Seawater desalination can be a viable solution to global fresh water scarcity. Recent innovations integrating electricity have shown to enhance efficiency and functionality in advanced desalination systems by leveraging salinity gradients and thermoelectric effects to generate electricity, while applying input electric current to improve desalination performance via Joule heating. This review highlights the role of electricity in recent advanced desalination technologies, emphasizing its impact on freshwater production and renewable energy generation. Electricity-driven systems, incorporating solar thermal and low-voltage electrothermal evaporation, ensure stable operation under varying environmental conditions. Input electricity boosts thermal efficiency, overcomes the limitations of inconsistent sunlight, and increases evaporation rates. Simultaneously, electricity-generating systems harness salinity gradients, thermoelectric conversion, and nanostructured materials to cogenerate electricity and freshwater simultaneously. This generated power sufficient to run small electronic devices offers practical solutions in remote or resource-limited areas. This dual functionality — enhancing desalination performance and generating electricity — addresses both water scarcity and energy needs. By examining the recent advancements in materials, system designs, and the water-energy nexus, this review explores the potential of integrated desalination systems for scalable and sustainable applications.

Interfacial solar steam generation (ISSG) stands as a promising technology in addressing global water scarcity, stemming from reasons like global warming and population growth. Despite its potential, ISSG faces challenges due to varying weather conditions and solar intensity fluctuations. To overcome these limitations, a novel approach by integrating photothermal and electrothermal Joule-heating effects is introduced in this study for a high-efficiency and salt-resistant all-weather, all-day seawater desalination. Hierarchical NiCo2S4 nanowires are fabricated on a Ni-foam (NCNNF) using a facile two-step hydrothermal method. Under photothermal evaporation, the NCNNF evaporator produces an evaporation rate of 1.57 +/- 0.08 kg m(-2) h(-1) with an evaporation efficiency of 77 % under 1sun illumination with good anti-fouling ability. In a simple water desalination setup, the surface temperature of the evaporator in a wet state reaches similar to 63.5 +/- 0.25 degrees C within 10 min by applying an input voltage of 1 V and 1sun irradiation condition, yielding an outstanding evaporation rate of 21.3 +/- 3.6 kg m(-2) h(-1) and evaporation efficiency of 80 %. The proposed evaporation device can resist salt accumulation on the evaporator surface in long-term operations. The present results would be utilized in developing high-performance Joule-heating assisted solar water evaporation devices, especially for all-day, all-weather desalination to produce clean potable water.

Solar energy offers several advantages for desalination, including affordability, eco-friendliness and sustainability. However, certain factors have influence on the evaporation rate and result in low yield. These factors include a low solar absorption rate, slow temperature rise, and insufficient heat trapping. To address these challenges, we integrated chitosan aerogel-impregnated with graphene nanoplatelets (CAGNPs) as a photothermal absorber (PTA) and soy wax (SWAX)-based thermal energy storage material (TESM) into spherical solar stills (SSS). This innovative combination enhances solar absorption rates and enables energy storage, thereby enabling all-day, all-weather freshwater production. Waste beverage aluminum cans were utilized to fill the phase change material (PCM) for storing thermal energy. Three identical SSSs were fabricated and their performance was examined from March to August 2023. This comprehensive evaluation demonstrated the effect of photothermal absorption and energy storage, elucidating their collective impact on system efficiency over this period. The test showed that the conventional SSS achieves a freshwater productivity of 1.6 L/m2 over 9 h. The integration of SWAX gives rise to 3.0 L/m2, significantly improving freshwater production compared to the conventional SSS. Moreover, the combined effect of CAGNP and SWAX into SSS results in substantial enhancement, yielding a freshwater productivity of 4.1 L/m2. The obtained exergy efficiencies for the conventional SSS, SSS-PCM, and SSS-CAGNP-SWAX were 1.21 %, 1.69 %, and 1.85 %, respectively. Furthermore, the use of SWAX facilitates the effective storage and release of thermal energy, enabling all-day, all-weather freshwater production.

Solar desalination provides a sustainable and eco-friendly solution for purifying wastewater, addressing environmental challenges associated with wastewater treatment. This study focuses on the purification of inorganic contaminants from laboratory chemical wastewater (ICWW) using a spherical solar still (SSS). To enhance the evaporation rate and overcome the impact of heavy metals on absorption efficiency, a carbonized balsa wood (CBW) solar evaporator was employed. Balsa wood pieces, carbonized at 250 °C for 15 min, were arranged in a SSS configuration. The CBW-integrated SSS demonstrated a remarkable freshwater productivity of 2.33 L/m2 for ICWW, surpassing the conventional SSS, which produced only 1.5 L/m2. The presence of heavy metal ions (Na+, Ca+, K+, and Mg2+) in ICWW significantly affected the evaporation rate, and the CBW solar evaporator exhibited an impressive removal efficiency of approximately 99%. Water quality parameters, including pH and chemical oxygen demand (COD), were investigated before and after treatment. The CBW-integrated SSS achieved an outstanding COD removal efficiency of about 99.77%, reducing the COD level from 229.51 to 0.521 mg/L. These results underscore the efficacy of the proposed solar desalination system in purifying ICWW, offering a promising approach to address environmental concerns associated with wastewater treatment.

Solar-powered freshwater harvesting is one of the accelerating trends today. Thanks to those who have developed efficient light-absorbing materials, latent heat energy storage, floatable solar desalination devices, and solar collectors that facilitate high freshwater production. Based on recent advances, the specific motivation of this review is to investigate the ways to accelerate all-day, all-weather freshwater production powered by solar energy. The major classifications are, (i) photothermal absorbers for atmospheric water harvesting, (ii) photothermal absorbers coupled with phase change material, (iii) photo-electrothermal Joule heating, (iv) floatable solar stills, and (v) solar still -integrated with phase change materials. The adoptability of compositional materials with their specific integrations and unique structural modifications facilitate the all-day, all-weather evaporation under natural solar irradiation. Furthermore, the selection of materials, need for their integrations, the ways to improve the condensation, limitations and future prospective are discussed. The continuous condensation after sunset improves the nighttime water collection. Among various methods claiming all-day, all-weather freshwater production, the photo-electrothermal Joule heating-driven solar desalination achieves the record-high evaporation rate of 98.7 kg m(-2) h(-1). The overall results conclude that the combined material advances lead to accelerate the evaporation rate and producing adequate freshwater production even under low-cloudy/off-sunshine conditions.

The development of efficient photothermal materials for solar steam generation (SSG) is important achieving high evaporation rates and efficiencies. Among various materials, biomass-derived photothermal absorbers (PTAs) can convert solar light into heat for solar desalination. This study pioneers the utilization of peanut shell as a renewable resource in solar desalination. Peanut shells, an agricultural waste with meso- and micropores, were utilized as an evaporator for interfacial solar steam generation (ISSG). Although peanut shells are an excellent source of protein, fat, and fiber, they are usually discarded after consumption. In this work, waste peanut shells were carbonized at 600 degrees C and 1000 degrees C to prepare carbonized peanut shell powder (CPS). Furthermore, the prepared CPS was coated onto polyvinyl alcohol (PVA) sponges for solar evaporation. The CPSderived PTAs were hydrophilized with sodium alginate (SA) and cross-linked by using CaCl2 to obtain PVA@SA-CPS evaporators for solar desalination. In the seawater desalination experiment, PVA@SA-CPS-1000 exhibited a stable evaporation rate that lasted for up to 14 cycles. It presented an evaporation rate of 2.16 kg m-2 h-1 with an efficiency of 90.4 % under 1 sun illumination. Sustainability, cost-effectiveness, low greenhouse emissions, and easy adoptability are the other features of CPS utilized for desalination and water treatment.

Solar-based desalination is one of the sustainable methods of obtaining clean water from contaminated water. Recent advances in the production of highly efficient photothermal absorbers have increased their evaporation rate. Improved solar absorption (> 94

Although solar desalination is a promising approach for obtaining freshwater, its practical application encounters challenges in achieving efficient photothermal evaporation. Recent research has focused on novel configurations of solar absorbers with unique structural features that can minimize heat loss. High-efficiency interfacial solar steam generation (SSG) can be achieved by optimizing the design of the absorber to harness incident heat energy on the top interfacial surface and ensuring a continuous water supply through microchannels. Artificially nanostructured absorbers might have high solar absorptivity and thermal stability. However, the manufacturing of absorbers is expensive, and the constituting materials are typically non-biodegradable. The unique structural configuration of natural plant-based solar absorbers provides a major breakthrough in SSG. Bamboo, as a natural biomass, possesses exceptional mechanical strength and excellent water transport through vertically oriented microchannels. This study aimed to enhance the performance of SSG with a carbonized bamboo-based solar absorber (CBSA). To achieve this goal, we optimized the carbonization thickness of the absorber by varying the carbonization time. Furthermore, the height of the CBSA was varied from 5 to 45 mm to determine the optimal height for effective solar evaporation. Accordingly, the highest evaporation rate of 3.09 kg m −2 h −1 was achieved for the CBSA height of 10 mm and top-layer carbonization thickness of 5 mm. The cost-effectiveness, simple fabrication, and superior desalination performance of the CBSA demonstrate a strong potential for practical applications.

Solar energy is one of the sustainable sources for many fruitful applications. Desalination of wastewater by solar power is a priority research focus and has attracted many researchers and scientists world-wide. However, handling industrial and other wastewater is typically a challenging task for effective treatment and re-use. The presence of contaminants in the effluent is hazardous to the environment and human health. In the present work, an attempt has been made to investigate different wastewaters including (i) garbage wastewater, (ii) waste vegetable water, (iii) landfill leachate, and (iv) pharmaceutical effluent fed into a solar distiller evaporated under natural solar illumination. Herein, different waste waters’ pH, chemical oxygen demand (COD), ammoniacal-nitrogen (NH 3 -N), arsenic (As), Barium (Ba), Cobalt (CO), Chromium (Cr), Iron (Fe), Mercury (Hg), Potassium (K), Manganese (Mn), Magnesium (Mg), Sodium (Na), Nickel (Ni), Phosphate (P), and Zinc (Zn) were investigated by the inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The concentration of NH 3 -N in the garbage wastewater, vegetables wastewater, landfill leachate, and pharmaceutical effluent were 157 mg/L, 142 mg/L, 161 mg/L, and 164 mg/L, respectively. The evaporated water output of garbage, waste-vegetable water, landfill leachate, and pharmaceutical effluents are 1.7 L/m 2 .day, 1.8 L/m 2 .day, 1.9 L/m 2 .day, and 1.65 L/m 2 .day, respectively. Finally, the test result reveals that the water quality is greatly improved after consecutive evaporation process by the solar distiller. This is one way to deal with the wastewater through a sustainable process for a better future.

Owing to the low productivity per unit area of a single basin solar still, a stacked solar still configuration which has two basins stacked together has gained popularity due to its increased output for the same area. This paper delivers a detailed comparison between single basin and stacked solar still configurations based on thermodynamic and economic analysis. A single slope single basin and double basin solar still of same base area of 0.5 m2 were fabricated and tested at Velammal Engineering College, Chennai, in the month of March 2020. The average daily productivity obtained from the single basin and stacked still configuration are 1.416 L/day and 1.913 L/day, respectively. The thermo-economic analysis gives detailed information about the exergy destruction of each component of the solar still and the overall exergy efficiency of both the configurations. The energy and exergy efficiency of the stacked solar still is higher than the single basin solar still due to lower energy loss in the stacked solar still configuration. In order to optimize the cost of the distilled water, an economic feasibility analysis is carried out, and it is observed that the cost per liter of distilled water produced from a single basin solar still is 29.9% higher than the stacked solar still. The payback period of the stacked solar still is 540 days, whereas it is 459 days for a single basin solar still. The results from the analysis further justify the thermo economic feasibility of a stacked solar still.

Solar energy-driven evaporation-based freshwater production is one of the sustainable ways to purify contaminated/salty water. Recent advances in solar absorbers' assemblies, design modifications, and integrations with heating sources improved the rate of freshwater productivity. However, the type of feed water affects the evaporation rate in a solar desalination system (SDS). Many studies used tap water with added contaminants to test the performance of a SDS and studied the water quality improvement. As a typical result, pH, total dissolved solids (TDS), and electrical conductivity (µS/cm) are reduced after solar evaporation. The performance of SDSs for real wastewaters are also important to understand, e.g., the reduction of high organic pollutants after solar evaporation. In this aspect, the main objective of the present work is to review solar distillation of real wastewaters and seawater by using SDSs. Further, the mechanism of a solar distiller with heat transfer principles, parameters affecting evaporation process, real wastewaters and seawaters purified in a solar distillation system, improvement of various parameters before and after solar evaporation, pathways of handling wastewaters, challenges, and future perspectives are discussed. Conclusively, SDSs are found to remove pollutants effectively after solar evaporation. The evaporation rate is relatively slower due to high concentration of pollutants that reduce vapor pressure. The COD removal of various real wastewaters, including sludge, kitchen, textile, palm oil, petroleum, water plant, and municipal wastewaters, was 98.13%, 97.85%, 96.84%, 96.71%, 87.99%, 86.99%, and 85.67%, respectively. The reduction rate of salt concentration in real seawater after evaporation in the solar distiller was 99.99%.

The conventional solar still is limited to a daily yield of approximately 2-3.5 kg/m(2)/day. To increase the yield, this study investigates experimentally the combined effects of latent and sensible energy storage together with magnetization. Paraffin and novel high-thermal conductivity nanomaterial (graphite plate) were used as latent and sensible heat storage materials, respectively. There was an overall increase of 62% and 235% in the daytime and night-time yield, respectively, giving a total yield of 5.5 kg/m(2)/day compared to 3.4 kg/m(2)/day for a conventional still. Enviro-economic parameters like emissions, CO2 mitigation and carbon credit (CC) earned were also investigated. Energy matrices analysis and water quality checks were performed to estimate the energy-payback time, life cycle conversion efficiency (LCCE) and purity of desalinated water. The cost per liter of freshwater was found to be 3.7% cheaper than for a conventional still and 69% cheaper than bottled water in India. Over a 30 year period, 40.3 Tonnes of CO2 will be mitigated contributing a CC and LCCE of $402 and 0.52, respectively. The proposed modified still is recommended as a substitute for conventional stills and stills with simple energy storage. (C) 2021 Elsevier Ltd. All rights reserved.

Solar desalination is one of the green energy processes to treat saline water and wastewater. Solar evaporation systems, formally solar stills, have been widely used to evaporate water to purify it. However, the evaporation rate in solar stills is typically low due to incoming energy used to heat the entire bulk water. In order to minimize the bulk heating, researchers have developed capillary flow-based, self-floatable, broadband photothermal absorbers (250-2500 nm wavelength) for fast solar evaporation. Recently, interfacial solar steam generation (ISSG) has attracted attention due to significant advantages in desalination and water treatment. In general, ISSG materials are classified into plasmonic metals, semiconductors, black carbon and polymer-based materials. The basic requirements for these photothermal materials include being self-floatable and having high solar absorption, fast water transport (capillary action) and low thermal conductivity to confine the heat locally. Some natural plant species satisfy these prerequisites and have been used as photothermal materials in solar steam generation (SSG). The present review exclusively focuses on the carbonized botanical species, including bamboo, corncob, corn-stalk, coconut-husk, carrot, fruit residues (cherry, grape, orange and apple), green algae, loofah fruit, magnolia fruit, mushroom, lotus leaf and seedpods, sugarcane, sunflower head, tofu, wheat flour and wood pieces for improving the evaporation rate and efficiency. Carbonization technique improves the solar absorption by increasing the carbon concentration. In addition, these floatable solar absorbers evaporate the water with the aid of natural microchannels. These materials not only improve the efficiency, but also have economic and environmental benefits.

Solar energy-driven desalination is one of sustainable means to produce reusable water. Recently, solar distiller formally known as a solar still (SS) has been commonly employed to get freshwater through evaporation and consequent condensation process. However, such passive systems are typically slow on the distillation process, because bulk heating requirement and other energy losses. To increase the fresh water productivity of the passive distillation systems, researchers have usually adopted concentrators, reflecting mirrors, evacuated tube collectors (ETC), energy absorbing-engineered nanoparticles and energy storage (sensible and latent heat) materials. In this manner, water in a distiller can obtain additional heat and speedy evaporation take place immediately. Thus, efficient integration of passive distillation is highly useful to achieve appreciable production rate of fresh water for human daily needs. In this aspect, many researchers continuously tried to develop new innovative technologies for effective solar desalination. The main objective of this assessment is to review the current integration strategies and consequences for improving the productivity of solar distillers. Here, the term integration comprises additional heat sources, including heat confinement to broadband nanoparticles (micro-integration), concentrators, reflecting-mirrors (macro-integration), latent heat storage (LHS), sensible heat storage (SHS), and wicking cloth-based absorbers. This review exclusively focused on the newest results in the year of 2020–2021. In addition, the challenges, limitations, and requirements for future prospects are discussed.

Traffic congestion and impediments are major problems nowadays in metropolitan cities which lead to an evergrowing traffic accident.Therefore the need of traffic management in order to avoid the unnecessary time wastage and tragic accidents is very important.Vehicle detection and counting plays a powerful role in the area of traffic surveillance system where efficient traffic management and safety are the main concern.In this project, we have implemented and resolved the issue of detecting vehicles from video frames.

The sun is the primary source of life on the earth. The heating effect of the sun provides a more fruitful environment for mankind. In addition, solar energy in the form of thermal radiation has been utilized for solar thermal applications and space heating. With abundant solar radiation, the emergence of the solar desalination has been emerged as a viable solution for water purification by utilizing solar stills. However, solar-powered distillation is relatively a slow process due to the requirement of bulk heating. To suppress thermal conduction to bulk water, various photothermal materials were employed. However, there are many governing parameters which influence the productivity, including solar intensity, cloud, wind, ambient air temperature, humidity, solar absorption of blackened surface, depth of bulk water, feed water type, angle of condensation surface, water film thickness, underneath the condensing surface, and experiment period. Further, systematic and continuous experiments for extended periods are essential for determining the stability and durability of a solar desalination system. The main objective of this article is to review all the experimental studies conducted for two months at minimum up to 1-year duration. In addition, all the SDSs handled in this study further were examined by solar geometrical factors, including day length (DL) and position of the sun or zenith angle (θz). As a result, the sunshine hours, day length, and the solar zenith angle play an important role in the water evaporation rate. Lower solar zenith angle and longer day length (more sunshine hours) are desirable for higher water productivity.

Sustainable solar energy powered desalination is a high priority research area, nowadays. Fresh potable water is one of humanity?s fundamental needs for living and flourishing. Efficient techniques for producing pure water from saline water and industrial wastewater with less conventional energy use or using renewable energy are urgently needed. Solar stills are one of such alternatives to produce pure water using solar energy. Novelty of this write up is discussion of basic concepts such as working principle of nanofluid, heat transfer in nanofluid and different preparation methods. These areas are discussed to bring the readers closer to the present scenario of suspended nanostructured engineering materials for solar distillation. Cost analysis with and without suspended nanoparticles are also summarized. Authors have also thrown light on effects of NPs (nanoparticles) on environment and health of living beings as a means to promote this technology. An important result is that nanofluids thermal conductivity is proportional to nanoparticles concentration to a certain limit. So, each nanoparticle has its optimum concentration where thermal conductivity is maximum in order to give maximum yield of pure water.

Solar desalination is one of the most sustainable solutions to produce freshwater from brackish water. The present research work aims to experimentally investigate the effect of a V-shape concentrator integrated with solar still (SS). The V-shape concentrator integrated with the conventional solar still (CSS) is used to supply the saline water at elevated temperature to the basin of SS, which augments the freshwater yield compared to CSS. The experimental investigation was performed at different brackish water depths of 0.01, 0.02, and 0.03 m, respectively. The SS system was evaluated based on water yield, energy, exergy, concentrator efficiency, and economic analysis. The freshwater yield of the solar still integrated with V-shape concentrator (SSVC) was found to be 5.47, 5.10, and 4.89 L/m2.day, whereas the yield of the CSS was 3.73, 3.27, and 2.91 L/m2 .day at the water depths of 0.01, 0.02, and 0.03 m, respectively. The daily energy and exergy efficiency of CSS were 38.5, 33.5, and 29.4% and 1.9, 1.5, and 0.97 % in the case of 0.01, 0.02, and 0.03m water depth , respectively. However, the integration of concentrator significantly augmented the energy efficiency to 57.4, 51.7, and 44.9% and exergy efficiency to 3.8, 3.3, and 2.8% for the respective water depths . Life cycle studies demonstrated that the freshwater cost per liter for CSS and SSVC were 0.0102 $ and 0.0117 $ respectively, at a water depth of 0.01 m. It was concluded that the addition of V-shape concentrator and minimum water depth is useful to augment the energy efficiency, exergy efficiency, and yield of the SS in the very economical way.

Ongoing to the modern societies and global economic developments, the water is recognized as one of the main concerns of humankind, particularly with the continuous decrease of the freshwater supply. Solar energy, which is abundant and available in many areas, can solve the problem of long-term energy and freshwater reduction in the whole world. Researchers do their best to solve this problem in different ways. Currently, many studies have used solar energy to improve the efficiency of evaporation, solar desalination, and wastewater treatment since it is the basis for freshwater. One of the new ways applied to achieve this is named "hydrogel", which has various structures. Hydrogel, as a novel light-absorbing material, is an effective technique to enhance photothermal solar efficiency conversion by decreasing the heat loss in the heat transfer process due to the heat localization on the air-water interface. Moreover, hydrogel has many pores structures with excellent water transport from the bottom to the water-air interface. Hydrogels are floatable, durable, anti-fouling, and suitable recycling materials, which are energetically favorable for harvesting and amplifying the steam generation. Furthermore, over the past three years, they have revolutionized solar water vaporization with an evaporation efficiency of 95% and the evaporation rate of 4 kg/(m(2). hr), which cannot be achieved by other materials.

Solar energy is a sustainable energy source with many applications. Desalination of ocean/wastewater with solar energy has attracted considerable interest worldwide. However, solar desalination is a slow process with poor efficiency. In order to improve performance, highly efficient photothermal absorbers have been introduced. The main objective of the present work is to investigate capillary flow driven high broadband (full solar spectrum) absorptivity nanostructured absorbers for sea/wastewater treatment. The recent development in porous and self-floatable nanomaterial-enriched absorbers have improved the evaporation process through high broadband solar absorptivity (>95%) and porosity (>99%). One motivation of the research is to link the researchers of traditional absorbers to research on advanced materials, so the results of low-efficiency capillary materials are compared with the highly efficient materials. The ions in the seawater, including Na+, Mg2+, K+, Ca2+ and other contaminants before and after desalination, are investigated. Further, the effectiveness, best applicable material, challenges and future projections are described. The advanced nanostructured photothermal absorbers have the potential of being the most suitable candidates to be used in solar desalination systems. More improvements are needed in the absorbers stabilities, salt-blocking, scalability, lack of toxicity and affordability for commercialization.