Global Water Demand Research Articles

Retention of micropollutants by polyelectrolyte multilayer based hollow fiber nanofiltration membranes under fouled conditions

To meet the increasing global water demand, local solutions, such as the reuse of greywater, are becoming of greater importance. While greywater reclamation has been implemented, full-scale adaptation has been limited by the occurrence of micropollutants in treated greywater effluent. To reduce the risks posed by micropollutants, advanced post-treatment is required. One promising technology is the implementation of hollow fiber nanofiltration, which has proven to effectively remove micropollutants. However, the effect of fouling on the overall membrane performance has received limited attention. In this research, the effect of fouling on the performance of polyelectrolyte multilayer nanofiltration membranes was evaluated. Filtration experiments were performed using hollow fiber nanofiltration membranes using model solutions and greywater effluent. Synthetic greywater effluent with different model foulants was implemented to simulate bio- and colloidal fouling. Afterwards, the fouling propensity of greywater effluent from a source-separated treatment plant was evaluated. The performed experiments demonstrated that the studied hollow fiber nanofiltration membranes are mainly sensitive to biofouling. Permeability loss was observed in all foulant experiments, and overall, sodium alginate most severely reduced the flux. Regardless of the loss in permeability, micropollutant retention remained relatively constant, demonstrating the potential suitability of hollow fiber nanofiltration membranes in greywater reclamation schemes.

Assessing Virtual Water Trade Balance of Agricultural Products (A Case Study of Mazandaran province)

According to World Bank Report (2021), the agricultural sector consumes 70 percent of global freshwater. Therefore, managing and exploiting water resources optimally as well as future planning in this sector is necessary. Limited access to water endowments, unequal distribution of water resources, climate changes and increasing global water demand have increased the importance of the issue. Aware of this situation, the main purpose of this study is to investigate the virtual water balance of selected agricultural products in Mazandaran Province with the Commonwealth of Independent States (CIS) in 2018. In this paper, by using CROPWAT and OPTIWAT software, first the water requirement of plants has been calculated and then, by processing the data of foreign trade of Mazandaran province with CIS, the trade balance of virtual water for selected agricultural products has been measured. The results of the present study show that the trade balance of virtual water in Mazandaran Province with the CIS in 2018 was 2816.76 million cubic meters, which indicates overall saved national water resources.The policy recommendation of this study is to pay special attention to virtual water and its combination in the upstream documents in order to conserve national water as well as social, economic and environmental sustainability.

Analysis of changing trend of water resources and water environment quality in china from 2009 to 2019

Based on the statistical analysis of China Water Resources Bulletin, China environmental situation Bulletin and national environmental statistics yearbook during 2008-2019, we summarized the water resources and water environment quality of seven major basins, and the proportion, main pollutants and change trend of various types of water quality are discussed. Meanwhile, wastewater discharge and pollution discharge are also analyzed. The results show that in the recent years, the overall water environment quality in China is improving, but the overall water environment quality is still not optimistic. Water resources are not only the basis for human survival and development, but also a strategic resource for the development of the national economy. According to the <<World Water Development Report 2018>> issued by the United Nations, the current global water demand is increasing at a rate of 1% per year. This demand will continue to increase, and my country's water resources are even scarcer, and the per capita consumption is only 1/4 of the global average. In the face of this situation, understanding the state and changing trends of my country's water resources and water environment, and putting forward targeted resource conservation and pollution control measures are of great significance to alleviating the problem of my country's water shortage.

Recent Advances in Carbon and Activated Carbon Nanostructured Aerogels Prepared from Agricultural Wastes for Wastewater Treatment Applications

The global demand for clean water has become increasingly important in the past decade as a result of the growing world population, civilization, and the increase in sources of contaminations. Aerogels are an exceptional form of porous materials with extraordinary unique properties. The aerogel has been fabricated from different inorganic and organic materials and incorporated with a variety of novel compounds for specific applications and to enhance its performance in the desired application. Activated carbon is well known for its water-pollutant adsorption, it has been prepared from several organic materials including agricultural wastes and used to treat water from organic dyes, heavy metals, oils, and toxic chemicals. However, as a powder form, activated carbon must be incorporated either into a filter or undergo a post-treatment step to remove the adsorbent from treated water. This review highlighted the development of agricultural waste-based carbon and activated carbon loaded nano-structured aerogels. A review of the types of aerogels and the properties based on the precursor materials was conducted to extensively discuss the potential use of agricultural waste-based carbon and activated carbon loaded nano-structured aerogels in wastewater treatment applications. We also discussed the challenges and future prospects of carbon and activated carbon nano-structured aerogels for wastewater treatment applications.

An analysis of finding the best strategies of water security for water source areas using an integrated IT2FVIKOR with machine learning

Worldwide, water security is adversely affected by factors such as population growth, rural–urban migration, climate, hydrological conditions, over-abstraction of groundwater, and increased per-capita water use. Water security modeling is one of the key strategies to better manage water safety and develop appropriate policies to improve security. In view of the growing global demand for safe water, intelligent methods and algorithms must be developed. Therefore, this paper proposes an integrated interval type-2 Fuzzy VIseKriterijumska Optimizcija I Kompromisno Resenje (IT2FVIKOR) with unsupervised machine learning (ML). This includes IT2FVIKOR for ranking and selecting a set of alternatives. Unsupervised machine learning includes hierarchical clustering, self-organizing map, and autoencoder for clustering, silhouette analysis and elbow method to find the most optimal cluster count, and finally Adjusted Rank Index (ARI) to find the best comparison within two clusters. This proposed integrated method can be divided into a two-phase fuzzy-machine learning-based framework to select the best water security strategies and categorize the polluted area using the water datasets from the Terengganu River, one of Malaysia’s rivers. Phase 1 focuses on the IT2FVIKOR method to select five different strategies with five different criteria using five decision makers for finding the best water security strategies. Phase 2 continues the unsupervised machine learning where three different clustering algorithms, namely, hierarchical clustering, self-organizing map, and autoencoder, are used to cluster the polluted area in the Terengganu River. Silhouette analysis is applied along with the clustering algorithms to estimate the number of optimal clusters in a dataset. Then, the ARI is applied to find the best comparison within the original data with hierarchical clustering, self-organizing map, and autoencoder. Next, the elbow method is applied to double-confirm the best clusters for each clustering algorithm. Last, lists of polluted areas in each cluster are retrieved. Finally, this 2-phase fuzzy-Machine learning–based framework offers an alternative intelligent model to solve the water security problems and find the most polluted area.

The global challenges facing the water resources and irrigation sector

Population growth has significantly increased while the water resources have not. In 1950, per capita water share was 12,050 m3/year, reduced to 7,310 m3/year in 2000 and is expected to be 4,580 m3/year by 2050. This is a significant reduction of 62% in per capita water share within a century. At the same time, water consumption is expected to increase by 50% by 2050. There is an urgent need for more water supply. In addition, according to the UN Department of Economic and Social Affairs, DESA (www. un.org/en/desa), the world population is expected to increase from 8 billion in 2022 to 9.8 billion in 2050 and to 11.2 billion in 2100. Subsequently by 2050, the food demand is expected to increase by 100% requiring more irrigation water (globally, on average, irrigation consumes 70% of freshwater resources). More efficient irrigation networks and irrigation systems, as well as water saving technologies, are needed to meet this challenge. The future climate change predicts more frequent extreme events of flood and drought. Irrigation and food production requires a steady water supply throughout the year. Climate change predicted increased and reduced rainfall in different parts of the world. Reduced rainfall leads to reduced runoff, river flow and groundwater recharge. Steady water supply for irrigation and food production can only be met by more storage reservoirs. Currently, there is a gap between water supply and demand and it is continuously increasing. By 2030, a 40% overall gap between global water supply and demand is expected and this will increase further by 2050. The gap between water supply/availability and future demand is widening over time. We will need to increase water supply by using non-conventional water resources, increasing rainwater and runoff harvesting and store water in reservoirs. Dams and reservoirs provide a steady flow for the whole year enabling us to apply integrated water management for agriculture and food production under changing climate. For the future, multipurpose dams and reservoirs for water and energy security are preferred over single use dams and reservoirs. Improving the irrigation application and conveyance efficiencies by lining the canal network and reservoirs will help in reducing losses by seepage and leakage. Using more efficient irrigation systems can also help in water saving. Adopting the concept of Water-Energy-Food Nexus is necessary for a holistic management to produce more crop per drop per kilowatt per unit area of land.

Impact of Hydrogel on Agriculture – A review

Water is one of the most essential natural resource, which is often costly and limiting particularly in arid and semi arid regions. Under climatic changing scenario, fresh water resources at global level is synchronizing day by day and creating water scarcity and transforming more irrigated area to rainfed. The use of water holding amendments like hydrogel polymer enhancing the water and nutrient use efficiency and will become more important over time, especially in arid and semi arid region. Hydrogel has unique characteristics that it retains water and nutrient from their surrounding area and will help in alleviating moisture stress of crop plants during prolonged dry period and where irrigation facilities are available this technology could reduce the number of irrigation applied to crops. The dose of hydrogel as suggested in the literature varies from 2.5 to 5 kg/ha depending on the soil texture. A lower dose is recommended for clayey soil while a higher dose is recommended for sandy soil. Nowadays water management is considered as one of the biggest challenge in arid and semi arid region of world, in fact by 2030 global water demand probably to be 50% higher than today, resulting in water scarcity. Many research finding confirmed that hydrogel not only used for saving of water/irrigation, but also have tremendous potential to improve the physical and biological properties of soil. In this paper, responses of hydrogel polymers on various crops are reviewed.

Augmenting environmental flow information with water temperature: case study in Eastern Canada

The increasing global water demand and climate change put freshwater resources and riverine ecosystems at risk of increasing scarcity and conflict in water usage. Stream biota may be confronted with increasing stressful aquatic habitat conditions due in part to increasing water temperatures. In response to these issues, environmental flows play a crucial role in flow assessment, water resource management and the protection of aquatic biota. Environmental flows (eflows), also known as instream flow requirements, refer to the amount of water needed in rivers to maintain a balanced aquatic ecosystem. Recently, the inclusion of river temperature in the assessment of eflows has raised interest, especially in the context of climate change and dam operations, which are altering the river thermal regimes and affecting aquatic habitat. This study focuses on hydrological metrics that can be used to prescribe eflows in Atlantic Canada and Quebec (Eastern Canada). Eflow analyses were conducted jointly with the analyses of river temperatures at 61 sites. The results show that summer environmental flow metrics can be associated with relatively high water temperatures during a period when water withdrawals may be important. Classifying rivers according to their thermal regime during summer low flow periods prior to prescribing an eflow target is therefore recommended.

Improved reference evapotranspiration methods for regional irrigation water demand estimation

Temperature- and radiation-based methods are widely used for reference evapotranspiration (ETo) estimates and in regional irrigation water demand studies, especially in areas with limited weather data. A major limitation is that without local calibration, the constant parameters used in these methods usually cannot ensure the same reliability in regional analysis. On the other hand, the controlling variables of ETo under different climatic conditions and how they are related to the structures of these methods have not been adequately addressed yet. Herein, we evaluated the performance of three commonly used temperature-based methods, i.e., Thornthwaite (Th_T), Blaney-Criddle (BC_T), and Hargreaves and Samani (HS_T), and five radiation-based methods, i.e., Makkink (Ma_R), Priestley-Taylor (PT_R), Jensen and Haise (JH_R), Turc (Tu_R), and Abtew (Ab_R), for regional ETo estimates and calibrated them using the Penman-Monteith method. Monthly meteorological data (1961–2010) from 15 weather stations in Texas, United States, covering humid, subhumid, semiarid, and arid climates, were used. The HS_T method is recommended for regional analysis if reliable wind speed and relative humidity data are not available. The radiative component was the driving factor of ETo, accounting for 72− 84% of its variation in the warm season in all climates. Therefore, temperature- and radiation-based methods performed well and showed little variation in the warm season. However, we demonstrated that the vapor pressure deficit impact on ETo variations could be as high as 43–49% in the cool season in subhumid, semiarid, and arid climates, and wind speed impact on ETo variations was 4–12% and 10–16% in humid, semiarid, and arid climates, respectively. To accurately reflect these impacts, we adjusted the HS_T and PT_R methods by multiplying a calibration-free coefficient. By doing so, the accuracy of ETo under cool, dry, and windy conditions is considerably improved compared with the locally calibrated methods. The adjusted HS_T and PT_R methods can significantly improve the efficiency and accuracy of applying the less data-intensive ETo methods to predict regional or global irrigation water demand.

Development of an Irrigation System for Predicting Watering Time with ANFIS Method for Chili Plants

Recently, precision farming has become a necessity due to the increasing global demand for staples and water. Thus, farmers will need the availability of sufficient water and fertile soil to meet these needs. Due to the limited availability of both resources, farmers need solutions that change conventional farming systems. Precision farming is the solution to deliver larger and more profitable yields with fewer resources. Currently, several artificial intelligence-based irrigation models have been proposed to use water more efficiently. However, the limited irrigation capabilities of the previous model make it unsuitable for unpredictable climates. The authors conducted research on ANFIS-based intelligent irrigation systems for irrigation system models and the Internet of Things (IoT) to connect sensors to actuators via the cloud. The daily water requirement parameter for plants can be determined using conventional measurements (Gravimetry), this parameter will be the output parameter in the ANFIS modeling. This modeling is compared with reference measurements (conventional) resulting in a fairly accurate accuracy of 87.5%. The proposed system is simple and affordable which makes the technology more precise.

Ion transport channels in redox flow deionization enable ultra-high desalination performance

Redox flow deionization (RFD) is an emerging derivative of redox flow cell technology that desalinizes salt water while simultaneously storing energy. However, conventional RFDs are limited by high specific energy consumption and low salt removal rates caused by low ionic conductivity in low-salinity ranges (especially < 3000 mg L–1). This study investigates the potential of ion transport channels composed of ion exchangers to enhance ionic conductivity in low-salinity ranges. The RFD cell with ion exchangers (IE-RFD) exhibited significantly lower resistance and specific energy consumption than conventional RFD cells when processing low salinity feeds. A finite element analysis demonstrated that the current density in the ion exchangers, especially where the ion exchangers were in contact, was much higher than that of the surrounding solution, indicating effective ion transport in low-salinity ranges. The IE-RFD cell showed excellent desalination performance (99.4% at 10 000 mg L–1) and low energy consumption (0.99 Wh L–1). We did not observe any deterioration in performance over 10 d of continuous desalination. Compared with other electrochemical desalination technologies, e.g., membrane capacitive deionization, flow capacitive deionization, and traditional RFD, the IE-RFD is superior in terms of energy consumption, salt removal ability, and stability. This study described an efficient strategy to enhance the desalination performance of RFDs through ion transport channels. With further optimization, this technology could help to alleviate the critical global demand for fresh water using minimal energy.

A photoelectrochemical reactor for ion separation and hydrogen production

Global water demand has been rising rapidly due to increased industrial activities and personal consumption. The regulations and restrictions specifically introduced to achieve sustainable environmental targets have pushed the industry to adopt effective treatment methods to reuse the wastewater streams accordingly. For this reason, developing such systems that can produce reusable and useful by-products is important along with wastewater treatment. Accordingly, a photoelectrochemical reactor is designed and studied for the treatment of textile wastewaters and reclamation of sodium hydroxide. The presently designed reactor combines some of the aspects of photoelectrochemical cells and electrodialysis process. Various potentials are considered and applied to the reactor to investigate the hydrogen production rates and efficiencies of the reactor. The conductivity removal efficiencies are then found to be 37%, 39%, 55%, 66%, 87% while the color removal efficiencies are 96%, 95%, 91%, 75%, 74% for 1.7, 1.9, 2.1, 2.3 and 2.5 V, respectively. Furthermore, the hydrogen production rates for illuminated studies are measured as 0.024, 0.041, 0.061, 0.170, 0.302 mmol/h, respectively.

Impacts of Energy Transition on Life Cycle Carbon Emission and Water Consumption in Japan’s Electric Sector

The United Nations (UN) proposed the Sustainable Development Goals (SDG 17) in 2015, together with The Paris Agreement endorsed by 195 signatories and state parties, to address sustainable development-related issues through ambitious and dynamic actions. The transition of the energy system is at the heart of greenhouse gas (GHGs) mitigation which is required to achieve those goals and the electric sector is the core of energy system of interest while the GHG with the largest contribution to rising temperature is carbon dioxide. However, in addition to being centrally relevant for carbon emissions, the electric sector is also an important water consumer. This study applied a hybrid life cycle assessment (LCA) model with the disaggregated electric sector to investigate the impacts on carbon emission and water consumption of the energy transition in Japan under the Sixth Strategic Energy Plan. The results indicate that the electricity mix under the Nationally Determined Contribution (NDC) scenario can cut 50% of existing carbon emissions while intensifying the water consumption by 36% from the life cycle perspective in which 30% are foreign water footprints. The Kaya identity analysis confirmed this conclusion and explained the impacts of four driving factors (population, economy, electricity intensity, and electricity mix) qualitatively and quantitatively showing that the development of technologies and continuous efforts in energy saving can provide a substantial contribution to sustainable development. The results confirmed that the efforts proposed by Japan’s NDC for emission reduction through an energy transition in the electric sector can meet the expectation of achieving the Paris Agreement goals but will also pose greater challenges to the future global water demand in the energy system and regional water stress.

Assessment and Optimization of Coagulation Process in Water Treatment Plant: A Review

The rapid growth of the human population, industrialization, and urbanization has threatened the global demand for safe drinking water. Water treatment plant plays a vital role in purifying the raw water for consumer use. The typical water treatment process are coagulation-flocculation, sedimentation, and filtration. Among them, the coagulation-flocculation process is the primary stage in the treatment process. This paper reviews and discusses the optimization strategies of a coagulation-flocculation process to enhance overall treatment efficiency. The working principle of the coagulation-flocculation process is first discussed to understand the treatment process better. Next, the importance of aluminum-based coagulants is addressed as chemical coagulants are one of the key factors that can improve the process. The removals of natural organic matter (NOM) by the coagulation-flocculation process were reviewed as NOM normally contributes to the discoloration of water. The optimization of coagulant dosage was also discussed to depict the consequence of uncontrolled dosage. Finally, dosing control strategies in real-time were discussed, namely direct and indirect dosing control.

An Overview of Groundwater Monitoring through Point-to Satellite-Based Techniques

Groundwater supplies approximately half of the total global domestic water demand. It also complements the seasonal and annual variabilities of surface water. Monitoring of groundwater fluctuations is mandatory to envisage the composition of terrestrial water storage. This research provides an overview of traditional techniques and detailed discussion on the modern tools and methods to monitor groundwater fluctuations along with advanced applications. The groundwater monitoring can broadly be classified into three groups. The first one is characterized by the point measurement to measure the groundwater levels using classical instruments and electronic and physical investigation techniques. The second category involves the extensive use of satellite data to ensure robust and cost-effective real-time monitoring to assess the groundwater storage variations. Many satellite data are in use to find groundwater indirectly. However, GRACE satellite data supported with other satellite products, computational tools, GIS techniques, and hydro-climate models have proven the most effective for groundwater resources management. The third category is groundwater numerical modeling, which is a very useful tool to evaluate and project groundwater resources in future. Groundwater numerical modeling also depends upon the point-based groundwater monitoring, so more research to improve point-based detection methods using latest technologies is required, as these still play the baseline role. GRACE and numerical groundwater modeling are suggested to be used conjunctively to assess the groundwater resources more efficiently.

Desalination Technology in South Korea: A Comprehensive Review of Technology Trends and Future Outlook.

Due to advances in desalination technology, desalination has been considered as a practical method to meet the increasing global fresh water demand. This paper explores the status of the desalination industry and research work in South Korea. Desalination plant designs, statistics, and the roadmap for desalination research were analyzed. To reduce energy consumption in desalination, seawater reverse osmosis (SWRO) has been intensively investigated. Recently, alternative desalination technologies, including forward osmosis, pressure-retarded osmosis, membrane distillation, capacitive deionization, renewable-energy-powered desalination, and desalination batteries have also been actively studied. Related major consortium-based desalination research projects and their pilot plants suggest insights into lowering the energy consumption of desalination and mitigation of the environmental impact of SWRO brine as well. Finally, considerations concerning further development are suggested based on the current status of desalination technology in South Korea.

Examining the antimicrobial efficacy of granulated tetraacetylethylenediamine derived peracetic acid and commercial peracetic acid in urban wastewaters.

The ever-increasing need for access to safe water has meant that alternative water sources and innovative water reclamation approaches are often required to meet the global water demand. As a result, many wastewater treatment facilities have faced regulatory pressure to seek alternative disinfection methods that ensure public health safety, while adhering to regulations that set limits on carcinogenic disinfection by-products (DBPs). Peracetic acid (PAA) is an emerging wastewater disinfectant in the United States that has been widely used in other industries such as food sanitization and does not produce carcinogenic DBPs. However, several factors such as transport, storage, and physical and chemical effects have stymied its widespread use in wastewater markets. Therefore, the purpose of this study was to examine the antimicrobial efficacy of an on-site generated PAA compared against a commercially available PAA. Antimicrobial efficacy was assessed using standard fecal contamination indicators (i.e., total coliforms and Escherichia coli) in six urban wastewater treatment facilities ranging in size and treatment processes. Overall, few statistical differences were found between the antimicrobial efficacies of on-site generated PAA and commercially available PAA; however, before becoming more widely utilized, the on-site PAA should be tested against emerging fecal contamination indicators (e.g., human norovirus and enterovirus) and be assessed in terms of economic and sustainability impacts. PRACTITIONER POINTS: Alternative Ct approaches should be considered when using disinfectants like PAA. On-site generated PAA can achieve the same level of disinfection as commercial PAA. On-site generation of PAA may help further its use as a wastewater disinfectant.

Influence of Different Crop Establishment and Irrigation Methods on Growth and Growth Indices of Rice

The increasing global demand for water in many sectors has become a universal concern. Challenge is to develop advanced production systems that allow rice production to be sustained in the face of waning water availability. With the intention to find the efficient water saving technology and establishment method, a field experiment was conducted at Zonal Agricultural Research Station, V. C. Farm, Mandya, University of Agricultural Sciences, and Bangalore during Kharif 2018. The experiment was laid out in split plot design with three main plot irrigation treatments and five sub plot rice establishment treatments. The paddy variety used was ‘MTU 1001’. Objective was to study the irrigation and establishment methods on growth of rice. The results revealed that, continuous flooding recorded significantly higher plant height (80.67 cm) at harvest. Whereas, alternate wetting and drying (AWD) recorded higher leaf area index (5.06), CGR at 30 to 60 DAS, 60 to 90 DAS and 90 DAS to harvest (1.49, 3.50 and 2.47 g m-2 day-1, respectively), NAR at 30 to 60 DAS and 60 to 90 DAS (7.19 and 4.37 mg cm-2 day-1, respectively). Among establishment methods, manual transplanting recorded higher plant height (81.82 cm), LAI (5.70), DME (55.77), AGR at 30 DAS (0.36 g day-1), CGR at 30 to 60 DAS and 60 to 90 DAS (1.73 and 3.94 g m-2 day-1, respectively) and LAD at 30 to 60 DAS, 60 to 90 DAS and 90DAS to harvest (49.50, 128.70 and 272.80, respectively). However, mechanical transplanting recorded significantly more number of tillers m-2 (765.67), NAR at 30 to 60 DAS and 60 to 90 DAS (9.96 and 4.41 mg cm-2 day-1, respectively). AWD method of irrigation in mechanical transplanting and manual transplanting are found to be better among all other methods due to the higher growth and development.

Enhanced Rocking Chair Capacitive Deionization for Accelerated Water Desalination

Based on a report from the World Economic Forum, the global demand for water is projected to exceed supply by 40 percent, raising concerns about the prospect of achieving clean water supply for all[1]. This challenge emphasizes the need for technologies that enable the supply of clean water with minimal economic cost and footprint on the environment. Capacitive deionization (CDI) has emerged as an effective technology for desalinating brackish water for human consumption by removing ions through the passage of electrons [2]. Although the technology has gained prominence particularly because of its environmental friendliness, it is still limited in desalination performance (e.g., rate and capacity), spurring research into ways of improvement [3]. In a bid to improve the desalination rate of CDI, rocking-chair capacitive deionization (RCDI) eliminates the need for a subsequent cycle of salt concentration following a cycle of salt rejection by enabling simultaneous salt concentration and rejection in a single cycle. The RCDI cell design which typically consists of a pair of capacitive electrodes and respective channels separated by an ion-exchange membrane, enables continuous charging-discharging. This design results in the alternating production of a dilute and concentrate stream within two separate channels in the cell[4].In this work, insights into a new design will be introduced that leverages the blueprint of RCDI to further expedite water desalination rate by incorporating ion-exchange resins into the cell design. By integrating the ion resins into the cell design, in this meeting, faster salt removal and concentration in both compartments of the cell will be demonstrated, when operated under similar conditions with a typical RCDI cell. This new design provides an opportunity for not only improved desalination rate but also energy savings for desalination. In addition, we will also elucidate the competition between faradaic reactions and capacitive storage occurring in the compartments of the desalination cells by examining pH swings during operation. References https://www.weforum.org/our-impact/closing-the-water-gap/ X. Gao, A. Omosebi, Z. Ma, F. Zhu, J. Landon, M. Ghorbanian and K. Liu, Environmental Science: Water Research & Technology, 5(4), 660-671 (2019).Y. Liu, X. Gao, K. Wang, X. Dou, H. Zhu, X. Yuan, L. Pan, Journal of Materials Chemistry A,8(17), 8476-8484 (2020).D. Lu, C. Xu, Y. Wang and W. Cai, Desalination, 510, 115090 (2021).

Sulfonated Phthalocyanine Redox Flow Cell for Electrochemical Water Desalination

A reliable clean water supply is now one important and challenging issue for the human society. With the facts that only 0.4% of the water on earth is readily drinkable and 98% of the water is saltwater, water desalination for clean water production has become a key strategic solution to satisfy the increasing global water demand. Over the years, different saltwater desalination technologies were researched and developed, including reverse osmosis membrane desalination (RO), electrodialysis (ED), capacitive desalination (CDI) and multi-effect distillation (MED). However, some inherent technical issues, like high operation cost, large capital cost and/or low desalination capacity, associate with these existing technologies that lead to a high clean water production cost and limit their applications. Thus, there is a need of new water desalination technology that can purify saltwater with low cost and high efficiency.In this work we report a new water-soluble nickel phthalocyanine tetrasulfonic acid tetrasodium salt (NiPcTATS)-based redox flow desalination battery (RFDB) for safe, effective and efficient water-salt separation. The fabricated RFDB cell exhibited a high desalination rate at 3.4 gNaCl/(molNiPcTATS∙hr) even with a low 0.5 V cell voltage and required as low as 11.5 kJ/mol salt in energy consumption. The cell showed excellent reversibility and durability for long-term operation, benefiting from the fast-redox kinetics and chemical stability of the redox couple. With no consumption of the redox couple and energy recovery during the salination process, this new method provides a continuous desalination capability with unlimited salt removal capacity. We also demonstrated the use of simple solar panel for effectively driving the RFDB cell, proving it a promising and practical technology for clean water production in remote places like islands and ships.