Seed Crystals Research Articles

Multiple element approach to P recovery and recycling: A green and sustainable strategy by using fused magnesia waste ash

Recovery of phosphorus through controlling the crystallization of struvite (MgNH4PO4·6H2O), a slow-release fertilizer, is highly attractive, but costly if large amounts of magnesium and alkali have to be added. In this study, a strategy for synchronously recovering phosphorus and nitrogen resources from wastewater and magnesium resources from solid waste was proposed. We demonstrated the fused magnesia waste ash (FMWA), an industrial by-product of magnesia which might serve as a cost-effective source of magnesium and alkali. The results showed that a recovery efficiency of 93.0 % PO43− and 88.8 % NH4+ from synthetic wastewater and 46.6 % Mg2+ from the FMWA was achieved when the ratio of [Mg2+]:[NH4+]:[PO43−] was 1.8:1:1. The magnesium release potential of FMWA was 10 times more than that of other known magnesium-containing solid wastes, due to the process in electric melting furnace damaged the lattice structure of magnesite and converted magnesite to magnesia. XRD analysis showed that crystalline struvite was the major product. The undissolved components of FMWA (MgCO3, MgO and SiO2) acted as crystal seeds, increasing the particle size and accelerating struvite precipitation. The application of FMWA for phosphorus fixation can reduce costs by 98.3 % compared with MgCl2. This research paves the way for employing FMWA in efficient recovery of phosphorus from wastewater, simultaneously achieving the resource utilization of industrial waste.

The morphology of liquid CO2 hydrate films at different temperatures under saturation pressure

CO2 hydrate film formed on the surface of water droplets in liquid CO2 was studied via digital microscope system and in situ Raman spectrometer. Temperature significantly affects the initial morphology and lateral growth rate of hydrate film. In the temperature range of 273.15–279.15 K under corresponding saturation pressure of liquid CO2, the growth and development process is primarily separated into three stages, that is, rapid lateral growth, rapid thickening, and slow development. However, in the temperature range of 280.15–282.15 K, the growth and evolution of hydrated film is dominated by rapid lateral growth and slow development processes, while the rapid thickening disappears on our experimental scale, caused by the decrease in the driving force. Each of these two temperature ranges has unique characteristics and interesting discoveries during the hydrate film formation and development. For hydrate film formed at 283.15 K, the formation of hydrate is very difficult. It needs to nucleate inside the droplet with the assistance of the hydrate crystal seeds remaining in the water droplet after decomposition, so that the small hydrate crystals can grow in the water phase, and as the crystals get larger, they will eventually emerge on the droplet’s surface and produce a complete hydrate film. Combining the experimental phenomena during the growth and development of hydrate films at various temperatures, the further growth of the hydrate phase during the generation process mainly depends on the mass transfer process of water molecules through the hydrate film. This work provides valuable information on the mechanism of nucleation, growth and decomposition of liquid CO2 hydrate crystals, which is of great significance for applications in seafloor CO2 gas sequestration.

Fate of calcium, magnesium, and phosphate during Fe electrocoagulation: An investigation for mitigating cathodic scaling in phosphate removal process

Fe electrocoagulation (Fe-EC) is efficient for the removal of phosphate (PO43−-P). The fate of Ca2+, Mg2+, and PO43−-P during the Fe-EC process is unclear, resulting in the difficulty for mitigating the cathodic scaling. After Fe-EC treatment for 10 min at 10 mA/cm2, PO43−-P was mainly distributed in the sediment (>90 %). Ca and Mg was mainly distributed in the solution (54 % − 97 %), followed by in the sediment (2 % − 44 %) and on the cathode (0 % − 6 %). Although only a small amount of Ca and Mg was precipitated on the cathode, with a long term operation, cathodic scaling would still occur. The precipitation of Ca on the cathode was mainly caused by the presence of HCO3− with other precipitates which directly precipitated with OH− as crystal seeds, because the precipitation of CaCO3 did not depend on the local pH near the cathode. The precipitation of Mg on the cathode was mainly caused by a lower applied current, because Mg(OH)2 which formed on the cathode would be prevented by H2 evolution with a higher current. Accordingly, the strategies for preventing cathode scaling are proposed. The precipitation of Ca can be prevented by increasing the current both with HCO3− and crystal seeds, and by increasing the current only with PO43−-P. It is hard to prevent the precipitation of Ca by controlling the current only with HCO3−. The precipitation of Mg can be prevented by increasing the current. With the initial concentrations of PO43−-P, HCO3−, Ca2+, and Mg2+ in the real wastewater 1.0 mg/L, 48 mg/L, 150 mg/L, and 30 mg/L, respectively, the amounts of Ca and Mg deposited on the cathode were much less at 10 mA/cm2 (5.8 ± 2.9 mg/L, 1.1 ± 0.3 mg/L) than those at 1 mA/cm2 (28.6 ± 4.6 mg/L, 5.0 ± 0.4 mg/L). With the above controlling strategies, the cathode scaling can be alleviated under different water quality conditions.

MAX phase-derived tin nano-/micro-wires with controlled diameter through seeded growth

Nano-scaled one-dimensional (1D) metallic materials show tremendous potential in various important technological applications, such as flexible transparent electrodes and catalysis. However, achieving scalable preparation of nanoscale 1D metallic materials remains a significant challenge for most metallic compositions. The phenomenon of A-site whisker growth from MAX phases provides an opportunity for innovative 1D metal fabrication techniques. However, the whisker diameters derived from MAX phases are often too large to satisfy the requirements of advanced technologies. Herein, we introduce Sn nanocrystals with different particle sizes as the initial seeds to tune the diameter of Sn whiskers, fed by the atomized tin resulted from the mechanochemical decomposition of Ti2SnC. It was found that incorporating nano-scaled (50–300 nm) and micro-scaled (0.5–1 μm) Sn crystal seeds resulted in the growth of whiskers with diameters matching the respective seed sizes, and the reduced melting point phenomenon of the nano-sized Sn wires conformed to the size-dependent behavior of metal nanowires. The diverse A-site elements within MAX phases implied that this method could be a generic strategy for synthesizing various nanoscale 1D metallic materials with controllable diameters.

Role of Crystal Seed in Aluminum Hydroxide Crystallization from Ammonia System with Added NH4Al(SO4)2·12H2O

Role of Crystal Seed in Aluminum Hydroxide Crystallization from Ammonia System with Added NH4Al(SO4)2·12H2O

Hydration and deliquescence behavior of calcium chloride hydrates

The phase transitions of calcium chloride between various hydrates and solid–liquid phase transitions are common in many natural and industrial processes. Recent studies have revealed some discrepancies in investigating the hydration and deliquescence of calcium chloride using different methods. In this study, water vapor sorption analysis and Raman measurements on CaCl2·2H2O and CaCl2·6H2O and their dehydration products were conducted. The results indicate two possible hydration sequences from lower hydrates to deliquescence at 298.15 K: (1) Hydration of the monohydrate to the dihydrate, followed by the formation of β-CaCl2·4H2O, ending with its deliquescence at 18.5 % RH; (2) Hydration of the monohydrate to the dihydrate, followed by the formation of α-CaCl2·4H2O and of the hexahydrate, ending with its deliquescence at 29 % RH. It was observed that the transition from pure dihydrate to β-CaCl2·4H2O occurs spontaneously, instead of hydration to the thermodynamically stable α-CaCl2·4H2O. The latter phase is only formed in the presence of crystal seeds of α-CaCl2·4H2O that remained after dehydration. Additionally, direct deliquescence of β-CaCl2·4H2O and thus absence of hydration to hexahydrate at 298.15 K is reported for the first time, which could be explained by the more similar lattice structure of CaCl2·2H2O (orthorhombic) and β-CaCl2·4H2O (monoclinic) than α-CaCl2·4H2O (triclinic). Apart from that, an explanation for the observed transformation sequence is proposed, considering the impact of the enhanced solubility of β-CaCl2·4H2O compared to the α-CaCl2·4H2O. The resulting water to salt ratio below six may contribute to the absence of CaCl2·6H2O formation. A Raman spectrum of CaCl2·H2O not reported previously is also provided.

Efficient and selective CO2 capture at low concentration from CH4 or N2 using Zn-MOF@AFP composite

The synthesis of structured CO2 adsorbents with high separation selectivity, strong stability, and low cost to meet industrial needs is very challenging. Here, we synthesized an ultra-stable Zn-MOF (Zn2(3-amion-1,2,4-triazolate)2(oxalate), Zn2(Atz)2Ox), and adopted an efficient in-situ growth strategy to produce millimeter-sized spherical Zn2(Atz)2Ox@AFP (Amino-Functionalization Poly(acrylates), AFP) composite. Due to the heterogeneous crystallization induced by the nanoscale crystal seeds and the confined space of AFP, the three-dimensional (3D) Zn2(Atz)2Ox bulk crystals transformed into 2D nanosheets with higher CO2 adsorption efficiency and faster kinetics. Zn2(Atz)2Ox@AFP has a high affinity for CO2 (2.05 mmol g−1 at 0.05 bar and 313 K) while exhibiting an inhibitory effect for N2 (only 0.051 mmol g−1 at 1.0 bar and 313 K), leading to an excellent ideal adsorbed solution theory (IAST) selectivity (2990 for CO2/N2 (5/95, v/v)). Interestingly, Zn2(Atz)2Ox@AFP exhibits a unique gating effect on CH4 adsorption, which further extends its application range to natural gas purification. Dynamic breakthrough experiments confirmed that Zn2(Atz)2Ox@AFP can selectively capture CO2 in the simulated CO2/N2 (5/95) and CO2/CH4 (5/95) mixed gases.

Solvothermal Preparation of Crystal Seeds and Anisotropy-Controlled Growth of Silver Nanoplates.

We synthesized silver nanoplates using the solvothermal method and, for the first time, placed them as crystal seeds in a water-based growth solution, thereby successfully achieving the large-scale production of silver nanoplates. The synthesis method enabled independent control of the lateral size and vertical size of the silver nanoplates. More specifically, the lateral size could be adjusted within the range of 565 nm-1.682 μm, while the vertical size was achieved by introducing Cl- as a capping agent and the vertical size was thickened from 18.28 to 40.41 nm.

Polydopamine-modulated anisotropic co-growth plasmonic blackbody for efficient ultra-broad-spectrum quenching to establish multicolor fluorescent immunoassay

Fluorescence quenching immunoassays have received increasing attention due to their high signal-to-noise ratio, among which multi-color fluorescence quenching methods have great advantages in detecting multiple targets. Preparing an efficient and broad-spectrum quencher is a prerequisite for establishing high-performance multicolor fluorescence quenching immunoassays. In this study, we propose a polydopamine (PDA) modulated seedless co-growth method to synthesize anisotropic plasmonic blackbody (APB) with highly branched chrysanthemum −like shape for efficient ultra-broad-spectrum quenching and utilize APB to establish a sensitive multicolor fluorescent immunoassay. The key to APB synthesis lies in the reduction of Au3+ by dopamine, which simultaneously undergoes oxidation and self-polymerization in situ to form a PDA film. This film continuously deposits on the Au crystal seeds, creating a robust end-capping effect and inducing continuous anisotropic growth of Au. The dual synergistic effects of PDA and the unique 3D-spatial structure contribute to APB’s robust ultra-broad-spectrum UV absorption (6.86 × 1011 L cm−1 mol−1) from 300 to 800 nm, along with efficient ultra-broad-spectrum fluorescence quenching ability (90.1 %). This quenching ability extends to various types of fluorescence microspheres covering the range of 300–800 nm with different excitation and emission spectra. Subsequently, we applied APB in the development of a multicolor fluorescence quenching immunochromatographic assay, enabling simultaneous detection of chloramphenicol (limit of detection, LOD = 0.0045 ng/mL) and sulfadimidine (LOD = 0.038 ng/mL) in milk. This research not only offers a novel direction for designing efficient broad-spectrum quenchers but also advances the practical application of fluorescence quenching sensors.

PENGEMBANGAN POTENSI PARIWISATA MELALUI WISATA EDUKASI DI KAMPUNG BUDAYA SAMIN BOJONEGORO

One of the tourist attractions developed in the Samin Cultural Village which is located in Japanese Hamlet, Margomulyo Village, Margomulyo District, Bojonegoro Regency is through educational tourism on the cultivation of matoa fruit and crystal guava. The development of this educational tourism began with outreach activities to local pokdarwis to plant matoa fruit and crystal guava seeds in the camping area. The research method used by the author is qualitative research. The data collection technique used in this research is through direct observation, interviews, recording documents and journal articles. Interactive data analysis techniques. The research results show that with a variety of natural and cultural tourism potential, this village is developing educational tourism about matoa fruit and crystal guava, which are suitable for planting in the area. This development involves outreach and planting seeds, aimed at increasing tourist visits and community income.

Facile synthesis of Ni-phyllosilicate assisted by polyacrylamide at room temperature for CO2 hydrogenation to methane

To elucidate the effect of solution viscosity on the synthesis of Ni-phyllosilicate, polyacrylamide was incorporated to create a viscous aqueous medium containing of sodium metasilicate, nickel nitrate and NH4F. The enhanced viscosity promotes the dispersion of the initial formed crystal seeds and the growth of Ni-phyllosilicate, culminating in a Ni-rich NiPs-RT-6 of a high Ni content of up to 55.2 wt%. Residual polyacrylamide elimination was accomplished via calcination, concurrently enhancing metal-support interaction. The as-synthesized samples display a nanoflower morphology with nanospheres overlaid with numerous thin nanosheets. The relatively small Ni particles around 5.7 nm were obtained after reduction even at a very high Ni loading, owing to its strong metal-support interaction. NiPs-RT-6 achieves a CO2 conversion of 75.9% at 450 °C, 0.1 MPa, 60 L g−1·h−1, which closely approximates thermodynamic equilibrium. The turn over frequency for CO2 (TOFCO2) was substantial, calculated at 3.7 × 10−3 s−1, accompanied by activation energy (Ea) of 80.6 kJ·mol–1. In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) further disclosed that m-HCOO– serves as a crucial intermediate following a formate reaction pathway. With its high Ni content, finely distributed Ni particles, and strong metal-support interaction, NiPs-RT-6 demonstrates promising catalytic activity in CO2 methanation.

Improved length of calcium sulfate crystal seeds and whiskers via ball milling and hydration treatment

Elucidating the effect of growth periods on the quality of calcium sulfate whiskers (CSWs) prepared from calcium sulfate dihydrate (DH) is imperative. Herein, crystal seeds and whiskers were prepared from DH in a water–glycerol system. Longer whiskers were obtained from crystal seeds prepared via hydration of DH for 30 s than via ball milling for 5 min followed by hydration for 20 s. The attachment of cetyltrimethyl ammonium bromide and glycerol additives to the whisker tops promoted whisker growth. The whisker sponges exhibited good thermal barrier properties and compression cycle stability.

Fundamental effects of using power ultrasound to accelerate C3S hydration

Activation of cement hydration accelerates hardening of concrete, enables faster production rates or production at similar frequency but significantly reduced CO2 emissions. The present study sheds light at the reason for accelerated cement hydration when power ultrasound (PUS) is applied during mixing.The investigations analysed the effect of PUS on dissolution of tricalcium silicate (C3S), homogeneous precipitation of C-S-H as well its effect on C3S-hydration. A combination of analytical techniques such as electric conductivity, optical emission spectroscopy, thermogravimetry, conduction reaction calorimetry, scanning electron microscopy and specific surface analysis were applied. It was revealed that PUS has a significant effect on paste hydration, which is induced by heterogenous nucleation of C-S-H and CH immediately after sonication. These hydrates were formed and dispersed by sonication thus acting as in-situ formed crystal seeds which shorten the induction period of C3S hydration.

In Situ Synthesis of Self-Assembly Supramolecular Crystal Seeds within Continuous Carbon Nanofibers for Improved Fiber Graphitic Structure

In Situ Synthesis of Self-Assembly Supramolecular Crystal Seeds within Continuous Carbon Nanofibers for Improved Fiber Graphitic Structure

In Situ Monitoring and Tuning Multilayer Stacking of Polymer Lamellar Crystals in Solution with Aggregation-Induced Emission.

Many types of self-assembled 2D materials with fascinating morphologies and novel properties have been prepared and used in solution. However, it is still a challenge to monitor their in situ growth in solution and to control the number of layers in these materials. Here, we demonstrate that the aggregation-induced emission (AIE) effect can be applied for the in situ decoupled tracing of the lateral growth and multilayer stacking of polymer lamellar crystals in solution. Multilayer stacking considerably enhances the photoluminescence intensity of the AIE molecules sandwiched between two layers of lamellar crystals, which is 2.4 times that on the surface of monolayer crystals. Both variation of the self-seeding temperature of crystal seeds and addition of a trace amount of long polymer chains during growth can control multilayer lamellar stacking, which are applied to produce tunable fluorescent patterns for functional applications.

Regulating Charge Transport Dynamics at the Buried Interface and Bulk of Perovskites by Tailored‐phase Two‐dimensional Crystal Seed Layer

AbstractTargeting the trap‐assisted non‐radiative recombination losses and photochemical degradation occurring at the interface and bulk of perovskite, especially the overlooked buried bottom interface, a strategy of tailored‐phase two‐dimensional (TP‐2D) crystal seed layer has been developed to improve the charge transport dynamics at the buried interface and bulk of perovskite films. Using this approach, TP‐2D layer constructed by TP‐2D crystal seeds at the buried interface can induce the formation of homogeneous interface electric field, which effectively suppress the accumulation of charge carriers at the buried interface. Additionally, the presence of TP‐2D crystal seed has a positive effect on the crystallization process of the upper perovskite film, leading to optimized crystal quality and thus promoted charge transport inside bulk perovskites. Ultimately, the best performing PSCs based on TP‐2D layer deliver a power conversion efficiency of 24.58 %. The devices exhibit an improved photostability with 88.4 % of their initial PCEs being retained after aging under continuous 0.8‐sun illumination for 2000 h in air. Our findings reveal how to regulate the charge transport dynamics of perovskite bulk and interface by introducing homogeneous components.

Regulating Charge Transport Dynamics at the Buried Interface and Bulk of Perovskites by Tailored-phase Two-dimensional Crystal Seed Layer.

Targeting the trap-assisted non-radiative recombination losses and photochemical degradation occurring at the interface and bulk of perovskite, especially the overlooked buried bottom interface, a strategy of tailored-phase two-dimensional (TP-2D) crystal seed layer has been developed to improve the charge transport dynamics at the buried interface and bulk of perovskite films. Using this approach, TP-2D layer constructed by TP-2D crystal seeds at the buried interface can induce the formation of homogeneous interface electric field, which effectively suppress the accumulation of charge carriers at the buried interface. Additionally, the presence of TP-2D crystal seed has a positive effect on the crystallization process of the upper perovskite film, leading to optimized crystal quality and thus promoted charge transport inside bulk perovskites. Ultimately, the best performing PSCs based on TP-2D layer deliver a power conversion efficiency of 24.58 %. The devices exhibit an improved photostability with 88.4 % of their initial PCEs being retained after aging under continuous 0.8-sun illumination for 2000 h in air. Our findings reveal how to regulate the charge transport dynamics of perovskite bulk and interface by introducing homogeneous components.

Effect of zinc(II) and caustic content on the decomposition of sodium aluminate solutions and relevance to the Bayer process

The impact of zinc (Zn) on the seed decomposition process of sodium aluminate solution at different caustic concentrations was investigated. The results showed that as the concentration of Zn(II) in sodium aluminate solution increased from 0 to 1000 mg/L, the decomposition efficiency of the solution and average grain size of the resulting aluminum tri-hydroxide (ATH) changed little at a caustic concentration of 141 g/L. At caustic concentrations of 160 g/L and 177 g/L, the decomposition efficiency increased from 35.8% and 21.6% to 40.6% and 24.9%, respectively, while average grain size of the ATH crystal seeds increased from 14.2 and 9.25 μm to 17.9 and 15.9 μm, respectively. The XRD, FT-IR, and SEM analyses showed that zinc can enter the ATH seeds and interact with the α-ATH crystal planes. It may also form interactions with the AlO octahedral growth structure, thus promoting solution decomposition and influencing crystal growth. The research results will provide valuable references for improving the quality of alumina products.

Silica Based Material as a Potential Adsorbent in Reducing Sterol Glucoside Level in Palm Oil Biodiesel

In recent years, biodiesel has emerged as a popular alternative to fossil fuels due to its superior properties. However, the presence of bioactive compounds, known as sterol glucosides (SGs), in crop-based biodiesel has posed a challenge for producers, as they act as crystal seeds and can cause gel formation or precipitation in cold temperatures. This can lead to issues with the quality of biodiesel during storage or use in vehicle engines. To address this issue, a study was conducted to explore the use of silica-based materials as an adsorbent to reduce SGs concentration in palm oil biodiesel. Natural resources silica material with a size of less than 100 µm was used in the process. The results showed that the use of silica gel led to the removal of 63.09 % of SGs in palm-based biodiesel due to its high surface area (556 m2/g) and porosity (0.79 cm3/g). Fourier transform infrared spectroscopy (FTIR) analysis indicated that the silicate and hydroxyl groups on the adsorbent’s surface were responsible for SGs adsorption. Importantly, the quality of the biodiesel before and after the adsorption treatment met all the specifications of the EN 61214 standard. This research suggests that the use of silica-based materials could be a promising solution for reducing SGs concentration in crop-based biodiesel, and could potentially improve its overall quality.

Exploring the separation properties of high-Si CHA membranes for the CO2 capturing technology: Impact of the selective layer thickness and growth mechanism

This study investigates the influence of the CHA selective layer's thickness, coated on a mono-channel alumina support using the secondary growth method, on the performance of CO2 separation from CH4. The membrane layer's thickness was explored by adjusting the concentration and duration of the seeding process, as well as the distribution of crystal size in the suspension. Single gas analysis results revealed that utilizing smaller crystal seeds, with an average crystallite size of approximately 600 nm, exhibited the highest performance. Furthermore, a membrane thickness of 2.1 μm demonstrated an ideal CO2/CH4 permselectivity of 205 with a CO2 permeance of 2.39 x 10-6 [mol/(m2sPa)]. For the equimolar CO2 - CH4 gas mixture, the high-Si membrane displayed a CO2/CH4 selectivity of 210 with a CO2 permeance of 8.06 x 10-7 [mol/(m2sPa)]. In both gas permeation measurement, CO2 permeance exhibited a slight linear decrease with increasing thickness, while CH4 permeance initially decreased and then increased non-linearly.