One of the primary challenges encountered when employing concrete with lightweight aggregate involves displacing expanded clay grains within the solution's liquid phase to ensure necessary fluidity (workability) while upholding high stability (structural viscosity and segregation resistance). To achieve this objective, the rheological parameters of the self-compacting cement matrix have been regulated by deliberately adjusting the functional groups of additives and the microfine mineral filler, employing analytical methods from computer materials science. Through the analysis of rheometric results obtained from investigating various solution mixtures, the most suitable model that describes their rheological behaviour has been identified. The impact of finely dispersed fly ash excipient, a carboxylate superplasticiser, and a stabiliser additive on the rheological parameters of self-compacting lightweight concrete mixes has been established. The inclusion of these complex additives in the composition has enabled substantial alterations in the flow index across a wide range (0,030-0,798). This adaptability allows for the adjustment of the mortar mixture's rheological behaviour throughout a spectrum ranging from «abnormally viscous liquid» to «Newtonian liquid». This approach, examining the singular-factor dependencies' analysis on the coefficients of rheological behaviour models, aids in addressing the primary challenge encountered when using concrete with lightweight aggregate.

Polyrate 2023: A computer program for the calculation of chemical reaction rates for polyatomics. New version announcement

Polyrate 2023: A computer program for the calculation of chemical reaction rates for polyatomics. New version announcement

Phase equilibria and thermodynamic re-assessment of the Cu–Ti system

Several as-cast and annealed Cu–Ti alloys were prepared for microstructural, compositional, structural and thermal characterizations. The formation of CuTi2 was congruent and CuTi3 was not found in both as-cast and annealed specimens. The temperatures of nine invariant reactions were determined. The Cu–Ti system was thermodynamically re-assessed according to the experimental phase equilibria and thermochemical properties from this work and the literature. The solution phases Liquid (L), fcc-A1 (Cu), bcc-A2 (βTi) and hcp-A3 (αTi) were treated as substitutional ones. The intermetallics compounds Cu2Ti, Cu3Ti2, Cu4Ti3 and CuTi2 with negligible solubility were described as line ones with the formula CupTiq, while βCu4Ti and CuTi with remarkable solubility were modeled with the formula (Cu,Ti)r(Cu,Ti)s. A group of reliable thermodynamic parameters of the Cu–Ti system were obtained. The calculated results agreed reasonably well with the experimental ones.

Single Mode Lasing from CsPbBr3 Microcrystals Fabricated by Solid State Space‐Confined Growth

AbstractAll‐inorganic metal halide perovskites, such as CsPbX3 (X = Br, Cl, or I), have attracted significant interest for a new generation of integrated, high‐performance optoelectronic devices. To realize the full potential of layer‐by‐layer devices, perovskite crystal thin films are preferred over crystal ingots, considering carrier loss during carrier transport. The space‐confined method is a facile way of fabricating perovskite crystal films in a geometrically confined space to break the isotropic growth. Many researchers have reported effective preparation of large‐area perovskite films using this method. However, most space‐confined methods require growth in a liquid phase (solution), which can cause uncontrollable nucleation, surface traps, and unsatisfactory device performance. In this work, a pure solid‐state space‐confined strategy to grow CsPbBr3 films for the first time without relying on solution conditions is developed. The regular shapes of CsPbBr3 films prepared by this solid‐state space‐confined strategy can function as effective multimode and single‐mode Fabry–Perot (F–P) microlasers under optical pumping. This work overcomes the challenge that the conventional space‐confined method can only be adapted to the liquid phase. It also opens a new approach for making high‐quality microlasers, which are significant for photonic integrated circuits and optoelectronic devices.

The Contribution of Theoretical Prediction Studies to the Antioxidant Activity Assessment of the Bioactive Secoiridoids Encountered in Olive Tree Products and By-Products.

Assessment of the antioxidant activity of different types of natural compounds is a complex research area that encompasses various in vitro tests and in vivo studies. Sophisticated modern analytical tools permit the unambiguous characterization of the compounds present in a matrix. The contemporary researcher, knowing the chemical structure of the compounds present, can carry out quantum chemical calculations that provide important physicochemical information assisting the prediction of antioxidant potential and the mechanism behind the activity of target compounds before further experimentation. The efficiency of calculations is steadily improved due to the rapid evolution of both hardware and software. It is possible, consequently, to study compounds of medium or even larger size, incorporating also models that simulate the liquid phase (solution). This review contributes to the establishment of theoretical calculations as an inherent part of the antioxidant activity assessment process, having as a case study the complex mixtures of olive bioactive secoiridoids (oleuropein, ligstroside, and related compounds). The literature indicates great variability in theoretical approaches and models used so far for only a limited number of this group of phenolic compounds. Proposals are made for standardization of methodology (reference compounds, DFT functional, basis set size, and solvation model) to facilitate comparisons and communication of findings.

Microstructures and properties of PVDF membranes: effect of the solvent

The polyvinylidene fluoride (PVDF) membranes were synthesized using immersion precipitation technique. The effect of four solvents, N, N-dimethyl formamide (DMF), N, N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO) on the water flux and beef serum albumin (BSA) rejection efficiency was reported. The structure and morphology of PVDF membranes were studied using Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and water contact angle measurements. The cross-section of a membrane formed in a DMF as a solvent exhibit a spongy/fingerlike hybrid structure, while DMSO favors the formation of more porous structure. The increase in the solvent mass fraction facilitates liquid phase separation and solution casting, and changes the structure of PVDF membrane from denser, bicontinuous structure to a looser, stacked structure. Moreover, the results revealed that the properties of PVDF membranes sub-layer are controlled by the diffusion rate of the nonsolvent. The membrane with the best performance was prepared using 80% DMF (mass fraction) as a solvent, and it reached water flux of 66 L·m−2·h−1, and 91.53% BSA rejection efficiency.

Light-induced protein structural dynamics in bacteriophytochrome revealed by time-resolved x-ray solution scattering.

Bacteriophytochromes (BphPs) are photoreceptors that regulate a wide range of biological mechanisms via red light–absorbing (Pr)–to–far-red light–absorbing (Pfr) reversible photoconversion. The structural dynamics underlying Pfr-to-Pr photoconversion in a liquid solution phase are not well understood. We used time-resolved x-ray solution scattering (TRXSS) to capture light-induced structural transitions in the bathy BphP photosensory module of Pseudomonas aeruginosa. Kinetic analysis of the TRXSS data identifies three distinct structural species, which are attributed to lumi-F, meta-F, and Pr, connected by time constants of 95 μs and 21 ms. Structural analysis based on molecular dynamics simulations shows that the light activation of PaBphP accompanies quaternary structural rearrangements from an “II”-framed close form of the Pfr state to an “O”-framed open form of the Pr state in terms of the helical backbones. This study provides mechanistic insights into how modular signaling proteins such as BphPs transmit structural signals over long distances and regulate their downstream biological responses.

Thermodynamic optimization of the constitutive binaries of the LiCl/RbCl/CaCl2-NaCl-UCl3-PuCl3 systems

This study is aiming at building a set of self-consistent thermodynamic database of the constitutive binaries of the LiCl/RbCl/CaCl2-NaCl-UCl3-PuCl3 systems, and evaluating whether LiCl, RbCl or CaCl2 is an appropriate additive of NaCl-UCl3-PuCl3 matrix fuel of Molten Salt Reactor in terms of CALculation of PHAse Diagrams (CALPHAD) method. Substitutional solution model was adopted to describe the liquid phase and solid solution phase, while compound energy formalism was used to depict the intermediate phases. The model parameters were optimized based on the experimental data and theoretical predicted values. The thermodynamic parameters for describing the constitutive binaries of LiCl/RbCl/CaCl2-NaCl-UCl3-PuCl3 were ultimately obtained. Phase diagram information such as liquidus surface projections, isothermal sections and vertical sections of the LiCl/RbCl/CaCl2-NaCl-UCl3-PuCl3 system were predicted from the models with the optimized parameters. The effect of LiCl, RbCl and CaCl2 on the isothermal sections and melting temperature of NaCl-UCl3-PuCl3 matrix fuel was also investigated. The results show that RbCl is suitable as the candidate additive component of NaCl-UCl3-PuCl3 matrix fuel from the thermodynamic viewpoint, while LiCl and CaCl2 not. This work not only enriches the thermodynamic databases of NaCl-UCl3-PuCl3 matrix fuel, but also provides a direct guidance for the design and preparation of nuclear fuel in the Molten Salt Reactor.

Optimum design and key thermal property of NaCl–KCl–CaCl2 eutectic salt for ultra-high-temperature thermal energy storage

NaCl–KCl–CaCl 2 eutectic salt was developed using the thermodynamic calculation and experimental validation for the ultra-high-temperature thermal storage. Substitutional solution model (SSM) was used to describe the liquid phase and solid solution phase, and stoichiometric compound was applied to depict the intermediate phase. The predicted eutectic temperature (481.3 °C) of NaCl–KCl–CaCl 2 eutectic salt agrees well with experimental value (496.3 °C). The actual eutectic point of NaCl–KCl–CaCl 2 system is placed at T = 496.3 °C, X NaCl = 0.408 mol, X KCl = 0.075 mol and X CaCl2 = 0.517 mol. The fusion enthalpy is 171.5 J/g. The weight loss is only 1.7 wt% even at 900.0 °C and 939.0 °C is determined to be the upper limit of working temperature. The average liquid specific heat capacity is 0.80 ± 0.15 (J/g⋅ o C). The cost of NaCl–KCl–CaCl 2 eutectic salt is only 51.6% of solar salt and 54.3% of NaCl–KCl–MgCl 2 salt. SSM of thermodynamic calculation can be used as a reasonable model to optimize the chlorides salts in future. The developed NaCl–KCl–CaCl 2 eutectic salts have relatively better thermo-physical properties particularly excellent ultra-high-temperature thermal stability and lower cost, and can be considered as the ultra-high-temperature thermal energy storage materials. ∙NaCl–KCl–CaCl 2 salts were developed by thermodynamic calculation and experiment. ∙The calculated eutectic point agrees well with the experimental result. ∙The decomposition temperature of NaCl–KCl–CaCl 2 salt is 939.0 °C. ∙NaCl–KCl–CaCl 2 salts have better thermo-physical properties and lower cost.

The Fe–Cr–Zn system in relation with the galvanizing process in chromium-added zinc bath

Abstract Taking into account new experimental measurements, the Fe –Zn – Cr ternary system is critically modified at 460 °C. A continuous solid solution between ζ-FeZn13 and CrZn13 compounds is shown but is shared at 460 °C by the stable CrZn17 compound containing about 2 wt.% Fe. This ternary system is assessed with the CALPHAD method using the PARROT modulus of the Thermo-Calc software. The liquid and solid solution phases are modeled with Redlich– Kister –Muggianu equations. The intermetallic compounds ζ-(Fe,Cr)Zn13 and CrZn17 are treated as stoichiometric compounds in the binary systems. The experimental Fe and Cr solubilities at various temperatures modify the shape of the liquidus curve and are satisfying for industrial applications. A set of parameters consistent with most of the available experimental data on both phase diagram and solubility measurements is obtained by optimization. A comparison with previous experimental work is also presented and a reactional model between iron substrate and Zn–Cr bath is proposed. This optimization allows to interpret the growth of intermetallic layers and the formation of dross when galvanizing in Cr-added Zn bath.

Thermodynamic modeling of ZrO2–CaO–TiO2 system

The phase diagram of ZrO2–CaO–TiO2 system was essential for the development of photocatalytic materials and refractory materials. In this work, the ZrO2–CaO–TiO2 system was accessed by using the CALPHAD method. The substitutional solution models were used to describe liquid and solid solution phases, the sub-lattice models were used to describe ternary compounds, and then the thermodynamic parameters were obtained by the least square method combined with literature experiment results. The acquired thermodynamic parameters were used to calculate the isothermal sections of the ZrO2–CaO–TiO2 system at 1473 and 1673 K. There existed a good agreement between experimental and predicted phase relationships, the experimental points which were inconsistent with calculated results may be attributed to experimental errors and the sluggish kinetics of cations for ZrO2-based materials. In order to further verify the validity of the database, the thermodynamic parameters were also used to simulate the thermodynamic properties (specific heat capacity, enthalpy, and entropy) of CaZrTi2O7 within 5% errors. Good consistency demonstrated that the present thermodynamic database was self-consistent and credible.

Measuring Solute Concentration with Terahertz Time-Domain Spectroscopy in Single and Multiphase Systems.

A versatile setup based on a microfluidic platform allows investigation of liquid samples at various temperatures with terahertz time-domain spectroscopy. The setup is applied to develop a novel method that performs temperature and concentration calibrations of liquid samples at terahertz frequencies. Other than measuring the concentration of pure liquid phase solutions, it enables the studies of local concentration of semicrystalline systems. An equivalent solute concentration during crystallization can be calculated from the extracted absorption at low frequencies. The MgSO4-water system is discussed as an example to illustrate the idea of this method.

Effect of impurities of CH3OH, CH3COOH, and KOH on aqueous phase reforming of glycerol over mesoporous Ni–Cu/CeO2 catalyst

Impurities are inevitable in crude glycerol, a by-product of biodiesel, which has a great influence on aqueous phase reforming (APR). This work investigates three impurities (CH3OH, CH3COOH, and KOH) in the aqueous phase reforming of glycerol (GAPR) using a mesoporous Ni–Cu/CeO2 catalyst at three temperatures. The experiment results indicate that the increase of temperature is beneficial to the conversion of glycerol into gas products, but not favor to the proportion of H2 in the gas phase. The presence of CH3OH almost has not affected the total gas volume, while CH3COOH and KOH decreased and increased the gas volume, respectively. The deactivation of the catalyst occurs under acidic conditions because the active phase Ni on the catalyst surface is lost in the hydrogen evolution reaction. KOH has the greatest influence on the gas phase composition, which greatly increases the H2 production and the proportion of H2. The results of liquid-phase solution analysis show that the addition of CH3COOH promoted the dehydration of glycerol, which is contrary to the results obtained by adding KOH. CH3OH, as the final product of glycerol dehydrogenation and decarbonization, is added to the initial solution, which will be conducive to the dehydration reaction. The addition of CaO can increase the H2 production in the APR of glycerol solution containing impurities.

Thermodynamic modelling of the ternary Bi-Ga-Te system for potential application in thermoelectric materials

Thermoelectric materials have drawn widespread attention because they can enable the direct conversion between electric and thermal energy. Over the years, different materials such as skutterudites, clathrates, intermetallic alloys, eutectic alloys, chalcogenides have been explored for Thermoelectric (TE) applications. Amongst the eutectic alloys, the Bi-Ga-Te system exhibits promising potential as a TE material. Accordingly, in this study, we performed the thermodynamic optimization and critical evaluation of binary Bi–Ga, Bi–Te, Ga–Te, and ternary Bi-Ga-Te systems using the CALPHAD method. It is observed that the Ga–Te system shows asymmetric liquid solution properties with strong negative enthalpy of mixing, whereas the Bi–Te liquid exhibits the symmetric regular solution behavior. Moreover, the Bi–Ga liquid solution has a positive enthalpy of mixing. Therefore, Modified Quasichemical Model (MQM) using pair approximation was utilized to describe the diversified thermodynamic properties of liquid solution in sub-binaries by taking into account the Short-Range Ordering (SRO). By merging the binary optimization results with a proper interpolation method, the liquid solution properties and phase diagram information in the Bi-Ga-Te ternary system were also reproduced successfully without any adjustable ternary parameter. Several ternary eutectic compositions were suggested for designing TE alloy with enhanced properties using the developed database.

Arsenic in the geo-environment: A review of sources, geochemical processes, toxicity and removal technologies

Impact of arsenic (As) contaminated groundwater on human health, through drinking and irrigation practices, is of grave-concern worldwide. This paper present the review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water. Groundwater with high As concentration is detrimental to human health and incidents of As contamination in groundwater had been reported from different parts of the globe. More serious known As contamination problem as well as largest population at risk are found in Bangladesh, followed by West Bengal state in India along the Indo-Gangetic plains. Large scale natural As contamination of groundwater is found in two types of environment such as strongly reducing alluvial aquifers (ex. Bangladesh, India, China and Hungary) and inland basins in arid or semi-arid areas (ex. Argentina and Mexico). The provisional guideline of 10 ppb (0.0 l mg/l) has been adopted as the drinking water standard by World Health Organization (WHO). In the aquatic environment, the release, distribution and remobilization of As depend on temperature, redox potential, speciation, and interaction between liquid solution and solid phases. As predicaments in the environment is due to its mobilization under natural geogenic conditions as well as anthropogenic activities. Arsenic mineral is not present in As contaminated alluvial aquifer but As occurs adsorbed on hydrated ferric oxide (HFO) generally coat clastic grains derived from Himalayan mountains. As is released to the groundwater mainly by bio-remediated reductive dissolution of HFO with corresponding oxidation of organic matter. The development of strongly reductive dissolution of mineral oxides (Fe and Mn) at near-neutral pH may lead to desorption and ultimately release of As into the groundwater. As release through geochemical process is more important factor in alluvial aquifers causing As contamination rather than sources of arsenic. As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones, and also cancer of liver, kidney, gall bladder and the intestines. It is necessary to adopt highly successful technology to treat As contaminated water into the acceptable limit for human consumption. Universally accepted solutions are not developed/available even after the lapse of almost forty years since slow As poisoning identification in tens of millions of people especially in Bengal delta. The issue poses scientific, technical, health and societal problems even today.

Development and adaptation of the technology of air biotreatment in trickle-bed bioreactor to the automotive painting industry

The automotive painting industry is a source of environmental pollution caused by Volatile Organic Compounds (VOCs) present in the discharged ventilation air. To contribute to the mitigation of this type of air pollution, Ekoinwentyka Ltd. developed – from pilot scale to full scale – and adapted the technology of Compact Trickle Bed Bioreactor (CTBB) whose operating principle builds upon co-current downflow of the gas phase (polluted air) and liquid phase (solution of mineral salts) through a packed bed where active microorganisms are immobilized in the biofilm on the surfaces of packing elements. Pilot-scale bioreactor 0.32 m in diameter and 1.50 m total height had its packed bed inoculated with a consortium of microorganisms dominated by Pseudomonas fluorescens bacteria. During the experimental programme that lasted several months, the flow rate of air drawn from the ventilation system of the painting shop was changing between 1.0 and 10.0 m3/h and the inlet concentration of VOCs ranged from 10 to 200 ppm. By measuring VOC concentration in the purified air, the factor of VOC biodegradation was found to range between 85 and 99%. Based on pilot-scale experiments, full-scale CTBB has been developed 2.8 m in diameter and 10 m total height and installed as an add-on component of the ventilation system of the painting shop. Test operation at gas flow rates up to 6000 m3/h, confirmed VOC biodegradation factor at the level of 85–99% thus proving a positive result of CTBB technology adaptation to the conditions of the automotive painting industry.

Improved mechanical and wear properties of Cu-Ga-In ternary alloys through liquid reinforcement

In this work, novel Cu-Ga-In alloys are designed with systematic variation in the liquid and solid solution phases to mimic the nature-inspired structures and their properties. A combination of characterization techniques such as X-ray Diffraction (XRD), Optical microscopy, scanning electron microscopy (SEM) and 3D X-ray tomography along with thermodynamic calculations confirm the presence of liquid and solid solution phases in the microstructure. The effect of the liquid phase in increasing the ductility and toughness is clearly demonstrated in the present study. It is shown that the liquid phase can arrest the crack movement during the fracture that leads to improved toughness in the Cu-Ga-In based alloys. Moreover, the presence of the liquid phase also improves the wear properties of these alloys. The present alloys exhibited better hardness and reasonable yield strength compared to the existing Cu alloys in the literature. Especially Cu65In20Ga15 alloy exhibits the hardness of 660Hv and the yield strength of 335.49 MPa which is higher than conventional copper alloys.