Freshwater Scarcity Research Articles

Acceptance of on-site wastewater treatment and reuse in Bengaluru, India: The role of perceived costs, risks, and benefits

In dealing with water pollution and freshwater scarcity, on-site treatment and reuse of domestic wastewater has shown to be a promising solution. To increase on-site wastewater treatment and reuse, some cities, among them Bengaluru in India, have mandated the installation and use of the necessary technology in certain building types. However, even with a mandate, a successful and sustainable implementation of the technology, including reliable operation, monitoring, and maintenance, depends on the acceptance (i.e. positive valuation) of the technology and its use by the (prospective) users. Literature on technology acceptance indicates perceived costs, risks, and benefits of the respective technology as key predictors of acceptance. Therefore, the present online study assessed this relationship for on-site systems in Bengaluru. The relation was analysed separately for mandated users of on-site systems (N = 103) and current non-users (i.e. potential prospective users, should the mandate be expanded; N = 232), as the perceptions might differ between the two groups, due to the personal experience with the technology among users. The results show that for mandated users and non-users, acceptance of on-site systems is explained by perceived benefits only, namely a positive image of users, environmental benefits, and, only for non-users, also financial benefits for the city. The findings suggest that interventions aimed at promoting on-site systems should include emphasis on the benefits of on-site systems. Whenever possible, interventions should be tailored to the target group's individual cost, risk, and benefit perception.

Aquaponics as an integrated agri-aquaculture system (IAAS): Emerging trends and future prospects

Aquaponics, an integrated agri-aquaculture system, is an interdisciplinary approach that addresses the water-food-energy nexus of United Nations' sustainable development goal and increasing demands of global population at minimal ecological cost. Embracing the ‘circular bio-based economy’ concept, aquaponics has exhibited immense potential for reduced resource utilization, discharge mitigation, nutrient, energy, wastewater recycling, and production of highly nutritious food within the system. Aquaponics has attained increased public interest in recent years in urban areas, in line with the trend towards greater productivity with limited resources, diving it from small-scale operation to brink of commercialization. The holistic analysis of scientific articles on aquaponics has perceived the transition of research trends from optimization of system performance (component ratio, hydraulic loading rate, etc.) to adoption of marine, inland saline, decoupled aquaponics and nutrient management to address challenges like freshwater scarcity, depleting marine resources, salinization, nutrient deficiency for plants, etc.; yet a constructive scientific concept is still limited. Marine, inland saline, and decoupled aquaponics has increasingly gained popularity in last decades, yet further expansion is demanded as a way forward to tackle the global challenges. This article provides insight into the prevailing state-of-art with recommendations for future orientation of research for developing this sustainable production technology.

CONDENSATION, DESALINATION, AND WATER RECYCLING TO ENCOUNTER WATER STRESS

Water is a gift of life from Allah. In Al-Quran, it is stated “And We sent down from the sky water (rain) in (due) measure, and We gave it lodging in the earth, and verily, We are able to take it away.” (1). Though water is indispensable for life and livelihoods, it is becoming a world-pressing societal and geopolitical critical issue, knowing that 800 million people worldwide cannot afford primary access to potable water and that nearly 2.2 billion people lack access to a safe water supply. As a result, freshwater scarcity is now the world's second most pressing concern, after the prompt population increment issue. If the problem of freshwater scarcity persists, ‘the world will miss water-related SDGs by a wide margin’; more than 40% of the world's population will be living in ever-seriously water-stressed regions by 2035 (2); ecosystems will become weakened and will be unable to meet population freshwater supply ; and developing countries will be the most affected, with 80% of their illnesses caused by a lack of access to water as well as poor water quality. To tackle the increased water shortage, reasonable water management methods are required. This article proposes three efficient sustainable water techniques for producing fresh water and thus meeting water scarcity's massive demand, along with their benefits and drawbacks. They are Condensation, desalination, and water recycling.

Determinants of water consumption in Thailand: sustainable development of water resources

PurposeFreshwater availability is reducing globally, due to increasing demand with population growth and climate change and is disproportionately impacting developing countries. This study aims to investigate the dynamics of water access and consumption across all regions of Thailand with various characteristics and water systems. Understanding the relationship between institutional, economic and climate variables in Thailand’s water management is important for water scarcity planning. Our paper fills a gap in the literature by examining the determinants of water consumption and exploring potential water management policies.Design/methodology/approachThe authors empirically analyze the determinants of water consumption in Thailand, including institutional, economic and climate variables. The authors use data sets from both metropolitan and provincial waterworks authorities (PWA), as well as economic and meteorological macro-level data. The authors also adopt an auto-regressive distributed lag (ARDL) model and a Johansen cointegration test to estimate short- and long-run effects of the variables on water consumption.FindingsThe authors confirm a negative relationship between water pricing and consumption and verify a positive relationship between economic growth and water consumption across most regions of Thailand. Furthermore, the authors reveal a clear relationship between climate factors and water consumption and an inverse relationship between income and water consumption in metropolitan area. Findings indicate that authorities, especially PWA, should examine high water use in agriculture and develop regulations to ensure equitable water distribution to sustain economic growth. The authors recommend that water prices are increased within specific income thresholds to prevent impacting low-income families and to secure higher public revenue. In pursuit of environmental sustainability, the authors also recommend increasing public awareness of freshwater scarcity through education programs and investment in water-saving technologies. Differences among regions should be considered when developing water management strategies, which could be monitored through the respective water boards.Originality/valueThis study provides deep insight into the key factors that drive both water prices and water consumption in poor and rich areas. The unique nature of the research indicated that the paper will be of interest to policymakers and the academic community. The findings are relevant for water consumption management in Thailand and other developing countries with similar characteristics.

Simulation and Optimization of Renewable Energy-Powered Desalination: A Bibliometric Analysis and Highlights of Recent Research

Seawater desalination is emerging as one of the preferred systems for dealing with the problems of freshwater scarcity, which makes it necessary to redouble efforts to obtain an optimal and competent production process. For this reason, the coupling of water desalination and renewable energy systems is not surprising. This study applied a bibliometric analysis to evaluate the research trends on desalination systems and renewable energies from an engineering approach using optimizations or simulation techniques. The Scopus database was used for this study, selecting articles published between 2009 and 2022. A general analysis was carried out regarding trends in the number of articles produced, number of citations, subject area, journals, countries, institutes, and authors. Further, a more specific analysis was then performed in terms of renewable energy technologies used and preferred optimization/simulation methods and software used. The results also revealed that the field is growing, based on the number of articles published and the increase in citations. On the other hand, it was found that the most studied renewable energies, in coupling with desalination systems and from an optimization/simulation approach, are solar and wind.

Using Direct Solar Energy Conversion in Distillation via Evacuated Solar Tube with and without Nanomaterials

As is widely known, the issue of freshwater scarcity affects practically all people, and all are looking for innovative and workable ways to attempt to solve this issue. In this work, a novel method of desalination is proposed. The proposed system consists of a solar collector (PTSC), evacuated pipe (EP), condenser (CU), and separation unit (SU). The working principle of the system is heating the feed saline water using the PTSC and EP and controlling the water flow rate to control the output conditions of the EP. The produced vapor is therefore separated from salty water using the SU. In addition, the generated steam is condensed into the CU to produce a freshwater distillate. Consequently, the effect of solar radiation on the affecting temperatures was tested. In addition, the effect of using different water flow rates (6, 7.5, 10, 20, 40, and 60 L/h) inside the EP on the system productivity was investigated. The primary findings of this work may be highlighted in relation to the experiments conducted. At midday, when ultraviolet irradiance reached its highest, the EP’s water flow entrance and outflow had the largest temperature differential. In addition, the lower the water flow rate inside the EP, the higher the water temperature, the higher the evaporation rate of the system, and the greater the freshwater productivity of the system. At 6 L/h, the water’s highest temperature was 92 °C. Moreover, the best performance of the system was obtained at 7.5 L/h, where the freshwater production and average daily effectiveness of the distillate process were 44.7 L/daytime and 59.6%, respectively. As well, the productivity of EP was augmented by around 11.86% when using graphite nanoparticles. Additionally, the distilled freshwater from the system operating at the flow rate of 7.5 L/h costs 0.0085 $/L.

Efficient air water harvesting of TpPa-1 COFs@LiCl composite driven by solar energy

Adsorbent-assisted air water harvesting (AWH) may help alleviate the current global freshwater scarcity crisis. However, the weak sorption capacity of various adsorbents and the high energy required to release water are two long-standing problems. Herein, we propose a class of green and clean adsorbent, TpPa-1@LiCl composite, whose sorption capacity is greatly improved to 0.37 and 0.80 ​g ​g−1 under 30% and 90% relative humidity (RH), respectively, and which has excellent stability, showing only a slight decrease (0.79%) after 10 sorption–desorption cycles (1400 ​min). This TpPa-1@LiCl composite can reach equilibrium within 2 ​h and undergo complete desorption in 30 ​min under air mass 1.5 ​G irradiation. A corresponding solar-driven AWH device can complete up to 4 sorption–desorption cycles per day, with each cycle capable of collecting 0.34 ​g ​g−1 water without additional energy input, which implies TpPa-1@LiCl composite has the potential for achieving sorption-assisted AWH with high efficiency and rapid cycling.

Use of condensed water from air conditioning equipment as a strategy to face the global scarcity of freshwater: a review

The increase in the world's demand for water has become one of the most relevant topics on environmental sustainability and the conservation of water resources. As a result of the scarcity of potable water, processes such as the use of water through practices, techniques, and technologies for its efficient use have become essential for future generations. Among the possibilities for using water, air conditioning systems stand out, due to the formation of condensed water during operation. The world's population is increasingly concerned about environmental issues, showing that it is necessary to seek alternatives to recycle water, whether for use in gardening, sewage systems, washing sidewalks, and cars, among others. The present study carried out a literature review to reflect on the theme of the reuse of condensation water from air conditioners as a strategy for the sustainable use of water resources and enhancing the future of planet Earth.

ANN-based prediction of ammonia nitrogen for wastewater discharge indicators under carbon neutral trend

IntroductionWith the rapid development of society and urbanization, greenhouse gas emissions have increased, leading to environmental problems such as global warming. The rise in urban water consumption has also resulted in increased sewage discharge, exacerbating freshwater scarcity and water pollution. Understanding the current status and spatial distribution of greenhouse gas emissions in China's sewage treatment industry is crucial for emission reduction measures and controlling ammonia nitrogen pollution.MethodsThis study comprehensively investigates greenhouse gas emissions from sewage treatment plants, analyzing influencing factors and predicting future spatial and temporal distributions. The uncertainty of ammonia nitrogen emissions is calculated using the IPCC's error propagation method, considering uncertainty ranges of variables. Additionally, an artificial neural network is employed to predict ammonia nitrogen content in sewage discharge, aiming to prevent excessive levels in wastewater.Results and discussionThe proposed model outperforms others with an R-Squared score of 0.926, demonstrating its superior accuracy in predicting ammonia content in wastewater. These findings contribute to better emission reduction strategies and control of ammonia nitrogen emissions. This model can effectively prevent excessive ammonia nitrogen content in discharged wastewater, contributing to water pollution control. In conclusion, this study highlights the importance of understanding greenhouse gas emissions from sewage treatment plants and their impact on water pollution. The research provides valuable insights into emission reduction measures, emission prediction, and technological innovations suitable for China's specific conditions. By effectively managing ammonia nitrogen emissions and adopting the proposed predictive model, the goals of carbon neutrality and environmental sustainability can be better achieved.

Biochar Made into Efficient Electrodes for Capacitive Deionization

The scarcity of freshwater has attracted the attention of countries around the world. Capacitive deionization (CDI) is a burgeoning ElectroSorb Technology with low price and high efficiency. It is important for CDI to prepare electrodes with inexpensive and high adsorption capacity. The deionization efficiency depends on the properties of the CDI electrodes. In this paper, porous carbon materials derived from corncobs, cornstalks, and waste cigarette butts have been used as efficient electrodes for CDI desalination. Compared with cornstalks and waste cigarette butts, the results showed that corncobs activated at 800 °C (CBC-800) had the best properties. The specific surface area (SSA) and capacitance (Ccv) of the CBC-800 are 1201.9 m2/g and 141.4 F/g, respectively. And the adsorption capacity (SAC) is 19.2 mg/g. CBC-800 is a prospective biomass material for CDI technology.

Water-Saving Dyeing Process: A Sustainable Approach for Exhaust Dyeing of Cotton Fabric

The global demand for water onservation and sustainability in textile anufacturing is imperative in addressing the scarcity of fresh water and environmental pollution. This study introduces an innovative water-saving process for exhaust dyeing of cotton fabrics with reactive dyes, without compromising the dyeing quality or requiring extra investments. Traditional textile dyeing practices consume approximately 120 liters of fresh water per kilogram of cotton fabric, contributing to environmental degradation. In this research, a process modification is proposed that recycles water used for neutralization and rinsing at the second step of the dyeing process. This recycled water is utilized in the fourth step, effectively reducing the total water consumption to 104 liters per kilogram of fabric, thus saving 16 liters per kilogram without any additional investment. The dyed fabrics produced using this water-saving process exhibit excellent colorfastness, matching the quality of conventionally dyed textiles. The color fastness to light, washing, rubbing, and perspiration meets international standards. CMC tests indicate no significant differences compared to the existing dyeing process. Implementing this eco-friendly approach can not only significantly reduce water consumption and wastewater generation but also diminish the need for costly water treatment and effluent management facilities. This research paves the way for cleaner production in the textile industry, promoting water conservation, reducing environmental pollution, and minimizing production costs.

The rain deluge and flash floods of summer 2022 in the United Arab Emirates: Causes, analysis and perspectives on flood-risk reduction

Across the hyperarid Arabian Peninsula, preparing to face evolving risks of flash-flood hazards against projected scenarios for climate change requires both an understanding of the extreme rainfall events responsible and the implementation of appropriate mitigation/adaptation measures. In July 2022, torrential storms affected northeastern UAE. The damaging impacts prompted a broader consideration of flash-flood risks, especially for rapidly-urbanising arid landscapes. Occurring unexpectedly in mid-summer when rainfall is normally absent, the storms were produced by a combination of climatic and oceanic conditions: ITCZ position, unusual westward extension of a humid air mass from the Indian monsoonal trough, a cool sea-surface temperature anomaly that drove strong onshore moisture advection, and orographic precipitation enhancement by the coastal ranges. A foreign media suggestion that cloud seeding was partly responsible, however, is contested. Although flood emergency management was coordinated and effective, it is argued that various strategies may be strengthened to reduce future disaster risks. These include increased monitoring of mountain wadi systems to augment meteorological forecasts with hydrological information, and improved modelling to predict runoff-generation processes better in ungauged catchments. Greater capture of floodwaters to infiltrate and replenish groundwater aquifers also supports ongoing national efforts to develop sustainable solutions for addressing freshwater scarcity.

An ecofriendly and efficient wood-based polyoxovanadate solar evaporation generator

Currently, freshwater scarcity is a global challenge, and developing low-cost methods for purifying, desalinating, and distilling seawater is crucial. Natural wood, owing to its advantages of high hydrophilicity, low density, microporous channels, and low thermal conductivity, is widely considered a vehicle for solar evaporation. However, the majority of the reported wood-based solar evaporation generators have been economically inefficient, with limited evaporation rates under low-power solar irradiation. Herein, we developed an ecofriendly and efficient wood-based solar evaporation generator comprising a material with excellent photothermal conversion efficiency, polyoxovanadate, loaded on the wood surface with a natural channel structure. The solar evaporation generator exhibited high light absorption capacity (∼98%) in the wide wavelength range of 200–1200 nm, rapid water transport through the wood channels, minimal heat dissipation due to the adiabaticity of the wood, and reduced evaporation enthalpy. Therefore, the overall evaporation efficiency was increased, and a high evaporation rate of 2.23 kg m−2 h−1 and solar-vapor efficiency of 90% under 1 Sun was observed. This environment-friendly, low-cost, and high-efficiency evaporation generator has enormous potential for practical applications in solar desalination and water purification.

Effect of Cu-doped GO nanoparticles on polyphenylsulfone nanocomposite membrane surface and its application for the removal of organic pollutants and antibacterial analysis

One of the primary concerns in environmental and industrial applications is the selective removal of organic pollutants and the inhabitation of microbial growth. Recognizing the rising industrial discharge and scarcity of fresh water has pushed us to invent cost-effective and sustainable separation technology. The main goal of this study is to investigate the interactions between Cu-doped GO nanohybrid nanoparticles and polyphenylsulfone polymer in order to develop superior nanocomposite flat-sheet membranes that have synergistic effects on organic pollutant removal efficiency along with antibacterial activities. Herein, a simple and effective wet-chemical route has been explored for the synthesis of Cu-doped GO nanohybrid nanoparticles. The properties of the Cu-doped GO nanohybrid nanoparticles and their integration into the polyphenylsulfone membrane matrix were confirmed using different types of characterization methodologies. The findings of the characterization clearly stated that the incorporation of an appropriate amount of Cu-doped GO nanohybrid nanoparticles was favourable to the enhancement of membrane surface properties. The performance ability of the as-prepared membranes was investigated for the selective removal of three different types of dyes from aqueous solutions as the targeted organic pollutants: bromothymol blue, congo red, and methylene blue. The significant water permeability achieved with an optimized Cu-GO/PPSU nanocomposite membrane was 20.6 L/m2h.bar, and the dye rejection was around 99%, 95%, and 91% for congo red, bromothymol blue, and methylene blue, respectively, based on dye concentrations. Moreover, the membrane's antibacterial effectiveness was observed against Gram-positive (S. aureus, E. faecalis, S. epidermidis) and Gram-negative (K. pneumonia, P. aeruginosa, E. coli) bacteria. According to the findings, nanocomposite membranes significantly inhibit both Gram-positive and Gram-negative bacteria from growing. This approach is ideal for a point-of-use water treatment process because of the convenience and low cost of developing and implementing these membranes for the removal of a wide range of organic pollutants and microorganisms.

Biocomposite Cryogels for Photothermal Decontamination of Water.

An effective and sustainable approach to deal with the scarcity of freshwater is interfacial solar-driven evaporation. Nonetheless, some serious challenges for photothermal materials still need to be considered, such as long-term stability in harsh environments, eco-friendly materials, and cost-effective and simple fabrication processes. Keeping these points in mind, we present a multifunctional silver-coated vegetable waste biocomposite cryogel that not only exhibits high porosity and enhanced wettability and stability but also possesses high light absorption and low thermal conductivity favorable for heat localization, solar steam generation, and efficient photothermal conversion efficiency. The achieved solar evaporation rate is 1.17 kg m-2 h-1 with a solar-to-vapor conversion efficiency of 81.11% under 1 Sun irradiation. The developed material is able to effectively desalinate artificial seawater and decontaminate synthetic wastewater (e.g., water containing dye molecules and mercury ions) with an efficiency of >99%. Most importantly, the composite cryogel presents antifouling properties, and in particular, salt antifouling ability and anti-biofouling properties. Thus, the numerous functionalities of the biocomposite cryogel make it a cost-effective promising device for prolonged water decontamination processes.

Soilless Cultivated Halophyte Plants: Volatile, Nutritional, Phytochemical, and Biological Differences.

The use of halophyte plants appears as a potential solution for degraded soil, food safety, freshwater scarcity, and coastal area utilization. These plants have been considered an alternative crop soilless agriculture for sustainable use of natural resources. There are few studies carried out with cultivated halophytes using a soilless cultivation system (SCS) that report their nutraceutical value, as well as their benefits on human health. The objective of this study was to evaluate and correlate the nutritional composition, volatile profile, phytochemical content, and biological activities of seven halophyte species cultivated using a SCS (Disphyma crassifolium L., Crithmum maritimum L., Inula crithmoides L., Mesembryanthemum crystallinum L., Mesembryanthemum nodiflorum L., Salicornia ramosissima J. Woods, and Sarcocornia fruticosa (Mill.) A. J. Scott.). Among these species, results showed that S. fruticosa had a higher content in protein (4.44 g/100 g FW), ash (5.70 g/100 g FW), salt (2.80 g/100 g FW), chloride (4.84 g/100 g FW), minerals (Na, K, Fe, Mg, Mn, Zn, Cu), total phenolics (0.33 mg GAE/g FW), and antioxidant activity (8.17 µmol TEAC/g FW). Regarding the phenolic classes, S. fruticosa and M. nodiflorum were predominant in the flavonoids, while M. crystallinum, C. maritimum, and S. ramosissima were in the phenolic acids. Moreover, S. fruticosa, S. ramosissima, M. nodiflorum, M. crystallinum, and I. crithmoides showed ACE-inhibitory activity, an important target control for hypertension. Concerning the volatile profile, C. maritimum, I. crithmoides, and D. crassifolium were abundant in terpenes and esters, while M. nodiflorum, S. fruticosa, and M. crystallinum were richer in alcohols and aldehydes, and S. ramosissima was richer in aldehydes. Considering the environmental and sustainable roles of cultivated halophytes using a SCS, these results indicate that these species could be considered an alternative to conventional table salt, due to their added nutritional and phytochemical composition, with potential contribution for the antioxidant and anti-hypertensive effects.

Informing watershed management in data-scarce Indian Himalayas

Anthropogenic water stress, especially in mountain habitats worldwide, affects water supply and threatens water security. Evaluating past trends, assessing current conditions, and anticipating future change is paramount for the sustainable use of increasingly scarce freshwater resources. This study simulates water yield using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to generate reliable information for decision-making related to watershed management programs in data-scarce Himalayan regions. The results are translated into watershed indices easily communicable to watershed managers, stakeholders and administrative agencies. The analysis demonstrates the utility of hydrological modeling using limited data within a scoping protocol for the pre-implementation phase of any watershed management program.

Application of UF and RO for power plant's wastewater treatment and recycling for environmental sustainability

Abstract Global indicators have warned of freshwater scarcity in Asia. However, the utilization of freshwater resources has skyrocketed for commercial and industrial purposes without any strategy for recycling and reuse. The power plant's wastewater/reject mainly consisted of cooling tower blowdown water and reverse osmosis (RO) plant reject water. Due to the high turbid nature of reject water, pretreatment was carried out to achieve SDI15 <3 by employing multimedia filters (MMF), activated carbon filters (ACF) and ultrafiltration (UF). Operational parameters of RO membranes were optimized (11.5 bar, 29 °C) to achieve maximum water recovery along with higher rejection rates of critical scale forming species such as 81% total dissolved solids (TDS), 73% calcium hardness and 72% silica (Si). After accounting for backwash water and other concentrate rejections, the membrane treatment plant has achieved an appreciable recovery rate of more than 44%. The RO membrane-treated water was then incorporated in the cooling tower and a 16% reduction in freshwater makeup was achieved. Reduction of microbial growth rate as well as corrosion and scaling in the cooling tower was observed due to the reuse of treated water. This is to confirm here that brackish water RO membranes can act as a strong contender for reject water reclamation and effective utilization.

Efficient fog harvesting on metal surfaces with venation-inspired wetting patterns fabricated via laser-based maskless approach

The issue of global freshwater scarcity has become more pressing as climate change effects intensify. Fog harvesting has emerged as a sustainable and promising solution to address this problem, and wettability-patterned surfaces have shown potential in enhancing fog harvesting efficiency. In this study, two venation-like surface wetting patterns, i.e., the broadleaf and coniferous tree patterns, were directly fabricated on an aluminum alloy (AA6061) using a laser-assisted functionalization method, which offers greater flexibility in creating innovative patterns without the need for a mask. The superhydrophobic region featured low-roughness, isotropic, random nanostructures, while the superhydrophilic regions consisted of highly structured porous microchannels. The resulting surface patterns demonstrated a significant increase of up to 100 % in fog harvesting capability compared to the untreated surface. By adjusting the number of leaves, the fog harvesting efficiency of the venation-like patterns can be further improved while maintaining the same energy investment.

PEI-GOs/PVA photothermal sponge with enhanced interfacial solar steam generation and seawater desalination

Solar water evaporation technology based on photothermal materials is regarded as one of green and critical technologies for addressing freshwater scarcity. However, practical application of photothermal materials is limited by their high preparation cost, low evaporation efficiency, and poor photothermal conversion. In this study, a facile sponge with excellent photothermal and mechanical properties has been fabricated by mechanical-mixing and chemical-crosslinking of polyethyleneimine modified graphene oxide nanosheets (PEI-GOs), formaldehyde, polyvinyl alcohol (PVA) and sulfuric acid catalyst. The as-prepared PEI-GOs/PVA sponge shows excellent light absorption (95.1 %) under standard sunlight intensity of 1.0 sun (1 kW m−2) and a wide wavelength range of 200–2500 nm. The achieved high evaporation rate (1.80 kg m−2 h−1) is 4.7 times those of pure water (0.38 kg m−2 h−1). Moreover, the simulated seawater desalination experiment shows that the sponge has a good long-term stability and an average photothermal conversion efficiency of 88.5 %. The water purified by the sponge exceeds the quality of urban daily water. Therefore, this study offers a new facile route for fabricating a kind of photothermal sponge with good light absorption capacity, and water evaporation properties, which has potential application in seawater desalination.