Shortage Of Freshwater Resources Research Articles

Boosted Near-Infrared Photothermal Conversion in Rare Earth Ions-Doped 2D SnSe Nanosheets for Solar-Powered Water Evaporation Systems.

Solar-powered water evaporation as a clean and abundant renewable energy-efficient desalination technology provides a promising strategy to solve the shortage of freshwater resources. However, the development and application of solar vapor technology are hindered by the relatively low near-infrared photothermal conversion efficiency of existing materials and the lack of effective improvement strategies. In this work, the conductivity characteristics of 2Dsemiconductors are capitalized on the high visible light absorption and ultra-low thermal. Specifically, rare-earth ion dopants into SnSe nanosheets, significantly boosting their near-infrared photothermal conversion efficiency and solar water evaporation performance are introduced. Remarkably, the photothermal conversion efficiency of the doped SnSe nanosheets surged from 51.56% to 82.11%, surpassing many previously reported photothermal materials. Furthermore, leveraging these nanosheets with enhanced photothermal conversion efficiency, a solar interfacial evaporation system is constructed. The evaporation rate of 2.17kgm-2h-1 and the efficiency of 96.5% can be achieved at one solar irradiance, and it also has good salt-resistance properties. The findings demonstrate the potential of rare earth ion-doped 2D semiconductor nanosheets in solar water evaporation, paving the way for future sustainable desalination solutions.

Biomimetically spider web-like hydrogels for high-efficiency solar evaporators

With the increasing population, the shortage of freshwater resources has become a problem faced by human beings. Although many hydrogel solar evaporators achieved high evaporation rates by increasing the intermediate water content to reduce the enthalpy of water evaporation, it is still challenging to explore effective photothermal materials to construct efficient hydrogel solar evaporators. Here, inspired by the spider web structure, interconnected porous hydrogels were proposed by cross-linking heterojunctions and polymers. For the first time, MXene heterojunction is applied to solar evaporators. The introduction of SnS2 greatly improves the light absorption of MXene, at the same time, benefiting from the multi-scale macro/micro fiber network structure, MXene-SnS2 hydrogel (MSH) has a good “lock-in” performance, which makes the heat locally distributed near the evaporable water. As a result, the MSH evaporator has a low enthalpy of evaporation, with an evaporation rate of 3.3606 kg m−2 h−1 in 3.5 wt% salt water, and can maintain 1.9 kg m−2 h−1 even in 10.5 % brine. The evaporators present superior purification performance for seawater, could maintain high and stable evaporation performance for 72 h. This design principle and excellent performance provide a potential method and design concept for seawater desalination.

Biomimetic multi-functional 3D fog collector: Independent of fog flow direction

The shortage of freshwater resources has a great impact on the daily life of human beings, and fog collection has become an effective mitigation measure. In this paper, inspired by the nanofabricated desert beetle, honeycomb, Euphorbia antiquorum L. and cactus, a 3D fog collector combining a conical array structural gradient and a wettability gradient was presented, with special three-dimensional array structure (TA-L/B (PPC)) that ensures that the fog-collecting efficiency of the samples is virtually independent of the direction of the fog flow. The fog collection efficiency of sample TA-L/B (PPC) is close to 4.3 g·h−1·cm−2, a value that is 1.77 times higher than the surface fog collection efficiency of the copper sheet (OS) sample. By rationally designing the surface structure of the sample, the fog circulation process is accelerated, and a sustainable and stable fog collection process is achieved.

Assembled Wood-Polyester Fabric-Hydrogel Janus Evaporator for Sustainable Seawater Desalination.

Solar-driven interfacial evaporation technology is a novel and efficient desalination process that helps alleviate the global shortage of freshwater resources. We developed a Janus evaporator assembled from cotton hydrogel, hydrophilic polyester fabric (PF), and Hydrophobic Wood (PW). By doping graphene oxide and TiO2 as light-absorbing materials within the hydrogel, we achieved a high absorptivity of over 90% across the entire solar spectrum. The hydrophilically modified PF, combined with the PW substrate, provided robust water transport and reduced thermal losses. Subsequent optical path simulations using TracePro74 software verified that the sawtooth light-trapping design of the wood substrate increased multiple light reflections and absorption (compared to a flat structure), enhancing light absorption capabilities. The sawtooth interface also enlarged the evaporation area, further boosting evaporation performance. The cleverly designed evaporator exhibited an evaporation rate of 1.722 kg m-2 h-1 and an efficiency of 83.1% under 1 sun irradiation. Additionally, after applying polydimethylsiloxane to the single surface of the photothermal hydrogel for low surface energy treatment, the resulting Janus structure demonstrated asymmetric wettability that prevented salt ions from accumulating on the irradiated interface. After 8 h of continuous evaporation in saline water (10 wt %), only slight salt crystallization occurred at the edges. The evaporator maintained long-term stability during a 15 day cyclic test, and the produced freshwater fully met the relevant drinking water standards. The components of the evaporator are characterized by simple fabrication, low cost, and eco-friendliness, offering significant application potential in the global context of energy conservation and emission reduction initiatives.

Application Research of an Automatic Control Seawater Reverse Osmosis (SWRO) System Based on the Siemens PLC

To solve the global environmental problem of a shortage of freshwater resources, seawater desalination is considered one of the most promising solutions. In this research, the main novelty of the seawater desalination system lies in its utilization of a reverse osmosis unit as the core process for producing drinking water. By optimizing the pretreatment section in the process flow, a seawater reverse osmosis (SWRO) control system based on Siemens PLC with a high degree of automation was developed, which has the advantages of convenient maintenance and monitoring. In addition, through research on reverse osmosis systems, the results showed that within two years of operation, the total desalination rates of the primary and secondary reverse osmosis systems were not less than 99% and 97.5%, respectively. Furthermore, the water quality after desalination was tested. When the doses of CaCl2, MgCl2 and NaHCO3 were 20 mg/L, 15 mg/L, and 50 mg/L, respectively, high-quality drinking water was obtained. Finally, a reasonable process plan and corresponding estimates were given for the complex water source conditions. Compared with traditional seawater desalination systems, our system has the advantages of easy operation, efficient water production and lower price. Accordingly, this study will help to solve drinking-water problems in some freshwater-scarce regions.

Effect on Concrete by Using Partial Pharmaceutical Industrial Waste Water

Water is a precious resource essential for human life and valuable for development. The total demand for water increases as the region's population grows. This could lead to a strain on water supplies, particularly in areas with a shortage of freshwater resources. Water is also required for the construction industry. With slightly under eight billion people on the planet today, there is an increasing need for water due to water stress brought on by climate change. Water shortage is mainly caused by urbanization. The deficiency of water is rapidly becoming a problem all over the world. This project studies the use of wastewater effluent in place of potable water in plane concrete production. The wastewater sample obtained from the MIDC Kurukumb, Daund, was tested for pH, Total Dissolved Solids (TDS), Chloride, Hardness, Alkalinity and Sulphate. To achieve M40 grade concrete mix, wastewater is replaced by 0% to 100% with an interval of 25%.

Janus structured photothermal conversion materials prepared from carbonized corn straw particles for portable air water extraction devices

The utilization of photothermal conversion materials to enhance the desorption performance of hygroscopic salt solutions through interfacial photothermal effects presents a promising approach for the continuous extraction of water from the atmosphere. To improve the desorption efficiency of hygroscopic salt solutions, the objective of this research is to employ agricultural and forestry residues, such as corn straw, in conjunction with polyurethane sponges, for the production of an innovative Janus structure carbonized biomass photothermal conversion material. Compared to single-layer structured photothermal conversion materials, the pure water evaporation rate increased from 2.42 kg m-2 h-1 to 3.20 kg m-2 h-1 when utilizing the Janus structured photothermal conversion material. Remarkably, this material demonstrates outstanding resistance to salt, allowing it to endure 8 h evaporation cycles with 30 wt% NaCl without salt crystallization. Therefore, it is well-suited for the continuous desorption of liquid hygroscopic agents. Moreover, the portable air–water extraction device, which incorporates Janus structural photothermal conversion material to enhance the performance of 30 % LiCl, has been shown to effectively extract water in practical settings. It achieves a water intake rate of 1.74 L m-2 d-1 at 50 % humidity. This approach is distinguished by its simplicity, cost-effectiveness, and efficient utilization of solar energy resources, providing a promising solution to mitigate the shortage of fresh water resources.

Application of VIC-WUR model for assessing the spatiotemporal distribution of water availability in anthropogenically-impacted basins

Climate change, rapid increase in population, and urbanization have given rise to over-exploitation and shortage of freshwater resources. Acquiring accurate representations of fresh water availability is therefore crucial to sustainable development. Based on the underlying hydrological processes and storage types, fresh water can be divided into blue and green water components. Hence, quantification of the spatio-temporal distribution of blue and green water requires estimating the components of terrestrial water cycle. In this study, a framework is proposed to evaluate the water scarcity using the blue and green water concept. In this framework, the Wageningen Institute and Research (WUR) version of the Variable Infiltration Capacity Model (VIC) is employed to simulate terrestrial water cycle. Compared to VIC model, VIC-WUR model employs additional modules to account for sectoral water demands, return flows, and groundwater withdrawals, however, very limited number of its applications have been reported so far. The Divandareh-Bijar (DBJ) basin in west of Iran is selected because it has experienced severe anthropogenic alterations in the past three decades. To address precipitation and parameter uncertainty, the VIC-WUR model is separately calibrated for three precipitation datasets. As a part of this framework, the calibrated model is used to simulate blue and green water components and their corresponding scarcity metrics for the first time. According to the results, blue and green water resources in the DBJ are relatively scarce. The results also highlight the importance of considering anthropogenic impacts on the spatiotemporal dynamics of green and blue water resources. Additionally, quantification of the uncertainty in blue and green water components can help produce more reliable estimations for intelligent management of water resources. The ANalysis Of VAriance (ANOVA) method is therefore used to quantify the contribution of three major factors, including precipitation inputs, model parameters, and the interaction of these two, on the uncertainty of calculated water scarcity metrics. Structural uncertainty is implicitly addressed through the use of the modified version of the VIC model. The results indicate seasonality of these contributions for the two metrics under investigation and the differences in relative contribution of different sources to the overall uncertainty. The proposed framework could be employed to identify water stress in various spatiotemporal scales across the globe.

Dual-Interface Solar Evaporator with Highly-Efficient Thermal Regulation via Suspended Multilayer Design.

Facing the increasing global shortage of freshwater resources, this study presents a suspended multilayer evaporator (SMLE), designed to tackle the principal issues plaguing current solar-driven interfacial evaporation technologies, specifically, substantial thermal losses and limited water production. This approach, through the implementation of a multilayer structural design, enables superior thermal regulation throughout the evaporation process. This evaporator consists of a radiation damping layer, a photothermal conversion layer, and a bottom layer that leverages radiation, wherein the bottom layer exhibits a notable infrared emissivity. The distinctive feature of the design effectively reduces radiative heat loss and facilitates dual-interface evaporation by heating the water surface through mid-infrared radiation. The refined design leads to a notable evaporation rate of 2.83kg m-2 h-1. Numerical simulations and practical performance evaluations validate the effectiveness of the multilayer evaporator in actual use scenarios. This energy-recycling and dual-interface evaporation multilayered approach propels the design of high-efficiency solar-driven interfacial evaporators forward, presenting new insights into developing effective water-energy transformation systems.

Preparation and properties of a metal-organic frameworks polymer material based on Sa-son seed gum capable of simultaneously absorbing liquid water and water vapor

Atmospheric water harvesting (AWH) technology has attracted significant attention as an effective strategy to tackle the global shortage of freshwater resources. Work has focused on the use of hydrogel-based composite adsorbents in water harvesting and water conservation. The approaches adopted to make use of hygroscopic inorganic salts which subject to a “salting out” effect. In this study, we report the first use of modified UIO-66-NH2 as a functional steric cross-linker and Sa-son seed gum was used as polymeric substrate to construct super hygroscopic hydrogels by free radical copolymerization. The maximum water uptake on SMAGs (572 cm3·g−1) outperforms pure UIO-66-NH2 (317 cm3·g−1). Simultaneously, our first attempt to use it for anti-evaporation applications in an arid environment (Lanzhou, China) simulating sandy areas. The evaporation rate of the anti-evaporation material treated with 0.20 % super moisture-absorbent gels (SMAGs) decreased by 6.1 % over 64 h period under natural condition in Lanzhou, China. The prepared material can not only absorb liquid water but also water vapor, which can provide a new way for water collection and conservation technology. The design strategy of this material has wide applications ranging from atmospheric water harvesting materials to anti-evaporation technology.

High anti-corrosive and Scalable CDs/BCN heterostructure photocatalysts for efficient H2 production in natural seawater

Photocatalytic natural seawater-derived splitting to produce hydrogen is one of the most potential strategies to alleviate the shortage of freshwater resources and energy crisis. Nevertheless, the complicated composition of natural seawater poses substantial challenges to the activity and stability of photocatalysts. Here, we report on the fabrication of carbon dots (CDs) and B elements co-modified carbon nitride (i.e. CDs/BCN) via precursor-mediated supramolecular self-assembly and subsequent NaBH4-assisted thermal reduction as well as its implementation as seawater-derived H2 production. The fabricated CDs/BCN exhibits the flaky porous structure capable of providing more transport channels for the generated gases (e.g. H2) and precipitates (e.g. Mg(OH)2, Ca(OH)2) during the seawater splitting process. Benefitting from cooperation of CDs and B elements i.e. the inhibited recombination of electron-hole pairs as well as the extended optical absorption range of CN, the optimal CDs/BCN-2 under visible-light irradiation exhibits the high H2 production rate up to 10369 μmol g-1 h-1 in natural seawater. The proven satisfactory reusability and the corresponding structural stability demonstrate the excellent corrosion resistance of CDs/BCN-2 in natural seawater. Additionally, CDs/BCN-20 photocatalyst synthesized via 20-fold precursor amplification procedure still displays efficient photocatalytic performance of 9022 μmol g-1 h-1, indicating its potential for industrial applications.

Chloride binding mechanism in seawater-mixed UHPC

The rapid development of marine concrete structures and the sharp shortage of freshwater resources contribute to the wide investigation of seawater-mixed ultra-high-performance concrete (SWUHPC). However, few studies have investigated the chloride ions (Cl-) binding mechanism of SWUHPC. Herein, the chloride binding experiments and molecular dynamics (MD) simulation were carried out to reveal the physically and chemically bound Cl- mechanisms of SWUHPC. The results of the experiments clearly demonstrate that the addition of silica fume (SF) led to a significant decrease in the capacity of Cl- binding. Conversely, the incorporation of metakaolin (MK) resulted in a marked increase in the content of chemically bound Cl-. Furthermore, it is revealed through MD simulations that the amount of physically bound Cl- heavily depends on the Ca/Si ratio of C-S-H. A higher Ca/Si ratio results in a stronger electrostatic effect of the C-S-H surface on Cl-, which increases the physical binding of Cl- via Ca-Cl bonds. In addition, it is found that Al[6] and Ca in the interlayer region of C-A-S-H formed the main structure layer (Ca4Al2(OH)122+) of Friedel’s salt, and then chemically adsorbed Cl- in the pore solution. These findings provide novel nanoscale insights regarding the physically and chemically bound Cl- mechanisms of SWUHPC.

Multi‐Dimensional Bionic Micro‐Nanostructure Surface for Controllable Fog Harvesting: from Fabrication to Application

AbstractWith the rapid growth of the population and the development of the economy, the shortage of freshwater resources has become a worldwide problem. Utilizing fog harvesting provides a practical solution to relieve the water shortage problem for residents in arid regions. This review summarizes the typical fog harvesting phenomena in nature in detail, the construction methods, fog harvesting performance, and the action mechanism of different biomimetic micro‐nano structures from one‐dimensional (1D), two‐dimensional (2D), and three‐dimensional (3D) perspectives. The influence of surface micro‐nano structure and wettability on water harvesting performance is analyzed. Finally, the challenges and future development directions of multi‐scale micro‐nano surface controllable water harvesting technology are summarized and prospected, which provides a good idea for the design of bioinspired micro‐nanomaterials and promotes water harvesting from scientific research to practical application.

Superhydrophobic Bulgy Windmill for Synchronous Efficient Fog Collection and Power Generation.

The shortage of freshwater resources is a serious problem faced by mankind in the 21st century. To maximize the acquisition of freshwater resources, numerous fog collectors have been constructed. In the process of fog collection accompanied by the movement of the wind, the mechanical energy brought about by the wind is often ignored. Based on this, inspired by beetles and origami art, we designed a windmill installation with a bump on the edge. Droplets nucleate at the windmill bulge and accelerate the transport process under the action of centrifugal force. This leads to quick fog collection and reduces the secondary evaporation rate of freshwater resources. The fog collection efficiency can reach 2.8 times that of the original sample. Moreover, the windmill can convert mechanical energy into electricity while collecting fog, and the operating voltage of a single windmill can reach 0.85 V. After the array, the amount of fog collected by the windmill and the power generation voltage can be increased by multiple times, which realizes the efficient use of energy and provides a new idea for the design of an efficient fog collector in the future.

A comprehensive review on adsorptive removal of azo dyes using functional materials

Abstract The shortage of freshwater resources caused by azo dye pollution is an acute global issue, which has a great impact on environmental protection and human health. Therefore, the use of new strategies for designing and synthesizing green, efficient, and economical materials for the removal of azo dyes is required. Among the various methods for removal of azo dyes, adsorption by using advanced functional materials, including nanomaterials, metal oxides, metal oxides–polymer composite, biomaterials, and porous materials, have attracted significant attention over the past few years because of their capabilities of brilliant removal efficiency, high selectivity, quick response, reversibility, flexibility in operation, and less harmful by-products. In this review, we report the adsorption of azo dyes and general design principles underlying the above-mentioned functional materials and, in particular, highlight the fundamental mechanisms and effect of various environmental conditions; also, current challenges and opportunities in this exciting field have been emphasized, including the fabrication, subsequent treatment, and potential future applications of such functional materials.

Highly efficient freezing desalination technology: Parameters optimization and model configuration

Seawater desalination has become an available route to reduce the shortage of freshwater resources. Lower energy consumption and suitable operational conditions make freezing crystallization a green technique in the desalination area. Herein, we coupled the sweating intensification with the freezing crystallization to reach a highly efficient desalination performance. Under the trajectory of the freezing temperature and time: 259.15 K and 150 min, the sweating temperature, heating rate, and sweating time: 272.15 K, 0.5 K/min, and 120 min, the desalination ratio exceeds 70 %. Meanwhile, we established the theoretical models to expound the intrinsic correlations of process variables and target parameters, to visualize the impurity migration. Two kinetic models are proposed to analyze temperature effects on the crystal layer growth, sweating melt flow, and inclusion entrapment. Next, the fractal slice model is proposed to describe the complex microstructure of the crystal pillar. The thermal coefficients are deduced based on the fractal theory, where the larger porosity is against thermal conduction. Finally, we discussed the kinetic and porosity effects on the impurity migration and desalination performance, and established a boundary layer model to correlate the separation efficiency with process kinetic and impurity distribution successfully.

Response of Soil Fungal Community to Biochar Application Under Different Irrigation Water Salinity

Saline water irrigation can alleviate the shortage of freshwater resources in the northwest arid zone, but long-term saline water irrigation can damage the soil fungal community structure. To alleviate the harm caused by salinity, biochar is used as a soil amendment to improve the soil fungal community structure. To investigate the intrinsic link between biochar application and the structural diversity of fungal communities in saline soils, two irrigation water salinity levels were set:0.35 dS·m-1 (fresh water) and 8.04 dS·m-1 (saline water). At each irrigation water salinity, two levels of biochar application were set:0 t·hm-2 (no application) and 3.7 t·hm-2 (application). High-throughput sequencing results showed that compared to that under fresh water irrigation, saline water irrigation increased fungal community species diversity and decreased fungal community species richness; biochar application under saline water irrigation reduced soil fungal community species diversity and species richness. The dominant fungal phyla in the soils of each treatment were Ascomycota, Mortierellomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Rozellomycota, and Cysticercales, and the dominant genera were Gibberella, Chaetomium, Sarocladium, Stachybotrys, and Fusarium. Compared to that under freshwater irrigation, saline water irrigation significantly increased the relative abundance of Basidiomycota and Chytridiomycota and significantly decreased the relative abundance of Ascomycota and Rozellomycota. The application of biochar under saline irrigation significantly increased the relative abundance of Ascomycota and Sarocladium but significantly decreased the relative abundance of Basidiomycota, Chaetomium, and Fusarium. LEfSe analysis showed that under the condition of no biochar application, saline irrigation reduced the number of potential biomarkers of fungal communities, whereas the application of biochar under the condition of saline irrigation increased the number of potential biomarkers of fungal communities. These results indicated that the application of biochar can improve the saline soil environment and fungal community structure and provide a theoretical basis for reasonable brackish water irrigation and soil fertilization in arid areas.

Highly Efficient and Durable P, Ru-CeO2 Self-supporting Electrodes Toward Industrial-level Hydrogen Production

The electrolysis of seawater has become a preferred method for hydrogen production since the current shortage of freshwater resources, offering an effective strategy to address the energy crisis. Nevertheless, this...

Janus membrane with asymmetric wettability for efficient oil/water separation

The rapid development of society and industry as well as the frequent occurrence of oil spills cause the shortage of fresh water resources, which not only affects human safety and life, but also impedes the world-wide sustainable development. To address these challenges, novel membrane materials with unique wettability properties have gained significant attention, particularly in the field of oil/water separation. In this research, we modified the hydrophobic PET fabric to achieve superhydrophilic characteristics using impregnation method. Subsequently, we electrospun hydrophobic PVDF fibers onto the superhydrophilic fabric surface, and PVDF/Ca10(PO4)6(OH)2@PET Janus membrane with asymmetric wettability was obtained. The membrane has an excellent unidirectional liquid transport capacity, and can effectively separate heavy oil or light oil, the separation efficiency is more than 90 %. The results also show that the Janus membrane can be used under alkaline conditions and has satisfactory tensile resistance and re-use performance. This work provides a new idea for Janus membrane design and effectively improves the application potential of the Janus membrane in the field of oil/water separation.

Multifunctional graphene/Ag hydrogel with antimicrobial and catalytic properties for efficient solar-driven desalination and wastewater purification

The increasing shortage of freshwater resources needs to be addressed urgently. Solar-driven desalination and wastewater purification are efficient and green methods to obtain freshwater resources. However, it is still a challenge to obtain efficient, stable, salt-resistant, antimicrobial, and antifouling evaporators. To address this challenge, in this study, polyacrylamide-based reduced graphene oxide hydrogels with a porous structure were synthesized in situ by a one-step radiative reduction method, and silver nanoparticles were introduced on this basis. Graphene/silver composite hydrogel (ArG-Ag) exhibits fast water transport, thermal localization, and low enthalpy of water evaporation, achieving an excellent evaporation rate of 3.089 kg m-2h−1 (one sun) and an evaporation efficiency of 122.7 %, as well as good mechanical stability, salt resistance, and salt ion purification after 8 cycles of evaporation. The ArG-Ag evaporator exhibits 99 % 24 h bacterial inhibition against E. coli and 210-day long-term mold resistance, effectively resisting biological contamination of seawater. In this study, multifunctional evaporators with integrated high efficiency evaporation performance, salt resistance, antimicrobial, antifungal, antifouling, and catalytic properties are proposed, which are expected to be used for seawater desalination and wastewater purification.