Sulfate Crystals Research Articles

Multiscale modeling of ammonia adsorption on zinc sulfate-doped activated carbon: Sensitivity analysis, parameter identification, and model validation

In this study four models are developed and validated to describe the dynamic adsorption of ammonia on zinc sulfate-doped activated carbon, ranging from simple single-scale to complex multiscale models. They are based on equations for mass balance, thermodynamics, hydrodynamics, and adsorption kinetics. Since the values of the parameters are needed for the implementation of the models, the doped activated carbon is characterized and ammonia isotherms measurements are performed at three different temperatures, i.e., 288, 303, and 313 K. A method based on parameter sensitivity analysis is used to evaluate the estimability of the unknown parameters of the Toth isotherm equation. Experimental breakthrough curves were then measured at various ammonia concentrations and gas flow rates. These curves were used to determine the overall mass transfer and axial dispersion coefficients, as well as the effective and intracrystalline diffusion, involved in the model equations. The models were implemented and solved using Comsol Multiphysics®. The study showed that the adsorption process was limited by the diffusion of ammonia and adsorption on the zinc sulfate crystal. The models were validated using breakthrough curves different from those used for parameter identification. The agreement between model predictions and measurements was evaluated using performance indices and confirmed by a Kolmogorov-Smirnov statistical test.

Inhibition of Barium Sulfat Crystal Formation in a Batch Method Crystallizer in the Presence of Cu and Zn

Deposits of barium sulfate are a common issue in the oil and gas industry. The presence of these crystals impacts oil and gas production, causing technical problems such as inhibiting flow rate, increasing pressure in the pipe, and causing the pipe to break and be damaged. The results of this study show the formation of barium sulfate (BaSO4) crystals with the batch crystallizer method at 300 °C under the influence of the stirring rotation speed (0 rpm, 120 rpm, 240 rpm, 360 rpm, 480 rpm) and the additive concentration (0 ppm, 5 ppm, 10 ppm, 15 ppm, 2atm). In this study, the BaSO4 crystallization experiment was performed in a glass beaker using a magnetic stirrer with a stirring rotation speed to react BaCL2 and Na2SO4. The results demonstrated that adding zinc chloride (ZnCl2) and copper (ii) chloride (CuCl2) additives reduced the mass of crystals formed. The amount of barium sulfate scale that forms can be affected by the rotational speed of the stirrer. According to SEM analysis, the crystal morphology of BaSO4 was orthorhombic, indicating that this crystal shape was typical of barite crystals. While XRD analysis confirmed the formation of barium sulfate (barite) crystals, it also demonstrated that the crystals formed were solid barite crystals.

Ferroelectric properties of triglycine sulfate crystals doped with glycine analogs

Single crystals of ferroelectric triglycine sulfate doped with glycine analogs serine, threonine, lactic acid, and alaninol were grown via the slow solvent evaporation method. The resulting ferroelectric domain structures and polarization–electric field hysteresis loops revealed that these dopants caused triglycine sulfate to form a multidomain structure. This was attributed to hydrogen bonds not being formed, which is significant in polarization reversal, due to the side chains and the substituents of the dopant molecules. Therefore, the dopants did not affect the surrounding dipoles enough to cause cooperative phenomena, such as dipole‒dipole interactions, and do not result in the formation of a single- domain, unlike alanine in our previous study.

Parametric study of calcium sulfate crystallization fouling in cross-flow heat exchanger using response surface methodology

Parametric study of calcium sulfate crystallization fouling in cross-flow heat exchanger using response surface methodology

Hybridization of Salt Hydrates with Solid–Solid Phase Change Materials: A Novel Pathway to Sorption Thermochemical Materials Manufacturing

AbstractMajor advancements are needed in the thermochemical energy storage (TCES) field to bring the technology to commercial levels. The current research strategies are focused on improving heat and mass transfer using different supporting materials to achieve mechanical integrity during storage. However, these strategies are still under development, and they have not overcome the lab scale yet. This work explores novel matrices to expand the material database for TCES composites. Pure structural matrices (cellulose) and novel matrices with storage potential (polymeric solid–solid phase change materials) are selected and combined with three well‐known thermochemical materials (TCMs) (MgSO4·6H2O, SrBr2·6H2O and MgCl2·6H2O), providing evidence of hybridized composites with storage capacity up to 2.4 GJ m−3with a 25–20 wt% of polymeric matrix. The polymer content is found to act as a nucleating agent in the magnesium sulfate crystallization process forming a synthetic monohydrate crystalline phase (Kieserite) and inhibiting the formation of the amorphous phase. The effect of the matrix is proved to induce certain structural deformation or changes not observed in the pure TCM sorption process. This phenomenon has the potential to benefit the stabilization of the TCM, e.g., inhibition of the formation of amorphous phase in magnesium sulfate composites.

A Polymorph of Dipeptide Halide Glycyl-L-Alanine Hydroiodide Monohydrate: Crystal Structure, Optical Second Harmonic Generation, Piezoelectricity and Pyroelectricity.

A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, β = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to deff=280 pCN-1, when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting.

Reverse Osmosis Membrane Scaling Inhibition using Kinetic Degradation Fluxion Media

Membrane fouling can lead to reduced efficiency, increased operating costs, and shorter membrane life, which can ultimate[1]ly impact the quality of potable water produced from seawater. The use of Kinetic Degradation Fluxion (KDF) media as a pretreatment method is promising because it can potentially reduce fouling caused by CaCO3 scaling and improve the per[1]formance of RO membranes. The study's methodology, which involves comparing two identical reverse osmosis systems with and without KDF pretreatment, is appropriate and well-designed. By comparing the salt rejection and permeability flow of the two membrane systems, the study can provide valuable insights into the effectiveness of KDF media in reducing foul[1]ing caused by CaCO3 scaling. The explanation of how KDF media works to prevent the formation of mineral hardness scale by altering the morphology of the insoluble Ca and Mg carbonate and sulfate crystals and creating a redox environment is helpful in understanding the potential mechanism behind the effectiveness of KDF media as a pretreatment method. By con[1]trolling the formation of mineral scale and other contaminants, KDF media can potentially lead to improved efficiency of the RO membrane. Results suggest that KDF media can be an effective pretreatment method for reducing fouling caused by mineral scaling in RO systems. The potential mechanism behind the effectiveness of KDF media is explained, and the obser[1]vation that only a small number of KDF discs were degraded over the 40-hour period indicates that KDF media can be used for multiple cycles of RO operation, reducing the frequency of media replacement and associated operating costs. The finding that the RO-KDF membrane remained healthy and efficient for 40 hours while fouling was observed in the RO system with[1]in 20 hours is also promising, as it indicates that the KDF media can effectively reduce membrane fouling caused by scaling, leading to improved efficiency and extended membrane life. However, further studies can explore the optimal conditions for using KDF media in RO systems to maximize its effectiveness in reducing fouling and extending the lifetime of RO mem[1]branes. Investigating the potential for KDF media to reduce fouling caused by other contaminants, such as organic matter or silica, would also be interesting

Monosodium glutamate as an effective electrolyte additive in lead acid battery

High-rate partial state of charge (HRPSoC) life and stability of lead-acid batteries are largely limited by the surface morphology of lead sulfate and the reactivity of anode plates. In this study, sodium glutamate (MSG) was introduced as an electrolyte additive for lead-acid battery to improve lead sulfate deposition process and lead sulfate crystal morphology at the interface between lead anode and sulfuric acid electrolyte, and the influence of MSG on battery performance were explored. By electrochemical tests and material characterization, it was proved that glutamic acid anion can promote the formation of uniform deposition of lead sulfate with a structure similar to stacked flakes, which make it easy to form active lead and restrain irreversible sulfate during the fast charging and discharging process.

ТЕХНОЛОГИЯ КРИСТАЛЛИЗАЦИОННОГО РАЗДЕЛЕНИЯ НИКЕЛЯ И КАДМИЯ ПРИ ПЕРЕРАБОТКЕ НИКЕЛЬ-КАДМИЕВОЙ ЭЛЕКТРОДНОЙ МАССЫ ЩЕЛОЧНЫХ АККУМУЛЯТОРОВ

The main stages of processing nickel-cadmium electrode mass of alkaline batteries, including: sulfuric acid leaching and subsequent crystallization of the main components of the system - cadmium and nickel in the form of double sulfates MSO4·(NH4)2SO4·6H2O (Tutton's salts), where M = Ni, Cd. As a result of the research, regularities in the behavior of nickel and cadmium at the stage of leaching with a solution of sulfuric acid and crystallization of double sulfates were revealed. It is shown that the separation of cadmium and nickel in the sulfuric acid solution of leaching of nickel-cadmium battery mass by crystallization of nickel and cadmium-ammonium double sulfates is achieved in three stages with the formation of crystals of the composition NiSO4·(NH4)2SO4·6H2O, in two stages of crystallization and the degree of extraction of nickel 99 %, as well as CdSO4·(NH4)2SO4·6H2O and CdSO4·(NH4)2SO4 at the third stage of crystallization. Iron remains in solution after all valuable components have been isolated.

Сернокислотная технология переработки серпентинитов с получением семиводного сульфата магния

The paper presents the developed technology for the processing of serpentinite by the sulfuric acid method.The technology provides for the following operations: sulfuric acid leaching of serpentinite, purification from impurities of a magnesium-containing solution and isolation of magnesium sulfate crystals. Also, the influence of the concentration of sulfuric acid on the degree of opening was established.

Numerical simulation on the crystallization-induced mechanical response in hardened cement paste under external sulfate attack

Durability degradation caused by external sulfate attack (ESA) is one of major reasons for early failure of concrete structures served in coastal and marine environments. This paper proposes a simplified chemo-mechanical model to analyze the behavior of ESA on hardened cement paste (HCP), namely the diffusion-reaction and expansion-mechanical process. In this work, the crystallization pressure from the supersaturated pore solution is the driving force of local expansion of HCP, and the filling process of ettringite crystal in porous system is explained in detail. Then, the equivalent expansive eigenstrain of local HCP is calculated by crystallization pressure, and used to quantitatively characterize the ESA-induced chemical damage. Finally, the global mechanical response in HCP specimen is analyzed by introducing the expansive eigenstrain, which is considered to be the direct cause of mechanical response. The simulational results of sulfate concentration, crystallization pressure and expansion deformation show consistency with experimental data. Additionally, despite the lack of experimental data on mechanical response, the simulational result of expansive stress satisfies the force equilibrium.

Influence of polymer and inorganic modifiers on the process of phase formation in potassium sulfate saturated solutions

The process of potassium sulfate crystallization from aqueous solutions in the presence of organic modifiers containing phosphonic, phosphate, sulfonic, sulfate and carboxyl functional groups has been studied. It is shown that the introduction of organic substances has an inhibitory effect on the formation of potassium sulfate crystals. Modifiers containing sulfonic, sulfate and phosphonic functional groups have the greatest inhibitory effect. The effectiveness of modifiers containing carboxyl groups is significantly lower. The formation of stable supersaturated solutions of potassium sulfate is achieved by introducing organic modifiers in an amount of 0.25 – 0.50%.

Effect of Sulfate Crystallization on Uniaxial Compressive Behavior of Concrete Subjected to Combined Actions of Dry–Wet and Freeze–Thaw Cycles

This study focuses on the influence of salt crystallization from sodium sulfate on uniaxial compressive properties of concrete subjected to the coupling action of dry–wet cycles and freeze–thaw cycles. Eight groups of concrete specimens with different concentrations of sodium sulfate solution (CSSS) and different numbers of drying and wetting cycles (NDWC) were designed. Three groups of specimens with different numbers of freezing and thawing cycles (NFTC) exposed to same dry–wet cycles and same sulfate concentration were prepared to study the effects of combined environmental conditions. Salt crystallization from sodium sulfate was generated under a cyclical dry–wet time ratio of 3:1. Scanning electron microscopy and X-ray diffraction analysis were used to analyze reaction products of sulfate and concrete matrix. The results show that under single sulfate dry–wet cycles, with the increase of CSSS and NDWC, the uniaxial compressive strength of concrete degrades as a parabola and corresponding strain increases as a parabola, except for the linear increase of CSSS strain. Subjected to the combined action of sulfate dry–wet cycles and freeze–thaw cycles, it shows that the uniaxial compressive strength of concrete decreases as a parabola with the increase of NFTC, but corresponding strains have no obvious variation. The sulfate salt attack in advance greatly accelerates the deterioration of specimens after freeze–thaw cycles. The common dimensionless predication model of stress–strain relationship of concrete subjected to the combined action of dry–wet cycles and freeze–thaw cycles has been established.

Efficient preparation of magnesium bicarbonate from magnesium sulfate solution and saponification-extraction for rare earth separation

To realize the recycling of magnesium sulfate wastewater in the hydrometallurgy and separation process of Baotou mixed rare earth (RE) concentrate, the research on preparation of magnesium bicarbonate (Mg(HCO3)2) solution from magnesium sulfate solution by CO2 carbonation, extraction separation and transformation of RE sulfate solution by saponified HDEHP was investigated. The key influencing factors and carbonation mechanism in the preparation of Mg(HCO3)2, and the distribution of RE, calcium and magnesium elements in the saponification extraction were systematically studied. The results show that the conversion of Mg(HCO3)2 during carbonation is inhibited by calcium sulfate, but promoted by increasing the concentration of magnesium sulfate and decreasing the carbonation temperature. Under the optimized conditions, Mg(HCO3)2 solution with impurities (such as Fe, Al and Si) of less than 15 mg/L is prepared stably and efficiently, and the conversion rate of Mg(HCO3)2 is more than 95%. After multi-stage cascade extraction of RE sulfate solution, the RE extraction recovery is greater than 99.5%. Calcium sulfate crystals do not precipitate during the process, and the raffinate phase is magnesium sulfate solution that is used for the preparation of Mg(HCO3)2 solution.

Geochemistry of Brine and Paleoclimate Reconstruction during Sedimentation of Messinian Salt in the Tuz Gölü Basin (Türkiye): Insights from the Study of Fluid Inclusions

The halogenesis of the Messinian Tuz Gölü Basin corresponds to the sulfate type and the magnesium sulfate subtype. Compared to the Messinian Sea brines, they have a slightly higher [Na+] concentration, which is 96.6–116.4 g/L, and a much lower [K+] concentration, ranging from 0.1 to 2.35 g/L. During salt sedimentation, the [Mg2+] concentration ranged from 6.1 to 14.0 g/L, and the [SO42−] concentration from 18.2 to 4.5 g/L. Physical–chemical reactions in the basin’s near-surface and bottom waters during the suspension of halite deposition had a decisive influence on the significant reduction of [SO42−] sedimentation brines. During these periods, there was an intensive influx of Ca(HCO3)2 into the sedimentation basin and the formation of glauberite layers. The formation of the glauberite resulted from the slow dissolution of pre-deposited finely dispersed metastable minerals—gypsum, sodium syngenite, or mirabilite. In fluid inclusions in the halite, the sulfate minerals being allogenic crystals of calcium sulfate, are represented by gypsum, bassanite, and anhydrite. Additionally, as the other sulfate minerals, glauberite, anhydrite, and thenardite are found within halite crystals. Sharp fluctuations in daytime air temperatures characterized climatic indicators of the summer period in the Tuz Gölü region: 15.6–49.1 °C. In the spring or cool summer–autumn period, the daytime air temperature in the region ranged from 15.7–22.1 °C, and in late spring and early summer, it ranged from 20.6 °C to 35.0 °C. During some periods, the Tuz Gölü halite crystallized at 61.8–73.5 °C. The extreme high-temperature crystallization regime at the bottom of the salt-bearing basin was achieved due to the emergence of a vertical thermohaline structure. The “greenhouse effect” in the Tuz Gölü was established only briefly but was periodically renewed due to the influx of “fresh” waters.

Influence of ammonium nitrate on the crystallisation of ammonium sulfate

ABSTRACT This study aims to explore the influence mechanism of ammonium nitrate produced by ozone denitrification on the crystallisation of ammonium sulfate, a by-product of ammonia desulfurisation. The laser method was used to study the influence of ammonium nitrate on the solubility and metastable zone width of ammonium sulfate. An experiment on the influence of ammonium nitrate on the particle size of ammonium sulfate was designed, and the influence mechanism was explored through scanning electron microscopy and X-ray diffraction. The findings showed that the addition of ammonium nitrate increased the size and aspect ratio of ammonium sulfate crystals. The addition of ammonium nitrate inhibited the dissolution of ammonium sulfate and widened its metastable zone. The addition of ammonium nitrate covered the active sites of crystal nucleus growth, which inhibited the formation of crystal nuclei to a certain extent, and crystal growth dominated the crystallisation process. Moreover, the addition of ammonium nitrate induced the preferred orientation of the specific crystal plane of ammonium sulfate, and the addition of a small concentration of ammonium nitrate decreased the crystallinity of ammonium sulfate. The research results can provide a reference for crystallisation optimisation and quality improvement of ammonium sulfate in the ammonia desulfurisation process.

Physicochemical Analytical Studies on Yttrium‐Doped Triglycine Sulfate Single Crystals

Single crystals of pure triglycine sulfate (TGS) and yttrium-acetate (0.5 mol%)-doped triglycine sulfate (YTGS) crystals are synthesized and the crystals are grown from aqueous solution by slow evaporation solution growth method. The grown crystals are subjected to single crystal and powder X-ray diffraction studies to identify the morphology and structure. Both the grown crystals are packed in a monoclinic crystal system and the lattice parameters of YTGS crystal are a = 9.138 Å, b = 12.72 Å, and c = 5.728 Å, whereas the doped TGS are, a = 9.134 Å, b = 12.61 Å, and c = 5.723 Å. The lattice parameters are slightly distorted due to the incorporation of yttrium ion into the lattice sites of the TGS crystal. The thermal stability of the grown crystals is investigated by differential thermal analysis (DTA) and thermogravimetric studies. DTA curve shows a lower decomposition temperature for YTGS crystal than for pure TGS crystal. The functional groups of the grown crystals are identified by Fourier transform infrared spectral studies. The surface morphology of the crystals is examined by scanning electron microscopy. Dielectric studies are carried out to identify the phase transition temperature and to find the dielectric constant of the YTGS crystals.

Crystallization of nickel sulfate and its purification process: towards efficient production of nickel-rich cathode materials for lithium-ion batteries.

NiSO4·6H2O is an important salt for the battery-making industry. The extraction of nickel sulfate relies on the hydrometallurgical processing of nickel ores as well as the recycling of nickel-containing products. The last step in hydrometallurgical processing is the crystallization of nickel sulfate. Because of the similar ionic radius and ionic charge between nickel and magnesium ions, magnesium undergoes isomorphous substitution and replaces nickel ions in the crystal lattice structure of NiSO4·6H2O. This poses a challenge as achieving the desired metal salt purity is difficult, resulting in an inferior cathode material for nickel-containing batteries. In this work, the removal of magnesium during the purification process of NiSO4·6H2O crystals via a repulping process was thoroughly investigated. Moreover, the impurity uptake mechanisms of magnesium into NiSO4·6H2O crystals were investigated. The results indicated that repulping NiSO4·6H2O crystals with a saturated NiSO4 solution results in 77% removal of magnesium. Using a second-stage repulping process is less effective with only 26% magnesium removal. The purification efficiency of the two repulping stages was quantified by the equilibrium distribution coefficient, which corroborates the trend of decreased removal of magnesium in the second stage of repulping compared with the first stage. The primary impurity uptake mechanisms of magnesium into NiSO4·6H2O crystals were identified to be surface adsorption and lattice substitution (isomorphous substitution).

Electron transparent nanotubes reveal crystallization pathways in confinement.

The cylindrical pores of track-etched membranes offer excellent environments for studying the effects of confinement on crystallization as the pore diameter is readily varied and the anisotropic morphologies can direct crystal orientation. However, the inability to image individual crystals in situ within the pores in this system has prevented many of the underlying mechanisms from being characterized. Here, we study the crystallization of calcium sulfate within track-etched membranes and reveal that oriented gypsum forms in 200 nm diameter pores, bassanite in 25-100 nm pores and anhydrite in 10 nm pores. The crystallization pathways are then studied by coating the membranes with an amorphous titania layer prior to mineralization to create electron transparent nanotubes that protect fragile precursor materials. By visualizing the evolutionary pathways of the crystals within the pores we show that the product single crystals derive from multiple nucleation events and that orientation is determined at early reaction times. Finally, the transformation of bassanite to gypsum within the membrane pores is studied using experiment and potential mean force calculations and is shown to proceed by localized dissolution/reprecipitation. This work provides insight into the effects of confinement on crystallization processes, which is relevant to mineral formation in many real-world environments.

Development of (2D) graphene laminated electrodes to improve the performance of lead-acid energy storage devices

In the present work, studies on the performance of Graphene-laminated lead acid battery electrodes were carried out. Knowing the performance and the behavior of lead electrodes and their constituents during exposure to the electrolyte medium, sulphuric acid, is critical. An effort has been made to enhance the battery performance by coating (laminating) the electrodes with Carbon material (Graphene). The primary objective of the lamination process on the electrodes is to act as a sulfate inhibitor and to increase the performance of lead-acid batteries. The electrodes were laminated with the prepared graphene solution by an immersion technique. The morphological studies were carried out using SEM, and the elemental analysis of the coating was performed using EDAX. To examine the growth of the lead sulfate crystals on the electrode surface, the structural analysis was conducted with powder XRD. The electrochemical behavior of the laminated electrodes is compared with control batteries under similar operating conditions and was investigated by the “two-electrode system.” It is observed from the experimental results on the electrical characteristics that both (Positive and Negative) laminated electrodes and only negative laminated electrode batteries showed better performance in charge acceptance and cranking ability by 09% & 34%, respectively. The performance of batteries prepared with laminated electrodes is encouraging when compared to the control batteries against 1.29 sp. gr of H2SO4 electrolyte. These studies lay a foundation for further investigations to explore the wider utilization of 2D- Graphene lamination for developing next-generation lead-acid batteries.