Desalination Effect Research Articles

Effects of magnetized ionized water and Bacillus subtilis on water and salt transport characteristics and ion composition in saline soil

AbstractMagnetized ionized water and Bacillus subtilis are essential for enhancing soil salinity leaching and improving soil structure. To explore the combined effects of magnetized ionized water and B. subtilis on water–salt transport in saline soil, a one‐dimensional vertical infiltration experiment was conducted. This study evaluated the soil water and salt distributions, infiltration model parameters and composition of exchangeable base ions with magnetized ionized water (M) and nonmagnetized‐ionized water, alongside varying amounts of B. subtilis [B0 (0%), B1 (1.5%), B2 (3.0%), B3 (4.5%), B4 (6.0%)]. The results showed that magnetized ionized water increased the infiltration volume and wetting front depth. As the application amount of B. subtilis increased, the changes in these two indicators initially increased but then decreased. The sorptivity parameter (S) mirrored this trend, whereas the shape coefficient (α) showed the opposite pattern. Compared with the B0 treatment, the MB1 treatment increased the 0–20 cm soil water content by 14%, decreased the salt content by 13% and improved the desalination rate by 98%, with the efficiency increasing by 62%. Moreover, the total exchangeable base ions increased, with the highest (Ca2++ Mg2+) and lowest Na+ contents observed under B1. MB1 notably enhanced infiltration and water–salt transport, demonstrating significant desalination effects.

Black Body-Inspired Chemically Oxidized Nanostructures with Varied Perforations: A New Frontier in Solar Desalination

Ideal black bodies absorb all electromagnetic energy without reflecting it. As it does not reflect or transmit light, it appears black when cold. Heated black bodies emit black body radiation, a temperature-dependent spectrum. This idea helps scientists and engineers comprehend heat radiation and design efficient solar desalination absorbers. This work uses the black body concept to create three non-contact nanostructured single-slope solar stills (NCNSSSs) with varied perforation diameters (2.4 mm, 3.2 mm, and 3.8 mm). The chemical oxidation of mirror-polished perforated stainless steel 304 sheets resulted in highly absorptive top surfaces with 90% absorptivity. The structures’ bottom surfaces were coated with a commercial high-emissivity coating to make them 85% emissive. The developed non-contact nanostructures absorbed maximum solar light and converted it into infrared radiation using a highly emissive bottom coating and a very absorptive top coating. Water, an excellent absorber of infrared (IR) radiation, readily absorbs the IR radiations and evaporates through the perforations, thus producing a desalination effect. Experiments were conducted parallelly in three NCNSSSs under the same weather conditions at three water depths. It was observed that non-contact nanostructure perforation diameters affected solar still performance. The NCNSSS-3 (3.8 mm) achieved a 9.89% and 13.47% higher productivity than the NCNSSS-2 (3.2 mm) and NCNSSS-1 (2.4 mm) at a 5 mm water depth. Additionally, fouling studies, expedited corrosion studies, and water quality assessments (TDS, salinity, fluoride, chlorides, nitrates, sodium) were performed. Water eminence examinations confirmed that the collected freshwater was bacteria-free and safe to drink.

Optimized Irrigation Strategies for Saline Soil Remediation in Agricultural Lands Under Water-Limited Conditions

Soil salinization is a prevalent global issue, significantly impacting crop cultivation and food production. This study investigates the potential of sustainably harnessing rainwater for the remediation of saline soils in water-scarce regions. Soil column leaching experiments were performed to evaluate the effectiveness of different methods for salt removal from the tillage layer. The findings demonstrated that intermittent leaching was more effective than continuous leaching in remediating NaCl-type saline soils. When continuous leaching with 27 cm of rainwater was applied, the salt removal in soil layers below 5 cm ranged from 12.28% to 26.86%. Intermittent leaching increased the salt removal rate to between 44.49% and 54.18%. This higher desalination efficiency of intermittent leaching is attributable to the extended soil–water contact time. When the leaching time in continuous leaching was increased from 1.5 h to over 4.5 h, comparable desalination effects were produced. The rainwater leaching demonstrated similar salt removal patterns in Na2SO4-type saline soils. However, due to the stronger affinity of SO42− for clay particles, their effluent concentration and removal were lower than Cl− under the same conditions. To optimize desalination efficiency, operational parameters can be adjusted to reduce the leaching depth of rainwater from 27 cm to 15 cm, and the interval between leaching events from 24 h to 4.5 h. The findings of this study may serve as a valuable reference for saline soil restoration and improvement efforts in water-scarce regions.

Enhanced operating voltage and desalination performance using ionic liquids as electrolyte for flow electrode capacitive deionisation

Flow-electrode capacitive deionisation (FCDI) technology is a promising approach for desalinating brackish water. Selecting the electrolyte with a high voltage window is essential for improving the FCDI performance. In this study, ionic liquids were used for the first time as a new electrolyte for FCDI systems. The water-desalting efficiency was selected as the evaluation index, and single-factor experiments were conducted on the activated carbon content of electrode slurry, brine flow rate, initial brine concentration, and electrolyte volume ratio, respectively. Box-Behnken design response surface experiments were used and models were constructed to analyse the desalting results of the single factor influence and interaction effects for the aqueous and ionic liquid systems respectively, to determine further the key influencing factors and optimal conditions for the brine desalination in the FCDI system. The results showed that the brine flow rate was the most significant factor affecting the desalination efficiency of the aqueous and ionic liquid FCDI systems (p < 0.0001). The optimal process conditions for the ionic liquid system fitted by the model were as follows: 6.6 wt% activated carbon content in the electrode slurry, a brine flow rate of 45 mL/min, an initial brine concentration of 1 g/L, and an electrolyte ratio of N, N-Dimethylformamide/1-ethyl-3-methylimidazolium tetrafluoroborate = 3. The desalination effect of FCDI under the above optimal process conditions was up to 99.739% at a voltage of 3.5 V, and the water-desalting efficiency was still maintained at over 95% after 20 cycles. Compared with the aqueous electrolyte, using ionic liquid electrolytes significantly improves the desalination rate and cycling stability, and this study provides new ideas and methods for developing and applying high-performance electrolytes in FCDI systems.

Exergy Optimization of a Hybrid Multi Evaporative Desalination Plant powered by Solar and Geothermal Energy

Abstract An energy and exergy analysis has been conducted on a hybrid desalination system powered by solar energy using vacuum collectors and geothermal energy. This system is specifically designed to operate under the environmental conditions of southern Tunisia. The desalination plant is mainly constituted by a solar collector field, a thermal energy storage system, a Multiple Effect Distillationunit (MED) system, an evaporative condenser, and a geothermal energy recovery system. The analysis is performed using computational code established with EES software. A parametric study is conducted to examine the effects of key operating parameters on plant performances. The operating mode is determined for winter and summer seasons. Obtained results show that thermal storage system provides thermal power permitting continuous operation for about 8 hours during the nighttime period. The storage tank is the most contributor in exergy destruction with approximately 4.3 kW in winter and 5.5 kW in summer followed by the solar collector field of about 3.6 kW in winter and 3.8 kW in summer. The exergy efficiency of the desalination effects reaches 70 % in winter and 75 % in summer. The daily production of drinking water is about 12 m3/day in winter and 14 m3/day in summer. This meets the daily drinking water needs of around 3000 persons.

A Theoretical Model for the Hydraulic Permeability of Clayey Sediments Considering the Impact of Pore Fluid Chemistry

The chemistry of the pore fluid within clayey sediments frequently changes in various processes. However, the impacts of pore fluid chemistry have not been well included in the hydraulic permeability model, and the physical bases behind the salinity sensitivity of the hydraulic permeability remains elusive. In this study, a theoretical model for the hydraulic permeability of clayey sediments is proposed, and impacts of the pore fluid chemistry are quantitatively considered by introducing electrokinetic flow theory. Available experimental data were used to verify the theoretical model, and the verified model was further applied as a sensitivity analysis tool to explore more deeply how hydraulic permeability depends on pore fluid chemistry under different conditions. Coupling effects of pore water desalination and the effective stress enhancement on the hydraulic permeability of marine sediments surrounding a depressurization wellbore during hydrate production are discussed. Results and discussion show that the hydraulic permeability reduction is significant only when the electric double layer thickness is comparable to the characteristic pore size, and the reduction becomes more obvious when the ion mobility of the saline solution is smaller and the surface dielectric potential of clay minerals is lower. During gas hydrate production in the ocean, the salinity sensitivity of the hydraulic permeability could become either stronger and weaker, depending on whether the original characteristic pore size of marine sediments is relatively large or small.

Effect of desalination of Sargassum algae on its potential use as a stabilizer in sustainable earth-based bricks

Since 2011, Caribbean beaches have been flooded by massive quantities of pelagic Sargassum, causing environmental, health and financial problems. The use of Sargassum ash as a stabilizer in the manufacture of bricks can help mitigate the economic impact of Sargassum grounding by adding value. This study assesses the effect of the Pelagic Sargassum algae desalination process on the properties of the biomass as well as the potential application of their ash as a stabilizer in soil-based bricks. Fresh Sargassum algae was subjected to two cycles of immersion in water, then calcined under different conditions (temperature and time) and characterized. The desalinated Sargassum ash (SA) was used to partially replace cement in the stabilization of earth bricks. Characterization of raw and desalted Sargassum shows a reduction in ash content from 28.44 to 17.25 % after desalination. Furthermore, the thermo gravimetric analysis show a slight reduction in the initial degradation temperature between 204 and 602 °C, which is associated with a reduction in the amount of residual char from 35 % to 27 %. The results of the XRF analysis of the SA showed a very low alumiosilica content (SiO3 + Al2O3 < 4 %), but a significant increase in CaO content after desalination from 21.96 to 50.17 %. The XRD results of the SA are consistent with the XRF analysis which reveals that the desalination process significantly increased the CaCO3 content from 19 to 67 %, while KCl decreased significantly from 26 to 8 %. Furthermore, the characterization of the composites reveal that partial substitution of 10 wt% cement by SA calcined at 700 °C for 2 h has no significant effect on water absorption, density, compressive strength and chemical composition of earth bricks. This material could help reduce pollution linked to the decomposition of sargassum on Caribbean coasts and beaches, as well as greenhouse gas emissions linked to cement production.

The halotolerant white sea anemone Anthothoe chilensis, highly abundant in brine discharges zones, as a promising biomonitoring species for evaluating the impacts of desalination plants

Seawater desalination raises concerns about its environmental repercussions, particularly the impact of brine discharge on benthic communities. In this study, we evaluated the effects of desalination and artificial brines on the sea anemone Anthothoe chilensis, following its observed proliferation near a brine outfall from a Chilean desalination plant. We measured biomarkers for oxidative stress (ROS content, lipid peroxidation, and protein carbonylation), antioxidant response (thiols), and osmotic stress (free amino acids and proline) in individuals collected from a brine discharge pipe (∼56 psu) and compared them to a population living in natural seawater salinity. Additionally, we conducted controlled laboratory experiments where A. chilensis specimens were exposed to a control salinity of 33 psu and to elevated salinities of 37 and 42 psu for 24 and 48 h. Results revealed a significant decrease in oxidative damage biomarkers, such as protein carbonylation and ROS content, along with an increase in free amino acids, proline, and thiols content at higher salinity levels, particularly under controlled conditions. These findings demonstrate the remarkable efficient cellular stress responses of this highly halotolerant species, which could potentially promote risky A. chilensis blooms in brine discharges areas. Additionally, this study provides valuable biomarker information for assessing the short-term impacts of brine discharges, which can be used in biomonitoring programs within the desalination sector.

Low-temperature desalination driven by waste heat of nuclear power plants: A thermo-economic analysis

Nuclear desalination is one of the ideal options to achieve net-zero emissions. However, most nuclear desalination plants extract steam from the power cycle to drive desalination, leading to a reduction of electricity output. To avoid the parasitic effects of desalination on the power cycle, this study considers recovering waste heat from the power plants' condensers to drive low-temperature desalination systems, including spray-assisted low-temperature desalination system (SLTD), multi-effect distillation system (MED) and spray-assisted multi-effect distillation system (SMED). Thermodynamic and economic models of the three desalination systems are firstly established and validated with experimental data. Then, the impacts of key design, operation and economic parameters are evaluated using the validated models. Results reveal that the productivity and thermodynamic efficiency are promoted by increasing the cooling water flowrate of desalination condenser, enlarging the heat exchanger area and lifting the heat source temperature, while the number of effects has an optimal value of 3. Under the optimal configuration, the gained-output ratio and Second Law efficiency of a 20 m3/day SLTD plant are 0.71 and 1.25 % respectively. In terms of economic performance, the levelized-cost of desalinated water (LCOW) for three plants can be reduced substantially under a larger plant capacity and longer lifespan. When the plant capacity exceeds 20,000 m3/day, the LCOW of SLTD can be reduced to 0.757 $/m3, which is lower than all other desalination systems coupled with power plants or renewable energy sources.

Predictive Modeling for Solar Desalination Using Artificial Neural Network Techniques: A Review

&lt;p&gt;Due to the limitations of fossil fuels and the environmental problems associated with their usage, renewable energy sources have been exploited for desalination through the employment of various technologies and mediums. One of the most useful renewable energy sources for solar desalination, both directly and indirectly, is solar energy. The effectiveness of solar desalination is influenced by a variety of parameters, making it challenging to forecast their performance in particular circumstances. Artificial neural networks (ANNs), PSO, ANFIS, RO, and genetic algorithms would all be suitable techniques for their modeling and output predictions in this context. In the current research, multiple data-driven approaches are used in-depth to perform modeling of solar-based desalination facilities. By utilizing these methods with the proper inputs and structures, it can be deduced that the results of the solar desalination units can be consistently and correctly projected. Additionally, several suggestions are offered for future research in the relevant areas of the study.&lt;/p&gt;&#x0D;

Experimental Study on the Desalination of Waste Leachate Using the Combined Freezing Method

The current high-salinity wastewater treatment technology is complex, costly, and carries the risk of secondary contamination. As a traditional desalination technology, the combined method using frozen technology has broad development prospects in wastewater treatment. This study investigates the desalination effects of waste leachate using three different methods: the frozen–gravity method (FGM), frozen–centrifugal method (FCM), and frozen–blowing methods (FBMs), under various experimental conditions. The results showed that the salt rejection of all three methods could reach more than 75% under the conditions of a freezing time of 12 h, freezing temperature of −15 °C, and ice production rate of 40%; the salt rejection of FGM increased at higher ambient temperatures, but it was not conducive to the removal of organic pollutants; the salt rejection of FCM was sensitive to the centrifugal time and centrifugal speed, with a significant correlation (p &lt; 0.05), the increase in centrifugal time and centrifugal speed can help to improve the salt rejection, and the increase in centrifugal speed in the range of 1000–2000 rpm can accelerate the discharge of concentrated brine more effectively; the frozen–crushed–blowing method (FCBM) in FBM has a salt rejection as high as 93.86% at an ice production rate of 25.80%, which reduces the salinity of the effluent from 4.07% to 0.25%, speeds up the desalination process, and improves the salt rejection compared to the other methods. This study provides a new perspective and reference for the treatment of high-saline wastewater.

Simulating Water and Salt Migration through Soils with a Clay Layer and Subsurface Pipe Drainage System at Different Depths Using the DRAINMOD-S Model

Soil salinization affects more than 25% of land globally. Subsurface pipe drainage is known for its effectiveness in improving saline–alkali land. The red clay layer (RCL) hinders soil improvement in the Hetao Irrigation District of Inner Mongolia, China. The soil water and salt migration rules at different buried depths and RCL were studied based on the field subsurface pipe drainage test and simulation using the DRAINMOD-S model (Version 6.1). The following implications can be drawn from the results: (1) Although the RCL affected the accuracy of the model, the calibrated statistical results met the application requirements, and the DRAINMOD-S model can be used to analyze subsurface pipe drainage under different distribution conditions of the RCL. (2) The RCL can reduce the drainage efficiency of the subsurface pipe, specifically when the distribution is shallow. (3) The soil desalting rate increased with an increase in the buried depth of the subsurface pipe. The desalination effect of shallow soil was better than that of deep soil. The RCL reduced the drainage and salt removal efficiency of the subsurface pipe. Burying the subsurface pipe as far above the RCL as possible should be considered. Thus, it is feasible to apply the DRAINMOD-S model to relevant studies.

Desalination of Hamipterus tianshanensis fossil by electrokinetic method: evaluation for treatment of clay-rich sandstone

The fossils of Hamipterus tianshanensis (Wang et al. in Curr Biol 24:1323–1330, 2014) and their eggs have important scientific significance because they can provide unique information about the reproduction, development, and evolution of pterosaurs. The fossils and the rock surrounding them have, however, been weathered, which including powdering and flaking, since they were relocated from Xinjiang to Beijing. The high content of soluble salts is a significant factor in fossil deterioration because the dissolution–recrystallization process can generate tremendous pressure and lead to decreased mechanical strength. This study evaluated the electrokinetic desalination performance for the fossils, and two types of poultices employed including paper pulp from Bioline® and CKS121 (cellulose: kaolin: sand = 1:2:1, w/w). Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), ion chromatography (IC), and other methods were applied to evaluate the desalination effect. The surface salt content reduction by applied direct current (DC) was about 70%, and the inner salt content reduction was about 80%. The experimental results suggest that the electrokinetic method is a promising way to desalinate fossils. Nonetheless, cracks appeared in the surrounding rock crack after electrokinetic desalination, which can be explained by the montmorillonite swelling-induced stresses. Pre-consolidation, especially for electro-chemical method may solve the cracking problem for the clay-rich sandstone desalination.

Efficient desalination method using a subsurface drainage pipe with rice husk in paddy fields

The 2011 tsunami from the Great East Japan Earthquake caused severe soil salinization in agricultural lands. Soil salt removal using a subsurface drainage pipe with rice husk has been widely used in many paddy fields. However, desalination was frequently decided based on the expertise of construction contractors in Japan resulting in inefficient desalination methods that led to a significant wastage of freshwater resources and a long duration for agricultural restoration. Previous studies have either simulated conventional subsurface drainage without considering the rice husk zone or focused only on rice husk subsurface drainage systems excluding pipes. However, no quantitative research on a subsurface drainage pipe with rice husk has been conducted using numerical simulations. Accordingly, this study proposes highly efficient desalination methods for reducing freshwater wastage using an indoor experiment and numerical simulation. The indoor experiment of the subsurface drainage pipe with rice husk was set up in a soil tank of 900 × 200 × 900 mm (length × width × height), with reproduced salinization using NaCl solution inundation and soil desalination using freshwater. Thereafter, calibration and validation using HYDRUS-2D confirmed the model's accuracy in reproducing the movement of water and salt in the soil profile. The effects at a ponding water depth of 50–300 mm under various conditions on desalination efficiency and leaching water quantity were simulated. The results suggested that as the same desalination effect is achieved, low ponding water depths with multiple desalting cycles will reduce the quantity of leaching water. Moreover, under low ponding water depth conditions, prolonging the flooding duration will cause a decrease in the desalination effect. In addition, for the same quantity of leaching water, increasing the pipe burial depth is more beneficial to desalination than expanding the rice husk zone width. This study provides theoretical guidance for water conservation and high-efficiency desalination using the subsurface drainage pipe with rice husk for post-disaster early restoration of paddy fields.

Feasibility Study of a Reverse Osmosis Desalination Unit Powered by Photovoltaic Panels for a Sustainable Water Supply in Algeria

In recent years, reverse osmosis water desalination has developed rapidly and has become the most competitive and widely used technology in the world. The number of desalination plants is increasing rapidly as freshwater needs increase. Various membrane technologies have been developed and improved, including nanofiltration (NF) and reverse osmosis (RO), whose desalination costs have been relatively reduced. Therefore, this work proposes an experimental study for a small desalination unit based on RO generated by renewable energy, which is mainly suitable for arid regions or desert areas that do not have electricity and water and can be applied for emergency treatment to meet strong freshwater resource needs. In this study, to meet the drinking water demand, a reverse osmosis desalination system is designed and evaluated in order to improve and optimize its operation. This system has a daily capacity of 2 m3. We used brackish groundwater, which has been characterized as reference water, to produce synthetic water for different salinities until seawater. The analysis is based on data obtained from experiments carried out in the standalone RO pilot designed for the production of fresh water. For this purpose, we conducted relevant experiments to examine the influence of applied pressure, salt concentration and temperature on the RO membrane performance. The effects of different factors that affect the energy consumption in the RO desalination process were analyzed, and those with significant influence were explored. The effectiveness of RO desalination coupled with a photovoltaic (PV) energy system is shown. We found the recovery rate for system operation to be 32%. An optimization study is presented for the operation of an autonomous RO desalination system powered by photovoltaic panels. The energy produced by the PV system was used to feed two pumps forthe production of drinking waterwithanRO membrane, under the conditions of the town of Bou-Ismail. As results, a 3 kWp PV system was installed based on the energy demand. The design data have shown that a 3 kWp PV system can power a 1.8 W RO load given the Bou-Ismail climate. Energy consumption in the case study under Bou-Ismail weather conditions were analyzed. The desalination of brackish water at a TDS value of 5 g/L requires an energy of about 1.5 kWh/m3. Using seawater at a TDS value of 35 g/L, this value increases to 5.6 kWh/m3. The results showed that the optimal recovery rate for system operation was determined to be 32% for a feedwater salinity of 35 g/L, and 80% for a feedwater salinity of 1 g/L.

Desalination brine effects beyond excess salinity: Unravelling specific stress signaling and tolerance responses in the seagrass Posidonia oceanica.

Desalination has been proposed as a global strategy for tackling freshwater shortage in the climate change era. However, there is a concern regarding the environmental effects of high salinity brines discharged from desalination plants on benthic communities. In this context, seagrasses such as the Mediterranean endemic and ecologically important Posidonia oceanica have shown high vulnerability to elevated salinities. Most ecotoxicological studies regarding desalination effects are based on salinity increments using artificial sea salts, although it has been postulated that certain additives within the industrial process of desalination may exacerbate a negative impact beyond just the increased salinities of the brine. To assess the potential effect of whole effluent brines on P. oceanica, mesocosm experiments were conducted within 10 days, simulating salinity increment with either artificial sea salts or brines from a desalination plant (at 43 psμ, 6 psμ over the natural 37 psμ). Morphometrical (growth and necrosis), photochemical (PSII chlorophyll a fluorometry), metabolic, such as hydrogen peroxide (H2O2), thiobarbituric reactive substances (TBARS) and ascorbate/dehydroascorbate (ASC/DHA), and molecular (expression of key tolerance genes) responses were analyzed in each different treatment. Although with a still positive leaf growth, associated parameters decreased similarly for both artificial sea salt and brine treatments. Photochemical parameters did not show general patterns, although only P. oceanica under brines demonstrated greater energy release through heat (NPQ). Lipid peroxidation and upregulation of genes related to oxidative stress (GR, MnSOD, and FeSOD) or ion exclusion (SOS3 and AKT2/3) were similarly incremented on both hypersalinity treatments. Conversely, the ASC/DHA ratio was significantly lower, and the expression of SOS1, CAT, and STRK1 was increased under brine influence. This study revealed that although metabolic and photochemical differences occurred under both hypersalinity treatments, growth (the last sign of physiological detriment) was similarly compromised, suggesting that the potential effects of desalination are mainly caused by brine-associated salinities and are not particularly related to other industrial additives.

Black Soldier Fly (Hermetia illucens) Larvae Frass Organic Fertilizer Improves Soil Quality and the Productivity of Durum Wheat

ABSTRACT Hermetia illucens L. known as Black Soldier Fly (BSF) is gaining worldwide interest as the most prevalent species in insect farming. In the current study, we evaluated under greenhouse conditions, the comparative performance of Black Soldier Fly Larvae (BSFL) frass as an organic fertilizer and a traditional organic amendment: cow manure (CM), on soil rhizosphere properties and durum wheat agro-morphological, physiological, and yield parameters. Both organic fertilizers were applied at doses of 7.5 t/ha (BSFL7.5 and CM7.5), 15 t/ha (BSFL15 and CM15) and 30 t/ha (BSFL30 and CM30). The results showed that applying BSFL frass with 7.5 and 15 t/ha had an acidifying as well as a desalination effect on soil compared to CM. The highest mineral nitrogen, phosphorus, and potassium contents were recorded in soils receiving 30 t/ha of BSFL frass. Microbial biomass was found to be improved by applying the lowest doses of BSFL frass. Durum wheat plants grown in pots treated with BSFL frass had the highest height, dry root weight, and chlorophyll indicators. The PCA analysis identified grain yield, yield component, and soil nutrients as major drivers for the variability among samples. Our results highlight the potential of BSFL frass to improve soil health and wheat yields in an environmentelly-friendly way.

Exploring purification methods to improve retrieval of collagenous binder residues from archeological murals

A comparison was conducted on five methods for purifying collagenous residues extracted from paint replicas. The bicinchoninic acid method was used to quantify proteins recovered by these purification methods, and the conductivity in purified solutions was monitored. Statistical analysis was carried out by multivariate analysis of variance (MANOVA). The effect of different purification processes upon the molecular structure of the retrieved proteins was characterized with the aid of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), ultraviolet (UV) absorption spectroscopy, and circular dichroism (CD) spectroscopy. The results showed that the five methods all had significant desalination effects, among which dialysis, ultrafiltration, and ethanol precipitation could achieve lower conductivity. The protein recovery rate of dialysis was remarkably higher than the rates of other methods. With the aging time of the paint replicas, the recovery rates of all purification methods showed a downward trend, with the advantage of dialysis becoming more and more remarkable. No significant differences were found in the molecular weight and microstructure of the residues retrieved by the five purification methods, indicating that the impacts of different purification processes on the microstructure of proteins / peptides are approximately the same. A total of 29 identified peptides (consisting of 18 unique ones) corresponding to rabbit collagen were successfully detected in a model sample using the improved pretreatment. This paper concluded that dialysis is a more promising purification method for archeological paint samples with a higher potential to retrieve more residues for subsequent analysis.

A risk assessment on Zostera chilensis, the last relict of marine angiosperms in the South-East Pacific Ocean, due to the development of the desalination industry in Chile

Seagrasses, which are considered among the most ecologically valuable and endangered coastal ecosystems, have a narrowly limited distribution in the south-east Pacific, where Zostera chilensis is the only remaining relict. Due to water scarcity, desalination industry has grown in the last decades in the central-north coasts of Chile, which may be relevant to address in terms of potential impacts on benthic communities due to their associated high-salinity brine discharges to subtidal ecosystems. In this work, we assessed ecophysiological and cellular responses to desalination-extrapolable hypersalinity conditions on Z. chilensis. Mesocosms experiments were performed for 10 days, where plants were exposed to 3 different salinity treatments: 34 psu (control), 37 psu and 40 psu. Photosynthetic performance, H2O2 accumulation, and ascorbate content (reduced and oxidized) were measured, as well as relative gene expression of enzymes related to osmotic regulation and oxidative stress; these, at 1, 3, 6 and 10 days. Z. chilensis showed a decrease in photosynthetic parameters such as electron transport rate (ETRmax) and saturation irradiance (EkETR) under hypersalinity treatments, while non-photochemical quenching (NPQmax) presented an initial increment and a subsequent decline at 40 psu. H2O2 levels increased with hypersalinity, while ascorbate and dehydroascorbate only increased under 37 psu, although decreased along the experimental period. Increased salinities also triggered the expression of genes related to ion transport and osmolyte syntheses, but salinity-dependent up-regulated genes were mostly those related to the reactive oxygen species metabolism. The relict seagrass Z. chilensis has shown to withstand increased salinities that may be extrapolable to desalination effects in the short-term. As the latter is not fully clear in the long-term, and considering the restricted distribution and ecological importance, direct brine discharges to Z. chilensis meadows may not be recommended.

Spring irrigation with magnetized water affects soil water-salt distribution, emergence, growth, and photosynthetic characteristics of cotton seedlings in Southern Xinjiang, China

BackgroundSpring irrigation with freshwater is widely used to reduce soil salinity and increase the soil water content in arid areas. However, this approach requires a huge amount of freshwater, which is problematic given limited freshwater resources. Utilizing brackish water for spring irrigation in combination with magnetized water technology may be a promising alternative strategy.ResultsThe objective of this study was to evaluate the effects of four spring irrigation methods (freshwater spring irrigation (FS), magnetized freshwater spring irrigation (MFS), brackish water spring irrigation (BS), and magnetized brackish water spring irrigation (MBS)) on soil water and salt distribution, emergence, growth, and photosynthetic characteristics of cotton seedlings. The results showed that for both freshwater and brackish water, magnetized water irrigation can increase the soil water content for improved desalination effect of irrigation water. Additionally, spring irrigation with magnetized water promoted cotton emergence and seedling growth. Compared with FS treatment, cotton finial emergence rate, emergence index, vigor index, plant height, stem diameter, and leaf area index of MFS treatment increased by 6.25, 7.19, 12.98, 15.60, 8.91, and 20.57%, respectively. Compared with BS treatment, cotton finial emergence rate, emergence index, vigor index, plant height, stem diameter, and leaf area index of MBS treatment increased by 27.78, 39.83, 74.79, 26.40, 14.01, and 57.22%, respectively. Interestingly, we found that spring irrigation with magnetized water can increase the chlorophyll content and net photosynthetic rate of cotton seedlings. The rectangular hyperbolic model (RHM), non-rectangular hyperbolic model (NRHM), exponential model (EM), and modified rectangular hyperbolic model (MRHM) were used to fit and compare the cotton light response curve, and MRHM was determined to be the optimal model to fit the data. This model was used to calculate the photosynthetic parameters of cotton. Compared with FS treatment, the net photosynthetic rate (Pnmax), dark respiration rate (Rd), light compensation point (Ic), light saturation point (Isat), and the range of available light intensity (ΔI) of MFS were increased by 5.18, 3.41, 3.18, 2.29 and 2.19%, respectively. Compared with BS treatment, the Pnmax, Rd, Ic, Isat and ΔI of MBS were increased by 26.44, 29.48, 30.05, 5.13, and 2.27%, respectively.ConclusionThe results show that spring irrigation with magnetized brackish water may be a feasible method to reduce soil salt and increase soil water content when freshwater resources are insufficient.