Concentrated Salt Solutions Research Articles

Comparative Effect of Physiological Salts upon Micellization of T1304 and T1307.

We present a comprehensive investigation on the interaction of tetronics (T1304 and T1307) with some important physiological salts (NaH2PO4, KH2PO4, Na2CO3, NaCl, and KI). Thermodynamic and microstructural aspects of these interactions were studied as a function of the solution temperature, pH and salt concentration. Characterizations were performed using turbidimetric, calorimetric, and scattering techniques. We show that, at ambient temperature, T1304 molecules aggregated to form spherical core-shell aggregates displaying a unimodal distribution pattern. On the other hand, unimers and large clusters dominated in the case of highly hydrophilic T1307. Its micellization was promoted in the presence of salts as per the following trend: NaCl < KH2PO4 < NaH2PO4 ≪ Na2CO3. Aggregation was found to be endothermic, and hydrophobic interactions (TΔSmic > ΔHmic) prevailed. The enthalpy-entropy compensation plot was found to be linear for both copolymers. Demicellization occurred in the presence of KI as it facilitated the buildup of water structures around the copolymer chains. This could be verified from the increase in the cloud point, critical micelle concentration, and free energy. Overall, the temperature and salts inflicted a stronger hydrophobic effect upon T1304 in comparison to T1307.

Study on CAT activity of tomato leaf cells under salt stress based on microhyperspectral imaging and transfer learning algorithm

Salt stress easily leads to oxidative stress and promotes the catalase (CAT) response in tomato leaves. For the changes in catalase activity in leaf subcells, there is a need for a visual in situ detection method and mechanism analysis. This paper, taking catalase in leaf subcells under salt stress as the starting point, describes the use of microscopic hyperspectral imaging technology to dynamically detect and study catalase activity from a microscopic perspective, and lay the theoretical foundation for exploring the detection limit of catalase activity under salt stress. In this study, a total of 298 microscopic images were obtained under different concentrations of salt stress (0 g/L, 1 g/L, 2 g/L, 3 g/L) in the spectral range of 400–1000 nm. With the increase in salt solution concentration and the advancement of the growth period, the CAT activity value increased. Regions of interest were extracted according to the reflectance of the samples, and the model was established by combining CAT activity. The characteristic wavelength was extracted by five methods (SPA, IVISSA, IRFJ, GAPLSR and CARS), and four models (PLSR, PCR, CNN and LSSVM) were established according to the characteristic wavelengths. The results show that the random sampling (RS) method was better for the selection samples of the correction set and prediction set. Raw wavelengths are optimized as the pretreatment method. The partial least-squares regression model based on the IRFJ method is the best, and the coefficient of correlation (Rp) and root mean square error of the prediction set (RMSEP) are 0.81 and 58.03 U/g, respectively. According to the ratio of microarea area to the area of the macroscopic tomato leaf slice, the Rp and RMSEP of the prediction model for the detection of microarea cells are 0.71 and 23.00 U/g, respectively. Finally, the optimal model was used for quantitative visualization analysis of CAT activity in tomato leaves, and the distribution of CAT activity was consistent with its color trend. The results show that it is feasible to detect the CAT activity in tomato leaves by microhyperspectral imaging combined with stoichiometry.

Optically induced electrothermal microfluidic tweezers in bio-relevant media

Non-contact micro-manipulation tools have enabled invasion-free studies of fragile synthetic particles and biological cells. Rapid electrokinetic patterning (REP) traps target particles/cells, suspended in an electrolyte, on an electrode surface. This entrapment is electrokinetic in nature and thus depends strongly on the suspension medium’s properties. REP has been well characterized for manipulating synthetic particles suspended in low concentration salt solutions (~ 2 mS/m). However, it is not studied as extensively for manipulating biological cells, which introduces an additional level of complexity due to their limited viability in hypotonic media. In this work, we discuss challenges posed by isotonic electrolytes and suggest solutions to enable REP manipulation in bio-relevant media. Various formulations of isotonic media (salt and sugar-based) are tested for their compatibility with REP. REP manipulation is observed in low concentration salt-based media such as 0.1× phosphate buffered saline (PBS) when the device electrodes are passivated with a dielectric layer. We also show manipulation of murine pancreatic cancer cells suspended in a sugar-based (8.5% w/v sucrose and 0.3% w/v dextrose) isotonic medium. The ability to trap mammalian cells and deposit them in custom patterns enables high-impact applications such as determining their biomechanical properties and 3D bioprinting for tissue scaffolding.

Three-phase partitioning constructed by pH-responsive deep eutectic solvents and sugars for purification of radish (Raphanus sativus L.) peroxidase

Ammonium sulfate and t-butanol are widely used in conventional three-phase partitioning (TPP); however, their use is not eco-friendly. In this study, a novel TPP was developed using pH-responsive deep eutectic solvents (DESs) and sugars as substitutes for t-butanol and ammonium sulfate, respectively. This TPP was further used for the separation and purification of radish (Raphanus sativus L.) peroxidase (POD). DES-3 (dodecanoic acid: decanoic acid = 1:1) and sucrose were selected as optimal phase-forming components. Single-factor experiments were performed to investigate the factors influencing the TPP process, and three major factors (sucrose concentration, extraction time, and extraction temperature) were optimized by response surface methodology (RSM). Under the optimized conditions, the POD recovery and purification fold reached 101.66% and 11.56, respectively. Cyclic experiments confirmed the retrievability of DESs. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the novel TPP had better purification efficiency than the traditional TPP. The method proposed in this study is more efficient than conventional TPP, and it does not require the use of organic solvents and high concentration salt solutions. Therefore, this method is promising in the application of TPP.

Extreme Water Uptake of Hygroscopic Hydrogels through Maximized Swelling-Induced Salt Loading.

Hygroscopic hydrogels are emerging as scalable and low-cost sorbents for atmospheric water harvesting, dehumidification, passive cooling, and thermal energy storage. However, devices using these materials still exhibit insufficient performance, partly due to the limited water vapor uptake of the hydrogels. Here, the swelling dynamics of hydrogels in aqueous lithiumchloride solutions, the implications on hydrogel salt loading, and the resulting vapor uptake of the synthesized hydrogel-salt composites are characterized. By tuning the salt concentration of the swelling solutions and the cross-linking properties of the gels, hygroscopic hydrogels with extremely high salt loadings are synthesized, which enable unprecedented water uptakes of 1.79 and 3.86gg-1 at relative humidity (RH) of 30% and 70%, respectively. At 30% RH, this exceeds previously reported water uptakes of metal-organic frameworks by over 100% and of hydrogels by 15%, bringing the uptake within 93% of the fundamental limit of hygroscopic salts while avoiding leakage problems common in salt solutions. By modeling the salt-vapor equilibria, the maximum leakage-free RH is elucidated as a function of hydrogel uptake and swelling ratio. These insights guide the design of hydrogels with exceptional hygroscopicity that enable sorption-based devices to tackle water scarcity and the global energy crisis.

ENERGY- AND RESOURCE-SAVING PROCESSES INVOLVING THE POLYMER PHASE

The paper deals with the processes of application and production of various polymer materials. By coating the surface of mineral fertilizer granules with hydrophobic polymer films, fertilizers with controlled release of nutrient components were obtained. Such fertilizers can prevent the leaching of nutrients, prevent the negative impact on the environment and reduce fertilizer consumption. Methods for calculating the particle distribution function by the degree of coating characterizing the uniformity of coating on fluidized bed particles for stationary and non-stationary modes of operation of the apparatus are considered. The process of applying a thick composite coating to the surface of urea granules in a pan granulator was also investigated. A simple method for calculating the size distribution of the obtained granules with a composite shell is proposed. The actual problem of developing a method for predicting the kinetics of nutrient release from polymer-coated fertilizer granules based on a fairly simple mathematical model of the process has been solved. Studies of the combined polymerization and drying process in the synthesis of polyacrylamide and sodium methacrylate copolymer with methacrylic acid amide have shown that its use at the final stage of obtaining water-soluble acrylic polymers is very effective. This technique allows to reduce the total time of the technological cycle. The process of obtaining polyethylene powder by the method of elastic-deformation grinding of polymer gel and a two-stage process of solvent removal from polymer powder with the return of the solvent to the technological cycle has been developed. The rational technological parameters of the electrodialysis process of contaminated steam condensate of mineral fertilizers plant have been identified, which allows to obtain a more concentrated salt solution, which is used as a secondary raw material, as well as a desalinated solution used as process water. For citation: Lipin A.G., Lipin A.A. Energy- and resource-saving processes involving the polymer phase. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 7. P. 203-213. DOI: 10.6060/ivkkt.20236607. 6836j.

3D-printed tripodal porous wood-mimetic cellulosic composite evaporator for salt-free water desalination

Solar desalination based on interfacial evaporation has been proven promising in producing clean water. However, so far, the lack of a facile preparation strategy and effective salt rejection has profoundly limited its potential for practical applications. Herein, inspired by the unique liquid transportation of natural wood, we report on a three-dimensional (3D) printed tripodal porous wood-mimetic cellulosic composite evaporator for long-term salt rejection, starting from cost-effective materials such as cellulose and carbon black. The printed evaporator displays a broadband solar absorption (>97%) and an extremely low thermal conductivity (0.075 W m−1 K−1), indicating its high photothermal conversion efficiency and outstanding thermal management. The printed tripodal porous evaporator contains large-sized channels (∼1 mm in diameter) that function as salt regenerating pathways, micropores (∼30 μm) and submicron pores (∼1 μm) for rapid water transport and efficient supply. Fluidic simulation reveals that large channels with high water flux lead to the salt concentration gradient between large and small channels via submicropores, meanwhile, the concentrated water at the top layer transports downward by diffusion and convection, further making the spontaneous horizontal and vertical salt exchange. Such a tripodal porous structure endows the evaporator with a high efficiency of ∼75% in a highly concentrated salt solution (15 wt% NaCl) under 1 sun irradiation, as well as superior salt-rejection property (100 h continuous evaporation in 15 wt% NaCl). This strategy, starting with sustainable cellulose-based composite materials and being able to balance the evaporation performance and long-term stability, opens up new doors toward clean water production.

Solid Phase Extraction Penicillin and Tetracycline in Human Serum Using Magnetic Graphene Oxide-Based Sulfide Nanocomposite

Herein, we report a procedure for separating and preconcentrating antibiotics from human serum using a novel adsorbent of magnetic graphene oxide (MGO) and cadmium sulfide (CdS) nanoparticles. The adsorbent (MGO@CdS) was characterized using Fourier transformed infrared spectrometry (FT-IR), energy dispersive X-ray spectroscopy (EDX), and field emission scanning electron microscopy (FE-SEM). The effective parameters for extraction efficiency were investigated, including the desorption solvent’s nature, pH, adsorbent dose, salt concentration, extraction time, and volume of sample solution and desorption solvent. The proposed procedure proved to be fast (20 min), simple (two stages), and cost-effective (20 mg of nanoparticles). Under the optimum conditions, satisfactory linearity (R2 &gt; 0.992) was obtained, and limits of detection (LOD) were estimated as 4.5 µg L−1 (for tetracycline) and 5.7 µg L−1 (for penicillin) and a linear dynamic range (LDR) from 20 to 200 µg L−1. The magnetic solid phase extraction (MSPE) method based on MGO@CdS has achieved a satisfactory recovery (71.5–109.5%) in human serum for the selected antibiotics. Finally, the antibiotic’s release was studied in simulated fluids of the gastric (pH = 1.2) and intestine (pH = 7.4). In this light, we demonstrate that the newly introduced adsorbent can be used in drug extraction from different biological media.

OBTAINING AN EMULSIFIER OF INVERSE EMULSIONS WITH A CORROSION INHIBITOR PROPERTIES

Reverse emulsions are widely used in oil production processes; moreover, due to a number of unique properties, they are used both in drilling and in killing wells, and for leveling the injectivity profile, as well as in repair and isolation works as a liquid packer. Most industrial emulsifiers belong to the class of fatty acid amides derived from natural and synthetic carboxylic acids and amines (primary and secondary) or amino alcohols. Given that many technological operations, such as killing with concentrated salt solutions (reverse emulsions are used as blocking fluids), treatment of the bottomhole zone with acid compositions (reverse emulsions are used as an acid diverter), are accompanied by intense corrosion of metal equipment and require additional costs for corrosion inhibition, we set ourselves the goal of developing an invert emulsifier with corrosion inhibitor properties. Using rapeseed oil and 2-[(2-aminoethyl)amino]ethanol as the initial compounds of the catalytic reaction under the action of alkali, amidoamine was obtained, which has the properties of an emulsifier of reverse emulsions and a corrosion inhibitor. Synthesis conditions are described and proof of the structure of the resulting compound is given. Its surface-active properties, emulsifying ability, as well as inhibitory activity under conditions of carbon dioxide corrosion were determined.

Polyelectrolyte Brush Interacting with Ampholytic Nanoparticles as Coarse-Grained Models of Globular Proteins: Poisson-Boltzmann Theory.

The self-consistent field Poisson-Boltzmann framework is applied to analyze equilibrium partitioning of ampholytic nanoparticles (NPs) between buffer solution and polyelectrolyte (PE) polyanionic brush. We demonstrate that depending on pH and salt concentration in the buffer solution, interactions between ionizable (acidic and basic) groups on the NP surface and electrostatic field created by PE brush may either lead to the spontaneous uptake of NPs or create an electrostatic potential barrier, preventing the penetration of NPs inside PE brush. The capability of PE brush to absorb or repel NPs is determined by the shape of the insertion free energy that is calculated as a function of NP distance from the grafting surface. It is demonstrated that, at a pH value below or slightly above the isoelectric point (IEP), the electrostatic free energy of the particle is negative inside the brush and absorption is thermodynamically favorable. In the latter case, the insertion free energy exhibits a local maximum (potential barrier) at the entrance to the brush. An increase in pH leads to the shallowing of the free energy minimum inside the brush and a concomitant increase in the free energy maximum, which may result in kinetic hindering of NP uptake. Upon further increase in pH the insertion free energy becomes positive, making NP absorption thermodynamically unfavorable. An increase in salt concentration diminishes the depth of the free energy minimum inside the brush and eventually leads to its disappearance. Hence, in accordance with existing experimental data our theory predicts that an increase in salt concentration suppresses absorption of NPs (protein globules) by PE brush in the vicinity of IEP. The interplay between electrostatic driving force for NP absorption and osmotic repelling force (proportional to NP volume) indicates that for large NPs with relatively small number of ionizable groups osmotic repulsion overcomes electrostatic attraction preventing thereby absorption of NPs by PE brush.

Effects of Aging and Immersion on the Healing Property of Asphalt-Aggregate Interface and Relationship to the Healing Potential of Asphalt Mixture.

The self-healing ability of asphalt-aggregate bonding interfaces can maintain the mechanical properties of asphalt mixtures. However, the interface's healing ability will also be affected by moisture and aging. In order to clarify the influence of moisture and aging on the healing ability of a bonding interface, the effects of healing period and temperature on the self-healing level of interfacial strength were measured. The healing master curve of the strength was established. Thereafter, the effects of soaking time, salt solution concentration, and thermal aging on the healing degree of interfacial strength were measured. Based on digital image processing technology and the meso-finite element method, the influence of the interface on the healing performance of the mixture was simulated and analyzed, which was then verified by the beam bend healing test. The results show that the healing index of bonding strength increases with the ascent of healing temperature and period. Healing index gradually decreases with the extension of soaking period, and the higher the concentration of salt in the solution, the worse the healing performance of interfacial strength. After asphalt aging, the healing potential of the interface is weakened. There is a good linear relationship between the healing level of an asphalt-aggregate interface and the level of strength and fracture energy of the mixture. However, the actual healing level of an asphalt mixture is obviously lower than that of the interface, due to the addition of mineral filler. This paper provides a method for predicting the recovery performance of asphalt pavement.

EFFECTS OF WATER, KOH, HCl AND IONIC STRENGTH ON SWELLING CAPACITY OF CARBOXYMETHYL CELLULOSE (CMC) BASED GRAFT COPOLYMER HYDROGEL

Hydrogels are three-dimensional crosslinked polymers with several uses in the administration and loading of drugs as well as the capacity to hold enormous amounts of water or biological fluids. Using carboxymethyl cellulose, N,N-dimethyl acrylamide (DMA), 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS), N,N-bisacrylamide (MBA) as a crosslinker, and potassium persulate (KPS) as an initiator, the CMC-g-poly(DMA-co-AMPS) was created. FTIR spectroscopy was used to characterize the CMC-g-poly(DMA-co-AMPS). In distilled water, KOH, and HCl, the CMC-g-poly(DMA-co-AMPS)'s swelling capability was assessed. CMC-g-poly(DMA-co-AMPS has the largest swelling ratio in KOH, followed by HCl, while pure water has the lowest swelling ratio. Various salt solutions (FeCl3.6H2O, CuCl2, and NaCl) were used at predetermined times in distilled water to test the effect of ionic strength on CMC-g-poly(DMA-co-AMPS). The swelling of CMC-g-poly(DMA-co-AMPS) increased with the increase in salt solution concentration, and the ionic strength of a solution is the measure of the concentration of ions in salt solutions. In salt solutions (CuCl2, NaCl, and FeCl3.6H2O), the maximal swelling ratio of CMC-g-poly(DMA-co-AMPS) is 10.5g, 10.0g, and 9.5g, respectively.

Effects of Sodium Bicarbonate Stress on Seed Germination and Seedling Growth of Mustard (Brassica campestris L.)

Numerous stresses cause negative impacts on crops and salinity-alkalinity plays a significant role in these stresses that harm the crops and their production. Sodium bicarbonate is an alkaline salt that also affects crops. The present experiment was performed to study the impacts of seed germination and early seedling growth of mustard under various NaHCO3 salt treatments. This experiment was a completely randomized design, and seeds of mustard were sown in petridishes lined with Whatman No. 1 filter paper in triplicates. Different concentrations (0, 2.5, 5.0, 7.5, and 10.0 mM) of NaHCO3 salt solution were used to moisten the filter papers. The control (0 mM) treatment was applied using distilled water. The seedlings were measured on the fourteenth day of sowing. The outcomes demonstrated that the germination percentage declined significantly at sodium bicarbonate salt treatments (5.0, 7.5, and 10.0 mM), while the % DFC for germination was found to be increased with increasing salt levels. In various salt (2.5, 5.0, 7.5, and 10.0 mM) concentrations, there was a significant reduction got in seedling growth, as assessed by the seedling vigor index, length of seedlings, and fresh weight of seedlings. The percentage of phytotoxicity increased while the tolerance index dropped with salt treatments. The dry weight of shoot and whole seedlings was also inhibited significantly by salt treatments (2.5, 5.0, 7.5, and 10.0 mM), and root dry weight got a significant reduction at (5.0, 7.5, and 10.0 mM) levels of salt treatments.

Materials and Corrosion in Seawater Reverse Osmosis Plants: A Review

Desalination is emerging as one of the most promising solutions to extraction and increasing global demand for drinking water. A water purification process called reverse osmosis (RO), in which dissolved solids are separated from solutions by partially permeable membranes. Advances in membrane technology have resulted in the removal of up to 99% of salts in seawater. However, the process and system of seawater treatment RO are associated with many problems, such as scaling and fouling of the membranes, corrosion of the pumps, valves and piping system due to the highly concentrated salt solution and high chemical consumption. Nowadays, these problems have become very critical as they severely affect the desalination process and also massively deteriorate the performance and lifetime of the system components and materials. To ensure that the desalination process is always the best option for a low-maintenance, highly efficient and cost-effective system and process, a comprehensive study of these problems is essential. Therefore, this article addresses the characteristics of metallic materials and corrosion problems in the reverse osmosis process of seawater desalination, as well as the best solutions to focus on and evaluate for an optimal seawater desalination process, and the selection of the category of duplex stainless steels suitable for seawater desalination plants to reduce maintenance, avoid plant shutdown and ensure plant safety.

DETERMINATION OF THE QUALITATIVE INFLUENCE OF FACTORS ON THE SENSITIVITY OF THE CAPACITIVE HUMIDITY SENSOR OF A TWO-LAYER STRUCTURE BASED ON MULTIFACTOR DISPERSION ANALYSIS

A multifactorial dispersion analysis was applied in order to qualitatively assess the influence of the following factors: thickness of the moisture-sensitive layer; the thickness of the polymer coating as a protective layer; the concentration of the NaCl salt solution as an adsorbent material and their combined effect on the sensitivity of the capacitive humidity sensor of the two-layer structure. Capacitive humidity sensors of a two-layer structure, made on a sitall substrate, served as experimental samples. The copper film, which forms the covers of the capacitive humidity sensors, is applied to the surface of the sitall substrate in the form of a meander. In the developed design, the moisture-sensitive layer is hygroscopic salt, which performs the function of a dielectric. A moisture-absorbing film of polymethylmethacrylate serves as a protective layer. A multifactorial plan is developed for the case of three qualitative factors. Using multifactorial dispersion analysis, it was proved that the response of the model, that is, the sensitivity of the capacitive humidity sensor of the two-layer structure, is influenced by such factors as the thickness of the protective layer, the concentration of the NaCl salt solution, as well as the combined effect of factors such as the thickness of the moisture-sensitive layer + the concentration of the salt solution; the thickness of the protective layer + concentration of the salt solution. That is, the difference in the response values of the model is related to the change in the value of the factor and cannot be caused only by its random nature. However, the response of the model is significantly affected by the combined effect of the factor − the thickness of the protective layer + the concentration of the salt solution. In this case, the value of Fisher’s criterion, which is observed in the experiment, significantly exceeds the critical value of Fisher’s criterion F &gt;Fkr (13.01&gt;4.49). The influence of such factors as the thickness of the moisture-sensitive layer; the thickness of the moisture-sensitive layer + the thickness of the protective layer; the thickness of the moisture-sensitive layer + the thickness of the protective layer + the concentration of the salt solution is insignificant, that is, the difference in the response values of the model is due to its random nature. Using the dispersion analysis of the influence of the factor, it was proved that the sensitivity of capacitive humidity sensors is affected not only by the concentration of the NaCl salt solution, which was used to create a moisture-sensitive layer, but also by the design of the sensor.

Novel double staining of the stratum corneum with fluorescent ε-poly-l-lysine and anionic dextran.

ε-Poly-l-lysine (PLL) is a cationic polymer consisting of 25-35l-lysine residues. Our previous study revealed that fluorescently labelled PLL can stain the stratum corneum (SC) via ionic interactions between PLL and SC constituents. In this study, to further clarify the mechanisms underlying the interaction between PLL and the SC, the staining properties of fluorescent PLL were compared with that of fluorescently labelled anionic dextran (aDex), which has approximately the same molecular weight as PLL. SC samples were collected by non-invasive tape stripping and stained with fluorescent PLL and/or fluorescent aDex. Fluorescence images were acquired using a fluorescence microscope and then analysed. The SC could be stained with either fluorescent PLL or aDex, both of which were inhibited by the addition of high concentrations of salt solutions. In particular, aDex staining was inhibited at a lower salt concentration than PLL staining. Moreover, PLL staining was inhibited under acidic conditions, while aDex staining was inhibited under neutral to alkaline conditions. Double staining of SC with both fluorescent polymers produced heterogeneous staining patterns: corneocytes stained with both polymers, corneocytes stained with PLL or aDex in a mutually exclusive manner, and unstained corneocytes. Staining of SC samples from the face was more extensive than staining of SC samples from the inside of the upper arm with both polymers. In addition, pretreatment of the SC with ethanol resulted in enhanced staining with both polymers. These results suggest that double staining of SC with both polymers can provide information on the damaged SC. Staining of SC with fluorescent PLL depends on its properties of a cationic and hydrophobic polymer with appropriate molecular size, which can distinguish the damaged SC. Double staining of SC with fluorescent PLL and aDex is a novel approach to obtain information for the analysis of skin conditions.

Construction of layered double hydroxides on wood surfaces for wood coloring

Wood dyeing usually requires a large concentration of metal solution, which when released to the atmosphere as waste liquid, causes pollution. In this study, a metal-organic framework (MOF) with micron-size structure was in-situ grown on a wood surface as a template and precursor for a layered double hydroxide (LDH). The LDH had a nanoscale structure and was generated on the wood surface from ultra-low concentration NiCl2 solution. The generation was based on a hydrolytically induced exchange process between the MOF and hydroxide ions. The results of following this procedure showed that petal-like Co/Ni-LDH with micro-nano composite structure was formed on the wood surface. Due to the LDH, a uniform light green color was formed on the wood surface at a reaction temperature and time of 60 ℃ in 34 min, respectively. To improve the hydrophobicity of the LDH layer, a long chain alkyl with low surface energy was introduced into the lamellae from a sodium stearate solution, constructing a superhydrophobic layer on the wood surface. The modified wood surface showed excellent UV light aging and water resistances. Moreover, Ni2+ was replaced with Mn2+, Fe3+, Cu2+, and Zn2+ ions and dark brown, yellow, blue, and white colors, respectively, were formed on wood. The present method is also suitable for other wood. Wood surface color adjusted by LDH uses low concentration of metal salt solution and proved to be a mild and green wood color toning method.

Marine oil spill remediation by Candelilla wax modified coal fly ash cenospheres

Biodegradable candelilla wax (CW) was creatively used for hydrophobic modification of coal fly ash cenospheres (FACs), a waste product from thermal power plants, and a new spherical hollow particulate adsorbent with fast oil adsorption rate and easy agglomeration was prepared. CW was confirmed to physically coat FACs and the optimum mass of wax added to 3 g of FACs was 0.05 g. From a series of batch scale experiments, CW-FACs were found to adsorb oil, reaching adsorption efficiency of 80.6% within 10 s, and aggregate into floating clumps which were easily removed from the water's surface. The oil adsorption efficiency was highly dependent on hydrophobicity of the used adsorbent, the adsorption of Venezuela oil onto CW-FACs was found to be a homogenous monolayer, and the capacity and intensity of the adsorption decreased as temperature increased from 10 to 40 °C. The Langmuir isotherm model was the best fit, with the maximum adsorption capacity achieved at 649.38 mg/g. CW-FACs were also found to be highly stable in concentrated acid, alkaline and salt solutions, as well as for spills of different oil products. Furthermore, the retention rate of the oil adsorption capacity of the CW-FACs after 6 cycles of adsorption-extraction was as high as 93.2%. Therefore, CW-FACs can be widely used, easily recycled, and reused for marine oil spill remediation, which is also a good alternative disposal solution for FACs.

Vacuum Impregnation of Ascorbic Acid and Calcium Lactate Improves Quality Attributes and Functionality of White Button Mushrooms

Ascorbic acid (1% w/w) and calcium lactate (1% w/w) were vacuum impregnated into mushrooms to improve their physicochemical quality. Experiments were carried out using central composite design under response surface methodology with four independent variables, viz., solution temperature (ST) (35-55°C), salt concentration (SC) (4-12%), vacuum pressure (VP) (50-170 mbar), and immersion time (IT) (30-90 min) with constant solution to sample ratio (4 : 1). The ascorbic acid content of mushroom increased with vacuum pressure with a maximum content of 30.68 mg/100 g. The results also suggested that calcium lactate allowed a better maintenance of texture during storage. The optimum conditions obtained for vacuum impregnation (VI) were 41°C, 10%, 140 mbar, and 75 min of solution temperature, salt concentration, vacuum pressure, and immersion time, respectively. Under these conditions, the corresponding responses were 22.14%, 2.31%, 28.74 mg/100 g, 0.28%, 4.61, 9.85 N, and 5.37 of water loss, solute gain, ascorbic acid, titratable acidity, colour change, texture, and pH, respectively. The vacuum impregnated mushrooms had more firmness, soluble solids, and ascorbic acid content than the control group. Therefore, the result suggested that vacuum impregnation could be used as an effective and simple technique to improve the quality of mushroom.

Facile Preparation of Large‐Sized Columnar α‐HH Crystal via a NaCl Salt Bath Method

AbstractAlpha high‐strength hemihydrate gypsum (CaSO4·0.5H2O, α‐HH) with a large‐size columnar crystal (average size: 135.31 µm, maximum size: 500 µm) is successfully prepared via a NaCl salt bath method using salt gypsum as a raw material. The effects of preparation condition (salt solution concentration, salt bath time) on the crystalline phase and crystal grain size of the α‐HH and on the strengths of the cement bulks from α‐HH are investigated. Furthermore, to explore the formation mechanism of the large‐size columnar crystal of the α‐HH, the samples obtained by varying the salt bath time of the reaction system are characterized with field‐emission scanning electron microscopy, X‐ray diffraction, and laser particle size analysis. Based on the characterization results, a formation mechanism of the large‐sized α‐HH is proposed. That is, NaCl self‐diffusion creates a local high‐concentration salt solution environment, which is conducive to the recombination of small‐size HH crystals formed by dihydrate gypsum dissolution and HH recrystallization to grow into large‐sized α‐HH crystals.