Crystallization Of Inorganic Salts Research Articles

In situ visualization of salt crystallization in sub-/supercritical water environments

Elevated temperature and pressure conditions in sub-/supercritical water environments hinder the direct observation of salt crystallization phenomena, resulting in indeterminate salt crystal morphologies. In this study, an innovative experimental apparatus has been developed to conduct in situ investigations into the crystal morphology of various types of inorganic salts. The results indicate that the critical temperature of the water-salt system is higher than that of pure water systems, with phase transition thresholds for saturated NaCl-H2O and KCl-H2O systems 671.4 K and 728.1 K, respectively. A distinct “flash crystallization” phenomenon is observed during the crystallization of inorganic salts, accompanied by different crystal morphologies. KCl crystals exhibit a dispersed particle form, NaCl crystals manifest in a finely fragmented accumulation form, and Na2SO4 crystals present transparent feather-like structures. The size of NaCl crystals formed on the surface of a Ni wire at 622.8 K through heterogeneous nucleation ranges from 200.4 μm to 450.9 μm. The crystallization characteristics of salt in sub-/supercritical water are influenced by various factors, including electric dipole moment interactions, common ion effect, the effect of type I salts on type II salts, and homo/heterogeneous nucleation.

Characteristics of carbon black recycled from lightly pyrolyzed tire rubber and its impact on the high-temperature performance of asphalt

Waste cooking oil (WCO) is commonly used as an excellent reaction medium for the mild pyrolysis of ground tire rubber (GTR). Carbon black is a byproduct of rubber pyrolysis with varying properties depending on the pyrolysis process. To promote the utilization of pyrolytic carbon black (CBp) in asphalt modification, this study aims to characterize the low-temperature pyrolysis carbon black (LTCB) produced through the co-pyrolysis of GTR and WCO, and assess its impact on the high-temperature performance of asphalt. LTCB260 was separated by toluene extraction from the waste rubber-oil mixtures (WRO) containing the highest concentration of soluble substances. The identification of LTCB260 was conducted by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results indicated that the pure carbon black content in LTCB260 is 57.35 %, which is lower than CBp and N330. Bound rubber and inorganic salt crystals were observed to be randomly distributed on the surface of LTCB260. High-temperature performance tests conducted on asphalt indicated that the high-temperature deformation resistance of the LTCB260-modified asphalt was comparable to that of the other two carbon black-modified asphalts when using the same mass of carbon black. This suggests that despite being coated with impurities on its surface, the carbon black released from lightly pyrolyzed ground tire rubber still positively influences the high-temperature rheological properties of asphalt. However, when the carbon black content in WRO is significantly lower than that of the light component, the beneficial effect of carbon black on the high-temperature performance of asphalt may not be evident.

Modelling the flux decline induced by gypsum scaling in direct contact membrane distillation

Scaling has been a major technical challenge in the membrane distillation (MD) process, hindering the broader application of MD processes. Despite the increasing number of studies on MD scaling, there are limited prediction tools to describe the scaling process and help make informed decisions about the experimental conditions to prevent scaling and its irreversible damage. In this paper, a semi-analytical model was developed based on the classical nucleation theory and crystal growth to model the membrane area reduction caused by the deposition of inorganic salt crystals on the membrane surface, which is equivalent to the decrease in permeate flux resulting from scaling. The model was developed using calcium sulphate, a model scalant. The model was validated and verified with available literature data, and it has been proved that the model has the capability to produce reasonable predictions on the onset of flux decline and the declining rate with respect to the experimental data with the coefficient of determination (R2) ranging from 0.74 to 0.96. The sensitivity analysis was applied on the model, which revealed that flux decline would happen earlier in the case of higher feed temperature, higher feed velocity, and higher initial feed concentration.

Chemical composition-dependent hygroscopic behavior of individual ambient aerosol particles collected at a coastal site

Abstract. This study investigated the hygroscopic behavior of individual ambient aerosol particles collected at a coastal site of Jeju Island, South Korea. The size of the particles changes along with the phase transitions during humidification and dehydration processes, and the chemical compositions of the particles were determined by optical microscopy and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), respectively. Of the 39 particles analyzed, 24 were aged sea spray aerosols (SSAs), with diverse mixing ratios of Cl− and NO3-. The ambient SSAs exhibited multiple deliquescence and efflorescence transitions that were dominantly influenced by NaCl, NaNO3, MgCl2, Mg(NO3)2, and organic species covering the surface of the aged SSAs. For Cl-rich SSAs with X(Na,Mg)Cl>0.4, although some particles showed very slow water uptake at low relative humidity levels (RH ≃30 %), two major transitions were observed during the humidification process. The first was at RH ≃63.8 %, regardless of their chemical compositions, which is the mutual deliquescence relative humidity (MDRH) level; and the second was at RH 67.5 % to 73.5 %, depending on their chemical compositions, which are the final deliquescence relative humidity (DRH) levels. During the dehydration process, the Cl-rich SSAs showed single-stage efflorescence at RH 33.0 % to 50.5 %, due to simultaneous heterogeneous crystallization of inorganic salts. For Cl-depleted SSAs with X(Na,Mg)Cl<0.4, two prompt deliquescence transitions were observed during the humidification process. The first was at MDRH 63.8 %, and the second was at RH 65.4 % to 72.9 %. The mutual deliquescence transition was more distinguishable for Cl-depleted SSAs. During the dehydration process, step-wise transitions were observed at efflorescence RH levels (ERH 24.6 % to 46.0 % and 17.9 % to 30.5 %), depending on their chemical compositions. Additionally, aged mineral particles showed partial or complete phase changes with varying RH due to the presence of SSAs and/or NO3- species. In contrast, non-reacted mineral and Fe-rich particles maintained their size during the entire hygroscopic process. The mixture particles of organic and ammonium sulfate (AS) exhibited lower deliquescence and efflorescence RH levels compared to pure AS salt, highlighting the impact of organic species on the hygroscopic behavior of AS. These findings emphasize the complexity of atmospheric aerosols and the importance of considering their composition and mixing state when modeling their hygroscopic behavior and subsequent atmospheric impacts.

Design spherical particles of potassium peroxymonosulfate compound salt with high stability and good powder properties via an agglomeration-dissolution mechanism

With the outbreak of COVID-19, disinfection protection has become a necessary measure to prevent infection. As a new type of disinfectant, potassium peroxymonosulfate compound salt (PMS) has the advantages of good bactericidal effect, non-toxicity, high safety and stability. However, the current PMS products with irregular particle shapes lead to poor flowability, high hygroscopicity, poor stability of reactive oxygen species (ROS) and serious caking problems. In this work, an agglomeration-dissolution mechanism was designed to prepare spherical PMS particles with large size (>300 μm) and high sphericity (up to 90%), effectively addressing the above problems. Shaping (dissolution and abrasion) is the key to improving sphericity, which is mainly controlled by the design of the heating mode, residence time and stirring rate. Compared with the irregular PMS particles, the large spherical particles present better flowability (angle of repose decreased by 35.80%, Carr's index decreased by 64.29%, Hausner's ratio decreased by 19.14%), lower hygroscopicity (decreased by 38.0%), lower caking ratio (decreased by 84.50%), and higher stability (the monthly loss of ROS was reduced by 61.68%). The agglomeration-dissolution mechanism demonstrates the crystallization, agglomeration, dissolution and abrasion process of inorganic salt crystals, providing an opportunity to prepare high-end inorganic crystal materials with high-quality morphologies.

Functionalizing cotton fabric via covalently grafting polyaniline for solar-driven interfacial evaporation of brine

Herein, we report a novel method for batch functionalization of cotton fabric by co-irradiation grafting polymerization of 4-aminostyrene and in situ grafting polymerization of aniline in sequence for solar-driven interfacial evaporation. The functionalized cotton fabric displayed strong absorption of solar light and good photothermal conversion property. And it not merely exhibited a high evaporation rate of 1.47 kg m-2h−1 when treating 3.5 wt% NaCl solution with evaporation efficiency of 97% performed on a simple tilted platform (under 1 kW m−2 of power density), but also showed excellent stability for outdoor natural evaporation over 60 days. Besides that, the tilted solar evaporator unexpectedly exhibited a high evaporation rate (1.38 kg m-2h−1) in the saturated NaCl solution (ca.26 wt%), which is superior to those fabric-based photothermal materials in reported literature, suggesting a great potential to the application to solar-driven evaporative crystallization of inorganic salts from brine. The promising strategy adopted here could be employed to facilitate the scale-up preparation of photothermal cotton fabrics and address current challenges in high-efficiency and sustainable solar-driven seawater desalination, even zero liquid disposal of industrial waste brine.

Regarding the Formation of Wood Material Fire Protection and the Mechanism of its Action

The theoretical aspects of wood material fire protection formation by esterification reactions are considered in the article. The reactivity of polysaccharides and polymers from which wood material is composed has been confirmed by the FTIR method. The IR spectra of the original standard samples of lignin and microcrystalline cellulose were taken and after treatment with solutions with concentrations of 10% of the mass. orthophosphoric (Н3РО4) and oxyethylene diphosphonic (CH3C(OH)(H2PO3)2) acids. Electron scanning microscopy revealed the crystallization of inorganic salts on the wood material surface, which play the role of flame retardants, as well as a film of organopolymer (polyhexamethylene guanidine polyphosphate), which forms a foamed layer of coke when heated. Thermogravimetric analysis (TGA) and gas chromatography (GC) methods show the mechanism of action of fire protection provided to wood material. The formation of foamed coke is visually shown and the results on the effectiveness of fire protection on the example of wood material treatment with a mixture of diammonium phosphate and ammonium sulfate are obtained.

Regulating the morphology of nanofiltration membrane by thermally induced inorganic salt crystals for efficient water purification

Nanofiltration (NF) membrane typically prepared by interfacial polymerization (IP) technology is facing the problems of low permeance and flux-selectivity trade-off effect, which will seriously affect the efficiency of water purification. Here, novel NF membranes with a thin and crumpled polyamide (PA) layer were obtained by introducing low concentration of soluble inorganic salts (≤2 wt%) in the IP process and thermally induced crystallization of inorganic salts in the heat treatment process. The forces generated by the growth of inorganic salt crystals inevitably stretched the nascent and flexible PA layer, and further the inorganic salt crystals can sacrifice themselves in water, contributing to the formation of a thin and rough PA layer with crumpled nanostructure. Using NaCl as an example, the resulting NF membrane exhibited the permeation flux as high as 84 L/m2 h at 4 bar while maintaining a high rejection of 96.2% for Na2SO4. Meanwhile, it is universal for other soluble inorganic salts such as KCl, Na2SO4, KNO3 and CaCl2 to improve the filtration performance of NF membrane. This study is the first to combine the growth of inorganic salt crystals with the morphology regulation of PA active layer in the heat treatment process, which will further expand the research method of NF membrane with efficient water purification.

Undercooling-directed NaCl crystallization: an approach towards nanocavity-linked graphene networks for fast lithium and sodium storage.

Despite the crystallization of inorganic salt is being technologically related to the fabrication of salt-templated materials, the two key steps, nucleation and crystal growth, still lack the kinetic control to enable precise design of salt scaffolds. Here, we study how the undercooling degree controls the construction of salt scaffolds by kinetically manipulating the nucleation and growth rates in a NaCl-F127-rhodanine system. An effective approach based on undercooling-directed NaCl crystallization is further proposed to tailor the morphology and structure of the carbon materials. Under different undercooling conditions (liquid nitrogen, -55 °C and -25 °C freezing), the salt scaffold can be tuned as spheroidal particles, ellipsoidal nanocrystal aggregates and cubic nanocrystals with round corners, respectively. Correspondingly, hollow carbon nanospheres, nanocavity-linked graphene networks (CGN) and graphene nanosheets (GNS) can be fabricated through a salt template method, respectively. The Li+ and Na+ storage mechanisms of 3D CGN and 2D GNS are discussed, focusing on the ion diffusion kinetics. The enhanced Li+ diffusion kinetics in the 3D interconnected network endows CGN with better rate performance than GNS as lithium-ion battery anode material, and Na+ adsorption dominates the Na+ storage in CGN as sodium-ion battery anode material. Our findings provide a general idea for the construction crystallization-induced architectures and offer valuable insights to achieve fast Li+/Na+ storage by boosting the ion diffusion kinetics.

Adding Crystals To Minimize Clogging in Continuous Flow Synthesis

For many carbon–carbon and carbon–nitrogen bond-forming reactions, the stoichiometric formation of inorganic salt crystals limits continuous flow synthesis by causing precipitation, agglomeration, ...

Integration of membrane distillation (MD) and solid hollow fiber cooling crystallization (SHFCC) systems for simultaneous production of water and salt crystals

A novel hybrid system of integrating membrane distillation (MD) and solid hollow fiber cooling crystallization (SHFCC) has been successfully developed for simultaneous production of fresh water and inorganic salt crystals from NaCl brine solutions. Porous PVDF hollow fiber membranes consisting of PTFE particles were spun for the MD subsystem, while non-porous PVDF hollow fibers were fabricated as heat exchangers for the SHFCC subsystem. To optimize the operation parameters, the Taguchi's method was utilized for experiment design including three key factors; namely, feed temperature (Tf), distillated amount (Wd) and water amount to wash away the scallant (Ww). Several response factors were experimentally investigated and their signal-to-noise ratios of each response were calculated to identify the optimal settings of control factors. As a result, the best combined parameters to maximize the crystal harvest took place at Wd = 14 g and Tf = 50 °C. Narrowly distributed NaCl crystals with a small mean size of 35–45 µm were successfully generated by the hybrid system, and a relatively long-term MD-SHFCC operation of 15 cycles was conducted to verify the system stability and feasibility. The 15-cycle experiments exhibited an impressive average MD water flux of about 8 kg/m2 h and continuous production of distillate water with a high purity (a NaCl concentration of 0.01 g/L) and NaCl salt crystals with a yield of 64 g per kg feed.

Incorporation of Nanoparticles into Inorganic Salt Crystals (review)

This article provides an overview of the literature data on the incorporation of nanoparticles into crystals of inorganic salts, particularly alkali metal halides, potassium dihydrogen phosphate and others. The description of methods of obtaining composite crystals salt:nanoparticles, their properties and practical application are overviewed. It is shown that the process of incorporation of nanoparticles into the matrix depends on many factors, so systematic study of the effect of various parameters on its course and efficiency remains actual problem.

Dendritic crystallization of inorganic salts in the presence of nanocrystalline cellulose

Crystallization of inorganic salts (NaCl, CuSO4·5H2O, and NiSO4·6H2O) in the presence of nanocrystalline cellulose results in dendritic growth. The dendritic crystals obtained with nanocrystalline cellulose as an additive are pure inorganic salts.

Crystal Growth to Foster Inquiry–Based Learning: First Year Science Laboratory

Crystals play an important and ubiquitous role in our everyday life with applications in medicine, industry, agriculture, and biotechnology. With the recent trends toward inquiry-based learning in undergraduate science teaching laboratory, we developed a crystals growth laboratory for first year students. While one objective is to learn how to grow and handle crystals, the laboratory is designed to foster the acquisition of basic scientific knowledge and hands on experience to develop critical laboratory skills. In this sense, it is targeted for students with diverse backgrounds and, in accord with the liberal arts curriculum at NYU Abu Dhabi readily includes non-science majors. The original inspiration for the lab came from the 1960 classic book "Crystals and Crystal Growing" by Holden and Singer. We have expanded on the emphasis there on inorganic salt crystals to require students to crystallize macromolecules as well, in a research driven environment. Similar to projects carried in more advanced courses, students write an outline of their project that is developed into a full proposal through a literature search stimulated by in class discussions and peer-review. Some of the learning goals include the ability to design and manage a research project, propose ideas and methods to explore the topic of interest, learn various techniques and equipment common in a science laboratory, the ability to analyze data, acquire best practices in lab safety, and most importantly develop their scientific writing skills. Following 4-5 weeks of crystal growing and characterization, students present their data at the end of the semester Crystal Growth Symposium first presenting a 5 minute flash poster-presentation followed by a poster session. The symposium is a collective effort to enhance the students' presentation and communication skills and to showcase and encouraging high quality of research. While still evolving, the laboratory has seen a variety of mainly student-initiated investigations not only exploring a variety of methods to grow crystals, but also in exploring the effect of magnetic field, vibration, temperature, or pH on crystal growth. We will present organizational details of the laboratory program and present examples of many posters that have been generated during four years of operating the laboratory.

Organic solvent‐assisted crystallization of inorganic salts from acidic media

AbstractBACKGROUNDSolvent displacement crystallization (SDC) provides an energy‐efficient alternative to evaporative crystallization potentially leading to crystal products of superior quality, both in terms of purity and size, due to better supersaturation control. The present work investigates the SDC process in terms of appropriate organic solvent selection and application to several metal (K+, Na+, Mg2+ Fe2+, Cu2+, Ni2+, Co2+, Zn2+, Fe3+ and Al3+) sulfate and chloride systems of hydrometallurgical interest.RESULTSCriteria for the screening of organic compounds with suitable physical and chemical properties have been established and 2‐propanol was selected as an effective salting out agent to precipitate crystalline metal sulfates of practical interest; differences in crystallization behaviour among the various salts were linked to the hydration energy of the cation. None of the tested metal chlorides could be successfully separated, due to enhanced metal chloride solubility in non‐aqueous solvents relative to water by formation of chloro‐complexes with larger stability constants.CONCLUSIONSThe solvent displacement crystallization process was investigated and selection criteria for the organic solvent were established. 2‐propanol proved to be the most effective salting out agent for metal sulfates resulting in > 90% cation removal. By contrast none of the metal chlorides could be successfully separated due to salting‐in behaviour. © 2014 Society of Chemical Industry

On a Mechanizm of an Electric Field Influence on Physicotecnical Specifications of Materials

The paper addresses experimental data that describe a constant noncontact electric field influence on physicotechnical specifications of materials, grown in an electric field, and conditioned in it. Experiments have shown that it is possible to control physical and technical specifications of materials changing intensity of a noncontact electric field during crystallization. It is observed that an electric field influences size, optical purity and conductivity of crystals grown in a field. Crystallization of inorganic salts in an electric field allows obtaining chemically pure crystals with minimum defects. A mechanism of an electric field influence on inorganic salts crystallization is provided.

Parameter Estimation for Crystallization Processes using Taylor Method

A high-order Taylor series based parameter estimation method is proposed for crystallisation processes. The process is represented using a moment model with unknown kinetic parameters associated with nucleation and growth phenomena. For the nonlinear least-squares problem related to parameter estimation, Taylor method is developed to calculate the residuals and the associated Jacobian matrix. Simulated and experimental case studies related to cooling crystallization of inorganic salts are used to evaluate the performance of the proposed method. These studies show that the predicted moments and concentration profiles obtained using Taylor method match the measured counterparts satisfactorily. Furthermore, the proposed method is found be computationally more efficient and numerically more accurate than traditional ODE solver based approaches.

A novel downstream process for 1,3-propanediol from glycerol-based fermentation

In this paper, a downstream process for purification of 1,3-propanediol from glycerol-based fermentation broth was investigated. The purification of 1,3-propanediol from fermentation broth was achieved by a process combining microfiltration, charcoal treatment, vacuum distillation, and silica gel chromatography. The broth was first filtered through hollow fiber cartridge, wherein 98.7% of biomass was removed. Soluble proteins and other color impurities in the broth were removed by the use of activated charcoal at optimal concentration of 30 g l(-1) where the soluble proteins in the broth decreased to 0.1 g l(-1) (96.0% protein loss). The obtained broth when concentrated by vacuum distillation resulted in the crystallization of inorganic salts. Subsequently, 1,3-propanediol was purified by gradient chromatography using silica gel as a stationary phase and mixture of chloroform and methanol as a mobile phase. Finally, with the optimal flow rate of 10 ml min(-1) and loading amount of 80 ml, the yield of 1,3-propanediol achieved was 89%. The overall yield of 1,3-propanediol using the proposed procedure was 75.47%. The developed method was found to be a simple, rapid, and efficient procedure for the purification of 1,3-propanediol from fermentation broth.

The analysis of crystallization of sodium chloride from the solution in vacuum crystallizer with the recirculation of the suspension

Crystallization from a solution most often is the final stage of many technological processes, and has a major role in bulk chemical industry. Basic requirements which stand before the process of crystallization are as follows: providing a minimum energy use-up together with a maximum specific capacity of the crystallizer, as well as with obtaining a product with the necessary degree of purity. These demands are successfully fulfilled by vacuum crystallizers with recirculation of suspension, which are the most promising apparatus for the crystallization of inorganic salts from solutions in bulk production. Vacuum crystallizers, like other chemical apparatuses, are described as a sum of physical and chemical phenomena which together create a unit process of crystallization of NaCl from water solutions. The term apparatus process unit (APU) was introduced and a vacuum crystallizer is described as the sum of APU and shown in a structural scheme. The analysis of the vacuum crystallizer was performed based on its APU component, using theoretical assumptions, the results published as well as the results of researches on models. A particular focus was given to the description of the mass and heat transfer, as well as to the hydrodynamics of fluids in the area where the starting solution and the recircular suspension are mixed, in the circulation channel and the central pipe, as well as in the area of vaporization. This study gives the conclusions made based on the investigation of vacuum crystallizers. .

МИНЕРАЛЫ: ПРИРОДНЫЕ СОЕДИНЕНИЯ И ЛАБОРАТОРНЫЕ ИМИТАЦИИ

Ways of laboratory synthesis of solid inorganic substances by analogy to the processes in the nature are considered. Techniques of synthesis of inorganic compounds in gels as a result of reactions with the counter or unilateral diffusion, sold in conditions of school chemical laboratory are resulted. It is shown, that the offered techniques can be used at the organization of design activity of pupils, and also at carrying out of the integrated lessons. The contents of lessons in chemistry-geography on a theme «Mineralization and structure of minerals» and in chemistry-biology on a theme «Crystallization of inorganic salts in alive organisms» is considered. It is shown, that modeling of natural processes serves in laboratory conditions means of formation of representations about material unity of the world surrounding us. Keywords: school chemical experiment, modeling of natural processes, synthesis in viscous environments, minerals.