Water Transmission Research Articles

High-efficiency, thermal stable, and self-floating silver nanowires/Ti3C2Tx MXene/aramid nanofibers composite aerogel for photothermal water evaporation and antibacterial application

Interfacial solar steam generation shows great potential as a technology for seawater desalination. However, there are still considerable challenges in manufacturing photothermal evaporators with ultra-low thermal conductivity, mechanical robustness, and high-temperature resistance. Herein, we report Ag nanowires/Ti3C2Tx MXene/aramid nanofibers (Ag/Ti3C2Tx/ANFs) composite aerogel photothermal evaporators with internal three-dimensional (3D) micropores and a layered structure. The ANFs porous frame, with excellent mechanical properties and low thermal conductivity, allows abundant water transmission channels and reduces heat loss. Ti3C2Tx MXene and Ag NWs, known for their broadband absorption capability and antibacterial properties, enhance photothermal conversion efficiency. The Ag/Ti3C2Tx/ANFs composite aerogel distinguishes itself with a wide compression range (2 %∼60 %), remarkable light absorption capacity (96 %), and low thermal conductivity (0.49 W/mK), excellent thermal stability ensures the composite aerogel could withstand a wide temperature range from ∼500 °C to ∼196 °C. As expected, under one sun illumination, the Ag/Ti3C2Tx/ANFs composite aerogel presents a high evaporation rate of 2.21 kg m-2h−1 with an energy efficiency of 92 %. In addition, this evaporator composite aerogel exhibits outstanding and efficient salt tolerance, desalination, antibacterial properties, and heavy-metal ion wastewater purification capabilities. The unique evaporator structure presented here offers a new perspective for the structural design of next-generation, high-efficiency solar evaporators.

Laboratory Evaluation on the Water Flooding Characteristics in Bottom Water Reservoir Containing Interbeds.

Sandstone reservoirs with bottom water drive are widely distributed all over the world, which are characterized by the complex process of oil and water storage and transmission. At present, the research on the water flooding process and oil-water evolution characteristics in bottom water reservoirs containing interbeds needs to be strengthened. In this study, water flooding experiments with different placements of the interbeds were conducted using a two-dimensional (2D) vertical model. The results demonstrated that the interbeds make the bottom water flow upward more evenly, resulting in decreased incursion speed, increased displacement area, and better displacement effect. Moreover, compared with the tilted interbed model, the horizontal model has a 6% higher oil recovery rate, exhibiting a better oil displacement effect. The results presented herein will provide important guidance on water control in bottom-aquifer oil reservoirs containing interbeds and will promote unconventional petroleum resources recovery.

Synergistic effects of trace sulfadiazine and corrosion scales on disinfection by-product formation in bulk water of cast iron pipe

The effects of trace sulfadiazine (SDZ) and cast-iron corrosion scales on the disinfection by-product (DBP) formation in drinking water distribution systems (DWDSs) were investigated. The results show that under the synergistic effect of trace SDZ (10 μg/L) and magnetite (Fe3O4), higher DBP concentration occurred in the bulk water with the transmission and distribution of the drinking water. Microbial metabolism-related substances, one of the important DBP precursors, increased under the SDZ/Fe3O4 condition. It was found that Fe3O4 induced a faster microbial extracellular electron transport (EET) pathway, resulting in a higher microbial regrowth activity. On the other hand, the rate of chlorine consumption was quite high, and the enhanced microbial EET based on Fe3O4 eliminated the need for microorganisms to secrete excessive extracellular polymeric substances (EPS). More importantly, EPS could be continuously secreted due to the higher microbial activity. Finally, high reactivity between EPS and chlorine disinfectant resulted in the continuous formation of DBPs, higher chlorine consumption, and lower EPS content. Therefore, more attention should be paid to the trace antibiotics polluted water sources and cast-iron corrosion scale composition in the future. This study reveals the synergistic effects of trace antibiotics and corrosion scales on the DBP formation in DWDSs, which has important theoretical significance for the DBP control of tap water.

Numerical modelling of dual function tanks for fire suppression and tuned liquid damper applications

Exceeding serviceability limits due to wind-induced motions in tall buildings can cause discomfort for residents and adversely affect auxiliary building services, such as elevator operations. A tuned liquid damper (TLD) is an attractive type of dynamic absorber because of its simplicity and affordability. However, its dimensions and geometry can be limited by available floor space. Utilizing dual-purpose water tanks for both damping and fire suppression purposes can be a feasible resolution to fire code requirements and building motion control. Several design criteria need to be considered to accommodate the fire code requirements and the proper tuning of the TLD. Consequently, in this study, a TLD tank is fitted with a perforated floor to divide it into two compartments that allow water transmission to meet fire code requirements. However, the sloshing motion within the tank is complex and computationally expensive to capture when using traditional simulation models. This paper presents a 2D ISPH code equipped with a macro-level model to capture the effect of the perforated floor on the overall sloshing response of the tank. The model is first evaluated using existing results from previous studies on tanks with horizontal baffles. Next, the ISPH model is used to numerically model the perforated floor using the Ergun resistance (ER) macro-level model. In addition, the perforated floor is also explicitly micro-level modelled using rigid boundary particles to validate the proposed ER model. A numerical analysis is then conducted under different excitation amplitudes and frequencies, with both time history and frequency response results being presented. A structure-TLD model is subsequently used to capture the structure-TLD system response under random excitation. Results show that the ER model can efficiently model tanks with dual functions under both harmonic and random excitation and across a wide range of amplitudes and frequencies, with appreciable computational time savings. The proposed tank with a perforated floor is found to be effective in serving as a dual-purpose TLD and storage tank for fire suppression in buildings.

Application of Benthic Microbial Fuel Cells in Systems of Year-Round Monitoring of Water Environment Parameters

The bioelectrogenic activity of sediments of natural microbial association of the Peter’s Bay of Japanese sea research was performed in a year-round experiment with parallel temperature, illumination and water electrical conductivity monitoring by means of benthic microbial fuel cell (MFC) and automatic online-monitoring. Several variants of underwater devices, including benthic microbial fuel cells, monitoring water environment sensor,information collection and transmission systems, have been developed. This device make electrical voltage up to 216 mV, specific power up to 239 mW/m2. Electrogenic activity of natural microflora depends on water temperature and reach maximum on summer with temperature about 20–25°C. The introduction of toxicants in form as hydrocarbons and cadmium into the sluge led to the suppression of microbial electrogenesis. However the introduction of inductor substances of microbial sulfidogenesis led to the stimulation of microbial electrogenesis. The possibility of functioning of the benthic MFC in the field of the Peter’s Great Bay in various climatic periods is shown. It is shown that such experimental devices serve as a basis for autonomous stations monitoring the state of the aquatic environment for a long time and in a wide range of conditions change. Thus, automatic registration of temperature, illumination and salinity of water with a frequency of 48 times a day was carried out for 13 months (11/28/2019–12/31/2020). The electrogenic activity of this microbiota upon MFC scaling can potentially become a new renewable energy source for low-power marine electronics, including those used in mariculture.

Numerical Simulation Analysis of Construction Support of Intersection Section in Extra-long Water Diversion Project Tunnels

The selected Middle Yellow River Diversion Project is an important backbone project of the planning and construction of the modern water network in Shanxi Province. The project is composed of water source project and water transmission project, the water transmission project is about 400 kilometers long, there are about 200 kilometers of total dry, about 100 kilometers of East Dry and West Dry each, with an average depth of about 400 meters. The intersection section studied in this paper is located under the ridgeline of Lvliang Mountain with a burial depth of more than 600 meters. Whether to support the excavation of the tunnel intersection section was simulated by three-dimensional numerical simulation analysis of different sections. The stress field of surrounding rock and liner and the distribution of plastic zones in surrounding rock were simulated and calculated. The research results provide a technical reference for the design of tunnel support and the formulation of construction schemes, which is of great significance for the construction safety and operation management of water diversion tunnels.

Boosting-photothermal properties of Cu/ Black TiO2 nanoparticles on biomimetics texture structure as high‐performance and self‐regenerating solar-evaporator

To address the global water crisis, solar vapor generation emerged as a promising technology for clean-water uptake from seawater. Black TiO2 with wide-spectrum absorbancy, non-toxicity, cost-effectively, and chemical stability has attracted great interest in efficient solar-driven evaporators. Herein, the black TiO2 nanoparticles were synthesized through one step and facile reduction process of white oxide powder squeezed between two layers of NaCl. The prepared powder was deposited on the bare and copper-treated cotton fabrics as light absorbers in the proposed solar steam generation (SSG) systems. Various structural and morphology characterization methods have been utilized to verify of synthesis procedure. Heat localization was performed by the floated yarn-stitched polyurethane (PU) foam as a holder for the fabrics. Continuous water transmission from the saline water container to the evaporation surface was done via capillary forces in the yarns. The hybrid absorber introduced a superior solar-thermal conversion efficiency of about 98.56 % and 1.94 kg.m−2 h−1 evaporation rate which was 3.13 times larger than the control one. Antifouling and recyclability properties of the samples were studied in outdoor conditions. The suggested hybrid-based (Cu/black TiO2) SSG with significant properties of simplicity, non-toxicity, and high evaporating activity opens new shortcuts toward green water desalination and also salt extraction demands.

Effect of Different Tillage and Residue Management Options on Soil Water Transmission and Mechanical Behavior

Understanding the variability in the mechanical and hydrological soil characteristics resulting from diverse tillage and residue management practices is essential for evaluating the adoption of conservation strategies to preserve soil’s physical well-being. Zero-tillage techniques combined with residue retention or incorporation have gained widespread recognition for their capacity to conserve soil and water resources, reduce energy consumption, and enhance soil quality and environmental sustainability. Nevertheless, the choice of tillage and residue management options may vary depending on the geographical locations and specific soil conditions. To assess the impacts of four distinct tillage and residue management approaches, a two-year experiment (2020–2021 and 2021–2022) was conducted: T1: conventional tillage followed by wheat sowing after the removal of rice straw (CT-RS); T2: zero tillage with wheat sowing using a Happy Seeder while retaining rice straw (ZT+RS); T3: conventional tillage followed by wheat sowing after rice straw incorporation using a reversible mouldboard plough (CT+RS); T4: minimum tillage with wheat sowing using a Super Seeder with rice straw incorporation (MT+RS); the effects were recorded on the physical soil properties. Our findings indicate that zero tillage combined with residue retention (T2) had a positive influence on various physical soil attributes. Notably, significant differences were observed among the tillage and residue management options, particularly in terms of the bulk density with T1 exhibiting the highest values and the lowest being in T2, whereas the soil penetration resistance was lowest in T3 compared to T1. In the case of T3, sandy loam and clay loam soils had the highest measured saturated hydraulic conductivity values, measuring 5.08 and 4.57 cm h−1 and 4.07 and 3.73 cm h−1, respectively. Furthermore, T2 (zero tillage with residue retention) demonstrated the highest mean weight diameter (MWD) and maximum water stable aggregate. These results collectively underscore the positive effects of adopting zero tillage and retaining residue (T2) on soil structure and quality, particularly concerning the mechanical and hydrological soil properties.

Response mechanisms of pipe wall biofilms in water supply networks under different disinfection strategy pressures and the effect of mediating halogenated acetonitrile formation

Residual chlorine and biofilm coexistence is inevitable in drinking water transmission and distribution networks. Understanding the microbial response and its mediated effects on disinfection byproducts under different categories of residual chlorine stress is essential to ensure water safety. The aim of our study was to determine the response of pipe wall biofilms to residual chlorine pressure in chlorine and chloramine systems and to understand the microbially mediated effects on the formation and migration of haloacetonitriles (HANs), typical nitrogenous disinfection byproducts. According to the experimental results, the biofilm response changes under pressure, with significant differences noted in morphological characteristics, the extracellular polymeric substances (EPS) spatial structure, bacterial diversity, and functional abundance potential. Upon incubation with residual chlorine (1.0 ± 0.2 mg/L), the biofilm biomass per unit area, EPS, community abundance, and diversity increased in the chloramine group, and the percentage of viable bacteria increased, potentially indicating that the chloramine group provides a richer variety of organic matter precursors. Compared with the chloramine group, the chlorination group exhibited increased haloacetonitrile formation potential (HANFP), with Rhodococcus (43.2%) dominating the system, whereas the prediction abundance of metabolic functions was advantageous, especially with regard to amino acid metabolism, carbohydrate metabolism, and the biodegradation and metabolism of foreign chemicals. Under chlorine stress, pipe wall biofilms play a stronger role in mediating HAN production. It is inferred that chlorine may stimulates microbial interactions, and more metabolites (e.g., EPS) consume chlorine to protect microbial survival. EPS dominates in biofilms, in which proteins exhibit greater HANFP than polysaccharides.

Integrated solar evaporator based on photothermal Cu-CuOx/NC with heat-insulated polyurethane foam enabling highly efficient salt-tolerant desalination and water purification

Renewable solar energy meeting photothermal materials provides a promising approach for freshwater production via interfacial steam generation. The design and manufacture of high-performance evaporators are still highly anticipated for practical applications. Herein, the robust and durable solar evaporator is proposed and fabricated by integration of photothermal Cu-CuOx/NC (CNC) and three-dimensional porous structure heat-insulated polyurethane (PU) foam with polyvinyl alcohol (PVA)/sodium alginate (SA) modifications. The designed PVA-SA-CNC/PU simultaneously possesses fast water transmission, broadband light trapping, satisfactory mechanical robustness and effective heat confinement. When applied as a solar evaporator, the PVA-SA-CNC/PU exhibits a high evaporation rate of 1.99 kg m−2 h−1 and operates stably within ten consecutive cycles under one-sun illumination, which can also handle salt tolerant desalination of seawater and saline water to sustainably produce freshwater. In addition, the functional versatility of the fabricated evaporator is explored to purify various wastewater. This study establishes a highly efficient integrated evaporator with multitasking water purification towards the solution of water shortage.

Chloro- and bromo-benzoquinone formation and transformation mechanisms in a drinking water-distribution system

Halogenated benzoquinones (HBQs) are frequently detected in tap water. HBQ levels are correlated with water age. As the water–transmission distance (water age) increases, the levels of bromo-benzoquinones (Br-BQs) decreased and those of chloro-benzoquinones (Cl-BQs) remained relatively stable in drinking water–distribution system in the presence of residual chlorine. 2,3,5,6-Tetrachloro-1,4-benzoquinone (TCBQ) and 2,6-dibromo-1,4-benzoquinone (DBBQ) were the most abundant Cl-BQ and Br-BQ, with maximum concentrations of 60.2 and 181.4 ng/L, respectively. TCBQ and DBBQ were chosen as representatives of HBQs to investigate their reactions with chlorine, including kinetics, pathways, and changes in toxicity. The hydrolysis and chlorination rates of HBQs were significantly pH-dependent, and the kinetic rates of DBBQ were faster than TCBQ in the pH range of 5–10. Chlorination converted highly toxic TCBQ and DBBQ to less-toxic chlorinated/brominated aliphatic disinfection by-products (DBPs), thereby reducing the overall toxicity of water bodies. This study provides comprehensive insights into the distinct life cycles of TCBQ and DBBQ in drinking water, covering formation, transformation, and toxicity. These findings provide a nuanced understanding of the risks posed by HBQs at various locations within the drinking water distribution system, offering valuable guidance for improving the control of DBPs in drinking water.

Hydrogen and oxygen isotope signal transmission in rainfall, soil water, and cave drip water in Liangfeng Cave, Southwest China

δD and δ18O isotope signatures were widely used as tracers to investigate recharge processes of rainfall transfer into caves in the vadose zones of karst regions. The present research systematically monitored rainfall, soil water, and drip water at the Liangfeng Cave in Guilin City, China, from January 2020 to September 2022, as these aspects remain poorly quantified. The δD and δ18O compositions of rainfall were depleted during the rainy season and enriched during the dry season. The local meteoric water line (LMWL) was described as δD = 7.98δ18O + 11.52. The dry season is mainly characterized by resident soil water, with little mobile soil water, whereas the primary source of recharged drip water is stored bedrock water on the top of the cave. During the rainy season, resident and mobile soil water exchanged with each other, resulting in homogenous δD and δ18O compositions across different soil depths and indicating a lack of ecohydrological separation; however, δD and δ18O signature in drip water may differ from the original observed in rainfall, suggesting that the residence time affected the response time of the drip water to rain. Moreover, mixed stored older water in the overlying bedrock was the primary drip water recharge source each season; thus, drip water's isotope amplitude values were more depleted than rainfall's. Distinct flow paths also created differences in the lag time and amplitude at each drip site. During high-intensity rain, the isotopic signals were rapidly transmitted by preferential flow at different soil depths and via drip water. The δD and δ18O signals in the drip water showed significant depleted excursions several months after high-intensity rainfall. These findings indicate that ecohydrological separation did not occur under any circumstances within the study area, and care should be taken when interpreting significant depleted excursions of δD and δ18O signals in drip water during the summer monsoon or the amount of rainfall in stalagmites across seasonal or interannual scales.

Estimating SVCV waterborne transmission and predicting experimental epidemic development: A modeling study using a machine learning approach

Viral infectious diseases significantly threaten the sustainability of freshwater fish aquaculture. The lack of studies on epidemic transmission patterns and mechanisms inhibits the development of containment strategies from the viewpoint of veterinary public health. This study raises an epidemic mathematical model considering water transmission with the aim of analyzing the transmission process more accurately. The basic reproduction number R0 was derived by the model parameter including the water transmission coefficient and was used for the analysis of the virus transmission. Spring viremia of carp virus (SVCV) and zebrafish were used as model viruses and animals, respectively, to conduct the transmission experiment. Transmission through water was achieved by connecting two aquarium tanks with a water channel but blocking the fish movement between the tanks. With the collected experimental data, we determined the optimal hybrid machine learning algorithm to analyze the transmission process using an established mathematical model. In addition, future transmission was predicted and validated using the epidemic model and an optimal algorithm. Finally, the sensitivity of model parameters and the simulations of R0 variation were performed based on the modified complex epidemic model. This study is of significance in providing theoretical guidance for minimizing R0 by manipulating model parameters with containment measures. More importantly, since the modified model and algorithm demonstrated better performance in handling freshwater fish transmission problems, this study advances the future application of transmissible disease modeling with larger datasets in freshwater fish aquaculture.

Study on the Hydraulic Response of an Open-Channel Water Transmission Project after Flow Switching

For the complex and changing water transfer conditions along the nullah water transfer project, it is of great significance to analyze the hydraulic response characteristics of the channel pool to ensure the safe and efficient operation of the project. In this paper, using the adjustable reservoir capacity of the channel pool, combined with the earliest and latest regulation time, a method is proposed to determine the optimal regulation time of water conservancy engineering structures through the hydraulic response characteristics. In order to validate the method, the hydraulic response characteristics of the channel pool during the whole regulation period were investigated using an actual river diversion project as an example. By using the Sobol global sensitivity analysis method, the sensitivity analysis of three variables (water transfer flow, upstream initial flow, and downstream water level) was conducted, and the results showed that the change of water transfer flow was the most-critical factor affecting the optimal regulation time. In order to quantitatively study the correlation between the water transfer flow and the optimal regulation time, the water transfer flow factor was coupled to the existing prediction model, and the results showed that the coupled model can efficiently predict the optimal regulation time, and the NSE coefficient can reach 0.98. In addition, the coupled model can be efficiently used to serve on-site dispatchers for accurately predicting the optimal regulation time and making the corresponding safety decisions.

Water scarcity risk through trade of the Yellow River Basin in China

Water scarcity poses economic risks and affects the quality of national and regional development. The risk of local water scarcity can be conveyed to downstream economies through interregional trade for potential economic losses. However, most previous water scarcity studies focused on the availability of adequate freshwater supplies, ignoring the economic losses associated with inadequate water quality. With the aggravation of water pollution, water scarcity caused by inadequate water quality is exacerbated. This study incorporates water quality and quantity into local water scarcity risk assessments, revealing the virtual water scarcity risks and transmission pathways of the cities and sectors in the Yellow River Basin (YRB) in China. The results show that the number of cities with severe water stress increases from 13 to 53 when water quality is considered. Virtual water scarcity risks transfer from upstream cities to downstream cities in Henan and Shandong Provinces, and high-risk cities in Henan can be identified by considering water quality. Key transmission pathways for intersectoral transfer are identified. This study validates the significance of considering water quality factors in water scarcity risk assessments and provides a perspective for policy decisions to mitigate water scarcity and thus ensure water security in the YRB.

MXene-reduced graphene oxide sponge-based solar evaporators with integrated water-thermal management by anisotropic design

The main issue limiting the performance of the solar evaporators is that water-thermal management is difficult to coordinate. Herein, we achieve integrated water-thermal management by designing hierarchical MXene-reduced graphene oxide sponges with anisotropic thermal conductivity and axial-directional water conveyance channels. The reduced graphene oxide acts as the sponge framework and carbon source for in situ synthesis of MXenes on the surface. The axial-oriented framework supports the structure and provides fast water transmission channels to the air-water interface. Meanwhile, the MXene nanosheets are vertically aligned on the framework surface, making the radial thermal conductivity of the sponges much greater than the axial one, which suppresses heat loss in the axial direction. The material exhibits an evaporation rate of 2.35 kg m−2 h−1 under one sunlight and maintains 85 % energy efficiency under weak sunlight (0.5-sun). Furthermore, the sponge shows a long working life with 96 % evaporation rate retention after a 30-day-sustained operation.

Reliability Analysis of Dynamic Load-Sharing Systems With Constrained and Changing Component Performances

Considerable research efforts have been expended in modeling load-sharing systems. The existing models, however, have various limitations, such as being limited to the exponential time-to-failure distribution, constant component performances, or performances without constraints. In this article, we make contributions by modeling a dynamic load-sharing system (DLSS), where the performance of each component is dynamic according to prespecified load-sharing principles and is limited by its capacity constraint. Moreover, the capacity constraint of a component can reduce due to degradations. In the proposed model, increasing failure rates are also involved since the surviving components must share the load of the failed component and continue working with increasing stresses. When the desired performance for a component exceeds the limitation, the entire system fails. An extended Markov process (EMP) method is proposed for evaluating the reliability of the considered DLSS with nonrepairable components. The proposed analytical method is flexible in handling arbitrary component time-to-failure distributions and in handling diverse load allocation mechanisms. Numerical studies of a power transmission system and a water transmission system are provided to validate the proposed method and its advantages. Effects of several model parameters are also investigated through case studies.

Ultrasonic Flow Meters and Microcontrollers for Precise Water Management with 6.45% Error Margin

Water management is crucial for human life, and precise measurement instruments are necessary to ensure efficient utilization. This study aimed to develop a water usage management system using ultrasonic flow meters and microcontrollers. The measurement results were displayed on a screen and sent via modbus to remote devices. To validate the accuracy of the system, a comparison between ultrasonic and manual flow meters was conducted, showing an error value of 6.45%. The implication of this study is the potential use of this system for water consumption control and transmission over long distances, contributing to sustainable water management.

Effect of geometry and hydraulic parameters on the bed morphology in a confluence using numerical approach

The confluence of rivers is an important phenomenon that is really vital for irrigation and water transmission networks. Investigation on bed morphology at the junction of two streams is of great importance. Flow complexity at confluences, as well as being at risks of rising water levels and flooding, interfering with the use of bridges, filling the inlets of the ponds and reducing the efficiency of water transport are resulted by this phenomenon. The purpose of this research is to investigate the effect of geometric and hydraulic parameters, such as junction angle, width ratio of two intersected canals, and Froude number on the bed morphology at intersection, using SSIIM2. Validation of the results of numerical model in terms of hydraulic and morphology parameters indicated good correlations coefficients of 0.9 and 0.68, respectively. In the next step, the effect of intersection angle (45, 60, 75, 90 and 105 degrees) on the scour depth was investigated. By decreasing the junction angle from 105° to 45°, the maximum scour depth reduced to about 96% and the scour hole dimensions were smaller and moved toward the confluence shore. Furthermore, the results showed that by increasing the width ratio from 0.5 to 1, and also, decreasing the Froude number ratio of tributary to main channel from 3 to 0.68, maximum scour depth decreased by 25% and 30%, respectively.

PDI-Based Organic Small Molecule Regulated by Inter/Intramolecular Interactions for Efficient Solar Vapor Generation.

Organic small molecules with processing feasibility, structural diversity, and fine-tuned properties have the potential applications in solar vapor generation. However, the common defects of narrow solar absorption, low photothermal conversion efficiency, and photobleaching result in limited materials available and unsatisfactory evaporation performance. Herein, the perylene diimide (PDI) derivatives are exploited as stable sunlight absorbers for solar vapor generation. Particularly, the N,N'-bis(3,4,5-trimethoxyphenyl)-3,4,9,10-perylenetetracarboxylic diimide (PDI-DTMA) is well-designed with donor-acceptor-donor configuration based on plane rigid PDI core. The efficient photothermal conversion is enabled through strong intermolecular π-π stacking and intramolecular charge transfer, as revealed by experimental demonstration and theoretical calculation. The PDI-DTMA with a narrow band gap of 1.17eV exhibits expanded absorption spectrum and enhanced nonradiative transition capability. The 3Dhybrid hydrogels (PPHs) combining PDI-DTMA and polyvinyl alcohol are constructed. With the synergistic effect of solar-to-heat conversion, thermal localization management, water activation, and unobstructed water transmission of PPHs, the high water evaporation rates can reach 3.61-10.07kg m-2 h-1 under one sun. The hydrogels also possess great potential in seawater desalination and sewage treatment. Overall, this work provides valuable insights into the design of photothermal organic small molecules and demonstrates their potentials in solar water evaporation.