Crystallization Time Research Articles

Influence of metal ions (Me: Fe, Cu, Co, Ni, Mn, Cr) on direct Z-scheme photocatalysts CN/Me-BTC on the degradation efficiency of tetracycline in water environment

BackgroundThe World Health Organization (WHO) reports that antibiotic resistance contributes to approximately 700,000 deaths yearly, with estimate suggesting a rise to 10 million deaths over the next 35 years. MethodsIn this study, direct Z-scheme heterojunction photocatalysts CN/Me-BTC (CN: graphite carbon nitride, Me: metal ions, BTC: benzene-1,3,5-tricarboxylic acid) were successfully synthesized using a hydrothermal combined microwave method, eliminating the need for toxic solvents and featuring a short crystallization time and low reaction temperature. Significant findingsThe study also explores the influence of various metal ions (Fe, Ni, Co, Mn, Cr, and Cu) on the morphological, physicochemical properties, and photocatalytic efficiency of tetracycline (TC) degradation. The CN/Me-BTC photocatalysts exhibit remarkable characteristics, including high visible light absorption, high surface area, low recombination rate between electrons and holes, and fast charge transfer ability.Among the synthesized photocatalysts, CN/FeBTC stands out with the highest efficiency in TC degradation (97.18 %) and degradation rate (decay constant k = 0.0197 min−1), surpassing CN by four times. The study comprehensively investigates factors influencing the TC degradation process, including catalyst mass, pH, antibiotic concentration, participating radicals, anions, and water sources. The mechanism of the photocatalytic process is elucidated based on radical quenching experiments and electrochemical properties.

Effectiveness study of recrystallisation method in pharmaceutical salt production from processed salt with zero waste concept

Indonesia's vast archipelago offers abundant seawater resources, holding the potential for salt production. Salt, a vital commodity in human life, typically contains sodium chloride and impurities like Ca2+, Mg2+, SO42−, and K+. Pharmaceutical salt is an industrial category adhering to pharmacopoeial standards regarding sodium chloride levels and impurity content, ensuring quality for drug preparations in Indonesia. Prior research indicates that recrystallisation, specifically evaporation crystallisation, enhances salt quality by increasing NaCl content. Chemical precipitating agents like NaOH and Na2CO3 can be introduced to improve salt purity further. This study aims to identify optimal conditions for pharmaceutical salt production from processed salt raw materials, considering crystallisation time, stirring speed, chemical additives (NaOH and Na2CO3), and double crystallisation stages. The method commences with pre-treatment, involving salt dissolution in distilled water to saturation, with the addition of precipitating agents as per designated variables. Precipitates formed from precipitating agents (NaOH and Na2CO3) are isolated through filtration. The filtrate undergoes evaporation crystallisation at 103 °C, varying between single and double crystallisation. Salt crystals are separated, dried, and weighed to calculate yield. Pharmaceutical salt is analysed for water content, NaCl, and impurities (Ca2+, Mg2+, SO42−, and K+). The optimal conditions for pharmaceutical salt production were double crystallisation with a 20 % excess of chemicals (NaOH and Na2CO3), 100 min of crystallisation time, and a stirring speed of 600 rpm. This yielded a 15 % NaCl content of 99.87 %, Mg2+ at 0 ppm, Ca2+ at 69.6 ppm, SO42− at 366 ppm, K+ at 370 ppm, and water content at 0.166 %. Notably, the pharmaceutical salt production process generates no waste, as byproducts like Mg(OH)2 and CaCO3 can be recycled and hold commercial value. However, it is essential to re-evaluate raw materials and technologies to address the market's high cost and competitiveness issues.

Tuning RHO Zeolite Crystallization Time and Precursors for Stable and Improved Methanol Conversion to Dimethyl Ether Compared to Conventional Catalysts

Tuning RHO Zeolite Crystallization Time and Precursors for Stable and Improved Methanol Conversion to Dimethyl Ether Compared to Conventional Catalysts

Remarkably facilitated crystallization of MSE-type zeolite by using an efficient organic structure-directing agent

Abstract A very powerful organic structure-directing agent (OSDA) for the synthesis of MSE-type zeolite was designed and successfully prepared. When using conventional OSDA, more than 10 d of crystallization time was necessary, whereas the use of the new type of OSDA gave a highly crystalline MSE-type zeolite using only 32 h of crystallization time.

Continuous flow synthesis of hierarchical low silica X zeolite

Zeolites, renowned for their versatile applications in catalysis, adsorption, and ion exchange, have long been synthesized using conventional batch processes. However, the inherent limitations of these methods, such as resource-intensive conditions and inconsistent product quality, underscore the need for a sustainable and efficient approach. In this study, a continuous flow synthesis process was established for the synthesis of industrially important low silica X (LSX) zeolite using a tubular reactor. The synthesis gel was subjected to aging for 5 days at room temperature to facilitate nucleation and crystal growth combined with the fast-heating rate in a tubular reactor at 363 K & 1.1 atm., which in turn produces LSX after 40 min. The synthesized product was confirmed by the XRD, FE-SEM, EDS, XRF, TEM, and N2 adsorption-desorption; the data was compared with the LSX sample synthesized by batch process. The result implies that LSX prepared by continuous flow has a pure phase of LSX with the hierarchical structure, which provides better adsorption capacity of CO2 at 298 K up to 20 bar. Due to continuous flow synthesis, the crystallization time was reduced and faster kinetics which may be helpful for scale-up the process for LSX synthesis.

Scalable Synthesis Methods for High‐Entropy Nanoparticles

High‐entropy materials (HEMs) represent a revolutionary class of materials that have garnered significant attention in the field of materials science due to their extraordinary properties in diverse fields of applications such as catalysis and electrochemistry. The past decade has witnessed a substantial increase in the study of these materials, exploring new synthesis routes and compositions. What began as the synthesis of high‐entropy alloys has expanded to encompass several classes of HEMs such as oxides, hydroxides, sulfides, nitrides, and carbides, among others. Several synthesis methods have been developed to produce these materials. This review therefore highlights the fundamental concepts of HEMs, including their core effects, with a major emphasis on their scalable synthesis routes. The advantages and drawbacks of these methods are also discussed. As HEMs transition from the lab to large‐scale production, there is a growing need for cost‐effective and scalable synthesis methods with high material yield suitable for a variety of applications like hydrogen storage, catalysis, batteries, supercapacitors, and fuel cells. Hence, this review serves as an introduction to scalable synthesis routes based on crystal structure, desired elements, synthesis times, and equipment costs.

Impacts of synthesis variables on spectroscopics evaluation of biobased fatty amide as alkylammonium salt’s precursor for perovskite

Ammonium salts are widely used in chemical industries as additives in cement industries, phase change materials in thermal cooling, ionic materials in electrochromic window and multifunction medium/precursor/catalyst in solar cells to improve the efficiency and stability. This work introduces a procedural enhancement by incorporating a liquid-liquid extraction purification process, resulting in a high-purity biobased fatty amide (FA) with tri-substitution and high-purity biobased tetraalkylammonium ammonium salt (TAS). Biobased FA derived from renewable sources was synthesized via an amidation reaction between fatty acids from vegetable oil with tris(3-aminopropyl)amine under reflux conditions, producing a precursor for TAS used in perovskite solar cell (PSC). This study aimed to optimize and determine the reaction condition of biobased FA at various key synthesis variables by investigating the effects of solvent selection, reaction and crystallization, temperature, catalyst, mole ratio, and dehydrating agent on synthesis yield. A multiple liquid-liquid extraction process was employed to enhance the purity of biobased FA by tunning the selection of solvent based on its relative polarity of the reactant and products. Response surface methodology (RSM) and central composite design (CCD) were utilized to optimize the total yield and the three key variables (reaction time, crystallization time, catalyst amount) respectively. The experimental model developed in this study demonstrated a high degree of fitness with the experimental data (F-value = 27.34), p-value < 0.05) and nonsignificant lack of fit. The model predicted a maximum synthesis yield percentage of 52.62 % under optimal conditions (reaction and crystallization time of 12 and 28 hours), respectively with 4.47 % catalyst). The coefficient of determination of R2 = 0.98 shows a high correlation with the predicted values and in good agreement with the experimental values. Physicochemical properties analysis using spectroscopies techniques, confirmed improved purity with 100% abundance yield of tri-substitution biobased FA and enhanced TAS’s purity up to 60%. The optimization study sheds light on the impact of key synthesis variables on the synthesis yield and percentage abundance (purity), advancing the development of more efficient and tailored sustainable construction materials. These findings highlight the potential of using biobased FA as a sustainable source for TAS production, contributing to a more environmentally friendly approach in PSC development.

Simple and rapid synthesis of zeolite W from K‐feldspar via the improved hydrothermal method

AbstractAn improved hydrothermal method was proposed to rapidly synthesize zeolite W from alkali fusion‐activated K‐feldspar. The effects of m (KOH)/m (K‐feldspar), n (SiO2)/n (Al2O3), n (H2O)/n (SiO2), crystallization time, and crystallization temperature on the synthesis of the zeolite W were investigated. The optimal synthesis conditions were m (KOH)/m (K‐feldspar) ratio of 1.5:1, the activation time of 2 h, and the activation temperature of 500°C, n (H2O)/n (SiO2) ratios of 42, n (K2O)/n (SiO2) of 0.90, n (SiO2)/n (Al2O3) of 5, crystallization time of 6 h, and crystallization temperature of 150°C. The mechanism for rapid synthesis of zeolite W was illustrated. In this process, Na2SiO3·9H2O and Al2(SO4)3·18H2O were first dissolved rapidly in the synthesis system to form an amorphous gel, which contributes to the accelerated crystallization process. Compared with the state‐of‐the‐art synthesis method, this method remarkably decreases the water content to be added in the synthesis process and crystallization time, avoids the pre‐preparation process of the xerogel, and enhances the utilization rate of K‐feldspar. This work provides an industrial‐friendly synthesis process of zeolite W and could realize the highly efficient utilization of K‐feldspar.

Nonequilibrium Criticality at the Onset of Time-Crystalline Order.

We explore the phase transitions at the onset of time-crystalline order in O(N) models driven out of equilibrium. The spontaneous breaking of time translation symmetry and its Goldstone mode are captured by an effective description with O(N)×SO(2) symmetry, where the emergent external SO(2) results from a transmutation of the internal symmetry of time translations. Using the renormalization group and the ε=4-d expansion in a leading two-loop analysis, we identify a new nonequilibrium universality class. Strikingly, it controls the long-distance physics no matter how small the microscopic breaking of equilibrium conditions is. The O(N=2)×SO(2) symmetry group is realized for magnon condensation in pumped yttrium iron garnet films and in exciton-polariton systems with a polarization degree of freedom.

Theory of parametric resonance for discrete time crystals in fully connected spin-cavity systems

Theory of parametric resonance for discrete time crystals in fully connected spin-cavity systems

A DSC study of undercooling thermodynamics and crystallization kinetics for liquid Ag-Si alloys

The undercooling thermodynamics and crystallization kinetics of pure silver, hypoeutectic Ag-2%Si, and eutectic Ag-3.1%Si alloys were explored with differential scanning calorimetry. Liquid silver was highly undercooled by an extent of 200 K (0.16Tm) within molten B2O3 denucleating agent. The nucleating incubation time and crystallization kinetics were investigated under isothermal condition. It was found that the crystal incubation time of nucleation generally decreased with enhanced undercooling. The analyses based on classical nucleation theory showed that heterogeneous nucleation was still dominant even at substantial undercoolings. The transformed solid fraction was derived to elucidate the crystallization kinetics of liquid silver by Johnson-Mehl-Avrami equation. The Avrami exponent was revealed to vary with liquid undercooling and crystallization extent. High cooling rate and denucleating agent were two effective ways to achieve large undercoolings for liquid Ag-Si alloys. The primary (Ag) dendrites were refined with increased undercoolings in hypoeutectic Ag-2%Si alloy. Irregular (Ag)+(Si) eutectics were the typical solidification microstructures for eutectic Ag-3.1%Si alloy at small undercoolings, while primary (Ag) dendrites displayed a remarkable volume fraction at extended undercoolings.

Dressing Stark splitting of time-resolved excitation spectra in Eu3+-doped BiPO4 micro-crystals

The Stark splitting of 5DJ-7FJ transitions has been investigated by time-resolved dressing excitation spectra in Eu3+-doped BiPO4 micro-crystals with different phase structures. The evolution of the Stark transition peaks significantly depends on the laser power, bandwidth, delay time, temperature, and phase structures of BiPO4 crystals. It is explained by photon-phonon coupling dressing effect. There is competition between the crystal field splitting and the dressing splitting alignment in the line-shape evolution. The time-resolved dressing excitation spectrum provides an effective method to investigate Stark splitting and modulate line-shape for applications in optical communication.

Tert-butyl carbazole modified non-fused ring electron acceptor generating high triplet state energy level for efficient organic solar cell

Two-dimensional side-chain plays a crucial role in the construction of efficient non-fused ring electron acceptors (NFREAs). Herein, we introduce a novel NFREA, PCT-4Cl, featuring a tert-butyl carbazole side-chain, and investigate its optoelectronic properties. Notably, PCT-4Cl exhibits a small singlet-triplet energy gap (ΔEST) of 0.25 eV. Blending PCT-4Cl with host eC9 or C8C8–4Cl acceptor extends the lifetime of singlet excitons and exciton diffusion length in the blend films. Moreover, the high energy level of the triplet state (ET1) in PCT-4Cl facilitates efficient transfer of triplet excitons to eC9 or C8C8–4Cl. The addition of PCT-4Cl to PM6:eC9 also leads to a longer crystallization time, restraining eC9 aggregation and enhancing crystallinity in the ternary blend films. Consequently, power conversion efficiencies (PCEs) of 18.84 % and 15.17 % are achieved based on the optimized ternary devices of PM6:eC9:PCT-4Cl (1:1:0.2, wt./wt./wt.) and PM6:C8C8–4Cl:PCT-4Cl (1:1:0.2, wt./wt./wt.), respectively, surpassing the performance of PM6:eC9 (17.34 %) and PM6:C8C8–4Cl (14.05 %). Furthermore, leveraging 2PACz as a hole transporting layer elevates the PCEs of the ternary OSCs to 19.25 % and 15.53 %. These findings underscore the significant role of the tert-butyl carbazole side-chain in elevating the ET1 of NFREA for efficient charge transfer, as well as its role in modulating the crystallinity, presenting a promising pathway for achieving high performance in both binary and ternary OSCs.

Preparation of Eu2+ and Dy3+ co-doped Sr2MgSi2O7 translucent long afterglow glass-ceramics by recrystallization-melting and their luminescence properties

In this work, a novel recrystallization-melting method was used to prepare Eu2+ and Dy3+ co-doped Sr2MgSi2O7 translucency long afterglow glass-ceramics with complete crystal development. The synthesis mechanism is discussed by analyzing the detection results of X-ray diffraction, scanning electron microscopy, phosphorescence spectra, and afterglow attenuation curves. The effect of different firing temperatures and crystallization time on the crystalline phase content, crystal size, and luminescence properties of the Sr2MgSi2O7:Eu2+, Dy3+ glass-ceramics samples were examined. The results show that, as compared with the traditional melt crystallization method or the two-step method, the recrystallization–melting method is able to form some Sr2MgSi2O7:Eu2+, Dy3+ crystals first under a temperature that is lower than that of the glass transition. With increasing firing temperature and crystallization time, crystal growth and recrystallization reached an equilibrium state, accompanied by the generation of liquid glassy phases. It is found that the afterglow properties are proportional to the crystalline phase content and crystal size, with the latter having a more significant effect. Under the condition of firing at 1050 °C for 10 h, tetragonal Sr2MgSi2O7 crystals with a maximum size of 20 μm were successfully synthesized for the first time. These crystals exhibited high integrity and optimal afterglow performance, with a duration close to 2 h. The recrystallization-melting method suits industrial production on large scales, and the firing temperature is evidently lowered, which effectively reduces the energy consumption of the synthesis process and significantly improves the long afterglow performance.

Evaluating the Role of Titanomagnetite in Bubble Nucleation: Novel Applications of Low Temperature Magnetic Analysis and Textural Characterization of Rhyolite Pumice and Obsidian From Glass Mountain, California

AbstractNucleation of H2O vapor bubbles in magma requires surpassing a chemical supersaturation threshold via decompression. The threshold is minimized in the presence of a nucleation substrate (heterogeneous nucleation, &lt;50 MPa), and maximized when no nucleation substrate is present (homogeneous nucleation, &gt;100 MPa). The existence of explosively erupted aphyric rhyolite magma staged from shallow (&lt;100 MPa) depths represents an apparent paradox that hints at the presence of a cryptic nucleation substrate. In a pair of studies focusing on Glass Mountain eruptive units from Medicine Lake, California, we characterize titanomagnetite nanolites and ultrananolites in pumice, obsidian, and vesicular obsidian (Brachfeld et al., 2024, https://doi.org/10.1029/2023GC011336), calculate titanomagnetite crystal number densities, and compare titanomagnetite abundance with the physical properties of pumice to evaluate hypotheses on the timing of titanomagnetite crystallization. Titanomagnetite crystals with grain sizes of approximately 3–33 nm are identified in pumice samples from the thermal unblocking of low‐temperature thermoremanent magnetization. The titanomagnetite number densities for pumice are 1018 to 1020 m−3, comparable to number densities in pumice and obsidian obtained from room temperature methods (Brachfeld et al., 2024, https://doi.org/10.1029/2023GC011336). This range exceeds reported bubble number densities (BND) within the pumice from the same eruptive units (average BND ∼4 × 1014 m−3). The similar abundances of nm‐scale titanomagnetite crystals in the effusive and explosive products of the same eruption, together with the lack of correlation between pumice permeability and titanomagnetite content, are consistent with titanomagnetite formation having preceded the bubble formation. Results suggest sub‐micron titanomagnetite crystals are responsible for heterogeneous bubble nucleation in this nominally aphyric rhyolite magma.

CO2 adsorption by coal fly ash zeolite and modified zeolite-templated carbon

Coal fly ash (CFA), as the main by-product of coal-fired power plants, has a high content of silica-aluminium elements that can be used to prepare zeolite by the alkali fusion method with sound CO2 adsorption capacity. Among the four effect factors of Si/Al, NaOH/CFA, H2O/AFP(alkali fusion product), and crystallisation time, NaOH/CFA had the greatest effect on the CO2 adsorption performance of coal fly ash zeolite (CFAZ), followed by Si/Al and H2O/AFP, and crystallisation time had the least effect. The CO2 adsorption performance of the samples was tested and analysed using the thermal analysis method, the CO2 adsorption amount of CFAZ reached 4.23 mmol g–1 (30 °C, 101 kPa). In addition, the CFAZ and the zeolite-templated carbon (ZTC) adsorption performance is poor at high temperatures. The co-precipitation method modification of CFAZ and ZTC can produce layered double hydroxide derived material, which can adsorb CO2 at high temperatures reached at 3.35 mmol/g (650 °C, 101 kPa). Moreover, ZTC modified with polydivinylbenzene as the hydrophobic material has a sound CO2 adsorption effect in high-humidity environments. Thus, different adsorbents also could be produced using CFA to capture CO2 with a wide temperature range between 25 and 650 °C.

The role of intra-oceanic arc in the growth of continental crust: Evidence from the Early Paleozoic Bainaimiao arc

The Early Palaeozoic arc-related formations in the northern margin of the North China Craton (NCC) belonging to the Bainaimiao arc belt is an important part of the eastern Central Asian Orogenic Belt (CAOB). The tectonic evolution of this belt remains controversial. Here we present detailed data on the geochronology and geochemistry on a newly identified Early Palaeozoic igneous suite from the Faku area in northern Liaoning. Zircon U–Pb dating of the Faku volcanic and intrusive rocks yielded weighted mean 206Pb/238U ages of ca. 458 Ma and 433–405 Ma, respectively, which represent their crystallization (eruption) times. Zircon Hf isotopic analyses show a low negative to positive εHf (t) values of − 0.33 to + 12.4, implying depleted characteristics of the source. The geochemical features of Laolingshan basaltic andesites display higher TiO2 and lower P2O5 contents, similar to that of mid-ocean ridge basalts, and relatively high Zr/Y and low Ta/Yb ratios, suggesting oceanic island arc basalt affinity. Therefore, we suggest that the Laolingshan basaltic andesites were formed in an intra-oceanic environment. The Bachagou granodiorites, with adakitic geochemical signatures, belong to the calc-alkaline and high-K calc-alkaline series, implying formation in an active continental margin tectonic setting. The Baerhushan granodiorites, which geochemically belong to S-type granites, were probably formed in a syn-collisional environment influenced by arc–continent collision. The Donggou granitoids, which have higher SiO2 and alkali and lower MgO and P2O5, show A-type granite features. Geochemical characteristics of the Donggou A-type granite suggest formation in an extensional setting caused by orogenic intermittent extension. The Baerhushan gabbro diorites, which display properties of both mid-ocean ridge and continental rift basalts, were produced under post-orogenic extensional tectonic setting after the arc–continent collision. Our study traces the Early Palaeozoic tectonic evolution of the south-eastern segment of the CAOB and the related accretionary tectonics.

Synchrotron radiation SAXS study of the species structure evolution in the synthesis process of MCM-56 zeolite

In the process of synthesizing zeolite, the evolution behavior of aluminosilicate species is crucial for investigating the crystallization mechanism and controlling the structure of desired zeolite. Herein, the synthesis process of MCM-56 zeolite was investigated by using the synchrotron radiation Small Angle X-ray Scattering (SAXS) technique. Based on the distance distribution function curves and Porod analysis, the particle distribution of the sol in the synthesis system transformed from a monodisperse spherical particle to a polydisperse lamellar structure. The results indicated that the particle size distribution, fractal dimension, and the evolution behavior of particles in sol vary with the variation of crystallization time. Specifically, the initial step involves the depolymerization of particles forming small particles approximately 1 nm. Subsequently, these small particles polymerize to form structural units ranging in size from 1 to 5 nm, and finally grow to form MCM-56 zeolite crystal by consuming aluminosilicate species. The SAXS results in conjunction with the XRD, SEM, FT-IR, and N2 adsorption-desorption analysis elucidate the evolution of aluminosilicate species and the crystallization process of MCM-56 zeolite at three stages, including the induction/nucleation period (0–84 h), the crystal growth period (84–108 h) and the crystal stability period (108–168 h). By virtue of the understanding for the structural evolution of the sol species, this work is expected to highlight the controllable synthesis of MCM-56 zeolite.

Synthesis and Crystallization Mechanism for SAPO-34 Zeolite Derived from Magadiite.

In this work, we explored the hydrothermal synthesize and crystallization process of SAPO-34 zeolites from two-dimensional layered silicate magadiite by using tetraethylammonium hydroxide (TEAOH) as a templating agent. Comprehensive characterization was conducted by XRD, SEM, FTIR, Raman, and BET. Time-resolved PXRD analysis revealed that SAPO-34 zeolite exhibited a steep growth curve when the crystallization time was 30 h, and the crystallinity reached 98.65 % at 48 h. Specifically, the disruption of the magadiite layer exposed charged silanol groups on the surface, fostering an affinity for AlO4 and PO4 species, thereby initiating the nucleation process. Under the guidance of TEAOH, these nucleation sites transformed into SAPO-34 nuclei, gradually advancing towards crystallization. FTIR and Raman analyses affirmed the presence of 6Rs, followed by D6R and 4Rs SBUs, along with the characteristic CHA structure. Combined with 29Si NMR established that disaggregated silicate minerals served as zeolite synthesis "seeds", enhancing nucleation sites and overall crystallization efficiency.

NaY zeolite synthesis from rice husk ash for Chromium(VI) ion adsorption

NaY zeolite in this study is novelly synthesized from rice husk ash with a one-stage process instead of passing the solid silica recovery process as usual. NaY zeolite applies to assess adsorption ability of chromium(VI) ions in water with varying key factors. The as-synthesized zeolite is characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscope, specific surface area analysis and inductively coupled plasma mass spectrometry with optical emission spectroscopy. As a result, the optimal conditions for silica extraction are at 90oC with a NaOH concentration of 4 M for 4 h with recovery efficiency 87.5%. NaY zeolite is successfully synthesized with Si/Al ratio of 10, aging time of 24 h and crystallization time of 24 h with synthesis yield of 31.25% and crystallinity of 96%. The optimal conditions for the chromium(VI) adsorption in aqueous solution are at pH 2.0, adsorption time of 120 min, initial concentration of 20 mg/L with an adsorbent mass of 0.1 g. The kinetics and adsorption isotherms show a good agreement with pseudo-second order and Freundlich adsorption isotherm model. NaY zeolite is synthesized via environmentally friendly approach with time and energy savings and shows its high adsorb-ability of chromium(VI) in water.