Increasing Salt Concentration Research Articles

Antipolyelectrolyte Response of Amphiphilic Sulfobetaine Polymer Coatings

AbstractZwitterionic, amphiphilic polymer coatings are an effective strategy to decrease biofouling. Yet their performance strongly depends on the mechanical properties, the degree of swelling, and the structure of the swollen hydrogels. These properties depend on the zwitterionic groups in the polymers and the properties of the surrounding electrolyte. Therefore, the influence of the ions present and their concentrations on the swelling behavior of amphiphilic zwitterionic copolymers is studied. Coatings of 3‐[N‐2′‐(methacryloyloxy)ethyl‐N,N‐dimethyl]‐ammoniopropane‐1‐sulfonate (SPE) with increasing amounts of butyl‐methacrylate (BMA) are compared to the respective homopolymers PSPE and PBMA. Surface plasmon resonance spectroscopy shows a salt concentration‐dependent anti‐polyelectrolyte behavior. A variation of the salts revealed that the anions dominated the swelling response, while a change of cations has hardly any effect. Small angle X‐ray scattering reveals the morphological changes in the polymer films that accompanied the swelling. With increasing salt concentration, the internal structure changed from compact pores in a gel‐like network to elongated cylindrical pores at higher salinities. The understanding gained from the presented multi‐technique approach allows to understand the behavior of zwitterionic coatings in saline solutions and helps to tailor the swelling response and mechanical properties for future marine and medical low‐fouling applications.

Ammonium hydrosulfide (NH_4SH) as a potentially significant sulfur sink in interstellar ices

Sulfur is depleted with respect to its cosmic standard abundance in dense star-forming regions. It has been suggested that this depletion is caused by the freeze-out of sulfur on interstellar dust grains, but the observed abundances and upper limits of sulfur-bearing ices remain too low to account for all of the missing sulfur. Toward the same environments, a strong absorption feature at sim 6.85 mu m is observed, but its long-standing assignment to the NH$_ $ cation remains tentative. We aim to spectroscopically investigate the plausibility of NH$_ $SH salt serving as a sulfur reservoir and a carrier of the 6.85 mu m band in interstellar ices by characterizing its IR signatures and apparent band strengths in water-rich laboratory ice mixtures. We then use this laboratory data to constrain NH$_ $SH abundances in observations of interstellar ices. Laboratory transmission IR spectra of NH$_ $:H$_ $S ice mixtures both with and without H$_ $O were collected. The apparent band strengths of the NH$_ $ asymmetric bending ($ $) mode and the SH$^ $ stretching mode in H$_ $O-containing mixtures were calculated with Beer's law plots. The IR features of the laboratory salts were compared to those observed toward a sample of four protostars (two low-mass, two high-mass) and two cold dense clouds without star formation. Apparent band strengths ranging from 3.2(pm 0.3)-3.6(pm 0.4)times 10$^ $ cm molec$^ $ and 3.1(pm 0.4)-3.7(pm 0.5)times 10$^ $ cm molec$^ $ are calculated for the NH$_ $ mode at sim 6.8 mu m/1470 cm$^ $ and the SH$^ $ stretching mode at sim 3.9 mu m/2560 cm$^ $, respectively, in NH$_ $SH:H$_ $O mixtures. The peak position of the NH$_ $ mode redshifts with increasing temperature but also with increasing salt concentration with respect to matrix species H$_ $O and NH$_ $. The observed 6.85 mu m feature is fit well with the laboratory NH$_ $SH:H$_ $O ice spectra. NH$_ $ column densities obtained from the 6.85 mu m band range from 8-23<!PCT!> with respect to H$_ $O toward the sample of protostars and dense clouds. These column densities are consistent with the optical depths observed at 3.9 mu m (the SH$^ $ stretching mode spectral region). A weak and broad feature observed at sim 5.3 mu m/1890 cm$^ $ is tentatively assigned to the combination mode of the NH$_ $ mode and the SH$^ $ libration. The combined upper limits of four other counter-anion candidates, OCN$^ $, CN$^ $, HCOO$^ $, and Cl$^ $, are determined to be lesssim 15-20<!PCT!> of the total NH$_ $ column densities toward three of the protostars. The redshift of the 6.85 mu m feature correlates with higher abundances of NH$_ $ with respect to H$_ $O in both the laboratory data presented here and observational data of dense clouds and protostars. The apparent band strength of the SH$^ $ feature is likely too low for the feature to be detectable in the spectrally busy 3.9 mu m region, but the 5.3 mu m NH$_ $ + SH$^ $ R combination mode may be an alternative means of detection. Its tentative assignment adds to mounting evidence supporting the presence of NH$_ $ salts in ices and is the first tentative observation of the SH$^ $ anion toward interstellar ices. If the majority (gtrsim 80-85<!PCT!>) of the NH$_ $ cations quantified toward the investigated sources in this work are bound to SH$^ $ anions, then NH$_ $SH salts could account for up to 17-18<!PCT!> of their sulfur budgets.

Study on solubility and solvation thermodynamics for the advancement of biorelevant activities of l-isoleucine and l-serine in aqueous ammonium chloride solutions in the temperature range of 288.15–308.15 K

This study investigated the dissolution behavior of l-isoleucine and l-serine in an aqueous salt solution (ammonium chloride), examining how variations in temperature and electrolyte concentration affect their solubility. We conducted careful experiments and used mathematical calculations to explore interactions at a molecular level. We observed that the structure of these amino acids and salt concentration in the aqueous medium influence their interactions, which affects dissolution. In the presence of electrolytes, l-isoleucine demonstrated a salting-out effect whereas l-serine showed a salting-in effect. This work examines the solute–solvent interactions of these solutes in aqueous ammonium chloride solutions. l-isoleucine exhibits a nonspontaneous reaction with increasing salt concentrations whereas l-serine shows spontaneous behavior. Gibbs free energy analysis revealed greater stability of l-serine. The pH and conductance measurements showed how these factors influence solution properties. This insight helps us comprehend the nature and behavior of these molecules in different situations, which could be helpful in drug formulation or protein purification in the future.

Irrigation of rangeland soils with coal seam water - A lysimeter study on soil physico-chemical properties

Groundwater extracted from coal seams may be a resource for irrigation of land in areas with low rainfall, but the effect of this water on soil properties needs to be established. A lysimeter study was conducted using intact soil cores (0.75 m diameter, 1.4 m deep) of four different soil types (Sodic Vertisol, Calcic Solonetz, Haplic Solonetz and Xanthic Lixisol) from southern Queensland, Australia, to study changes in soil physical and chemical properties under accelerated rates of irrigation with coal seam (CS) water (electrical conductivity (ECw) of 3 dS/m, pH of 8.8, and a sodium adsorption ratio (SAR) of 100). Cores were also alternately irrigated with deionised water to simulate rainfall, and either lucerne (Medicago sativa L) or Rhodes grass (Chloris gayana Kunth.) where grown in the lysimeters. The soil surface was treated with stoichiometric rates of elemental sulfur (1.4 t/ha) and gypsum (2.5 t/ha) prior to every 450 mm CS water irrigation to minimise changes in SAR and pH. Three of the soils (Vertisol, both Solonetz) had low leaching fractions (≤ 0.1 %) due to their clay texture and were initially saline in the subsoil (ECse 1.4–4.4 dS/m). Irrigation with CS water resulted in a gradual increase in salt content (EC) and SAR throughout the soil profile, but pH was not increased due to surface-applied elemental sulfur. The Lixisol had a higher hydraulic conductivity and leaching fraction (6.7 %) due to is loamy texture – in this soil, accumulated salts could be leached and no increase in salinity or pH were measured. Despite an increase in SAR for this loamy soil, no structural degradation was observed, and it could be sustainably irrigated with up to 3200 mm CS water (with cumulative irrigation volume of 5400 mm). Hence, leaching fractions rather than soil chemistry are good indicators to identify soils suitable for irrigation with CS water that is saline, alkaline, and sodic.

Cyanobacteria can benefit from freshwater salinization following the collapse of dominant phytoplankton competitors and zooplankton herbivores

Abstract Freshwater salinization is an increasing threat to lakes worldwide, but despite being a widespread issue, little is known about its impact on biological communities at the base of the food chain. Here we used a mesocosm set‐up coupled with modern high‐frequency sensor technology to identify short‐ and longer‐term responses of phytoplankton to salinization in an oligotrophic lake. We tested the effects of salinization over a gradient of increasing salt concentrations that can be found in natural lakes exposed to road salt contamination (added salt range: from 0 to 1500 mg Cl− L−1). The high‐frequency chlorophyll‐a (chl‐a) fluorescence measurements showed an increasing divergence of chl‐a concentrations along the salinization gradient over time, with substantially lower concentrations at higher salt levels. At the sub‐daily scale, we found a profound suppression of day–night signal cycles with increasing salinity, which could be related to physiological stress due to the impairment of photosynthesis via effects on the photosystem II or potential changes in the active migration of phytoplankton. Community analyses revealed a similar decline pattern for the total phytoplankton biomass and a collapse of the total zooplankton biomass. Interestingly, we found a loss of phytoplankton diversity coupled with a compositional re‐organization involving the loss of dominant green algae but increased biomass of salt‐tolerant cyanobacteria. Altogether, these results suggest that specific cyanobacterial taxa can benefit from freshwater salinization following the collapse of dominant phytoplankton competitors and zooplankton herbivores. The results also highlight the value of autonomous sensor technology to capture novel, small‐scale ecological responses to freshwater salinization, and thereby to track fast changes in primary producer communities.

Self-stratification and phase separation in drying binary colloidal films

HypothesisFilms that develop compositional heterogeneity during drying offer a promising approach for achieving tailored functionalities. These functionalities can be realized by strategically directing different components during the drying process. One approach to achieve this is through spontaneous size segregation of colloidal particles. Two variants thereof have previously been observed in binary suspensions: layer formation (self-stratification) due to kinetically driven concentration gradients, and micro-domain formation (phase separation) due to thermodynamic depletion interactions between the small and large species. Surprisingly, in the context of binary colloidal films, these phenomena have never been investigated concurrently during evaporation. ExperimentsWe show how we can achieve both self-stratification and domain formation in a single step. Using real-time 3D confocal fluorescence microscopy, we quantitatively unravel the effects of various parameters on the emergence of compositional heterogeneity. FindingsWe reveal that beyond a certain size ratio, micro-phase separation becomes a prominent mechanism dictating the final morphology. The initial volume fraction minimally affects the final domain size but significantly impacts self-stratification. Reducing the evaporation rate increases the domain size while minimizing stratification. Finally, reducing the colloidal electrostatic interaction by a small increase in salt concentration enhances phase separation yet reverses stratification. These findings unveil a strategy for harnessing two distinct size segregation mechanisms in a single film, forming a foundation for customizable self-partitioning coatings.

Elucidating the effects of hofmeister salts on the formation mechanism and biocompatibility of lysozyme-hyaluronic acid complexes

This study aimed to investigate the morphologies, biocompatibility, and formation mechanism of lysozyme-hyaluronic acid complexes in the presence of various Hofmeister salts. During the complexation of lysozyme (Lys) and hyaluronic acid (HA), salts can control the formation of colloidal nanoparticles, amyloid-like aggregates, and amorphous aggregates. Circular dichroism spectra revealed that the α-helix content of Lys involved in complexation significantly increased from 21.40 % to 34.19 %, whereas the β-sheet content significantly decreased from 38.65 % to 24.42 % with increasing salt concentration. The fluorescence spectra indicated that the number of binding sites for HA and Lys decreased from 2.19 to 0.63 as the salt concentration increased from 0 to 300 mM, which was consistent with the different anion-specific effects (NaCl < NaBr < NaI). Interestingly, in vitro experiment results demonstrated that colloidal nanoparticles and amorphous aggregates have good biocompatibility, with NCM460 cell viability exceeding 85.92 %, whereas amyloid like aggregates exhibit certain cytotoxicity, with cell viability significantly reduced to 50.47 %. Overall, these findings provide a better understanding of the conformational changes of Lys involved in complexation with HA in the presence of salts, expanding its application in the food and pharmaceutical industries.

Effect of succinonitrile on the structural, ion conductivity, and dielectric properties of PVDF‐HFP based solid polymer electrolytes

AbstractA detailed account of the poly(vinylidene difluoride‐co‐hexafluoropropylene) (PVDF‐HFP)/succinonitrile (SN)/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) based solid polymer electrolytes (SPEs) of various compositions is reported. SN is incorporated as plasticizer, while LiTFSI is employed as the source of lithium ions. Fourier transfer infrared (FTIR) spectroscopy reveals the formation of polar and electroactive γ crystal phase by PVDF in pristine PVDF‐HFP and the prepared SPE films. FTIR further confirms the interaction between the host polymer and the salt and between the salt and the plasticizer. The interaction between the salt and plasticizer suggests that SN not only offers the plasticization effect but also facilitates salt dissociation. The ion conductivity increases with increasing salt content up to 20 wt% but beyond that concentration a decline in ion conductivity is observed, which could be attributed to the ion pair association or cluster formation due to the excess salt concentration that reduces the availability of free ions and ultimately leads to the reduction in ion conductivity. After including SN in the SPE formulation, electrochemical impedance spectroscopy reveals a substantial increase in room temperature ion conductivity of the SPE from ~1.08 × 10−5 S cm−1 for pristine SPE with 20 wt% salt to ~2.7 × 10−4 S cm−1 for plasticized SPE with 40 wt% SN and 20 wt% salt. This is attributed to the plasticizing effect of SN that enhances ion mobility through the matrix and to the increased charge carrier concentration (SN facilities salt dissociation). The fabricated SPEs exhibit a significant enhancement in ion conductivity with increasing temperature and the maximum ion conductivity of 1.1 × 10−3 S cm−1 is attained at 393 K by plasticized SPE with 40 wt% SN content. The ion conductivity of all the prepared SPEs follows the temperature dependent Arrhenius behavior, suggesting the thermally activated ion hopping mechanism of ionic conduction. Further, the plasticized SPEs display near unity ion transference number indicating the predominance of the ionic mode of conduction. The dielectric and electric modulus analysis reveal a faster relaxation phenomenon and hence higher ion conductivity of the prepared SPEs with increasing salt and plasticizer content.

Mitigating Salt Stress with Biochar: Effects on Yield and Quality of Dwarf Tomato Irrigated with Brackish Water.

The increase in the frequency and magnitude of environmental stresses poses a significant risk to the stability of food supplies. In coastal areas of the Mediterranean, brackish water has long been considered a limitation on horticultural production. In this scenario, the use of biochar in agriculture could be considered a valuable tool to cope with the deleterious effects of salt stress. This work aimed to investigate, in a protected environment, the effects of different concentrations of biochar (0, 1, and 2% v/v) obtained from poplar (Populus L.) biomass on the yield and quality of dwarf San Marzano ecotype tomatoes irrigated with saline water at different concentrations of NaCl (0, 40 and 80 mM). The increase in salt concentration from 0 to 80 mM NaCl reduced the total yield (-63%) and the number of fruits (-25%), but improved the main quality parameters such as dry matter (+75%), total soluble solids (+56%), and polyphenol content (+43%). Compared to control conditions, biochar supplementation improved the total yield (+23%) and number of fruits (+26%) without altering the functional and organoleptic characteristics of the fruits. The promising results underscore the potential of biochar as a sustainable solution to amend soils in order to improve tomato production under unfavorable conditions such as high salinity. However, there is a need to clarify which adaptation mechanisms triggered by biochar amending improve production responses even and especially under suboptimal growing conditions.

Study on Preparation and Properties of Pickering Emulsions Prepared by Carboxymethyl Starch‐Xanthan Gum Nanoparticles

AbstractIn this work, carboxymethyl starch‐xanthan gum nanoparticles (CXN) with different ratios are prepared by ethanol precipitation method. The effects of different ratios, NaCl content, and pH on the particle size and zeta potential of the nanoparticles are investigated, as well as the rheological properties and stability of the CXN emulsions. The results show that with the increase of xanthan gum (XG), the particle size, and zeta potential of the nanoparticles decrease and the prepared emulsions have higher shear stress and viscosity, as well as greater thermal and storage stability. Changes in pH and NaCl concentration significantly affect the particle size and zeta potential values of the nanoparticles. Excess acids or bases increase the viscosity of the emulsions. At low salt concentrations (0.05 M), the emulsion viscosity increases significantly, after which the emulsion viscosity decreases with increasing salt concentration. Neutral pH conditions at room temperature are not conducive to the stability of the emulsions. At high temperatures (100 °C), high salt concentrations, excessive acids or bases can destabilize emulsions. This study provides a new way to reduce the particle size of nanoparticles and a feasible strategy for developing long‐term stable Pickering emulsion.

An Exceptionally Salt Tolerant Copoly(Maleimide Sulfobetaine) - Structural Requirements for Ultra-Salt Tolerance.

Zwitterionic polymers are an important class of polymers with far-ranging applications. In the widely studied poly(meth)acrylate and poly(meth) acrylamide-based zwitterions, properties can be tuned by changing the nature of substituents attached to ammonium ions. However, these changes influenced salt tolerance of zwitterionic polymers only to a limited extent. Upon adding salt these polymers expanded in solution initially. Further increase in salt concentration caused the polymer chains to shrink similar to the common water soluble, uncharged polymers thereby deteriorating the viscosity of aqueous solutions. In contrast to the conventional poly(meth)acrylate and poly(meth)acrylamide-based zwitterions, zwitterionic copolymaleimides showed substituent dependent salt-tolerant nature. In the absence of any substituent on the polymer backbone such as zwitterionic poly(ethylene-alt-maleimide) (ZI-PEMA) the viscosity of salt solutions increased both with the increasing salt concentration as well as the concentration of polymer. This is likely due to the continuous expansion of polymer coil in salt solutions with increasing salt concentration caused primarily by the rigidity of the polymer backbone. ZI-PEMA also enhanced the saturation limit of mono- and divalent salts like sodium chloride and hydrated calcium bromide in water. This property is useful for various applications like fish curing, for making high-density fluids, refrigeration, etc. across various industrial sectors.

Progressive failure of frozen sodium sulfate saline sandy soil under uniaxial compression

The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering. To study the effect of salt content and temperature on the progressive failure characteristics of frozen sodium sulfate saline sandy soil, a series of uniaxial compression tests were performed by integrating digital image correlation (DIC) technology into the testing apparatus. The evolution law of the uniaxial compression strength (UCS), the failure strain, and the formation of the shear band of the frozen sodium sulfate saline sandy soil were analyzed. The test results show that within the scope of this study, with the increase of salt content, both the UCS and the shear band angle initially decrease with increasing salt content before showing an increase. In contrast, the failure strain and the width of the shear band exhibit an initial increase followed by a decrease in the samples. In addition, to investigate the brittle failure characteristics of frozen sodium sulfate saline sandy soil, two classic brittleness evaluation methods were employed to quantitatively assess the brittleness level for the soil samples. The findings suggest that the failure characteristics under all test conditions in this study belong to the transition stage between brittle and ductile, indicating that frozen sodium sulfate saline sandy soil exhibits certain brittle behavior under uniaxial compression conditions, and the brittleness index basically decreases and then increases with the rise in salt content.

Experimental measurements and thermodynamic modeling of dissociation pressure of CO2 hydrate in sulfate solutions

Carbon capture and storage (CCS) has been a popular strategy to mitigate climate change and has attracted significant attention from both industry and academia. CO2 can be stored in the form of CO2 hydrate in deeper locations in an ocean, which makes it a potential option for CO2 sequestration. Dissolved salts in the ocean brine can significantly affect the dissociation pressure of CO2 hydrate. Sulfate salts are one of the most common salt species in the oceanic brine. Although various experimental studies have been conducted to investigate the phase behavior of CO2 hydrate in brine, few studies focus on the effect of sulfate salts on the dissociation pressure of CO2 hydrate. In this study, we build an in-house experimental setup to investigate the effect of monovalent and divalent sulfate salts on the dissociation pressure of CO2 hydrate. The dissociation pressure of CO2 hydrate in Na2SO4, K2SO4, MgSO4, and CuSO4 aqueous solutions is measured using the isochoric pressure search method at different concentrations over the temperature range of 274.36–––282.15 K and the pressure range of 1.50–––4.03 MPa. A hybrid methodology incorporating the Soave-Redlich-Kwong Equation of State (SRK EOS), the van der Waals-Platteeuw (vdW-P) model, and the Pitzer model is applied to predict the dissociation pressure of CO2 in sulfate solutions. In addition, the dissociation enthalpies of CO2 hydrate in these sulfate solutions are calculated using the Clausius-Clapeyron equation based on the measured dissociation points. The experimental results show that the dissociation pressure of CO2 hydrate in Na2SO4, K2SO4, and MgSO4 solutions is higher than that in pure water, and the dissociation pressure of CO2 hydrate in sulfate solutions increases with an increasing salt concentration. Conversely, CuSO4 barely affects the dissociation pressure of CO2 hydrate, which is mainly attributed to the lower molar concentration of the ions compared with the other salt solutions and the ion specificity of Cu2+. The prediction results are in alignment with the experimental data measured in this study, which proves the feasibility of the thermodynamic model in predicting the dissociation pressure of CO2 hydrate in sulfate solutions. Additionally, the calculated dissociation enthalpies of CO2 hydrate show a dependence on both temperature and salt concentration. It is also revealed that Cu2+ exhibits ion specificity in affecting the dissociation enthalpy of CO2 hydrate, likely due to its distinct ability to impact the cage occupancy of CO2 hydrate compared with the other ions. These findings enhance our understanding of the impact of sulfate salts on the dissociation behavior of CO2 hydrate and offer valuable insights for CO2 sequestration.

Solvation structures in weakly solvating solvents lead to hybrid vehicular/structural ion transport

Despite the reported benefits of weakly solvating electrolytes (WSEs), investigations on the solvation structures and ion transport mechanisms present in WSEs are limited. This is particularly the case for electrolytes containing the weakly solvating 1,2-diethoxyethane (DEE), which has shown great promise recently. It is for this purpose, we employ molecular dynamics simulations and quantum mechanical calculations to investigate the solvation structure and Li+ transport for lithium bis(fluorosulfonyl)imide (LiFSI) in DEE. From the results reported herein, it was found that at lower concentrations, solvent separated ion pairs are particularly stable, primarily due to the presence of FSI– in the second solvation shell of Li+. As the salt concentration increases, cation–anion complexes appear and form large aggregates. The presence of these large aggregates promotes a hybrid/structural diffusion mechanism at high concentrations, where Li+ ions readily exchange ligands with FSI– anions but remains coordinated with DEE molecules. Hence, the results reported herein investigate how the solvation structure influences transport properties in weakly solvating solvents and provides insights that can be used to optimize electrolytes for energy storage applications.

The effects of the deterioration of water resources in the Euphrates River within the city district in Basra Governorate

The research dealt with the effects resulting from the quantitative and qualitative deterioration of the water of the Euphrates River in Basra Governorate, after the river was cut off by an earthen dam in the (Chibayish) district before entering the study area in 2012. The research dealt with the effects of the deterioration on human health and cases of poisoning caused by the increase in salt concentration in River water. The research also explains the impact of deterioration on aquatic organisms, agricultural production, and the shrinkage of agricultural areas in the north of Basra Governorate, and the impact of this on population migration and the subsequent impact on societal security in Basra Governorate in general, and the resulting deterioration of pressure on the infrastructure in The center of Basra Governorate, and the physical and chemical characteristics of the water of the Euphrates River in Basra Governorate are consistent with Iraqi and international standards.

Salinity Studies in Quinoa (Quinoa Chenipodoum Willd) from Haditha Desert, Western of Iraq

The present studies were conducted to determine the effect of various concentrations of NaCl salinity on germination and growth of four genotypes of Quinoa Chenopodium Willd, namely G1 (KVL-SR2), G2 (Q-21), G3 (Q-37), and G4 (Regalona), exposed to 0, 60, 120, and 300 mM NaCl. The study was conducted at the Center of Desert Research, Egypt, and the experiment was carried out in the Plant Physiology Laboratory of the Center of Desert Studies. Seeds were treated with four different levels of NaCl concentration: 0, 60, 120, and 300 mM. The experiment followed a Completely Randomized Design with three replications. The germination experiment aimed to determine the effect of NaCl salinity on seed germination percentage. Seeds were placed in autoclaved petri dishes lined with two layers of filter paper, with fifty seeds per dish. Seeds were treated with 0, 60, 120, and 300 mM NaCl solutions (5 mL). The petri dishes were kept in the laboratory at temperatures ranging from 25°C to 28°C for four weeks. Water loss from the petri dishes due to evaporation was monitored using control petri dishes, and water was added every 24 hours as needed. A pot experiment was conducted using plastic pots containing 1700 grams of fine-sieved soil. Seeds of the aforementioned genotypes were sown in 500 grams of soil, separated from the rest of the pot's soil by a polythene sheet. Plants were watered on alternate days and subjected to salinity treatment 25 days after sowing. Fifty milliliters of nutrient solution (N ratio of 6:4) were also added to the salt solution per pot. The salt solution was applied to the 1200 grams of soil in the pot, and after complete absorption, the polythene sheet separating the soil containing plantlets was removed, allowing the roots of the seedlings to grow into the saline soil in the lower half of the pot. Thinning was done after one week, maintaining five plants per pot. The plants were harvested one month after the salinity treatment. It was observed that the germination percentage decreased as the salinity level increased. G1 was tolerant, while G4 was salt-sensitive compared to the other genotypes. Plant height, number of leaves, and number of nodes per plant decreased with increasing salt concentration. G3 was least affected, followed by G2, G1, and G4. Fresh weight, dry weight, and percentage water content of the plants also significantly decreased with increased salinity. The distribution of Na+ ions in various plant parts showed a high concentration in the roots, stem, leaf blade, and leaf sheath of all genotypes. The highest concentration of Na+ ions was found in the leaf sheath of all genotypes, followed by the stem, root, and leaf blade, with high water content even under the highest salt levels. An effective partition of Na+ and Cl- ions in the leaf sheath and the transport of K+ to the physiologically important leaf blade were observed in G1, while other genotypes did not exhibit this efficiency. The specific ion effect of NaCl on the total N status of plants was most pronounced in G1, followed by G2 and G3, while G4 maintained optimal N levels in the root and leaf blade. The tolerant genotype G1 could be utilized for rehabilitation in salt-affected areas.

Research on the Rheological Performance of Fast-Melting SBS-Modified Asphalt under Complex Environmental Factors

Currently, fast-melting SBS (Styrene-Butadiene-Styrene)-modified asphalt is widely used in pavements. However, in practical applications, complex environmental factors accelerate the deterioration of asphalt material properties, significantly affecting the service life of roads during their operational period. This study aims to examine the effects of complex environmental factors, including thermal oxidation, ultraviolet radiation, and various concentrations of salt solutions, on the high and low-temperature rheological properties of fast-melting SBS-modified asphalt (abbreviated as SBS-T-modified asphalt). Pressure aging–ultraviolet aging coupling and pressure aging–ultraviolet aging different concentration salt solution coupling were selected as the aging groups to simulate complex environmental conditions. Additionally, base asphalt and pressure-aged asphalt were used as control groups. The rheological properties of SBS-T-modified asphalt were evaluated using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The results indicate that multiple-factor coupling aging reduces both the high-temperature and low-temperature performance of SBS-T-modified asphalt compared to single-factor aging, although the impact on rheological properties is not consistent across all conditions. After the combined effects of UV aging and pressure aging, the rutting resistance and high-temperature performance of SBS-T-modified asphalt are most severely impacted. However, when coupled with salt-solution aging, the rutting resistance of SBS-T-modified asphalt improves, with the complex modulus increasing by approximately 30%. This indicates that the presence of the salt solution enhances the high-temperature performance of the asphalt. An analysis of the low-temperature rheological properties of SBS-T-modified asphalt based on Burgers model shows that the low-temperature rheological performance of SBS-T-modified asphalt worsens under three-factor coupling aging compared to two-factor or single-factor aging, leading to poorer crack resistance. Notably, after adding salt solutions, the thermal sensitivity of SBS-T-modified asphalt increases significantly, with the ΔTc value decreasing approximately sixfold for every 2% increase in salt concentration.

Facile synthesis of zeolitic‐imidazole framework‐67 (ZIF‐67) for the adsorption of indigo carmine dye

AbstractThis study aims to synthesize ZIF‐67 for the adsorption of indigo carmine (I.C.) dye. ZIF‐67 materials were synthesized under different conditions and the synthesis condition of ZIF‐67 giving the best adsorption efficiency was obtained. In batch adsorption studies, pH, adsorbent amount, contact time, initial dye concentration, and temperature effects were investigated. Adsorption data were applied to Langmuir, Freundlich, and Temkin isotherm models. The best correlation value was obtained in Langmuir isotherm (R2 = 0.999). The adsorption of I.C. dye with ZIF‐67 occurred in a monolayer with a homogeneous surface according to Langmuir isotherm. The highest adsorption capacity value of ZIF‐67 metal–organic framework for I.C. dye was found as 370 mg/g. Kinetic model studies were also performed and pseudo first‐order, pseudo second‐order, and intraparticle diffusion models were used. Pseudo second‐order was the best fitting kinetic model to the data (R2 = 0.997). Adsorption mechanisms of ZIF‐67 for I.C. dye include electrostatic interaction, π–π interaction, and hydrogen bonding. Thermodynamic studies showed that I.C. removal by ZIF‐67 is an exothermic and spontaneous process. ZIF‐67 was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), field emission scanning electron microscope (FE‐SEM), and N2 adsorption–desorption. The surface area of synthesized ZIF‐67 was found 1493 m2 g−1. The salt concentration effect on I.C. adsorption by ZIF‐67 was also investigated, showing an increase in adsorption capacities with increasing salt concentration. The regeneration study was carried out and after 5 cycles, the reduction in efficiency was 21%.

An Experimental Investigation on the Performance Analysis of Two-Stage Desert Cooler

The present experimental investigation reports the performance of both the single and two stage direct evaporative cooling systems in composite climatic conditions of Patna, India. A two-stage direct evaporative cooling system has been designed and fabricated. The first stage of the two-stage cooling system utilizes a heat exchanger designed internally to sensibly cool hot and arid ambient air. The effect of varying the frontal air velocity (0.5–9 m/s) and different saline water concentration (5–10%) on the performance of two stage direct evaporative cooler is investigated. The maximum effectiveness of single and two-stage desert cooler is found to be 0.7 and 0.98 at frontal velocity of 2 m/s and 2.5 m/s, respectively. The performance of the two-stage cooler with tap water is found to be 40% higher than the single stage desert cooler. The effectiveness of single and two stage desert coolers with tap water is found to be in the range of 6–11% and 9.3–14% higher compared to the saline water at salt concentrations of 5–10%, respectively. Moreover, increasing salt concentration leads to reduced relative humidity at the cooler exit, with the two-stage cooler exhibiting 28.5% lower relative humidity than single-stage desert cooler.

Effects of brackish water irrigation with different exogenous salt concentrations on the growth and rhizosphere salinity of Lycium barbarum

To investigate the effects of different typical exogenous salt concentrations on total soil salinity and the growth of Lycium barbarum under brackish water irrigation, and to determine the salinity threshold of irrigated brackish water that is conducive to the normal growth of Lycium barbarum while mitigating soil salinity accumulation. Four typical exogenous salts (NaCl, CaCl2, NaHCO3, Na2SO4) were selected and set at four concentrations (0.1, 0.5, 2.0, 4.0 g L−1) to conduct a field crossover experiments in the downstream region of the Hetao Irrigation District. The results showed that in the same fertility period, the growth rates of new branches, ground diameter, and crown width first increased and then decreased with rising concentrations of NaCl, CaCl2, and Na2SO4, but showed an inverse relationship with NaHCO3 concentrations. Furthermore, increasing salt concentrations linearly reduced the yield of dry fruits from Lycium barbarum and led to a notable accumulation of total soil salts. Utilizing an experimental research approach, a comprehensive analysis of involving multiple growth indices, stable yield, and soil salinity control of Lycium barbarum revealed that optimal growth occurs at salt concentrations of 0.1–0.5 g L−1 for different water quality areas within the irrigation area; using the method of path analysis identified the total soil salt and crown width as the primary direct and indirect factors influencing the yield of Lycium barbarum. The results of this study provide scientific basis and significant theoretical support for the safe and rational utilization of brackish water and cultivation of Lycium barbarum in typical regions with varying saline water qualities of Hetao irrigation area.