Population growth, industrialization and climate change have placed increasing stress on natural freshwater reserves, making conventional water sources inadequate. Coupled with rising energy constraints and environmental concerns, interest in desalination technologies that can operate more sustainably and efficiently has intensified. Among the available approaches, membrane desalination has gained particular importance because of its modularity, relatively low energy demand, and compatibility with decentralized water treatment. In parallel, thermoelectric devices have emerged as promising components for hybrid desalination systems due to their ability to convert temperature gradients into electricity or provide localized heating and cooling for process enhancement. This article presents a narrative review of thermoelectric integration in desalination systems, with particular emphasis on membrane desalination and membrane-hybrid water treatment configurations powered by renewable-energy or low-grade heat sources. The review examines the role of thermoelectric devices in relation to key membrane-based and hybrid desalination processes, including reverse osmosis, membrane distillation, electrodialysis, nanofiltration, forward osmosis, and selected hybrid systems. Particular attention is given to system configurations, renewable energy coupling pathways, functional roles of thermoelectric devices, water productivity, module output, desalination efficiency, water quality, and economic performance. The reviewed literature indicates that thermoelectric integration can provide meaningful benefits in hybrid desalination, particularly through improved thermal management, enhanced utilization of low-grade heat, and supplementary energy recovery. These opportunities appear especially relevant for thermally driven membrane systems such as membrane distillation and for membrane-hybrid configurations intended for decentralized or renewable-powered applications. However, the available evidence remains highly heterogeneous, with substantial variation in system scale, operating conditions, reporting metrics, and cost assumptions, which limits direct cross-study comparison and broad generalization of performance claims. This review highlights the technical challenges, reporting inconsistencies, and research gaps that currently constrain the practical development of thermoelectric-assisted membrane desalination and outlines future directions for membrane-aligned hybrid desalination research.
Polyamide thin-film composite reverse osmosis membranes were fabricated through interfacial polymerization (IP), wherein trimesoyl chloride (TMC) and isomeric diamine monomers including o-phenylenediamine (OPD), m-phenylenediamine (MPD), p-phenylenediamine (PPD), and methyl-substituted monomers such as 2,3-diaminotoluene (MOPD), 2,4-diaminotoluene (MMPD), 2,5-diaminotoluene (MPPD), and 2,6-diaminotoluene (2,6-MMPD) were employed. The membranes with high permeation flux and rejection ratio were eventually applied in the desalination of brackish water. The regional effects of the amino and methyl substituent on the desalination performance of the RO membranes in terms of permeation flux and rejection ratio were investigated extensively. A molecular dynamics simulation based on the configuration of monomers was performed to theoretically explore the effects of amino and methyl groups of the monomer on the packing density of the aromatic molecular structure and, consequently, on the desalination performance of the corresponding RO membranes. The RO membranes with integrated monomers exhibited two times higher permeation flux than that of a pristine RO membrane while remaining the high rejection ratio. Moreover, a long-term desalination performance of the RO membrane was also demonstrated, where two times higher permeation flux than that of conventional and commercial RO membranes was achieved, while the rejection ratio was maintained at 97.6% which was comparable with that of the commercial RO membranes.
Treating high-ammonia wastewater remains a significant challenge, primarily due to high energy consumption, risks of secondary pollution, and insufficient operational stability. Microbial Desalination Cells (MDCs), a bioelectrochemical technology, offer potential for simultaneous pollutant removal and energy recovery. However, a systematic understanding of their performance under high ammonia loads (e.g., > 1000 mg/L NH4-N) and the coupled effects of key operational parameters is lacking. This study constructed a three-chamber MDC to evaluate the effects of inter-electrode spacing, initial desalination-chamber NH4-N concentration, and anodic substrate type on electrochemical output and apparent NH4-N migration-related performance under controlled batch conditions. In addition, desalination-chamber NH4-N concentration profiles were descriptively compared under different anodic COD levels. Results showed that decreases in NH4-N concentration in the desalination chamber were consistent with transmembrane ion transport under the tested batch conditions, as evaluated using the membrane-area-normalized apparent migration flux ([Formula: see text]). Shortening the inter-electrode spacing from 5.5 to 3.5 cm increased the NH4-N migration removal rate ([Formula: see text]) from 2.12 to 3.17 mg L- 1 h- 1 and [Formula: see text] from 42.4 to 63.4 mg m- 2 h- 1. Compared with glucose, acetate increased [Formula: see text] from 55.8 to 77.8 mg m- 2 h- 1. These results identify operating-condition-dependent changes in apparent NH4-N migration-related performance and reveal their trade-off with power output and COD-removal-based coulombic efficiency (CE). The findings provide a laboratory-scale basis for subsequent contribution-partitioning studies and enrichment-side recovery coupling.
Solar-driven interfacial photothermal desalination has emerged as a promising strategy for addressing the growing global freshwater shortage by directly converting solar energy into localized heat for water evaporation. Recent advances in reverse multistage designs have achieved high evaporation rates and efficient water recovery. However, existing designs typically employ a single photothermal interface, resulting in strong dependence on the solar incident angle and optimal performance only under near-vertical irradiation. This limitation restricts their practical deployment under realistic, time-varying sunlight conditions and highlights the need for desalination architectures that can operate efficiently across a wide range of irradiation angles. Here, inspired by the multidirectional light exposure characteristics of Chimonobambusa quadrangularis, we design and fabricate a bionic evaporator incorporating multiple photothermal interfaces. The resulting reverse multistage system exhibits markedly reduced sensitivity to the solar incident angle under one-sun illumination. Notably, the multistage evaporator achieves an evaporation rate of 4.55 kg m-2 h-1 and a solar-to-steam efficiency of 300% even under horizontal irradiation. This work provides a practical strategy for enabling the efficient operation of reverse multistage desalination systems, overcoming a key barrier to their real-world deployment.
Freshwater production through solar desalination (SDS) is still limited due to low efficiency. This study investigates the effect of transverse cylinder vibrations on the performance of a SDS. The thermal behavior of the SDS is simulated based on a two-dimensional model based on the finite volume method. The effects of parameters affecting the SDS performance such as the amplitude and frequency of oscillation, the location of the cylinder, the temporal patterns of amplitude changes, and the surface temperature of the absorber have been evaluated. The results show that the transverse cylinder oscillation improves the system indicators and causes up to a 1.68-fold increase in water production, a two-fold increase in thermal efficiency, and a 1.97-fold increase in exergy efficiency. Also, the exponentially decreasing amplitude profiles cause the formation of vortices earlier and enhance convective transport in the desalination plant. Definite oscillatory patterns, if properly timed, can increase the system efficiency by up to 68%. The effectiveness of transverse cylinder vibrations is a function of the cylinder position, so that the closer the oscillating cylinder is to the glass cover, the more mixing the boundary layer and the better penetration of vortices, facilitating heat and mass transfer. The effect of the parameters studied on the system performance was evaluated using Sobol sensitivity analysis, and the results indicate that the most effective parameter is the ratio of current to amplitude. Based on the data available in this research and the ANFIS model, the system performance was predicted with a coefficient of determination of R2 = 0. 99.
Desalination by reverse osmosis (RO) of brackish water and seawater is a cost-competitive solution for supplying irrigation water in off-grid and water-stressed regions. This paper presents an experimental evaluation, thermodynamic analysis, and cost assessment of a solar photovoltaic brackish-water reverse osmosis (PV-BWRO) desalination system. Five feed salinity levels ranging from 993.6 to 3191.8 mg/L were tested. The results show that water production decreased with increasing feed salinity, from 3.29 m3/day at 24.6 mg/L to 1.48 m3/day at 152.9 mg/L. The calculated specific energy consumption values ranged from 1.80 to 3.61 kWh/m3 for solar irradiances of 1005.99 and 1018.47 W/m2, respectively. An exergy analysis revealed that the solar panels and pump operated at efficiencies of 11.7% and 38.9%, while exergy destruction was mainly concentrated in the pretreatment stage (28.72%), membrane modules (42.5%), and reject stream (28.5%). Although the overall system efficiency remained low (maximum of 1.39%), the results highlight substantial potential for improvement through enhanced maintenance, optimized pretreatment, and exergy recovery strategies. The unit water production cost ranged from USD 0.49 at 993.6 mg/L to USD 1.87 at 3191.8 mg/L, assuming a target permeate total dissolved solids concentration of 500 mg/L.
This paper proposes a Maximum Power Point Tracking (MPPT) algorithm for an off-grid, battery-less photovoltaic system that powers a solar desalination plant, including parallel reverse osmosis (RO) modules. The open circuit voltage and surface temperature of the PV array are first measured. Then the MP point voltage (VMP) is estimated. The PV voltage is estimated before each RO module is activated. So, the RO units are activated sequentially, before reaching the Maximum-Power-Point (MPP). A single-axis solar tracker is integrated to boost power generation capacity. The solar tracker, controlled by a calendar-based relay, does not require a radiation sensor. As the battery has no role in the steady operation of the system, it is replaced with pre-designed capacitors to handle the start-up inrush current of the tracker's motor in the absence of a battery. A two-stage return algorithm is proposed for the solar tracker to return the panels to their initial direction without the need for a battery. So the entire system works without a battery backup. Experimental results from a 1100-watt solar system powering ten RO modules with a total demand of 860 watts demonstrate that the simultaneous implementation of the proposed MPPT and the hourly-operating solar tracker can enhance water desalination capacity by 71%.
Solar-driven interfacial evaporation has emerged as a promising technology for freshwater production and energy sustainability. It leverages solar energy to efficiently evaporate water, enabling sustainable seawater desalination and wastewater purification. However, designing efficient evaporators that combine rapid water transport and high salt resistance remains a significant challenge. Drawing inspiration from the long-range ordered vasculature and anti-gravity water management mechanisms of taro stem, we fabricated a biomimetic aerogel featuring vertically aligned microchannels through a unidirectional freezing ice templating method. The aerogel integrates a core-shell SiC@C composite as a high-performance photothermal converter, a mechanically robust PVA/PAM double network forming the channel walls, and hydroxyapatite (HA) nanorods serving as both a thermal insulation skeleton and a mechanical reinforcement. In contrast to conventional aerogels with randomly oriented and tortuous pores, the biomimetic honeycomb architectures with vertically aligned channels endow the material with exceptional water transportation, thereby facilitating efficient salt ion diffusion and mitigating salt crystallization. Under 1 sun illumination (1 kW m-2), the aerogel achieves a high evaporation rate of 3.24 kg m-2 h-1, substantially outperforming most reported evaporators with disordered porous structures. The unique vertical channel configuration ensures continuous and stable desalination performance, highlighting its great potential as an effective solution to address global freshwater scarcity.
Graphene oxide (GO) membranes hold substantial promise for this application but are limited by structural instability in aqueous environments. This study introduces a composite membrane based on porous graphene oxide (PGO) with two-dimensional copper 1,4-benzenedicarboxylate (CuBDC) nanosheets grown in situ. The confined growth of CuBDC within the PGO laminar structure, via strong coordination between Cu2+ ions and oxygen-containing groups on PGO, not only stabilizes the PGO laminar structure but also induces NaCl rejection due to the appropriate pore size of the CuBDC. The resulting composite membrane demonstrated a high-water flux of 124 kg m-2 hour-1 in conventional pervaporation and 89 kg m-2 hour-1 in low-energy water carrier pervaporation, with NaCl rejection consistently above 99.9%. Technoeconomic analysis reveals that desalination using the fabricated membrane in a water-carrier pervaporation process results in a low annual expenditure. Overall, this study offers a promising strategy for stabilizing PGO membranes with excellent selectivity, paving the way for more energy-efficient desalination technologies.
Phosphorene, with its atomic-scale thickness, anti-fouling, stability, and self-passivation properties, is a potential candidate for large-scale desalination. Here, we investigate charged but overall neutral phosphorene nanopores of varying sizes namely, D16 (~28 Ų), D18 (~41 Ų), and D20 (~38 Ų) using molecular dynamics simulations to explore the effect of electrostatic edge modulation on water and ion transport. Five distinct spatial charge distributions (CD-1 to CD-5) were applied to the nanopore edges, introducing local asymmetries while preserving global charge neutrality. The D18 nanopore exhibited the highest water flux, for CD-4 and CD-5 distribution, which feature oppositely charged feed and permeate sides. These distributions generate strong axial electrostatic fields that align water molecules, reduce energy barriers, and significantly enhance transport efficiency compared to the more symmetric CD-1 to CD-3. Ion rejection rates for Na⁺ and Cl⁻ ranged from 95% to 100%, supported by steep Potential of Mean Force (PMF) profiles that indicate robust energy barriers to ion permeation. Molar concentration and water density profiles further reveal effective ion exclusion and enhanced structuring within the pore. These findings highlight the critical role of charge patterning and pore geometry in tuning membrane performance, establishing electrostatic modulation of charge-neutral phosphorene as a viable strategy for highefficiency water desalination.
This study evaluates the repurposed application of an expired non-sedating antihistamine drug (ENSAD), fexofenadine hydrochloride, as a high-performance "green" corrosion inhibitor for copper in 1.0 M HCl. Gravimetric results demonstrate a concentration-dependent inhibition efficiency reaching 96.4% at 120 ppm, with remarkable long-term stability (> 92.5% efficiency after 72 h). Adsorption behavior followed the Langmuir isotherm model, indicating the formation of a stable monolayer. The calculated Gibbs free energy (∆Goads =-33.8 kJ mol- 1) confirms a comprehensive physicochemical adsorption mechanism involving both electrostatic attraction and chemical coordination. Thermodynamic investigations revealed that the addition of ENSAD increased the activation energy from 30.36 to 53.89 kJ mol⁻¹, creating a substantial energy barrier against metallic dissolution. Electrochemical studies (PDP and EIS) confirmed ENSAD as a mixed-type inhibitor that significantly enhances charge transfer resistance (Rct). Quantum chemical parameters, including a low energy gap (ΔEg = 2.361 eV) and high softness (S = 0.424 eV- 1), corroborate the high reactivity and electron-donating capability of the molecule's heteroatoms (N, O) and π-systems. Surface characterization (SEM/EDX) visually and chemically confirmed the presence of a robust organic film. These findings position ENSAD as a technically viable, thermally stable, and sustainable alternative for corrosion protection in industrial acid cleaning and low-temperature desalination stages.
Novel mixed a starfish-like shaped magnetic iron-nickel alloy with Polyvinylidene fluoride (PVDF) matrix membranes were developed for water desalination using vacuum membrane distillation (VMD). This study highlights the alloy's unique morphology that coated by the hydrophobic polymer, which enhances water vapor transport through innovative pore formation and its permanent magnetic properties, distinguishing it from existing research. The membranes were characterized using scanning electron microscopy (SEM), Energy Dispersive X‑ray (EDX) analysis and mapping, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), and Thermal Gravimetric Analysis (TGA), along with measurements of Liquid Entry Pressure (LEP), static water contact angle, tensile strength, thickness, roughness, porosity, pore size and pore size distribution. Performance tests in a VMD system showed that the iron-nickel alloy increased membrane productivity by 47% compared to pristine PVDF membranes. The 0.2 wt% alloy with 14% PVDF achieved the highest porosity (74.32%) and flux (29.1 kg/m²·h), balancing surface roughness and structural integrity. In contrast, higher polymer content (18 wt% PVDF) negatively impacted porosity and led to performance trade-offs. Thus, this study emphasizes the critical interplay between porosity, roughness, thickness, and the magnetic properties of the alloy in optimizing membrane performance for VMD applications.
Solar-thermal interfacial desalination is a sustainable solution to meet the ever-increasing global freshwater demand. However, when treating actual ocean water, salt accumulation on the evaporator surfaces and brine discharge are major issues limiting the performance and posing environmental concerns. By utilizing a femtosecond laser surface processing technique, we create a multi-functional superwicking black metal (SWBM) panel that can pull a thin water film uphill across its surface, absorb nearly all solar radiation, and most importantly, automatically move the crystalized salts from the active regions to the passive regions for self-cleaning and salt collection. This SWBM serves as an energy-efficient, self-maintained, and additive-free and brine-discharge-free solar-thermal interfacial crystallizer (ABF-STIC) that simultaneously produces fresh water and harnesses nearly all salts directly from ocean water. This self-cleaning effect is attributed to the coffee ring effect and salt creeping, which can be enhanced by deeper and wider grooves, enabling self-cleaning even when treating real ocean water. Our ABF-STIC tracks the sun and operates continuously for a week to purify actual ocean water, achieving an average evaporation rate of 1.76±0.04 kg m-2 h-1 and salt harvesting rate of 61.74 ± 2.46 g m-2 h-1 under one sun, corresponding to ~ 74% solar to vapor conversion efficiency and nearly 100% salt extraction.
Brackish groundwater is an increasingly important freshwater source, yet inland desalination is constrained by energy cost and concentrate management. Electrodialysis (ED) is well suited to low-to-moderate salinity duties, but many optimization studies remain tied to a single salinity, recovery, or configuration, limiting transferable design guidance. This study develops a generalized energy-cost optimization framework for brackish-water ED across feed salinity and recovery using a one-dimensional axial stack model with concentration polarization and a two-step optimization. Step 1 identifies the minimum-energy operating point at various fixed membrane areas under a segmentwise limiting-current constraint, and Step 2 selects the cost-optimal membrane area using a normalized cost ratio, r, that captures local electricity tariffs and membrane costs. A practical feasibility screen based on the concentration factor, CF<5, is further introduced to exclude unrealistically severe high-recovery duties from the admissible design space. Over 1000-9000 ppm and recoveries of 0.50-0.90 (product quality fixed at 500 ppm), the cost-optimal per-cell voltage increases from ∼0.83 to ∼1.11 V/cell at R=0.90, while increasing cost ratio r from 25 to 150 W/m2 reduces the cost-optimal membrane area by ∼55%. The resulting optimization maps provide duty- and location-transferable guidance through r and identify membrane resistance and electrochemical-potential losses as primary targets for further performance improvement.
Water supply through economically and environmentally friendly approaches, especially in areas facing a water crisis, is one of the most pressing global challenges. The present study proposes a highly efficient reverse osmosis (RO) system for desalinating Persian Gulf water and explores its environmental impacts, energy efficiency, cost-effectiveness, and operational consistency. The designed RO system significantly decreased ionic concentration (90%), TDS (99.6%), electrical conductivity (99.4%), and NaCl (>95%). The life cycle assessment was conducted using the production of 1 m3 of potable water via reverse osmosis desalination of Persian Gulf seawater as the functional unit. The highest environmental burdens appeared to be human carcinogenic toxicity (48%) and freshwater ecotoxicity (19%), mainly from Mg2+, NO3-, and Cl- releases. The RO system adversely affected human health (96.33%) and ecosystems (2.35%) because of effluent and energy consumption, whereas fossil fuels dominated the resource category. Fossil fuels supplied 93.7% of the system's energy requirements, leading to 99.8% of the overall greenhouse gas emissions, specifically CO2 (70.65%) and CH4 (10.8%). Sensitivity analysis revealed that a 20% reduction in Mg2+ and NO3- inputs alleviated impacts by 43.81% to 95.21% across all categories. Furthermore, the Monte Carlo simulation revealed a coefficient of variation of <10% for all environmental categories, confirming the credibility and reliability of the results. The water production, capital, and operating expenses were calculated as $0.10/m³, $74,908.2/m³, and $409,687,014.2, respectively. Over a 20-year period, the net present value obtained was $1,984,510,642 with an 11-year payback period. Collectively, implementing an appropriate pretreatment and using renewable energy sources notably reduces the carbon footprint of RO system (>60%). The current investigation highlights the role of management strategies in mitigating the environmental impacts of RO systems.
Phytoremediation is an eco-friendly and cost-effective strategy applied for treating domestic and industrial wastewater contaminated with heavy metals (HMs). An experiment was conducted to evaluate the potential of water hyacinth (WH) (Eichhornia crassipes) to remove lead (Pb), chromium (Cr), cadmium (Cd), and nickel (Ni) from wastewater and to restore the physicochemical properties of treated wastewater. Results demonstrated that wastewater exposure reduced growth (25-57%) and physiological attributes (19-40%) of plants. Moreover, substantial quantities of metals were accumulated in plant tissues. Relative to initial plant concentrations, Cd increased by 46-65% in roots and 84-88% in shoots, Pb by 38-77% in roots and 85-93% in shoots, Cr by 49-69% in roots and 40-62% in shoots, and Ni by 7.2-85% in roots and 23-89% in shoots. In addition, a significant reduction in electrical conductivity (0.78-1.46 dSm-1) and neutralization of pH (7.53-7.87) of alkaline domestic wastewater and acidic industrial wastewater further improved water quality. Overall, the findings demonstrate that WH effectively removes multiple HMs from domestic and industrial wastewater, either in diluted or pure form to improve water quality and highlights its potential for sustainable wastewater remediation and reuse in agriculture. The present study provides a comparative and integrated assessment of water hyacinth-mediated phytoremediation using domestic, industrial, and mixed wastewaters. Unlike most previous studies focusing on single effluents or metals, the present work simultaneously evaluates multi-metal uptake (Cd, Pb, Cr, Ni), and post-treatment water quality improvement for further reuse in safe irrigation.
Due to the inherent differences in anion and cation adsorption mechanisms, designing a single Faradaic material that functions as an efficient symmetric capacitive deionization (CDI) electrode for desalination poses a significant challenge. Herein, by employing a simple n-type azabenzene compound, hexaazatrinaphthalene (HATN), as a template, we introduce strong electron-withdrawing cyano (C≡N) groups to drastically reduce its surface electron density, constructing an electron-deficient system with a positive surface potential and a highly positive permanent quadrupole moment (Qzz), denoted as HCNAP. This unique electronic structure triggers anion-π interactions and consequently enables anion adsorption. Meanwhile, the C═N and C≡N groups on the HCNAP skeleton maintain the function of cation adsorption. As a proof of concept, the symmetric CDI device fabricated with HCNAP exhibits outstanding desalination performance in a 500 mg L-1 NaCl solution, achieving a salt adsorption capacity of 53.88 mg g-1 and a removal rate of 10.1 mg g-1 min-1. Theoretical calculations and experimental results clearly reveal the adsorption mechanism of Na+ and Cl-. Besides, HCNAP presents favorable adsorption toward three additional cations and anions. This innovative strategy establishes a new paradigm for constructing bifunctional Faradaic electrodes for highly efficient desalination.
The escalating challenge of supplying freshwater stems from an alarming rise in water consumption driven by population growth and increased economic activity. With worsening freshwater scarcity, water pollution, and 80% of wastewater worldwide containing high TDS, heavy metals, and inorganic and organic contaminants, the need to obtain freshwater from nonfreshwater sources is essential. Capacitive deionization (CDI) is an emerging, promising electrochemical technique that offers robustness, cost-effectiveness, and high efficiency. CDI is a cost- and energy-efficient alternative for applications such as desalination and the elimination of heavy or radioactive metals. This review discusses the general concepts of CDI, including different cell designs, adsorption and desorption cycles, and evaluation parameters, to provide a foundation. Later, we describe the potential of metal-organic frameworks (MOFs) as electrode materials for CDI, the recently reported modifications and developments in MOF-based electrode materials, their CDI performance, and the underlying mechanisms for desalination and ion capture. This review concludes with future perspectives for further developments in the field of capacitive deionization.
Desalination brine discharge poses emerging threats to benthic marine organisms through combined salinity stress and metal contamination. This study investigated the individual and combined effects of salinity (35 ppt) and metal exposure (Cu, Fe, and Cd) on the sea cucumber Apostichopus japonicus by integrating ionomics, enzymatic biomarkers, and LC-MS/MS-based metabolomics. After 16 days of exposure, only Cd and Cu significantly accumulated in body wall tissues. Combined high salinity and metals contributed to a slight increase in Fe accumulation and a decrease in Cu accumulation. Metal exposure disrupted the balance of metal elements (e.g., Mn, Zn, Co, Ni), with interactive effects modulated by salinity. Antioxidants and immune-related enzymes (SOD, CAT, ACP, ALP, Na+/K+-ATPase) responded distinctly to metal and salinity stress, with salinity often dominating the combined stress response. Metabolomic profiling revealed that Cd and Cu under ambient salinity induced widespread metabolic perturbations, altering metabolites related to lipid metabolism, glutathione metabolism, and saponin biosynthesis. Notably, high salinity (35 ppt) alleviated some metal-specific metabolic effects, while salinity alone caused significant downregulation of bioactive saponins and flavonoids. These findings demonstrate that salinity modulates metal toxicity in sea cucumbers, with potential consequences for immune function, oxidative defense, and nutritional value. This study provides novel insights into the ecological risks of desalination brine discharge on benthic ecosystems.
The global water resource crisis is continuing to intensify, and it is urgent to develop low-energy consumption and sustainable water purification technologies. Traditional water purification technologies can address the issue of water shortage. However, these traditional water purification technologies have many limitations, including high energy consumption, secondary pollution, etc. Solar-powered water purification technology has become a current research hotspot due to low cost, high efficiency, and environmental friendliness. Solar-driven hydrogels (SDHs) with high hydrophilicity and porous structure, as the emerging water purification materials, can efficiently convert solar energy into thermal energy through photothermal conversion, thereby enhancing the efficiency of interface evaporation, which provides innovative solutions for seawater desalination and wastewater treatment. This article systematically reviews the advanced substrate materials and photothermal agents utilized in SDHs. Moreover, this review comprehensively introduces the preparation strategies and mechanisms of SDHs. Furthermore, this paper comprehensively explores the design principles for enhancing the efficiency of light-to-heat conversion and the rate of water evaporation, and improving mechanical strength, durability, and salt resistance. Finally, the review discusses the practical applications of SDHs in seawater desalination, heavy metal ion removal, organic dye degradation, etc., while exploring their innovative roles in multi-level solar energy utilization and water resource recovery.