Crystal Solution Research Articles

Rheology of concentrated crystal suspensions: sucrose fondants as hard particles in soft matter

Hard particle dispersions are abundant in food as well as technical applications. In particular, the production of many candies like fondants, crystalline sugars or creamed honeys involves agitation of concentrated suspensions of microscopic crystals in saturated solutions. However, the complex rheological behavior of such non-colloidal suspensions with poly-disperse, irregular particles is not fully understood. This work investigates different sucrose suspensions with a particle volume fraction of about 50%. After detailed image analysis of the varying particle size distributions and shapes, the flow properties are investigated by oscillatory rheology. Amplitude sweeps, frequency sweeps and thixotropy tests show the dependency of rheological behavior on the microstructure of the suspensions. In particular, all samples show characteristic strain softening with subsequent strain hardening that indicates jamming at large strains. This is observed irrespective of specifics in the particle shape and material, suggesting universal behavior due to the high particle volume fraction. They also show significant time-dependent behavior. However, sedimentation rates are higher and structure rebuilding is lower for larger particle sizes and dispersity. The observed strain softening and structure rebuilding are explained by rearrangement of the crystals: Under moderate strain amplitudes, friction and collisions are minimized, with a larger optimization potential for larger dispersities. When oscillations are reduced again, mainly small particles re-arrange in an arbitrary order over time, leading to an increase in loss and storage modulus and thus thixotropic behavior. This time-dependent process needs to be taken into account when measuring or processing concentrated crystal suspensions. Our findings contribute to a better understanding of concentrated suspensions simple in composition, but complex in their flow properties. The observed behavior strongly depends on the particle-particle interactions. Thus, our findings can be transferred to other areas involving concentrated, non-Brownian frictional suspensions of compact hard particles, as they are often found in food, technical applications or geology.

Calcium Phosphate-Induced Injury in Kidney Tubular Cells-Supersaturated Solution vs Preformed Crystals.

Crystalline nephropathy (CN) is characterized by deposition of microcrystals within the kidney tubular microstructure, specifically in the renal tubular cells. Nephropathic conditions have been observed in kidney stone patients as nephrocalcinosis, resulting from the deposition of calcium phosphate (CaP) microcrystals mainly within the renal tubule. CaP microcrystals trigger nephrotoxicity and cell death leading to acute and chronic kidney disease and in some cases end stage renal disease. Although supersaturation of calcium (Ca2+)- and phosphate (PO4 3-) ions in the urine was described as a main factor the precise mechanism of cell death by distinguishing the impact of supersaturated solution vs the crystalline substances is unclear. Here we show the differential effect of CaP solution vs preformed crystal (as crystalline CaP) on the nephrotoxicity and the degree and type of cell death using a murine kidney tubular cell line, LLCPK1. We examined the cellular [cell viability, lactate dehydrogenase (LDH) and H2O2 releases and Annexin+ propidium iodide (PI) staining] and molecular events [gene expressions, oxidative and endoplasmic reticular (ER) stress] towards understanding the mechanism of CN. The results of the study demonstrated that CaP in solution exerts injury effect on LLCPK1 cells. The addition of CaP solution showed stronger necrosis than the preformed crystals as shown by PI staining and the releases of LDH and H2O2. Overall, the results in the study revealed a novel mechanism differentiating the kidney cell injury between the insult mediated by supersaturated CaP solution and preformed CaP crystals.

Exploring Lysine Incorporation as a Strategy to Mitigate Postsynthetic Halide Exchange in Lead-Halide Hybrid Perovskites.

Lead-halide hybrid perovskites (RNH3PbX3, X = halide, e.g., Cl, Br, I; R = organic moiety) show promise for next-generation optoelectronic devices due to their simple synthesis routes, strong light absorption, and high photoluminescence quantum yield. However, postsynthetic halide exchange in lead-halide perovskites poses a challenge for the functionality of many perovskite devices. For example, in all-perovskite heterostructures, halide diffusion results in the formation of undesired mixed alloys rather than sharp interfaces required for many optoelectronic applications. To address this issue, we incorporated lysine molecules, one of the 20 common amino acids, into a hybrid perovskite MAPbBr3 (MA = CH3NH3) host and investigated their impact on the host's ability to undergo postsynthetic halide exchange. We immersed lysine-incorporated MAPbBr3 crystals in solutions containing Cl- or I- for varying durations and analyzed subsequent halide exchange-related changes using ion chromatography, high-resolution powder X-ray diffraction, and photoluminescence spectroscopy. Our findings unanimously indicate that incorporated lysine significantly impedes postsynthetic Cl- and I- diffusion into bulk MAPbBr3. Our new bioinspired approach opens a route toward mitigating postsynthetic halide exchange in lead-halide hybrid perovskites and improving the suitability of perovskite devices for optoelectronic applications.

Solution Thermodynamics of l-Glutamic Acid Polymorphs from Finite-Sized Molecular Dynamics Simulations.

Efficiently obtaining atomic-scale thermodynamic parameters characterizing crystallization from solution is key to developing the modeling strategies needed in the quest for digital design strategies for industrial crystallization processes. Based on the thermodynamics of crystal nucleation in confined solutions, we develop a simulation framework to efficiently estimate the solubility and surface tension of organic crystals in solution from a few unbiased molecular dynamics simulations at a reference temperature. We then show that such a result can be extended with minimal computational overhead to capture the solubility curve. This enables an efficient and self-consistent estimate of the solubility and limit of solution stability associated with crystal nucleation in molecular systems from equilibrium molecular dynamics without the need for sophisticated free energy calculations. We apply our analysis to investigate the relative thermodynamic stability and aqueous solubility of the α and β polymorphs of l-glutamic acid. Our analysis enables an efficient appraisal of emergent ensemble properties associated with the thermodynamics of nucleation from solutions against experimental data, demonstrating that while the absolute solubility is still far from being quantitatively captured by an off-the-shelf point charge transferable force field, the relative polymorphic stability and solubility obtained from finite temperature simulation are consistent with the experimentally available information on glutamic acid. We foresee the ability to efficiently obtain solubility information from a limited number of computational experiments as a critical component of high-throughput polymorph screenings.

Same but different: structural diversity of cytidine 5′-monophosphate (CMP) (an)hydrates

Crystal structure landscape investigations of cytidine 5′-monophosphate (CMP) obtained by solution crystallization and dehydration induced by temperature, humidity and vacuum.

High-Performing Direct X-Ray Detection Made of One-Dimensional Perovskite-Like (TMHD)SbBr5 Single Crystal With Anisotropic Response.

3D and 2D organic hybrid perovskites, as well as double perovskites, have demonstrated their suitability for direct X-ray detection. However, the sensitivity and stability of 3D perovskite X-ray detectors are currently being hindered by the existing constraints on ion movement. Therefore, there is an immediate need to develop X-ray detectors that are both highly sensitive and stable while also being environmentally friendly. The novel low-dimensional perovskites demonstrate exceptional inherent stability and effectively mitigate ion migration, thereby showcasing their remarkable photoelectric performance. Inspired by this, a solution crystallization method is employed to synthesize novel single crystals (SCs) of one dimensional (1D) (TMHD)SbBr5. The dimensions of the chained (TMHD)SbBr5 SC are 13×1.3×1.2 mm3 in size. The device based on a perovskite chain (TMHD)SbBr5 exhibits unique anisotropic X-ray detection performance with a sensitivity of 62.8 and 30.5 µC Gyair -1cm-2 in the parallel and perpendicular orientations, respectively. It can lead to the directional movement of ions, resulting in large carrier mobility under the action of electric fields, and effectively increase the sensitivity to X-ray detection.

Effect of Trisodium Citrate on the Electro-Crystallization of Electrodeposited Ni-Cu-Mo Alloy Coatings

The effect of trisodium citrate on the electrodeposition of nickel-copper-molybdenum in sulfate solution was explored in this paper. According to the results of the nickel-copper-molybdenum electrodeposition experiment, adding a certain amount of trisodium citrate into the electrodeposition solution inhibited the hydrogen precipitation reaction and accelerated the crystallization process on the plated surface to a certain extent, thereby improving the cathodic current efficiency. However, no change occurred to the nucleation mode in the process of electrodeposition crystallization, and it was consistent with the theoretical value of instantaneous nucleation before the peak current (t/tm≤ 1) was reached. The theoretical values of instantaneous nucleation were consistent. The epitaxial growth rate constant K* of the crystals was reduced after the addition of trisodium citrate into the electrodeposition solution, indicating the inhibitory effect of trisodium citrate on the growth of crystals in the electrodeposition solution. The diffusion coefficient of the nickel-copper-molybdenum ligand ions was reduced as well, suggesting the inhibitory effect of adding trisodium citrate into the plating solution on the cathodic mass-transfer process, which is conducive to promoting its cathodic polarization. Meanwhile, the growth rate of crystals was significantly affected by the applied potential.

Ecological strategy and optimization of the RSM process to remove organic pollutants (Violet Crystal) in aqueous solution from pine bark through adsorption modeling and experimental research

Ecological strategy and optimization of the RSM process to remove organic pollutants (Violet Crystal) in aqueous solution from pine bark through adsorption modeling and experimental research

Aqueous Dispersion of Xenes by Liquid Phase Exfoliation of Monoelemental Crystals in Melamine Solution.

Αfter the impressive evolution of graphene and its derivatives, a large number of two dimensional (2D) materials with important optical and electrical properties have been successfully fabricated. Liquid phase exfoliation (LPE) of layered and non-layered materials has become a widely applied method for the preparation of 2D nanostructures with an extensive variety of applications. However, in most cases organic solvents are used as liquid phase which are often toxic and environmentally unfriendly and lead to low yields. In this work, we present water as a suitable liquid phase and dispersion medium for the exfoliation of layered and non-layered monoelemental solids from IVA, VA and VIA groups of the periodic table, such as silicon, tin, bismuth and tellurium. The 2D nanostructures, silicene, stanene, bismuthene and tellurene are therefore prepared by a completely sustainable and environmentally friendly method. The prepared Xenes, as they are called, are fully characterized by microscopic and spectroscopic techniques.

Heat Pump Evaporation: an Alternative of Membrane Filtration System Aiming Pure Water Production

The daily electrical power generation and consumption in Hungary were analyzed, and a two-hour-long interval was specified for the 5000 MW excess power generation, and 1,500,000 MJ energy was identified as an excess. Two pure-water-producing systems (membrane-based system and heat pump evaporator) were compared to utilize this excess electrical energy at industrial scale. Heat pump evaporation was tested as an alternative method for pure water production because its role in pure water production hasn’t been discussed. Suspended-solid-free feed water was used for both systems. Lab-scale experiments proved that in the case of freshwater, the four-step membrane filtration technology can be replaced by a one-step heat pump evaporation, resulting in almost the same quality of pure water characterized by the conductivity; 2 and 4 μS/cm for membrane filtration and heat-pump evaporation, respectively. When using seawater at a lab-scale, the proposed membrane technology resulted in desalted water having a conductivity of 425 μS/cm; meanwhile, by heat pump evaporation, pure water could be attained, having a conductivity of 19 μS/cm. Considering the specific electric energy consumption at laboratory scale, the one-step heat pump evaporator surely exhibits an energy-saving method for pure water production; 6.12 MJ/L and 2.31 MJ/L were measured for membrane system and heat pump evaporator, respectively. Considering an industrial-scale make-up water demand, up-scaling calculations, including hydraulic calculations and pump selection producing the same amount of pure water, resulted in a reverse trend regarding specific electric energy consumption; 25.35 MJ/m3 and 14,850 MJ/m3 estimated for membrane system and heat-pump-evaporator, respectively. Both systems were analyzed in terms of environmental impacts. According to wastewater quality and their disposability, the wastewater of freshwater treatment can be drained into the sewage system, but in case of seawater crystallization of concentrated NaCl solutions is possible. Based on our analysis, the theoretically producible water quantity is more than physically attainable by the treatment technologies, thus more options shall be considered for the utilization of excess energy generation.

Influence of Additives on Crystallization of Calcium Phosphates from Prototypes of Blood Plasma

The paper presents the results of studies on the effect of additives on crystallization in solutions simulating the composition of human blood plasma. Synthesis from prototypes of human blood plasma in the presence of organic and inorganic additives was carried out, and it was found that the obtained solid phases consisted of octacalcium phosphate, B-type carbonate hydroxyapatite, and vitlocite. The effect of additives (magnesium ions, alanine, and glycine) on the crystallization of calcium phosphates was studied. It was found that the presence of additives in the model solution reduces the crystallite size and the fraction of carbonate hydroxyapatite in the solid phase. The bioactivity of synthetic samples was studied, and kinetic characteristics were established. A study of thermal transformations.

Structure, morphology and crystallization behavior of PVDF/Co nanowire nanocomposites under horizontal and vertical magnetic fields

So far, very limited research has been carried out on the fabrication of polyvinylidene fluoride (PVDF) composited with anisotropic magnetic nanostructures such as nanowires or nanorods, which can potentially provide specific reactions to magnetic fields. Here, single crystal Co nanowires (CNWs) with an average length and diameter of about 220 and 12 nm, respectively, are synthesized using a solvothermal method, followed by adding them to PVDF matrix in order to prepare flexible PVDF/CNW nanocomposites by solvent casting and solution crystallization processes at room temperature. The nucleation and growth of PCNW nanocomposites are investigated in the absence and presence of horizontal and vertical magnetic fields. According to FESEM images, in addition to the direction of the applied magnetic field, the presence or absence of CNWs induces different effects on the size of spherulites and the configuration of polymer chains. By adding CNW to the PVDF matrix in the absence of a magnetic field and under a horizontal magnetic field, the size of the spherulites in the pure PVDF film increases about 67 % (from 3 to 5 μm) and 300 % (from 3 to 12 μm), respectively. Under a vertical magnetic field, the addition of CNW reduces the size of the spherulites to 1 μm, thereby forming a film with a combination of spherulites and filamentary structure likely due to the nanowire-nanowire, nanowire-chain and chain-chain interactions. Also non-contact flexible triboelectric nanogenerators of magnetic force are fabricated.

Single‐Luminophore Molecular Engineering for Rapidly Phototunable Solid‐State Luminescence

AbstractSmart materials enabling emission intensity or wavelength tuning by light stimulus have attracted attention in cutting‐edge fields. However, due to the general limitation of the dense molecular stacking (in solid states, especially in crystals) on photoresponsivity, constructing rapidly phototunable solid‐state luminescent systems remains challenging. Herein, we present a new luminophore that serves as both a photoresponsive and a luminous group with enhanced conformational freedom to attain this goal, namely, relying on photoexcitation‐induced molecular conformational change of an ionized persulfurated arene based on weak intermolecular aliphatic C−H⋅⋅⋅π interaction. Together with the phosphorescence characteristic of the molecule itself, rapidly enhanced phosphorescence upon irradiation can be observed in a series of phase states, like solution state, crystal, and amorphous state, especially with a high photoresponsive rate of 0.033 s−1 in crystal state that is superior to the relevant reported cases. Moreover, a rapidly phototunable afterglow effect is achieved by extending this molecule into some polymer‐based doping systems, endowing the system with unique dynamic imaging and fast photopatterning capabilities. This single‐luminophore molecular engineering and underlying mechanism have implications for building other condensed functional materials, principally for those with stimuli responses in solid states.

Two-step nucleation and growth of crystals in a metastable solution with mass exchange with the environment

Two-step nucleation and growth of crystals in a metastable solution with mass exchange with the environment

Polymerization-induced ultrafast and massive growth of colloidal photonic crystals on hydrogel surface

Structural color materials based on colloidal photonic crystals (CPCs) have been extensively investigated since they can be prepared efficiently. Commonly, photonic hydrogels are prepared by a polymerizing pre-gel solution, in which colloids are self-assembled by passive methods. Except for magnetic colloids, the process of forming colloidal photonic crystals in a pre-gel solution requires hours to days, and it is almost impossible to assemble the colloids directly in hydrogels. Here, we present a mild strategy to prepare hydrogels with surface structural color, ordered colloidal arrays are formed at the air-hydrogel interface actively during the polymerization process, and bright structural color forms in minutes on a large scale. Polymer exclusion is the key driving force for the assembly of the colloids, other factors, such as evaporation flux, can also promote the colloids to assemble. Significantly, heterogeneous structural color patterns can be produced easily by exposing the hydrogel surface to air sequentially using a mask during the polymerization process. The simple and fast method provides a general route for preparing structural colored surfaces, which may be suitable for various applications.

Sustainable separation of molybdenum from mixed mineral acids generated as semiconductor industry waste streams using tributyl phosphate (TBP) by effects of hybrid machine learning models

This study explores the separation and optimization of molybdenum (Mo) from mixed mineral acids derived from semiconductor industry waste streams with tributyl phosphate (TBP) by implementing machine learning (ML) models. Considerable experimental tests were performed to evaluate the impact of various operational variables on the effectiveness of Mo extraction and stripping. The support vector regression (SVR) paired with harmony search algorithm (HSA), genetic algorithm (GA), and shuffled frog leaping algorithm (SFLA) were employed for enhancement in the separation process and structural optimization. The SVR-SFLA model yielded the most meticulous predictions, identifying optimal extraction conditions with a TBP concentration, mixing time, temperature, and O/A ratio of 50%, 30 min, 25 °C, and 1, respectively, achieving 77.8% efficiency. The derived results from the SVR-SFLA model, in tandem with the McCabe-Theil diagram, indicated a four-stage counter-current extraction process required to achieve a yield exceeding 99%. For the stripping process, the hybrid model indicated optimal conditions with 3 M NH4OH and an A/O ratio of 0.5 at 50 °C for 20 min, requiring two counter-current stages for nearly complete stripping. Feature importance analysis using a random forest algorithm (RFA) highlighted the NH4OH concentration and phase ratio as the most significant factors, contributing 40.3% and 29.1%, respectively, to the stripping from the loaded TBP phase. The final product, obtained after crystallization and thermal decomposition of the strip solutions, was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS), revealing 99.74% purity for molybdenum trioxide.

[formula omitted] Affects the crystalline calcium silicate hydrate minerals synthesized by fly ash-based silicon extraction solution and lime milk

When extracting amorphous silicon from fly ash using a strong alkaline solution, other elements such as Al also enter the silicon extraction solution in the form of AlOH4−. To systematically investigate the impact of AlOH4− on the synthesis of typical calcium silicate hydrate crystals in a silicon extraction solution, a specific amount of AlOH4− was added to the silicon extraction solution, and calcium silicate was hydrothermally synthesized at 90℃ and 230℃. Scanning electron microscopy (SEM) and Brunner−Emmet−Teller (BET) analysis revealed that with the increasing in AlOH4− content, microporous calcium silicate gradually loses its microporous morphology. While the specific surface area shows no significant change, the median pore diameter first increases from 1.47 nm to 1.58 nm and then decreases to 1.55 nm. The xonotlite fibers underwent a gradual refinement, diminishing from 0.28 to 0.15 µm. Simultaneously, the specific surface area increases from 28.87 to 56.8 m2/g. At an AlOH4− concentration of 3 mol/L, the microscopic morphology transforms into a sheet-like structure. X-ray diffraction (XRD) analysis reveals that AlOH4− promotes the formation of tobermorite while inhibiting the further development of calcium silicate. Additionally, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance indicate that Al can replace Si in the calcium silicate hydrate system, primarily substituting positions the Q2 and Q3 sites. Qualitatively, it is suggested that with the increasing incorporation of Al, the polymerization degree of the silicon-oxygen tetrahedra decreases. According to experimental results, the concentration of AlOH4− should be below 0.05 mol/L when synthesizing microporous calcium silicate hydrate and less than 0.2 mol/L when synthesizing fibrous xonotlite-type calcium silicate hydrate.

Study on the Performance of a Novel Double-Section Full-Open Absorption Heat Pump for Flue Gas Waste Heat Recovery

Open absorption heat pumps are considered one of the most promising methods for efficiently utilizing low-grade waste heat, reducing energy consumption, and lowering greenhouse gas emissions. However, traditional heat pumps have significant limitations in the range of flue gas temperatures they can recover, and their relatively low system performance further restricts practical applications. In this study, we propose a novel double-section full-open absorption heat pump driven by flue gas from the desulfurization tower. By designing the absorber with a double-layer structure, the system can recover more latent and sensible heat from the flue gas, significantly enhancing its thermal recovery capability. Additionally, replacing the traditional LiBr/H2O working pair with LiCl/H2O significantly reduces the risks of solution crystallization and equipment corrosion. Through comprehensive research, the strengths and weaknesses of the system were explored. The results indicate that this system effectively recovers flue gas waste heat within the temperature range of 30–70 °C. Specifically, at a flue gas temperature of 70 °C and a flow rate of 3 kg/s, the system achieves a COP of 1.838, along with a heating capacity of 158.83 kW and a ROI of 34.1%. These metrics demonstrate that the system not only delivers high performance but also exhibits excellent economic viability. Additionally, when the solution temperature is lowered to 10 °C, the system’s maximum COP reaches 1.96, reflecting a significant 30.67% improvement over traditional heat pumps. These findings highlight the system’s potential for application in coal-fired power plants, where varying levels of power output can benefit from enhanced thermal recovery and efficiency.

Exact analytical solution of the equations for a quasiequilibrium two-phase domain: permeability and interdendritic spacing

This study is concerned with the theoretical description of a quasi-stationary process of directional crystallization of binary melts and solutions in the presence of a quasi-equilibrium two-phase region. The quasi-equilibrium process is ensured by the fact that the system supercooling is almost completely compensated by heat released during the phase transformation. Quasi-stationarity of the process determining constancy of the crystallization rate is ensured by given temperature gradients in the solid and liquid phases. The system of heat and mass transfer equations and boundary conditions to them under these assumptions is dependent on a single spatial variable in the reference frame moving with the crystallization rate relative to a laboratory coordinate system. Exact analytical solutions to the formulated problem in parametric form are obtained. The parameter of the solution is the solid phase fraction in a two-phase region. The distributions of temperature and impurity concentration in the solid, liquid and two-phase regions of the crystallizing system, the rate of solidification, and the spatial coordinate in the two-phase region depending on the solid phase fraction in it are found. An algebraic equation for the solid phase fraction at the interface between the solid material and the two-phase region is derived. Exact analytical solutions show that the impurity concentration in the two-phase layer increases as the solid phase fraction increases. Moreover, the solid phase fraction at the interface solid phase — two phase region and its thickness increase as the temperature gradient in the solid phase and the solidification rate increase. The developed theory allows us to determine analytically the permeability of the two-phase region and a characteristic interdendritic spacing in it. Analytical solutions show that the relative permeability in the two-phase region increases from a certain value at the interface with the solid phase to unity at the interface with the liquid phase. The selection theory of stable dendritic growth allows us to determine analytically a characteristic interdendritic distance in the two-phase layer that decreases as the temperature gradient in the solid phase increases. An increase of impurity in the molten phase gives a decrease in the interdendritic spacing within a two-phase region.

Protein-Decorated Reverse Osmosis Membranes with High Gypsum Scaling Resistance.

The global challenge of water scarcity has fueled significant interest in membrane desalination, particularly reverse osmosis (RO), for producing fresh water from various unconventional sources. However, mineral scaling remains a critical issue that compromises the membrane efficiency and lifespan. This study explores the use of naturally occurring proteins to develop scaling-resistant RO membranes through an eco-friendly modification method. We systematically evaluate three protein modification techniques, namely, polydopamine (PDA)-assisted coating, protein conditioning, and protein drying, for fabricating membranes resistant to gypsum scaling. Protein conditioning is found to be the most effective approach, resulting in protein-decorated membranes with an exceptional resistance to gypsum scaling. We also demonstrate that a hydrated protein layer is essential for optimal scaling resistance. To further understand the mechanism underlying the scaling resistance of protein-decorated membranes, five proteins (i.e., bovine serum albumin, casein, lactalbumin, lysozyme, and protamine) with distinct physicochemical properties are used to explore the key factors governing membrane scaling resistance. The results of dynamic RO experiments indicate that the molecular weight of proteins plays a crucial role, with higher molecular weights leading to higher membrane scaling resistance through steric effects. However, static experiments of bulk crystallization highlight the importance of electrostatic interactions, where proteins with more negative charge delay gypsum crystallization more effectively. These findings suggest the difference between gypsum scaling in the RO and gypsum crystallization in bulk solutions. Overall, this research offers a novel approach to developing resilient and sustainable RO membranes for the desalination of feedwater with high scaling potential while elucidating mechanistic insights on the mitigating effects of protein on gypsum scaling.