Three-dimensional Crystallization Research Articles

Directional salt crystallization system for high-efficiency solar-driven evaporation to achieve zero-liquid discharge

Solar-driven interfacial evaporation is an efficient technology for water treatment, enabling the production of freshwater and the removal of impurities. However, achieving a high evaporation rate and a long-term stable operation is challenging due to the salt accumulation on the evaporation surface. In this study, a novel three-dimensional directional salt crystallization system is proposed. The melamine sponge modified with polydopamine and carbon black was used to transport brine, absorb sunlight, and generate steam. The non-photothermal evaporation regions were innovatively constructed by placing a thermally conductive aluminum structure with the deflector paper around the sponge, which increased the effective evaporation area of the system to accelerate the evaporation of brines from the overall system, resulting in an evaporation rate of 2.20 kg m−2 h−1 under one sun irradiation in a 15 wt% NaCl solution. Moreover, the non-photothermal evaporation regions were isolated from the evaporation interface as a salt crystallization region, which completely avoided salt accumulation at the evaporation interface and ensured the long-term stable operation of the system. Salt crystals can be easily collected by replacing the deflector paper regularly, and the salt collection efficiency is over 95 % to achieve zero-liquid discharge (ZLD) treatment. More importantly, the directional salt crystallization system achieves efficient purification of heavy metal ion wastewater and dye wastewater. Consequently, the system presents a highly efficient method for ZLD seawater treatment and wastewater purification.

Preparation of Li2O–Al2O3–SiO2–B2O3（LASB）glass-ceramic with low thermal expansion coefficient from spent hydrogenation catalysts and crystallization kinetics

The recovery of spent hydrogenation catalysts occupies advantages in both alleviating environmental burden and resource shortage. Whereas, the development of conventional hydrometallurgical recovery of molybdenum (Mo) and nickel (Ni) from spent MoNi/Al2O3 catalysts has been limited by the numerous processes and the accompanying generation of waste liquids and residues. Herein, A new recycling route for the preparation of spent hydrogenation catalysts with low thermal expansion coefficients (CTE) was proposed, which has the advantages of short process, green environment and high value utilization. The Li2O–Al2O3–SiO2–B2O3 (LASB) parent glass containing Mo and Ni were obtained by melting with different contents of the spent catalysts. The thermal expansion coefficient of the glass was minimized to 6.08 × 10−6/°C at an addition of 25 wt% of the spent catalysts. Moreover, according to the crystallization peak in DTA curve, glass-ceramics were prepared by one-step crystallization heat treatment at different crystallization temperatures. The main crystalline phase of the glass-ceramic precipitated by heating at 685 °C is β-quartz (Li2Al2Si3O10), which gives the glass-ceramics the lowest coefficient of thermal expansion (0.96 × 10−6/°C) of glass-ceramic as well as the maximum density (2.45 g/cm3) and Vickers hardness (705.8 Hv). Furthermore, the activation energy (354.65 ± 17.42) kJ/mol) and Avrami index (5.39) associated with crystallization were extracted from the fitting of different theoretical model, indicating the three-dimensional crystallization of the LASB glass-ceramics. This technology provides a waste-to-material strategy for hazardous waste and a clean production route for the preparation of the functional glass-ceramics.

The Effect of Acidity Coefficient on the Crystallization Properties and Viscosity of Modified Blast Furnace Slag for Mineral Wool Production.

The crystallization and viscosity of modified blast furnace slag are key factors in fiber forming conditions. In this paper, the crystallization behavior of modified blast furnace slag under continuous cooling conditions was studied by differential scanning calorimetry, and its crystallization kinetics with different acidity coefficients were established. On this basis, the evolution law of the crystallization phase and the influence of crystallization on the viscosity of modified blast furnace slag with different acidity coefficients were analyzed. The results indicated that the crystallization phases of slag with acidity coefficients of 1.05 and 1.20 were, respectively, Melilite and Anorthite. During the cooling process at the acidity coefficient of 1.05, the critical rates of precipitation of Melilite and Anorthite were 50 °C/s and 20 °C/s, respectively, while they were 20 °C/s and 15 °C/s, respectively, at the acidity coefficient of 1.20. With the increase of the acidity coefficient, the crystal growth mode of slag changed from two-dimensional and three-dimensional mixed crystallization to surface nucleation and one-dimensional crystallization. The crystallization activation energy of slag with acidity coefficients of 1.05 and 1.20 were 698.14 kJ/mol and 1292.50 kJ/mol, respectively. In addition, the change trend of viscosity was related to crystal size and content.

Experimental study of crystallization fouling by calcium carbonate: Effects of surface structure and material

Mitigation of crystallization fouling on heat transfer surface is crucial for developing highly efficient desalination techniques, because the tenacious and porous crystal layer can drastically deteriorate system efficiency. Surface modification is a potential approach to decrease scale formation and promote crystal removal, but some of the mechanisms between crystallization and substrate properties are still not fully understood. In this study, we use dual-angle microscopic visualization and image processing to quantify three-dimensional crystallization behavior and analyze the impact of surface structure and material. The transition of crystal size and distance with roughness and wettability are identified from statistical analysis. The determination of crystal porosity and effective thermal conductivity is enabled by visualized geometry and measured deposition mass. This study shed lights on potential strategies of surface modification to mitigate scaling in desalination by enhancing scale removal and localizing crystal growth.

Instrument for in situ hard x-ray nanobeam characterization during epitaxial crystallization and materials transformations.

Solid-phase epitaxy (SPE) and other three-dimensional epitaxial crystallization processes pose challenging structural and chemical characterization problems. The concentration of defects, the spatial distribution of elastic strain, and the chemical state of ions each vary with nanoscale characteristic length scales and depend sensitively on the gas environment and elastic boundary conditions during growth. The lateral or three-dimensional propagation of crystalline interfaces in SPE has nanoscale or submicrometer characteristic distances during typical crystallization times. An in situ synchrotron hard x-ray instrument allows these features to be studied during deposition and crystallization using diffraction, resonant scattering, nanobeam and coherent diffraction imaging, and reflectivity. The instrument incorporates a compact deposition system allowing the use of short-working-distance x-ray focusing optics. Layers are deposited using radio-frequency magnetron sputtering and evaporation sources. The deposition system provides control of the gas atmosphere and sample temperature. The sample is positioned using a stable mechanical design to minimize vibration and drift and employs precise translation stages to enable nanobeam experiments. Results of in situ x-ray characterization of the amorphous thin film deposition process for a SrTiO3/BaTiO3 multilayer illustrate implementation of this instrument.

Crystallization of Cholesterol in Phospholipid Membranes Follows Ostwald's Rule of Stages.

Crystallization of membrane-embedded components within phospholipid bilayers represents a distinct class of phase transformation that occurs in structurally organized, molecularly crowded, and dimensionally constrained amphiphilic fluids. Using unstable supported lipid bilayers-transiently assembled via surface-mediated fusion and spreading of bicellar precursors containing supersaturating concentrations of cholesterol-we monitor here the morphological evolution and dynamics of cholesterol crystallization within the membrane media. We find that the three-dimensional (3D) crystallization of cholesterol from an unstable two-dimensional (2D) in-membrane state proceeds via well-defined sequence of intermediates, including filaments, rods, helices, and 2D rectangular plates, before transforming into three-dimensional quadrilateral crystals-characteristic triclinic habit of cholesterol monohydrate. Our observations thus demonstrate that these structurally distinct cholesterol polymorphs are related to one another, contrasting with the notion that they represent disparate crystal habits stabilized by differences in lipid environments. Moreover, these observations indicate that cholesterol crystallization within the membrane media follows nonclassical multistep crystallization governed by the heuristic "Ostwald's rule of stages", which predicts that the crystallization kinetics proceed down the free energy landscape in a multistage process where each successive phase transition incurs the smallest loss of free energy relative to its predecessor. Furthermore, we find that the well-known cholesterol extracting agent, β-cyclodextrin, acts by catalytically tipping the equilibrium in favor of crystal growth adding cholesterol from the membrane phase to the crystal in a layer-by-layer manner. Taken together, our results provide a new description of in-membrane cholesterol crystallization and may pave for a screening tool for identifying molecular candidates that target cholesterol crystals.

Capturing the dynamics of Wigner crystals within the phase-field crystal method

An electronic phase-field crystal model is proposed where the thermodynamics of electrons are considered in a free-energy-functional formulation. The free-electron-gas system is considered initially as the noninteracting limit of the model. The excess free-energy contribution to the functional is incorporated by including Coulombic repulsions among electrons and exchange-correlation interactions. The evolution of an electron mean field is considered in the low-temperature limit using diffusive dynamics. Three-dimensional Wigner crystallization can be achieved from the model when the density of the system is lowered sufficiently. Through this approach, we are able to provide insight into topological defect formation and evolution during Wigner crystallization.

New approach to measurement of the three-dimensional crystallization front propagation velocity in strongly coupled complex plasma

The PK-3 Plus laboratory onboard the International Space Station is used to form complex plasma with a liquidlike particle subsystem in a metastable state and to observe the propagation of crystallization fronts corresponding to the surfaces of crystal domains. We propose the ‘axis’ algorithm of solidlike particles identification, which makes it possible to isolate different domains and their surfaces as well. Determination of the three-dimensional front velocity is based on its definition implying that there exists a small area of the domain surface propagating along some line perpendicularly to it. The velocity measured in this way is an important characteristic of the plasma crystallization kinetics. It proves to be almost independent of time and the direction of front propagation and amounts to ca. 60–80 μm s−1.

Nucleation activity at high supercooling: Sorbitol-type nucleating agents in polypropylene

Crystallization kinetics of polypropylene (PP) nucleated with sorbitol-type nucleating agents was studied with fast differential scanning calorimety (FDSC) at high supercooling and correlated to the optical characteristics of mold injected parts. FDSC was used for determination of the critical cooling rate for occurrence of non-isothermal crystallization and the time to maximum crystallization rate during isothermal crystallization after rapid cooling. The nucleating agents studied were 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS) and 1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl) methylene]-nonitol (TBPMN). In contrast to particulate nucleating agents, where the number of particles determines the number of heterogeneous nuclei, sorbitol-type nucleating agents self-assemble a nano-fibrillar super-structure by phase separation of sorbitol-type molecules that were previously dissolved in the polymer melt. An approach is proposed to describe the efficiency of nucleating agents self-assembly. In combination with haze data two different crystallization mechanisms are identified, which are interpreted as three-dimensional spherulitic crystallization at high haze and one-dimensional (rod or shish-kebab-like) crystallization at low haze.

Two-Dimensional versus Three-Dimensional Self-Assembly of a Series of 5-Alkoxyisophthalic Acids.

Physisorbed self-assembled monolayers (SAMs) have been suggested as potential models for three-dimensional (3D) crystallization. This work studies the effect of altering the chain length of 5-alkoxyisophthalic acid (C nISA) on self-assembled morphology in both two-dimensional (2D) and 3D to explore the extent comparisons can be drawn between dimensions. Previous studies of 5-alkoxyisophthalic acid at solid-liquid interfaces (2D) reported different morphologies for C5ISA and C6ISA-alkoxy chains on the one hand and C10ISA and C18ISA on the other. Independently, also in 3D a dependence of morphology on chain length has been reported, including an unexpected inclusion of a solvent in the 3D morphology of C6ISA, while the previous reports of 2D self-assembly were driven only by molecule-molecule and molecule-substrate interactions. However, a complete set of data for comparison has been missing. Here, we report scanning tunneling microscopy (STM) and molecular dynamics simulations performed for C2ISA self-assembled monolayers (SAMs) and STM imaging of C6ISA-C9ISA SAMs, to further examine self-assembly behavior in 2D. In 3D, X-ray diffraction analysis of C2ISA single crystals was carried out to complete the data set. With a complete set of data, it was observed that regardless of the dimension, short-chain-length C nISAs formed H-bonding-dominated structures, mid-chain-length C nISAs exhibited solvent-dependent morphologies, and long-chain-length C nISAs displayed van der Waals-dominated solvent-independent structures. However, the transition point among morphologies occurred at different chain lengths in 2D and 3D regardless of the dominant interaction. The results of this study inform the design of 2D films and guide the application of knowledge from physisorbed SAMs to 3D systems, including mixed-dimensional (2D/3D) van der Waals heterostructures.

Crystallization kinetics and heat treatment temperature on microstructure and properties of Na2O-CaO-P2O5 bioactive glass system

This study deals with the effects of heat treatment temperature on the thermal and mechanical properties of Na2O-CaO-P2O5 glasses and glass-ceramics. The major crystalline phase was calcium phosphate along with sodium calcium phosphate as the minor crystalline phases presented in the glass-ceramics. Vickers hardness, Knoop hardness and Young's modulus values of the glass-ceramics decrease with increasing of heat treatment temperature, however, the opposite trend is found for the fracture toughness values. H550 sample confirms the dendritic-like structure, H600 and H650 samples confirms the lamellar bone-like structures and H700 sample confirms the scaffold-like structure. The microstructure, with cluster of dendritic crystal and lamellar structure, indicates a typical two-dimensional crystallization mechanism, which agrees with the above analysis of Avrami exponent (n = 2.8) for glass sample at Tp1 while scaffold structure indicates a typical three-dimensional crystallization mechanism, which is in good agreement with the above analysis of Avrami exponent (n = 4.2) for glass sample at Tp2. Moreover, all Na2O-CaO-P2O5 bioactive glass-ceramics are not toxic to the living cell and have a good bioactive property.

Three-dimensional molecular and nanoparticle crystallization by DNA nanotechnology

Abstract

Optical properties and structure of Er:LaBGeO_5 laser-induced crystals-in-glass

Three-dimensional laser-induced crystallization of glass via localized heating by focused femtosecond laser irradiation promises the ability to create photonic integrated circuits. However, little work thus far has been done to demonstrate the feasibility of this technique to create crystals in rare earth-doped glasses that may serve as active elements of the circuit, such as lasers. To that end, crystals were grown in ErxLa1−xBGeO5 (x = 0.0, 0.01, 0.04) glasses via this technique and characterized using Raman and fluorescence spectroscopy. Erbium was found to be primarily incorporated within the crystal at the lanthanum site and its energy levels were quantified. The influence of different glass compositions and laser irradiation parameters on the strain gradient within the crystal cross-section as well as the erbium fluorescence is discussed.

Terminating DNA Tile Assembly with Nanostructured Caps.

Precise control over the nucleation, growth, and termination of self-assembly processes is a fundamental tool for controlling product yield and assembly dynamics. Mechanisms for altering these processes programmatically could allow the use of simple components to self-assemble complex final products or to design processes allowing for dynamic assembly or reconfiguration. Here we use DNA tile self-assembly to develop general design principles for building complexes that can bind to a growing biomolecular assembly and terminate its growth by systematically characterizing how different DNA origami nanostructures interact with the growing ends of DNA tile nanotubes. We find that nanostructures that present binding interfaces for all of the binding sites on a growing facet can bind selectively to growing ends and stop growth when these interfaces are presented on either a rigid or floppy scaffold. In contrast, nucleation of nanotubes requires the presentation of binding sites in an arrangement that matches the shape of the structure's facet. As a result, it is possible to build nanostructures that can terminate the growth of existing nanotubes but cannot nucleate a new structure. The resulting design principles for constructing structures that direct nucleation and termination of the growth of one-dimensional nanostructures can also serve as a starting point for programmatically directing two- and three-dimensional crystallization processes using nanostructure design.

Heterogeneous nucleation of Ba1-xSrxZn2Si2O7 from a BaO/SrO/ZnO/SiO2 glass using platinum as nucleation agent

Glasses in the system BaO/SrO/ZnO/SiO2 were doped with 0.01% platinum. During thermal treatment, the glasses were crystallized and the phase Ba1-xSrxZn2Si2O7 was formed. This phase has almost the same structure as the high-temperature phase of BaZn2Si2O7, which shows a negative coefficient of thermal expansion. In the obtained glasses, spherical particles of metallic platinum with diameters in the range from 300nm to 2μm are present. Detailed analyses of the curves obtained from differential scanning calorimetry enable the determination of the activation energies as well as the Avrami coefficients. The obtained values of the Avrami coefficients were close to 4, which correspond to three-dimensional bulk crystallization. Scanning electron microscopy was used to identify individual Ba1-xSrxZn2Si2O7 crystals with sizes of approximately 15μm. Transmission electron microscopy showed that these crystals are nucleated at the surface of spherical platinum particles.

Nb2O5-γ-Al2O3 nanofibers as heterogeneous catalysts for efficient conversion of glucose to 5-hydroxymethylfurfural.

One-dimensional γ-Al2O3 nanofibers were modified with Nb2O5 to be used as an efficient heterogeneous catalyst to catalyze biomass into 5-hydroxymethylfurfural (5-HMF). At low Nb2O5 loading, the niobia species were well dispersed on γ-Al2O3 nanofiber through Nb–O–Al bridge bonds. The interaction between Nb2O5 precursor and γ-Al2O3 nanofiber results in the niobia species with strong Lewis acid sites and intensive Brønsted acid sites, which made 5-HMF yield from glucose to reach the maximum 55.9~59.0% over Nb2O5-γ-Al2O3 nanofiber with a loading of 0.5~1 wt% Nb2O5 at 150 °C for 4 h in dimethyl sulfoxide. However, increasing Nb2O5 loading could lead to the formation of two-dimensional polymerized niobia species, three-dimensional polymerized niobia species and crystallization, which significantly influenced the distribution and quantity of the Lewis acid sites and Brönst acid sites over Nb2O5-γ-Al2O3 nanofiber. Lewis acid site Nbδ+ played a key role on the isomerization of glucose to fructose, while Brønsted acid sites are more active for the dehydration of generated fructose to 5-HMF. In addition, the heterogeneous Nb2O5-γ-Al2O3 nanofiber catalyst with suitable ratio of Lewis acid to Brönsted sites should display an more excellent catalytic performance in the conversion of glucose to 5-HMF.

Phasing and structure of bestrophin-1: a case study in the use of heavy-atom cluster compounds with multi-subunit transmembrane proteins.

The purification and three-dimensional crystallization of membrane proteins are commonly affected by a cumulation of pathologies that are less prevalent in their soluble counterparts. This may include severe anisotropy, poor spot shape, poor to moderate-resolution diffraction, crystal twinning, translational pseudo-symmetry and poor uptake of heavy atoms for derivatization. Such challenges must be circumvented by adaptations in the approach to crystallization and/or phasing. Here, an example of a protein that exhibited all of the above-mentioned complications is presented. Bestrophin-1 is a eukaryotic calcium-activated chloride channel, the structure of which was recently determined in complex with monoclonal antibody fragments using SAD phasing with tantalum bromide clusters (Ta6Br12·Br2). Some of the obstacles to obtaining improved diffraction and phasing for this particular channel are discussed, as well as the approach and adaptations that were key to determining the structure.

Three-dimensional orientation of poly(l-lactide) crystals under uniaxial drawing

Three-dimensional strain-induced crystallization upon poly (l-lactide) stretching revealed by X-ray diffraction texture analysis via pole figure measurements.

Fast solidification kinetics of parts of bituminous binders

Abstract A quantification of the kinetics of formation of the micro-phases in bitumen during cooling as it occurs in applications, e.g. a road pavement will enable a better prediction of the performance of asphalt in models and an understanding of functional properties and their development in time. This microphase formation is part of the process of physical ageing (hardening) and starts almost immediately after or instantaneously during cooling. The earlier proposed process of liquid liquid demixing within bitumen upon cooling is followed by a, at the beginning homogeneously nucleated and three-dimensional crystallization, which changes in the course of crystallization to 2-dimensional crystal growth and mixed nucleation, both homogeneous and heterogeneous.

Three-Dimensional Crystallization of Vortex Strings in Frustrated Quantum Magnets.

We demonstrate that frustrated exchange interactions can produce exotic 3D crystals of vortex strings near the saturation field (H=H(sat)) of body- and face-centered cubic Mott insulators. The combination of cubic symmetry and frustration leads to a magnon spectrum of the fully polarized spin state (H>H(sat)) with degenerate minima at multiple noncoplanar Q vectors. This spectrum becomes gapless at the quantum critical point H=H(sat) and the magnetic ordering below H(sat) can be formally described as a condensate of a dilute gas of bosons. By expanding in the lattice gas parameter, we find that different vortex crystals span sizable regions of the phase diagrams for isotropic exchange and are further stabilized by symmetric exchange anisotropy.