Increasing NaCl Concentration Research Articles

Bioelectrochemical stability improvement by Ce–N modified carbon-based cathode in high-salt stress and mechanism research

Although microbial fuel cells (MFCs) have potential for high-salt wastewater treatment, their application is limited by poor salt tolerance, deactivation and unstable catalytic performance. This study designed Ce–C, N–C, and Ce–N modified activated carbon (Ce–N–C) based on the catalytic mechanism and salt tolerance performance of Ce and N elements to address these limitations. With activated carbon (AC) as the control, this study analyzed the stability of the four cathodes under different salinity environments using norfloxacin (NOR) as a probe to assess the effect of cathodes and salinity on MFC degradation performance. After three months, comparing with other three cathodes, the Ce–N–C cathode demonstrated superior and stable electrochemical and power generation performance. In particular, the advantages of Ce–N–C in high-salt (600 mM NaCl) environment is more significant than no-salt or low-salt. The potential of Ce–N–C-End at current density of 0 was 14.0% higher than AC-End, and the power density of the MFC with Ce–N–C cathode was 105.7 mW/m2, which was 3.1 times higher than AC. Also, the stability of NOR removal under the function of Ce–N–C improved with the increase of NaCl concentration or operation time. The CeO2(111) crystal form, N–Ce–O bond and pyridine N might be the key factors in improving the catalytic performance and salt tolerance of the Ce–N modified carbon-based cathode using XPS and XRD analysis.

Assessment of Sodium Chloride (NaCl) Induced Salinity on the Growth and Yield Parameters of Cichorium intybus L.

The present study was done on the hypothesis that excess sodium chloride (NaCl) in the soil decreases the growth and yield of Cichorium intybus L. To investigate this hypothesis, a pot experiment was conducted in which chicory seeds were sown in garden soil-filled earthen pots and treated with three different doses of sodium chloride (45, 75, and 105 mM kg-1 soil) except the control, and each treatment was replicated three times. The results revealed that all the saline treatments significantly (p≤0.05) reduced the vegetative (including root and shoot length, dry weight, number of leaves, leaf area, number of branches, and photosynthetic pigments) and reproductive (mean fruit number/plant, mean seed number/fruit, and total seed yield/plant) growth parameters of Cichorium intybus. On increasing NaCl concentration in the soil, chlorophyll content significantly (p≤0.05) decreased while proline content in the fresh leaves increased significantly (p≤0.05). From the results, it is concluded that Cichorium intybus L. can tolerate a moderate level of sodium chloride stress (45-75 mM NaCl kg-1 soil) but is sensitive to high doses of sodium chloride stress (105 mM NaCl kg-1 soil).

Salinity-induced modulation of growth and accumulation of phytochemicals composition in in vitro root cultures of Azadirachta indica

Salinity is a destructive abiotic factor that negatively impacts the growth and development of stress-intolerant plants. Although the effect of salinity on the growth of Azadirachta indica (neem) under in vitro conditions has been widely studied, little is known about the biochemical properties of in vitro root cultures exposed to salinity stress. Therefore, this study aimed to investigate the effects of varying concentrations of salinity on the biochemical properties of A. indica root cultures, specifically on total pigment and phenolic contents, antioxidant activities, and the presence of phytochemicals and azadirachtin compound, at different incubation periods. The results demonstrated that the root cultures coped with increasing NaCl concentrations by altering their phenotype. The highest antioxidant potential was observed in root cultures grown on MSN media (Murashige and Skoog media containing 3 mg L−1 NAA) supplemented with 0.5% w/v NaCl for 4 weeks. Additionally, this media composition and incubation period also resulted in the highest total phenolic and anthocyanin contents. The accumulation of photosynthetic pigments significantly decreased when exposed to NaCl treatments after 4 and 8 weeks. Interestingly, short-term exposure to NaCl had a positive impact on the azadirachtin (AZA) content, while longer treatment duration significantly decreased it. The highest amount of AZA was quantified from root cultures elicited with 1.5% w/v NaCl for 4 weeks. These findings contribute to a better understanding of the effects of salinity stress on the biochemical properties of in vitro root cultures of A. indica. The findings can aid in the development of strategies to enhance the production of bioactive compounds with potential applications in the food and pharmaceutical industries. Additionally, the study provides insights into the physiological mechanisms and manipulation of secondary metabolite production associated with salt tolerance in A. indica and other related species.

Efficient removal of congo red dye using activated lychee peel biochar supported Ca-Cr layered double hydroxide

Congo red is a known carcinogenic and mutagenic dye, so its presence in bodies of water is dangerous. The present work aims to synthesize and characterize a layered double hydroxide (LDH)-biochar composite and evaluate its application in the adsorption of Congo red dye (CR). CaCr/LDH was anchored over lychee activated biochar through coprecipitation. The composite was characterized using scanning electronic mapping (SEM), energy-dispersive spectrometer SEM (EDS-SEM), Fourier transform infrared (FT-IR), X-ray powder diffractometry (XRD) and Brunauer-Emmet-Teller (BET). The effect of pH, adsorption kinetics, isotherms, ionic strength, and thermodynamic parameters were evaluated. The pH results show a stable adsorption capacity in a useful range of pH (pH 4–9). Adsorption kinetics fitted the Elovich model, suggesting a heterogeneous system. The maximum adsorption capacity value (qe) calculated was achieved by applying the Sips model, with 631.1 mg g−1 at 50 °C. Ionic strength experiments show that the capacity increased with increasing NaCl concentration, which is desirable for real use as other ions are commonly present in dye wastewater. π-π interactions and hydrogen bonding seems to be involved in the adsorption mechanisms. CaCr-LDH/lychee biochar has better structure stability over several adsorption–desorption cycles with anionic exchange regeneration (in comparison with thermal regeneration), wide operational pH and high adsorption capacity. Therefore, this new composite presents a very good potential for the adsorption of dye from waste- or ground- water.

High temperature oxidation and microstructural evolution of SiC layer of TRISO particles in the presence of NaCl

With the different types of advanced nuclear fission reactors, the reliability of the SiC layer in tristructural-isotropic (TRISO) particles exposed to different corrosive environments is of vital important. In the present work, the oxidation behaviors of the SiC layer of TRISO particles exposed in NaCl salts with the concentrations of 0.2–2 wt% at 800–1400 °C were investigated. The effects of NaCl concentration and oxidation temperature on phase composition, microstructure, and chemical composition of the TRISO particle samples were systematically investigated. The results show that, with the increase of oxidation temperature and NaCl concentration, the oxidation rate of SiC layer in TRISO particles was accelerated. However, the effect of NaCl concentration alone on the oxidation rate of SiC layer was not significant. This could be attributed to the volatility of NaCl at high temperature. In addition, just like other halogen salts, NaCl salts also reacted with the oxide layer to form silicate compounds, such as Na2SiO3, which provided a channel for both oxygen and fluoride ions to diffuse into the inner SiC layer. The results obtained in the present work can provide a guide for the application of TRISO particles in molten salt stacks of chlorine salt.

Study on the Corrosion Behavior of D36 Steel Plate and H62 Copper Alloy Net for Marine Aquaculture Facilities in Simulated Seawater

Marine aquaculture facilities have been working in a high salt and humidity marine environment for a long time, which makes them be inevitably affected by seawater corrosion, especially the main structures such as metal mesh and frame. Therefore, studying the corrosion behavior of net and frame steel is of great significance for the selection of materials and corrosion protection of marine aquaculture facilities. The influence of NaCl concentrations and immersion state on self-corrosion behavior and the influence of layer thickness and overlapping area on galvanic corrosion behavior of H62 copper alloy mesh/D36 steel plate was discussed in this study using weight loss and electrochemical measurements. The tensile tests were conducted to observe the influence of different corrosion conditions on maximum force and tensile strength of the net. The corrosion rate of the two materials increased rapidly with the increase of NaCl concentrations; the corrosion rate of both materials showed the decreasing trend with the extension of time, and the corrosion rate of H62 was always lower than D36 steel. When two materials were coupled, the galvanic corrosion rate would decrease with the increase of the layer thickness and overlapping area. The tensile results were consistent with the corrosion results. When these two materials work together, adding layer thickness or increasing the overlapping area is one of the ways to protect the frame steel to a certain extent.

Salt Tolerance of Limonium gmelinii subsp. hungaricum as a Potential Ornamental Plant for Secondary Salinized Soils.

Secondary salinization caused by climate change is a growing global problem. Searching for plants that can survive in areas with high salt content and even have decorative value was the focus of our research. Thirty plants of Limonium gmelinii subsp. hungaricum were planted in clear river sand; another thirty plants were planted in Pindstrup, a growing substrate enriched with 40% clay. With the latter, we modeled the natural soil. In addition to the control tap-water treatment, plants received 50, 125, 250, 375, and 500 mM NaCl solution irrigation twice a week. The leaf sizes of plants planted in sand decreased proportionally with the increasing NaCl concentration, and their dry matter content increased. In the clay-containing medium, leaf sizes increased, even at a concentration of 375 mM, although the dry matter content increased only at high concentrations. Carotene content in both media became higher, due to the higher NaCl concentrations, while proline content in the plants grown in sandy media increased, even with the 125 mM concentration. With our present experiment we proved the salt tolerance of the taxon, and even the soil's great importance in supporting the plant's salt tolerance.

Nanoscale Insights into the Influence of Seawater (NaCl) on the Behavior of Calcium Silicate Hydrate

Using seawater for concrete production is potentially advantageous from a sustainability perspective. However, the fundamental mechanisms underlying seawater-mixed concrete are far from being understood, especially from the nanoscale. Herein, molecular models are developed to study, for the first time, the influence of seawater (NaCl solutions) on the behavior of calcium silicate hydrate (C-S-H, the main binding phase of concrete). Thermodynamically, Na+ showed a strong adsorption capacity on the C-S-H surface, resulting in the partial release of Ca2+ from the surface (termed as “Na–Ca cation exchange”). Mechanically, the presence of NaCl in the interlayer solutions enhanced the bond performance between the C-S-H layers because Na+ ions provided a greater stress transfer capacity than H2O molecules. Under shear loading, the C-S-H layers slid over each other, with the interlayer solutions acting as a lubricant. An increase in NaCl concentration enhanced the sliding resistance, which was attributed to the increased viscosity of the interlayer solutions and strengthening of the solid–solution interfaces. The above atomic-level findings facilitate a better understanding of the influence of seawater on concrete properties.

Physiological and biochemical responses of Limonium tetragonum to NaCl concentrations in hydroponic solution.

Limonium (L.) tetragonum (Thunb.) A. A. Bullock, a halophyte that grows all over the southwest coast of Korea, is a medicinal plant with various pharmacological effects. The salt defense mechanism stimulates the biosynthesis of various secondary metabolites and improves functional substances. In this study, we investigated the optimal NaCl concentration for the growth and enhancement of secondary metabolites in hydroponically grown L. tetragonum. The seedlings grown for 3 weeks in a hydroponic cultivation system were treated with 0-, 25-, 50-, 75-, and 100-mM NaCl in Hoagland's nutrient solution for 8 weeks. No significant effect on the growth and chlorophyll fluorescence was observed for the NaCl concentrations below 100-mM. The increase in the NaCl concentration resulted in the decrease in the water potential of the L. tetragonum leaves. The Na+ content accumulated in the aerial part increased rapidly and the content of K+, which acts as an antagonist, decreased with the increase in NaCl concentrations in hydroponics. The total amino acid content of L. tetragonum decreased compared to the 0-mM NaCl, and most of the amino acid content decreased as the NaCl concentration increased. In contrast, the content of urea, proline (Pro), β-alanine, ornithine, and arginine was increased with an increase in NaCl concentration. The Pro content at 100-mM NaCl accounted for 60% of the total amino acids and was found to be a major osmoregulator as an important component of the salt defense mechanisms. The top five compounds identified in the L. tetragonum were classified as flavonoids while the flavanone compound was detected only in the NaCl treatments. A total of four myricetin glycosides were increased in comparison to the 0-mM NaCl. Among the differentially expressed genes, a significantly large change in Gene ontology was seen in the circadian rhythm. NaCl treatment enhanced the flavonoid-based substances of L. tetragonum. The optimum NaCl concentration for the enhancement of secondary metabolites of the L. tetragonum in the vertical farm-hydroponic cultivation system was 75-mM NaCl.

An electrochemically mediated ATRP synthesis of lignin-g-PDMAPS UCST-thermoresponsive polymer

It is a promising idea to graft zwitterionic polymers onto lignin and prepare lignin-grafted-poly [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (Lignin-g-PDMAPS) thermosensitive polymer with the upper critical solution temperature (UCST). In this paper, an electrochemically mediated atom transfer radical polymerization (eATRP) method was used to prepare Lignin-g-PDMAPS. The structure and property of the Lignin-g-PDMAPS polymer were characterized by the fourier transform infrared spectrum (FT-IR), nuclear magnetic resonance (NMR), X-ray electron spectroscopy (XPS), dynamic light scattering (DLS), differential scanning calorimeter (DSC). Furthermore, the effect of catalyst structure, applied potential, amount of Lignin-Br, Lignin-g-PDMAPS concentration, NaCl concentration on UCST of Lignin-g-PDMAPS were investigated. It was worth noting that polymerization was well controlled when the ligand was tris (2-aminoethyl) amine (Me6TREN), applied potential was −0.38 V and the amount of Lignin-Br was 100 mg. And the UCST of the Lignin-g-PDMAPS aqueous solution (1 mg/ml) was 51.47 °C, the molecular weight was 8987 g/mol, and the particle size was 318 nm. It was also found that the UCST increased and the particle size decreased with the Lignin-g-PDMAPS polymer concentration increased, and the UCST decreased and the particle size increased with the NaCl concentration increases. This work investigated UCST-thermoresponsive polymer which possessed lignin main chain combining the zwitterionic side chain, and provided a new way for development of lignin based UCST-thermoresponsive materials and medical carrier materials, in addition to expand the scope of eATRP.

Chitosan Nanoparticles as Seed Priming Agents to Alleviate Salinity Stress in Rice (Oryza sativa L.) Seedlings

Nanoparticle-based seed priming has opened new avenues in crop science due to their plant growth promoting potential. Similarly, biopolymers such as chitosan (CS) are widely studied as seed priming agents due to the biodegradable and biocompatible nature, ability to enhance germination percentage and overall seedling health. Therefore, priming with chitosan nanoparticles (CNPs) is a promising tool to enhance overall plant health. Here, we studied the effect of nanopriming with CNPs or CS (50 µg/mL) on morphological, physiological, and biochemical parameters of rice seedlings, grown in salinity stress conditions NaCl (0–250 mM). CNPs were synthesized using an ionic gelation method and characterized by scanning electron microscopy (50–100 nm), zeta potential analyser (Particle size distribution–373.5 ± 3.7 nm; polydispersity index- > 0.4; zeta potential–45.3 ± 2.5 mV) and profilometry (300–1500 nm hydrodynamic height). Morphological, physiological, and biochemical responses of rice seedlings grown from seeds primed with either CNPs or CS showed a positive effect on germination, seedling vigour, biochemical and antioxidant responses. Seeds primed with CNPs and CS demonstrated significantly higher germination potential and seedling vigour compared to control hydro-primed seeds when grown under increasing NaCl concentrations. These outcomes highlight that CNPs and CS can be used as potential seed priming agents to alleviate salinity stress in rice seedlings. However, further studies are warranted to understand the effect of CNPs and CS seed priming on the overall growth and development of rice plants as well as rice yield.

Maximum allowable retention for low-salt-rejection reverse osmosis membranes and its effect on concentrating undersaturated NaCl solutions to saturation

For conventional reverse osmosis (RO), the osmotic pressure difference limits the allowable concentration factor for concentrating NaCl solutions. The use of low-salt-rejection RO (LSRRO) membranes could allow much higher concentration factors, provided that these membranes show a sufficient decrease in NaCl retention with increasing NaCl concentration in the retentate. This work quantifies allowable NaCl retentions for LSRRO as function of the retentate concentration for different pressures. For a pressure of 70 bar allowable NaCl retentions start to deviate from retentions reported for commercial RO membranes at NaCl weight fractions below 0.1. NaCl retentions for commercial nanofiltration (NF) membranes are much lower than allowed for LSRRO, leading to high NaCl losses in permeate. The required NaCl retention for LSRRO as function of the NaCl retentate concentration therefore falls in between those reported for commercial RO and NF membranes, implying that LSRRO membrane development is required. Based on the obtained relations required concentration factors for the concentration of purified seawater RO retentate and depleted brine from chlor/alkali production have been determined. The concentration factor for LSRRO for concentrating solutions with a NaCl concentration of either 0.07 kg·kg−1 or 0.18 kg·kg−1 to saturation at 120 bar pressure is 4 – 5 times higher than for a case where full retention would have been allowed. By optimizing the unit lay-out to minimize NaCl loss in permeate, approximately 1.2 m2·kg−1·h membrane area per saturated NaCl solution flow produced would be required for concentrating a 0.18 kg·kg−1 NaCl solution to saturation, assuming a permeance of 0.36 kg·m−2·h−1·bar−1.

Isolation and identification of highly effective potassiumsolubilising bacterial strain from coastal soils

Soil potassium supplementation relies heavily on the use of chemical fertilizer, which has a considerablenegative impact on the environment. Potassium-solubilizing bacteria (KSB) could serve as inoculants.They convert insoluble potassium in the soil into a form that plants can access. This is a promising strat-egy for the improvement of plant absorption of potassium and so reducing the use of chemical fertilizer. In order to overcome poor potassium availability, potassium solubilising microorganisms can be used to ensure agriculture production. Hence, the study was aimed to isolate, identify, and characterise a potent bacterial species from coastal soils that can efficiently solubilise phosphate for plant absorption. From the five soil samples, a total of eight different discrete bacterial colonies were identified and they were named as MGK-01, MGK-02, MGK-03, MGK-04, MGK-05, MGK-06, MGK-07 and MGK-08. The screening of potassium solubilisation demonstrates that the greatest potassium solubilisation ability was found in the MGK-06 strain. Furthermore, the greatest potassium solubilisation under increasing NaCl concentrations were found in the MGK-06. Due to better potassium solubility and plant growth promoting activities, bacterial isolate MGK-06 was selected for molecular identification and bioinoculation studies. The molecular phylogeny revealed that the bacterial isolate MGK-06 is belongs to Azotobacter chrococcumspecies.

Effect of NaCl on Water Activity and Hydration Water Dynamics in Proteins by Quasielastic Neutron Scattering

AbstractEffect of NaCl on a protein hydration is of interest in interdisciplinary fields such as food science and extreme environment biology. Here, the protein hydration water dynamics with various NaCl concentrations at a constant water activity(Aw) by incoherent quasielastic neutron scattering (iQENS) are examined. Under the same Aw, the water content increases with increasing NaCl concentration. iQENS analysis of these samples shows no significant difference in the dynamics of water molecules despite of the difference of water content. This suggests that the hydration water dynamics should be suppressed in the present of NaCl. Water dynamics is affected by NaCl, but independent of this, there is a universal correlation between Aw values and water molecule dynamics.

Effects of temperature, provenance, drought stress and salinity on seed germination response and early seedling stage of Thymus atlanticus (Ball) Roussine

Thymus atlanticus (Ball) Roussine is a valuable aromatic and medicinal species endemic to Morocco. Climate change and anthropogenic threats are factors driving this species to vulnerability and extinction. Therefore, the current study aims to examine the effects of provenance, temperature, drought stress, and salinity on the germination parameters of T. atlanticus seeds and seedling vigor. Seeds are collected from two provenances (Saghro and Tizi n’Telghemt). Treatments included six alternating temperature regimes (10/0, 15/05, 20/10, 25/15, 30/20, and 40/25 °C), five osmotic potentials of aqueous solutions of polyethylene glycol (PEG-6000) (0, −0.1, −0.3, −0.6, and −0.9 MPa), and five concentrations of sodium chloride (NaCl) (0, 1, 2.5, 5, and 7 g/l). The two-way ANOVA test reveals that alternating temperatures, drought, salinity, and their interactions with provenance almost all have a significant impact on germination parameters. However, no significant effect is registered for the interaction between provenance and alternating temperatures on the final germination percentage (FGP). The highest FGP is recorded at several alternating temperatures (15/05, 20/10, 25/15, and 30/20 °C), and the maximum one is at 20/10 °C for both populations (Saghro and Tizi n’Telghemt, respectively 93% and 89%). This temperature regime is also the best in terms of germination time and speed. The most vigorous seedlings are obtained at 20/10 and 30/20 °C for Tizi n’Telghemt and Saghro populations, respectively. Concerning salinity and moisture stress, the results show that the increase in NaCl and PEG-6000 concentrations leads to a significant reduction in the germination capacity (FGP) and seedling vigor index as well as an increase in the mean germination time (MGT) of the two populations studied. The Saghro population tolerates the studied stresses better than the Tizi n’Telghemt population. These results may serve as guidelines for the domestication and rehabilitation of this medicinal plant.

Comparative Analysis of Antioxidant System and Salt-Stress Tolerance in Two Hibiscus Cultivars Exposed to NaCl Toxicity.

Hibiscus (Hibiscus syriacus L.) is known as a horticultural plant of great ornamental and medicinal value. However, the effect of NaCl stress on hibiscus seedlings is unclear. Little is known about H. syriacus 'Duede Brabaul' (DB) and H. syriacus 'Blueberry Smoothie' (BS). Here, the effects of solutions with different concentrations of NaCl on the organic osmolytes, ion accumulation, and antioxidant enzyme activity of hibiscus seedling leaves were determined. The results showed that the Na+/K+ ratio was imbalanced with increasing NaCl concentration, especially in BS (range 34% to 121%), which was more sensitive than DB (range 32% to 187%) under NaCl concentrations of 50 to 200 mM. To cope with the osmotic stress, the content of organic osmolytes increased significantly. Additionally, NaCl stress caused a large increase in O2·- and H2O2, and other reactive oxygen species (ROS), and antioxidant enzyme activity was significantly increased to remove excess ROS. The expression level of genes related to salt tolerance was significantly higher in DB than that in BS under different NaCl concentrations. Taken together, DB possessed a stronger tolerance to salt stress and the results suggest membrane stability, Na+/K+, H2O2, catalase and ascorbate peroxidase as salt tolerance biomarkers that can be used for gene transformation and breeding in future hibiscus research.

Efficient Labeling of Vesicles with Lipophilic Fluorescent Dyes via the Salt-Change Method.

Fluorescent labeling allows for imaging and tracking of vesicles down to single-particle level. Among several options to introduce fluorescence, staining of lipid membranes with lipophilic dyes provides a straightforward approach without interfering with vesicle content. However, incorporating lipophilic molecules into vesicle membranes in an aqueous solution is generally not efficient because of their low water solubility. Here, we describe a simple, fast (<30 min), and highly effective procedure for fluorescent labeling of vesicles including natural extracellular vesicles. By adjusting the ionic strength of the staining buffer with NaCl, the aggregation status of DiI, a representative lipophilic tracer, can be controlled reversibly. Using cell-derived vesicles as a model system, we show that dispersion of DiI under low-salt condition improved its incorporation into vesicles by a factor of 290. In addition, increasing NaCl concentration after labeling induced free dye molecules to form aggregates, which can be filtered and thus effectively removed without ultracentrifugation. We consistently observed 6- to 85-fold increases in the labeled vesicle count across different types of dyes and vesicles. The method is expected to reduce the concern about off-target labeling resulting from the use of high concentrations of dyes.

Water-in-water Pickering emulsion stabilized by cellulose nanocrystals as space-confined encapsulating systems: From establishment to stability

The development of new water-in-water (W/W) emulsion systems and the improvement of the long-term stability of emulsions could create opportunities for studying interfacial bionic systems and microencapsulation applications. In this study, the new W/W emulsion systems were constructed from hydroxypropyl methylcellulose (HPMC) and maltodextrin (MD). The effects of cellulose nanocrystals (CNC) and environmental factors (ionic strength and pH) on the stability of W/W Pickering emulsions were investigated. The stabilizing effect was observed at contents of CNC as low as 0.025 wt%. The W/W Pickering emulsion showed no phase separation within 30 days when the CNC concentration was above 0.025 wt%, indicating that the emulsions were stable during the observation period. The stability of W/W Pickering emulsions was driven by the electrostatic repulsion provided by the CNC adsorbed at the droplet interface, which decreased with increasing NaCl concentration. This was attributed to the charge-shielding effect of NaCl weakening the electrostatic repulsion of the CNCs at the emulsion droplet interface. Lactobacillus helveticus cells were encapsulated in the W/W Pickering emulsion. These results revealed that the developed W/W Pickering emulsions have potential applications in protecting the activity of probiotic bacteria and investigating the behavior of cells in restricted spaces.

Enhanced interfacial solar driven water evaporation performance of Ti mesh through growing TiO2 nanotube and applying voltage

Interfacial solar driven water evaporation (ISDWE) technology has been widely studied to desalinate seawater in aiming to alleviate the scarcity of clean water. In this paper, the ISDWE performance of Ti mesh was enhanced by anodized TiO2 nanotube film and applied voltage, and the water evaporation rate increased from 1.20 kg•m−2•h−1 to 2.48 kg•m−2•h−1. Due to hydrophilic and nanoporous nature of TiO2 nanotube film, the solar absorptivity, wettability of Ti mesh was improved, the water evaporation enthalpy was reduced, and the water evaporation rate reached 1.98 kg•m−2•h−1. For the superior ISDWE performance with applied voltage, electrothermal effect and internal electrical filed were proved to be contributing factors. The solar irradiation can enhance the electrothermal effect for the semiconducting nature of TiO2. The internal electrical field can optimize the solar absorptivity and water evaporation enthalpy through doping TiO2 and breaking water clusters. Moreover, the applied voltage also increased the salt-resistance property of Ti mesh coated with TiO2 nanotube film. When increasing NaCl concentration, stable water evaporation rate was attainable under 1.2 V, whereas continuous deceleration of water evaporation occurred without external voltage. Therefore, our study provides strategies for achieving high efficient and salt-free seawater desalination by ISDWE technology.

Influence of Soluble Salt NaCl on Cracking Characteristics and Mechanism of Loess

Under the conditions of drought, cracks are likely to appear in loess due to shrinkage, which leads to salt precipitation and accumulation on the surface of loess. Therefore, salinized lands are created in loess areas. Deep study into the influence of soluble salt content on the cracking characteristics and mechanism of loess is of great significance to engineering constructions, geological problems, and disaster prevention for salinized lands in loess regions. In this paper, free desiccation experiments were carried out on the loess samples with different NaCl concentrations (a soluble salt). A high-resolution digital camera was used to obtain the sequence images of loess during the drying process. With the advantage of digital image correlation (DIC) technology and the non-contact full-field strain measurement method, the local displacement and strain on the surface of loess samples were calculated. The microstructure and main elements distribution of loess samples were obtained by scanning electron microscopy (SEM) and energy-dispersive spectrum (EDS) methods. Finally, the influence of NaCl concentrations on cracking characteristics and mechanism of loess was analyzed. The results show that, with the increase in NaCl concentration, the evaporation rate of loess samples decreased and the residual water content increased. The NaCl content can prevent the development of desiccation cracks in loess.