LiCl Concentration Research Articles

Effect of process conditions on generation of hydrochloric acid and lithium hydroxide from simulated lithium chloride solution using bipolar membrane electrodialysis

A feasibility study was carried out on generation of hydrochloric acid and lithium hydroxide from the simulated lithium chloride solution using EX3B model bipolar membrane electrodialysis (BMED). The influence of a series of process parameters, such as feed concentration, initial acid and base concentration in device component, feed solution volume, and current density were investigated. In addition, the maximum achievable concentrations of HCl and LiOH, the average current efficiency, and specific energy consumption were also studied and compared in this paper to the existing literature. Higher LiCl concentrations in the feed solution were found to be beneficial in increasing the final concentrations of HCl and LiOH, as well as improving current efficiency while decreasing specific energy consumption. However, when its concentration was less than 4 g/L, the membrane stack voltage curve of BMED increased rapidly, attributed to the higher solution resistance. Also low initial concentration of acid and base employed in device component can improve the current efficiency. Increasing of the initial concentration of acid and base solution lowered energy consumption. Moreover, a high current density could rapidly increase HCl and LiOH concentration and enhance water movements of BMED process, but reduced the current efficiency. The maximum achievable concentration of HCl and LiOH generated from 130 g/L LiCl solution were close to 3.24 mol/L and 3.57 mol/L, respectively. In summary, the present study confirmed the feasible application for the generation of HCl and LiOH from simulated lithium chloride solution with BMED.

Preparation, characterization, and application of hydrogel derived from chitin with lithium chloride for growth and development of rosemary plants

AbstractIn this study, the N,N‐dimethyl acetamide (DMAc) solution with different lithium chloride concentrations of 3 wt%, 5 wt%, and 7 wt% by phase inversion in ethanol vapor to produce chitin hydrogels for plant growth. The chitin hydrogel prepared with a higher concentration of lithium chloride showed improvements in elastic and mechanical properties. The tensile strength was enhanced from 275.8 to 434 kPa for the chitin hydrogel with 3% and 7% of LiCl. While the reduction in water content suggested forming a denser hydrogel structure at higher LiCl concentrations; the water contact angle (WCA) value indicated that chitin‐derived hydrogels are hydrophilic. Moreover, the bio‐degradation experiment indicated the degradable percent of the chitin hydrogel placed in 10 mg/L of aqueous lysozyme solutions at 37°C increases during 7 to 28 days from 4.72 wt% to 5.45 wt%. The obtained hydrogel was suitable for the growth and development on rosemary plants. The condition CE15 with the hydrogel of 85 wt% chitin‐derived hydrogel and 15 wt% cellulose as best medium planting with the largest effect on the height, the crown's diameters and the number of level‐one branches of the rosemary plants.

Electrodeposition of Rhenium-Iron Alloy from Water-in-Salt Electrolytes

Rhenium is a refractory metal and has distinguished properties, including excellent wear resistance, superior tensile strength, high creep-rupture, and resistivity in elevated temperatures [1]. More interestingly, it is also a superconductor at cryogenic temperatures. Electrodeposited superconducting materials can be used to fabricate superconducting circuits for cryogenic quantum devices [2,3]. As rhenium oxide is often inevitably formed during rhenium deposition, which prevents further reduction of itself into rhenium metal, highly acidic electrolytes are typically required for rhenium electrodeposition [4]. A significant amount of proton in the electrolyte, however, exacerbates hydrogen evolution reaction, resulting in not only a low current efficiency but also hydrogen incorporation into the metal deposit. The latter often, causes cracks and pin holes in the deposited films. Water-in-salt electrolyte is an aqueous solution with super high concentration of salt, e.g. LiCl, where the hydration of salt depletes or significantly decreases free water molecules, thus disrupting the hydrogen bond network, and suppressing proton reduction. In our previous work, a water-in-salt electrolyte of super high concentration of LiCl was applied to electrodeposit rhenium and rhenium-cobalt alloy to mitigate hydrogen evolution reaction and film cracks [5,6].In this presentation, the study has been extended to rhenium-iron alloy. While the rate decrease of hydrogen evolution reaction upon the use of water-in-salt electrolyte was expected, a surprisingly strong enhancement of Re deposition rate in the presence of Fe was also observed. Figure 1 shows the partial current densities of rhenium during alloy deposition, where it not only showed more than 10x deposition rate compared with an elemental Re water-in-salt electrolyte.The morphology and crystallographic structure of ReFe films and the effect of annealing will be characterized with microscopic and diffraction techniques and will be discussed in conjunction with pure metal films. Superconductivity and the effect of alloying on the critical temperature will also be discussed in detail in the talk. Figure 1 . The rhenium partial current in the deposited films from different applied potential from four electrolytes with 0, 10, 20, and 35 mM iron.

Aqueous Electrolytes, MXene‐Based Supercapacitors and Their Self‐Discharge

Significant efforts have been dedicated to developing Ti3C2Tz‐based MXene aqueous supercapacitors (SCs) with improved energy and power densities. Notably less research has been devoted to an equally important characteristic of aqueous SCs, viz. self‐discharge (SD). The SD rates are rarely reported despite their crucial importance from a practical point of view. Herein, the SD rates in four different aqueous electrolytes: H2SO4, KOH, LiCl, and LiBr in Ti3C2Tz‐based aqueous SCs are compared. For the latter two, the SD rates vary as a function of salt concentration in the electrolytes with higher LiCl or LiBr concentrations having the lowest SD rates, viz. 78.3% and 81.5% in 14 m LiCl and LiBr, respectively, after 10 h. Further, the influence of dissolved oxygen and the purities of the starting powders are examined, and it is concluded that parasitic reactions, including oxygen, are responsible for the SD.

Study on the performance characterization and yarn mechanical properties of poly-m-phenylene isophthalamide nanofiber

In this paper, poly- m-phenylene isophthalamide (PMIA) staple fibers were dissolved in a LiCl/ N, N-dimethylacetamide solvent system in order to prepare PMIA nanofibers via the electrospinning method. The mean diameter of the nanofiber was between 72 and 247 nm and gradually increased with increasing LiCl concentration. PMIA nanofibers were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, a thermogravimetric analyzer and Brunauer–Emmett–Teller analysis. Besides, the tensile strength of PMIA nanofiber yarns was tested and analyzed, combining the orthogonal array method. The results showed that the diameter and uniformity of nanofibers decreased gradually with increasing PMIA and LiCl solution concentration. The thermal properties, the specific surface area and chemical structures of PMIA nanofibers were improved comparing with PMIA stable fiber. It was found out that the LiCl concentration could influence the interactions among polymer molecules and caused the fibrils to wrap around each other, forming fiber clusters. The LiCl concentration was the most important factor affecting the tensile strength of PMIA nanofiber yarn.

Electrospinning of polyvinylidene fluoride membranes: effect of membrane composition and fabrication conditions

Membrane fabrication by the electrospinning can provide tunable structure membranes with interconnected pores, large surface area, and high porosity. This study focuses on studying the effect of different membrane compositions (i.e., polymer concentration and inorganic additives) and electrospinning conditions (i.e., internal needle diameter, tip to collector distance, and feed flow rate) on the quality of polyvinylidene fluoride (PVDF) flat sheet membrane. A homogeneous dope solution was prepared by dissolving the PVDF in a mixture of dimethylacetamide (DMAc) and acetone. By using a scanning electron microscope (SEM), the electrospinning conditions producing beadles fibers are as follows: 16 wt% polymer concentration, 0.004 wt% LiCl concentration, 0.51 mm internal needle diameter, 15 cm tip to collector distance, feed flow rate of 1 ml/hr. Further analysis was conducted by using Fourier Transform Infrared Spectrometer (FTIR) and X-Ray Diffraction (XRD) to assess the impact of electrospinning on fibers elemental composition. Additionally, static water contact angle, porosity, fiber diameter, and pore size measurements reveal the formation of submicron hydrophobic fibers with random alignment.

Assessment of pilot direct contact membrane distillation regeneration of lithium chloride solution in liquid desiccant air-conditioning systems using computer simulation.

Membrane distillation (MD) has been increasingly explored for treatment of various hyper saline waters, including lithium chloride (LiCl) solutions used in liquid desiccant air-conditioning (LDAC) systems. In this study, the regeneration of liquid desiccant LiCl solution by a pilot direct contact membrane distillation (DCMD) process is assessed using computer simulation. Unlike previous experimental investigations, the simulation allows to incorporate both temperature and concentration polarisation effects in the analysis of heat and mass transfer through the membrane, thus enabling the systematic assessment of the pilot DCMD regeneration of the LiCl solution. The simulation results demonstrate distinctive profiles of water flux, thermal efficiency, and LiCl concentration along the membrane under cocurrent and counter-current flow modes, and the pilot DCMD process under counter-current flow is superior to that under cocurrent flow regarding the process thermal efficiency and LiCl concentration enrichment. Moreover, for the pilot DCMD regeneration of LiCl solution under the counter-current flow, the feed inlet temperature, LiCl concentration, and especially the membrane leaf length exert profound impacts on the process performance: the process water flux halves from 12 to 6 L/(m2·h) whilst thermal efficiency decreases by 20% from 0.46 to 0.37 when the membrane leaf length increases from 0.5 to 1.5 m.

Application and Analysis of Bipolar Membrane Electrodialysis for LiOH Production at High Electrolyte Concentrations: Current Scope and Challenges.

The objective of this work was to evaluate obtaining LiOH directly from brines with high LiCl concentrations using bipolar membrane electrodialysis by the analysis of Li+ ion transport phenomena. For this purpose, Neosepta BP and Fumasep FBM bipolar membranes were characterized by linear sweep voltammetry, and the Li+ transport number in cation-exchange membranes was determined. In addition, a laboratory-scale reactor was designed, constructed, and tested to develop experimental LiOH production tests. The selected LiCl concentration range, based on productive process concentrations for Salar de Atacama (Chile), was between 14 and 34 wt%. Concentration and current density effects on LiOH production, current efficiency, and specific electricity consumption were evaluated. The highest current efficiency obtained was 0.77 at initial concentrations of LiOH 0.5 wt% and LiCl 14 wt%. On the other hand, a concentrated LiOH solution (between 3.34 wt% and 4.35 wt%, with a solution purity between 96.0% and 95.4%, respectively) was obtained. The results of this work show the feasibility of LiOH production from concentrated brines by means of bipolar membrane electrodialysis, bringing the implementation of this technology closer to LiOH production on a larger scale. Moreover, being an electrochemical process, this could be driven by Solar PV, taking advantage of the high solar radiation conditions in the Atacama Desert in Chile.

Local structure in lithium chloride solution: a Monte-Carlo simulation study

ABSTRACT Monte-Carlo simulations and the nearest neighbour approach have been employed in the present study to investigate the structural properties of aqueous solutions of LiCl salt at ambient conditions. The calculations are performed at increasing concentration of LiCl starting from c = 0.1 m up to 10 m. The analysis shows that increasing salt concentration results in a reduction of the tetrahedral arrangement of water in favour of a non-tetrahedral arrangement characterised by an O–O–O angle between the reference oxygen and two of its four closest oxygen neighbours at 60°. Moreover, the LiCl concentration has a considerable effect on the hydrogen-bonding structure of water. By correctly choosing the nearest neighbours, it is found that the deviation in water structure is due to the presence of chloride ion, not lithium ion, in the first solvation shell of water. It is also demonstrated that in concentrated LiCl solution Cl− ions can substitute the fourth water neighbour which leads to a tetrahedral network formed by water molecules and Cl− ions around a central water molecule. The analysis of the effect of concentration increase on the arrangement of the four closest water molecules neighbours from a reference lithium cation allows us to elucidate a structural maker role of Lithium ion.

Differential acute impact of therapeutically effective and overdose concentrations of lithium on human neuronal single cell and network function

Lithium salts are used as mood-balancing medication prescribed to patients suffering from neuropsychiatric disorders, such as bipolar disorder and major depressive disorder. Lithium salts cross the blood-brain barrier and reach the brain parenchyma within few hours after oral application, however, how lithium influences directly human neuronal function is unknown. We applied patch–clamp and microelectrode array technology on human induced pluripotent stem cell (iPSC)-derived cortical neurons acutely exposed to therapeutic (<1 mM) and overdose concentrations (>1 mM) of lithium chloride (LiCl) to assess how therapeutically effective and overdose concentrations of LiCl directly influence human neuronal electrophysiological function at the synapse, single-cell, and neuronal network level. We describe that human iPSC-cortical neurons exposed to lithium showed an increased neuronal activity under all tested concentrations. Furthermore, we reveal a lithium-induced, concentration-dependent, transition of regular synchronous neuronal network activity using therapeutically effective concentration (<1 mM LiCl) to epileptiform-like neuronal discharges using overdose concentration (>1 mM LiCl). The overdose concentration lithium-induced epileptiform-like activity was similar to the epileptiform-like activity caused by the GABAA-receptor antagonist. Patch–clamp recordings reveal that lithium reduces action potential threshold at all concentrations, however, only overdose concentration causes increased frequency of spontaneous AMPA-receptor mediated transmission. By applying the AMPA-receptor antagonist and anti-epileptic drug Perampanel, we demonstrate that Perampanel suppresses lithium-induced epileptiform-like activity in human cortical neurons. We provide insights in how therapeutically effective and overdose concentration of lithium directly influences human neuronal function at synapse, a single neuron, and neuronal network levels. Furthermore, we provide evidence that Perampanel suppresses pathological neuronal discharges caused by overdose concentrations of lithium in human neurons.

Growth and Biochemical Responses of Potato Cultivars under In Vitro Lithium Chloride and Mannitol Simulated Salinity and Drought Stress.

Globally, drought and salinity stress critically constrain potato (Solanum tuberosum L.) production. Considering the impact of these stresses on crops and increasing food demand, insight into both tolerance and susceptibility is essential. The present study screens two potato cultivars, BARI-401 and Spunta, for their tolerance to simulated salinity and drought by in vitro LiCl and mannitol exposure. Plantlets treated with a range of LiCl (0, 10, 30, and 40 mM) and mannitol (0, 50, 100, 200, and 250 mM) concentrations were biochemically and physiologically characterized to assess their tolerance capacity. Shoot number, shoot length, root number, and root length were affected in both cultivars under higher LiCl and mannitol concentrations, even though Spunta was able to better maintain a higher shoot length under the 40 mM of LiCl and 250 mM of mannitol compared to BARI-401. The total phenol contents (TPC) in both cultivars were increased at the highest treatment concentration and the total flavonoids content (TFC) was decreased in BARI-401 as compared to Spunta. Higher free radical scavenging capacity (FRSC, low IC50 value) was recorded in Spunta as compared to BARI-401 with increasing treatment concentrations, which supports the high antioxidant capacity of Spunta. An inverse correlation between polyphenol oxidase (PPO) and TPC was noted in both cultivars. Peroxidase dismutase (POD) activity was increased significantly in both cultivars for all treatments, but activity was highest overall in Spunta. These physiological and biochemical analyses of both cultivars suggest that cultivar Spunta is more tolerant to salinity and drought stress. Further open-field experiments are required to confirm these results.

Genomic characterization and proteomic analysis of the halotolerant Micrococcus luteus SA211 in response to the presence of lithium

Micrococcus luteus SA211, isolated from the Salar del Hombre Muerto in Argentina, developed responses that allowed its survival and growth in presence of high concentrations of lithium chloride (LiCl). In this research, analysis of total genome sequencing and a comparative proteomic approach were performed to investigate the responses of this bacterium to the presence of Li. Through proteomic analysis, we found differentially synthesized proteins in growth media without LiCl (DM) and with 10 (D10) and 30 g/L LiCl (D30). Bi-dimensional separation of total protein extracts allowed the identification of 17 over-synthesized spots when growth occurred in D30, five in D10, and six in both media with added LiCl. The results obtained showed different metabolic pathways involved in the ability of M. luteus SA211 to interact with Li. These pathways include defense against oxidative stress, pigment and protein synthesis, energy production, and osmolytes biosynthesis and uptake. Furthermore, mono-dimensional gel electrophoresis revealed differential protein synthesis at equivalent NaCl and LiCl concentrations, suggesting that this strain would be able to develop different responses depending on the nature of the ion. Moreover, the percentage of proteins with acidic pI predicted and observed was highlighted, indicating an adaptation to saline environments. To the best of our knowledge, this is the first report showing the relationship between protein synthesis and genome sequence analysis in response to Li, showing the great biotechnological potential that native microorganisms present, especially those isolated from extreme environments.

Effects of Lithium Chloride and Nitric Oxide Inhibitor on Orthodontic Tooth Movement in the Rat

Orthodontic tooth movement in a rodent model is reduced by lithium chloride (LiCl), a mood-stabilizing agent with antithyroid effects. Considering the established inhibitory effect of N(omega)-nitro-L-arginine methyl ester (L-NAME) on orthodontic tooth movement and the possible role of nitric oxide synthase in LiCl mechanism of action, the question arises if these two mechanisms are synergistic. To answer this question, 70 male Sprague Dawley rats were randomly divided into seven groups: untreated group without any interventions (i), and the orthodontic tooth movement groups receiving daily saline injection (ii), 300 (iii), and 600 mg/kg (iv) of LiCl per os, 10 mg/kg of L-NAME (v) and the combinations of 300 (vi) and 600 mg/kg LiCl (vii) with L-NAME. The first molar was moved towards the incisor with 60 g of mesial tipping force applied by an activated fixed coil spring for two weeks. The resulted distance between the first and the second molar was measured using a feeler gauge. The serum parameters were also determined. We report here that both concentrations of LiCl significantly decreased tooth movement. Even though L-NAME was capable of reducing orthodontic tooth movement, no synergistic effects with LiCl were observed. Moreover, L-NAME had no impact on the robust and significant increase of thyroid-stimulating hormone (TSH) and decrease of triiodothyronine (T3) and thyroxine (T4) in the LiCl treated rats. These findings suggest LiCl significantly decreases the orthodontic tooth movement in rats; however, this ability seems not to be principally mediated through nitric oxide synthase.

The preconditioning of lithium promotes mesenchymal stem cell-based therapy for the degenerated intervertebral disc via upregulating cellular ROS

Adipose-derived stem cell (ADSC) is one of the most widely used candidate cell for intervertebral disc (IVD) degeneration-related disease. However, the poor survival and low differentiation efficacy in stressed host microenvironment limit the therapeutic effects of ADSC-based therapy. The preconditioning has been found effective to boost the proliferation and the functioning of stem cells in varying pathological condition. Lithium is a common anti-depression drug and has been proved effective to enhance stem cell functioning. In this study, the effects of preconditioning using LiCl on the cellular behavior of ADSC was investigated, and specially in a degenerative IVD-like condition.MethodThe cellular toxicity on rat ADSC was assessed by detecting lactate dehydrogenase (LDH) production after treatment with a varying concentration of lithium chloride (LiCl). The proliferative capacity of ADSC was determined by detecting Ki67 expression and the relative cell number of ADSC. Then, the preconditioned ADSC was challenged by a degenerative IVD-like condition. And the cell viability as well as the nucleus pulpous (NP) cell differentiation efficacy of preconditioned ADSC was evaluated by detecting the major marker expression and extracellular matrix (ECM) deposit. The therapeutic effects of preconditioned ADSC were evaluated using an IVD degeneration rat model, and the NP morphology and ECM content were assessed.ResultsA concentration range of 1–10 mmol/L of LiCl was applied in the following study, since a higher concentration of LiCl causes a major cell death (about 40%). The relative cell number was similar between preconditioned groups and the control group after preconditioning. The Ki67 expression was elevated after preconditioning. Consistently, the preconditioned ADSC showed stronger proliferation capacity. Besides, the preconditioned groups exhibit higher expression of NP markers than the control group after NP cell induction. Moreover, the preconditioning of LiCl reduced the cell death and promoted ECM deposits, when challenged with a degenerative IVD-like culture. Mechanically, the preconditioning of LiCl induced an increased cellular reactive oxidative species (ROS) level and activation of ERK1/2, which was found closely related to the enhanced cell survival and ECM deposits after preconditioning. The treatment with preconditioned ADSC showed better therapeutic effects than control ADSC transplantation, with better NP preservation and ECM deposits.ConclusionThese results suggest that the preconditioning with a medium level of LiCl boosts the cell proliferation and differentiation efficacy under a normal or hostile culture condition via the activation of cellular ROS/ERK axis. It is a promising pre-treatment of ADSC to promote the cell functioning and the following regenerative capacity, with superior therapeutic effects than untreated ADSC transplantation.

Cortical neurochemical signaling of gustatory stimuli and their visceral consequences during the acquisition and consolidation of taste aversion memory

The insular cortex (IC) has a crucial role in taste recognition memory, including conditioned taste aversion (CTA). CTA is a learning paradigm in which a novel taste stimulus (CS) is associated with gastric malaise (US), inducing aversion to the CS in future encounters. The role of the IC in CTA memory formation has been extensively studied. However, the functional significance of neurotransmitter release during the presentation of taste stimuli and gastric malaise-inducing agents remains unclear. Using microdialysis in free-moving animals, we evaluated simultaneous changes in glutamate, norepinephrine and dopamine release in response to the presentation of an innate appetitive or aversive gustatory novel stimulus, as well as after i.p. administration of isotonic or hypertonic gastric malaise-inducing solutions. Our results demonstrate that the presentation of novel stimuli, regardless of their innate valence, induces an elevation of norepinephrine and dopamine. Administration of a gastric malaise inducing agent (LiCl) promotes an elevation of glutamate regardless of its concentration. In comparison, norepinephrine release is related to the LiCl concentration and its equimolar NaCl control. Additionally, we evaluated their functional role on short and long-term taste aversion memory. Results indicate that the blockade of noradrenergic β1,2 receptors in the IC spares CTA acquisition and memory consolidation. In contrast, blockade of dopamine D1/D5 receptors impaired CTA consolidation, whereas the NMDA receptor blockade impedes both acquisition and consolidation of CTA. These results suggest that dopaminergic and noradrenergic release are related to the salience of conditioned taste stimuli. However, only cortical D1/D5 dopaminergic activity, but not the noradrenergic β1,2 activity, is involved in the acquisition and consolidation of taste memory formation. Additionally, glutamatergic activity signals visceral distress caused by LiCl administration and activates NMDA receptors necessary for the acquisition and consolidation of long-lasting taste aversion memory.

Muscle-inspired double-network hydrogels with robust mechanical property, biocompatibility and ionic conductivity

Inspired by muscle architectures, double network hydrogels with hierarchically aligned structures were fabricated, where cross-linked cellulose nanofiber (CNF)/chitosan hydrogel threads obtained by interfacial polyelectrolyte complexation spinning were collected in alignment as the first network, while isotropic poly(acrylamide-co-acrylic acid) (PAM-AA) served as the second network. After further cross-linking using Fe3+, the hydrogel showed an outstanding mechanical performance, owing to effective energy dissipation of the oriented asymmetric double networks. The average strength and elongation-at-break of PAM-AA/CNF/Fe3+ hydrogel were 11 MPa and 480 % respectively, which the strength was comparative to that of biological tissues. The aligned CNFs in the hydrogels provided probable ion transport channels, contributing to the high ionic conductivity, which was up to 0.022 S/cm when the content of LiCl was 1.5 %. Together with superior biocompatibility, the well-ordered hydrogel showed a promising potential in biological applications, such as artificial soft tissue materials and muscle-like sensors for human motion monitoring.

Dispersion stability and thermophysical properties of microencapsulated phase change material slurry for liquid desiccant dehumidification

The dispersion stability and the thermophysical properties of the microencapsulated phase change material slurry (MPCMS) for liquid desiccant dehumidification were investigated experimentally. The results show that, the dispersion stability of the MPCMS can be improved greatly by adding surfactant. The maximum absorbency of MPCMS with polyoxyethylene sorbitan monooleate (Tween80) is 4.1 times that of MPCMS with cetyltrimethyl ammonium bromide (CTAB). The monolayer adsorption model is suitable for predicting the optimal mass content of surfactant with the maximum relative error of 13.3%. The thermal conductivity of MPCMS is lower than that of the base fluid and decreases with the increasing MicroPCMs concentration, when the mass fraction of MicroPCMs increases from 0% to 2.0% at the temperature of 20 °C and 40 °C, the thermal conductivity decreases by 25% and 14.8%, respectively. When the mass concentration of MicroPCMs is lower than 1.0%, the thermal conductivity of MPCMS keeps increase with the temperature rise. While the mass concentration of MicroPCMs ranges from 1.0% to 2.0%, the thermal conductivity of MPCMS increases firstly and then declines gradually. Moreover, an improved interfacial layer based thermal conductivity calculation correlation was proposed, in which the influence of temperature and concentration of MPCMS were considered, the maximum deviation and mean deviation between the calculated value and the experimental one are 5.62% and 1.85%, respectively. In the range of phase transformation temperature, the specific heat capacity of the slurry can be significantly improved by the MicroPCMs, the maximum specific heat capacity of the MPCMS reaches 2.3 times that of the pure lithium chloride aqueous solution. In addition, the effect of the mass concentration of MicroPCMs on the specific heat capacity is much greater than that of the temperature and the mass concentration of LiCl. The findings provide experimental foundation and guidance for the practical application of MPCMS in liquid desiccant dehumidification.

Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis.

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

Simulation of direct contact membrane distillation regeneration of liquid desiccant solutions used in air-conditioning

Membrane distillation (MD) has great potential for the treatment of hyper saline waters, including liquid desiccant solutions used in air-conditioning systems. Previous experimental investigations have demonstrated the technical feasibility of MD for regeneration of liquid desiccant solutions. In this study, a direct contact membrane distillation (DCMD) process of the LiCl liquid desiccant solution was simulated using MATLAB software. The simulation was first validated using data obtained from experimental tests. Then, it was used to elucidate the water temperatures, LiCl concentration, and water flux profiles along the membrane leaf inside the DCMD membrane module. Finally, with the help of the simulation, the effects of membrane properties and process operating conditions on the DCMD process performance were systematically examined. The results obtained from this simulation enrich the knowledge and hence facilitate the realization of MD for the liquid desiccant solution regeneration application.

Chitin Hydrogels Prepared at Various Lithium Chloride/N,N-Dimethylacetamide Solutions by Water Vapor-Induced Phase Inversion

Chitin was chemically extracted from crab shells and then dissolved in N,N-dimethylacetamide (DMAc) solvent with lithium chloride (LiCl) at 3, 5, 7, and 10%. The concentrated chitin-DMAc/LiCl solutions were used for the preparation of chitin hydrogels by water vapor-induced phase inversion at 20°C. The coagulation process was investigated while altering the concentration of LiCl in the DMAc solution. The shear viscosity of the chitin solution increased with higher LiCl amounts and decreased when the concentration of LiCl was reduced by adding water to the chitin solution, implying high LiCl concentration delayed the coagulation of chitin solution in the presence of water. The viscoelasticity of the chitin solutions indicated the gel formation intensification was dependent on the dose of LiCl and chitin in the DMAc solution. After the chitin solution was coagulated, the resultant hydrogels had water contents of 387–461% and the tensile strength varied from 285 to 400 kPa when the concentration of LiCl in the hydrogel was adjusted to 3% and 7%, respectively. As for viscoelasticity, the complex modulus of the chitin hydrogels indicated that the increment of the LiCl concentration up to 7% formed the tight hydrogels. Atomic force microscopic (AFM) image revealed the formation of the entanglement network and larger domains of the aggregated chitin segments. However, the hydrogel prepared at 10% LiCl in DMAc solution exhibited weak mechanical properties due to the loose hydrogel networking caused by the strong aggregation of the chitin segments.