Water Structure Research Articles

Remote sensing and monitoring of water resources: A comparative study of different indices and thresholding methods

Water resources are essential for the ecological system and the development of civilization. Water is imperative factor for health preservation and sustaining various human activities, including industrial production, agriculture, and daily life. Remote sensing provides a cost-effective and practical means to detect and monitor water bodies, offers valuable insights into the impact of climatic events on water structures, especially in coastal lake regions. The research primarily utilizes Landsat-9 OLI-2 satellite images to evaluate the effectiveness of various water indices (WRI, NWI, MNDWI, NDWI) in combination with global automatic thresholding methods (K-Means, Zhenzhou's, Adaptive, Intermodes, Prewitt and Mendelsohn's Minimum, Maximum Entropy, Median, Concavity, Percentile, Intermeans, Kittler and Illingworth's Minimum Error, Tsai's Moments, Otsu's, Huang's fuzzy, Triangle, Mean, IsoData, Li’s). The study was carried out on Lake Nazik, Lake Iznik, and Lake Beyşehir, which have unique geographical characteristics, and examined the adaptability and robustness of the selected indices and thresholding methods. MNDWI consistently stands out as a robust index for water extraction, delivering accurate results across different thresholding methods in regions all three lakes. As a result of quite extensive analysis, it is obtained that MNDWI and NDWI are reliable choices for water feature extraction in various lake environments, but the specific index should consider the thresholding method and unique lake characteristics. The Minimum thresholding method stands out as the most effective thresholding technique, demonstrating impressive results across different lakes. Specifically, it achieved an average Peak Signal-to-Noise Ratio (PSNR) of 78.97 and Structural Similarity Index (SSIM) of 99.37 for Lake Nazik, 74.08 PSNR and 98.34 SSIM for Lake Iznik, and 63.96 PSNR and 93.61 SSIM for Lake Beyşehir.

Іntensification of ion exchange processes in water supply systems

In today's environment, special attention is paid to various methods of intensifying natural and wastewater treatment processes, improving existing treatment technologies, and introducing new methods and techniques to improve the quality of wastewater treatment and reduce the anthropogenic impact on the ecosystem. It is important to take into account not only the effectiveness of cleaning, but also its environmental friendliness and compliance with modern standards and requirements for environmental protection. This approach helps to ensure the sustainability of ecosystems and preservation of water resources for future generations. The article highlights the issues related to the use of physical methods of water treatment in water supply systems. To intensify the processes of ion exchange in water supply systems, a method of adjusting the mineral composition of natural and waste water using modified ion exchangers is proposed, which involves the simultaneous action of a magnetic field on the ion exchanger and the water to be treated. The use of magnetic modification of ion exchangers allows to increase the productivity of water treatment facilities by an average of 25-30%, with the receipt of filtrate of the required quality, to increase the duration of the filter cycle, to reduce the consumption of regenerative solutions, which indicates an increase in the efficiency of water treatment as a result of the use of magnetic modification. An increase in the dynamic volume capacity of ion exchangers by 15-20% was found, which indicates an improvement in ion exchange capacity due to the intensification of ion exchange processes in water supply systems. The intensification of ion exchange processes during the adjustment of the mineral composition of natural and wastewater using a magnetic field is determined by the following main factors: the effect of the magnetic field on the structure and properties of water filtered through the ionite and the effect of the magnet field on the activity and mobility of the exchanged ions, their diffusion and hydration, ion-exchange equilibrium, and other factors.

Ultraviolet (UV) light effect on the electrical potential of interfacial water

Water is one of the most essential elements of life. Despite many studies on the physical and chemical properties of water, many features are still not yet understood. Here, we consider the negative electrical potential in the water adjacent to the Nafion membrane. The electrical potential becomes more negative closer to the membrane, a feature that might arise from the special water structure (interfacial water) next to Nafion. Evidence has shown that the water was characterized by a UV absorbance at ∼270 nm. We hypothesized that such radiant energy might contribute to the electrical potential of the interfacial water. Here, the effect of exposure to light on this potential, at wavelengths of 275 nm, 370 nm and 650 nm was studied. The electrical potential became more negative under 275 nm wavelength UV light, while other two wavelengths had negligible effects. The result fits well with the ∼270 nm wavelength absorption peak reported in previous studies. Potentially, the absorbed UV energy helps fuel the ‘water battery’. The findings shed light on the mechanism underlying the character of interfacial water adjacent to hydrophilic surfaces.

Transferable Water Potentials Using Equivariant Neural Networks.

Machine learning interatomic potentials (MLIPs) have emerged as a technique that promises quantum theory accuracy for reduced cost. It has been proposed [J. Chem. Phys. 2023, 158, 084111] that MLIPs trained on solely liquid water data cannot accurately transfer to the vapor-liquid equilibrium while recovering the many-body decomposition (MBD) analysis of gas-phase water clusters. This suggests that MLIPs do not directly learn the physically correct interactions of water molecules, limiting transferability. In this work, we show that MLIPs using equivariant architecture and trained on 3200 liquid water structures reproduces liquid-phase water properties (e.g., density within 0.003 g/cm3 between 230 and 365 K), vapor-liquid equilibrium properties up to 550 K, the MBD analysis of gas-phase water cluster up to six-body interactions, and the relative energy and the vibrational density of states of ice phases. We show that potentials developed using equivariant MLIPs allow transferability for arbitrary phases of water that remain stable in nanosecond long simulations.

The large‐scale restoration of fire and water regimes in Everglades National Park reveal little change in plant diversity along an elevational gradient

Quantifying the response of plant diversity to large‐scale restoration is essential for measuring management success. One of the world's largest restoration efforts began in 2000 in the Everglades ecosystem in Florida, United States, through the Comprehensive Everglades Restoration Plan. In coordination with ongoing fire management, this restoration effort aims to restore natural hydrologic and fire regimes in this dynamic ecosystem. Restored water and fire regimes in the Everglades interact along an elevational gradient between seasonally inundated marl prairie and frequently burned pine rockland on Long Pine Key in Everglades National Park. To determine the impact of management on plant community richness and composition, we resampled transects spanning the elevational gradient between marl prairie and pine rockland initially sampled prior to the implementation of current restoration efforts (circa 1997–1999). We measured percent plant cover and developed generalized linear mixed models to determine the effects of fire frequency, average water depth, and elevation on plant species richness and composition across the two time periods. Additionally, we used species‐level random effects to examine how individual species respond to each environmental variable. We failed to detect any systematic shifts in plant composition in response to fire and water management. However, we found that complex interactions between fire and water structure plant composition and maximize species richness along gradients of water depth and elevation, with low, moderate, and high burn frequencies increasing richness in wet, moderately wet, and dry sites, respectively.

Loss of submerged macrophytes in shallow lakes alters bacterial and archaeal community structures, and reduces their co-occurrence networks connectivity and complexity.

Bacteria and archaea are important components in shallow lake ecosystems and are crucial for biogeochemical cycling. While the submerged macrophyte loss is widespread in shallow lakes, the effect on the bacteria and archaea in the sediment and water is not yet widely understood. In this study, 16S rRNA gene sequencing was used to explore the bacteria and archaea in samples taken from the sediment and water in the submerged macrophyte abundant (MA) and submerged macrophyte loss (ML) areas of Caohai Lake, Guizhou, China. The results showed that the dominant bacterial phyla were Proteobacteria and Chloroflexi in the sediment; the dominant phyla were Proteobacteria, Actinobacteriota, and Bacteroidota in the water. The dominant archaea in sediment and water were the same, in the order of Crenarchaeota, Thermoplasmatota, and Halobacterota. Non-metric multidimensional scaling (NMDS) analyses showed that bacterial and archaeal community structures in the water were significantly affected by the loss of submerged macrophytes, but not by significant changes in the sediment. This suggests that the loss of submerged macrophytes has a stronger effect on the bacterial and archaeal community structures in water than in sediment. Furthermore, plant biomass (PB) was the key factor significantly influencing the bacterial community structure in water, while total nitrogen (TN) was the main factor significantly influencing the archaeal community structure in water. The loss of submerged macrophytes did not significantly affect the alpha diversity of the bacterial and archaeal communities in either the sediment or water. Based on network analyses, we found that the loss of submerged macrophytes reduced the connectivity and complexity of bacterial patterns in sediment and water. For archaea, network associations were stronger for MA network than for ML network in sediment, but network complexity for archaea in water was not significantly different between the two areas. This study assesses the impacts of submerged macrophyte loss on bacteria and archaea in lakes from microbial perspective, which can help to provide further theoretical basis for microbiological research and submerged macrophytes restoration in shallow lakes.

Drinking magnetized water alters blood constituents, and structure of spleen and kidney in rabbits

This study aimed to investigate the effect of magnetic field on physicochemical properties of water and evaluating the effects of the magnetized water (MW ) on the productive performance, liver enzymes, spleen and kidney structure of rabbits. Water samples were collected to determine pH and electrical conductivity (EC), and water structure was investigated by Transmission Electron Microscopy (TEM). Twenty-four weaned Rex rabbits, 21 d old, were allotted into two experimental groups: the first group was assigned as control, received regular tap water (TW), and the treated group, received MW, for 5 weeks. Productive traits were recorded weekly and at the end of the experiment, blood samples, spleen and kidney were collected for examinations. Results showed that pH and EC of MW were higher than those of TW. In addition, the arrangement MW cluster showed a unique alteration on the nano-scale. Growth performance indicators were similar in both experimental treatments, except FCR of the MW rabbits was better than that of the TW rabbits. The MW had no significant effect on plasma concentration of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and creatinine in growing Rex rabbits received MW in comparison with those received regular TW. Spleen histological structure of rabbits of both groups was normal. However, the epithelial cells lining renal tubules of kidneys of rabbits in MW group appeared large with basophilic nuclei in comparison with TW group. Conclusively, magnetic field alters the physicochemical properties of water. The MW may consequently increase blood glucose level and spleen weight % and enhance kidney structure in growing rabbits. Moreover, more studies are still needed to know the benefits of providing the magnetized water to ‎animals. ‎

Long-term changes in water quality and structure of benthic animal communities in the Neva estuary under anthropogenic stress

In the Neva River estuary, 188 species and taxa of a higher rank of benthic animals were found, of which 129 were found in the eastern part of the Gulf of Finland. At present, the zoobenthos of the estuary is dominated by eurybiont species inhabiting polluted waters. We used integrated index IP' specially devised for water-bodies and rivers of the north-western Russia to assess the water quality and a state of ecosystems of the Neva estuary. It is based on structural parameters of zoobenthic communities and makes it possible to take into consideration the pollution by toxic and organic substances. On average the water quality of the Neva Bay assessed from IP′ values was relatively stable during 1994–2021. It was assessed as “polluted” with the exception of 2006 and 2015 caused by large-scale dredging works. In the period 1982–2021, the average number of zoobenthos species at one station in the Neva Bay almost doubled, from 12 ± 1 species in 1982 to 23±2 species in 2020. In the resort area of the eastern Gulf of Finland, the values of species richness and the Shannon index were much lower than in the Neva Bay, and on average for one station varied from 5±0.6 to 14±4 species and from 1.1±0.2 to 2.3±0.2 bit/ind. This is caused by the influence of salinity, eutrophication and pollution, and invasion of alien species. In addition to intense anthropogenic impact, the dynamics of the state of zoobenthos in this part of the estuary was determined by climate fluctuations.

Meteorological Data and Spectral Analyses of Non-Equilibrium Processes in Water during the Total Solar Eclipse of 11.08.1999 in Bulgaria

There are partial or total solar eclipses every year on our planet. They are observed from relatively small areas. From 1950 to 2100, three total solar eclipses fell within the territory of Bulgaria. The two solar eclipses from the 20th century were observed on 15.02.1961 and 11.08.1999. The next total solar eclipse will happen on 3.09.2081. The partial solar eclipses in Bulgaria were on 3.10.2005, 29.03.2006, 1.09.2008, 4.01.2011, and 25.10.2022. The question of the influence of solar eclipses on the Earth’s atmosphere, water, and living organisms is an area of interest for many researchers. In this connection, studies have been conducted on atmospheric and water parameters during partial and total solar eclipses. Most investigations were performed with meteorological data – temperature and humidity. In the last 30 years, other methods have also been applied for the investigations of solar eclipses – spectral methods with infrared (IR) spectroscopy, studies of magnetic and electric fields, polarization, and measurements of the parameters of the fluids in plants. Our studies have used meteorological methods and analyses. For the effects on the water, spectral methods are applied to the non-equilibrium energy spectrum (NES) and differential non-equilibrium spectrum (DNES). A deionized water sample examined during the solar eclipse on 11.08.1999 was used, aiming to analyze the parameters of NES and DNES. The deionized water control sample was tested on 10.08.1999 at the same time as the solar eclipse of the next day. The results of our research show relatively rapid and significant changes in air parameters during a solar eclipse, which are most prominent immediately after its culmination. The conditions of non-equilibrium arising during the solar eclipse allow for studying the restructuring of the hydrogen bonds of water molecules. The results of the current studies prove that the solar eclipse’s significantly affect water which is the primary substance in the Nature and living organisms. These data are consistent with other ones which also prove that, during a solar eclipse, the structure of water undergoes significant changes. By influencing the water, this natural phenomenon affects the whole Nature and all living organisms on the planet.

Thermal corrosion fatigue crack growth behavior and life prediction of 304SS pipeline structures in high temperature pressurized water

The influence of transient water temperature changes on the fatigue crack growth behavior of 304SS pipeline structures was studied based on high-throughput testing method through the modification of dual loop circulating water equipment. Results demonstrated that the fatigue crack growth rate gradually decreased with the decrease of cooling rate, and the crack growth rate was exponentially related to the cooling rate. Both the base material and weld of the stepped pipe showed a transgranular cracking mode, and propagated continuously by slip-oxidation mechanism. Compared with the fine equiaxed grain of the base material, the grain in the weld was coarse and the residual strain was large, and the crack growth rate of the weld was obviously higher. Then, the thermal fatigue crack growth rate model for stepped pipes was established by combining finite element thermo-mechanical coupling simulation and three-dimensional crack propagation analysis software, and the model was modified based on the experimental results.

Spectroscopic and Theoretical Identifications of Two Structural Motifs of (H2O)10 Cluster.

Precise characterization of archetypal systems of aqueous hydrogen-bonding networks is essential for developing accurate potential functions and universal models of water. The structures of water clusters (H2O)n (n = 2-9) have been verified recently through size-specific infrared spectroscopy with a vacuum ultraviolet free electron laser (VUV-FEL) and quantum chemical studies. For (H2O)10, the pentagonal prism and butterfly motifs were proposed to be important building blocks and were observed in previous experiments. Here we report the size-specific infrared spectra of (H2O)10 via a joint experimental and theoretical study. Well-resolved spectra provide a unique signature for the coexistence of pentagonal prism and butterfly motifs. These (H2O)10 motifs develop from the dominant structures of (H2O)n (n = 8, 9) clusters. This work provides an intriguing prelude to the diverse structure of liquid water and opens avenues for size-dependent measurement of larger systems to understand the stepwise formation mechanism of hydrogen-bonding networks.

Structural effects of water clusters on viscosity at high shear rates.

In this study, we use molecular dynamics simulations of liquid water to investigate how shear thinning affects the viscosity of liquid water by structural changes of the hydrogen bond network. The effect of shear on viscosity can be divided into two parts: shear-induced destruction of the hydrogen bond network and the influence of the water structure on shear viscosity. First, strong shear destroys tetrahedral structures and thus reduces the connectivity of the hydrogen bond network. It is mainly because shear deformation, characterized by compression and expansion axes, respectively, triggers the destruction and formation of hydrogen bonds, resulting in anisotropic effects on water structures. At the same time, shear destroys large clusters and enhances the formation of small ones, resulting in a decrease in average cluster sizes. Second, the change of viscosity obeys a power law relationship with the change of hydrogen bond structures, highlighting a one-to-one correspondence between structure and property. Meanwhile, in order to explain why the structure affects viscosity, we define hydrogen-bond viscosity and find that the cooperative motion of the water structures can promote momentum transfer in the form of aggregations. Hydrogen-bond viscosity accounts for 5%-50% of the total viscosity. Our results elucidate that water structures are the important structural units to explain the change of water properties.

Improving precipitation estimates for Turkey with multimodel ensemble: a comparison of nonlinear artificial neural network method with linear methods

AbstractEnsemble analysis is proven to provide advantages in climate change impact assessment based on outputs from climate models. Ensembled series are shown to outperform single-model assessments through increased consistency and stability. This study aims to test the improvement of precipitation estimates through the use of ensemble analysis for south and southwestern Turkey which is known to have complex climatic features due to varying topography and interacting climate forcings. The analysis covers an evaluation of the performance of eight regional climate models (RCMs) from the EUR-11 domain available from the CORDEX database. The historical outputs are evaluated for their representativeness of the current climate of the Mediterranean region and its surroundings in Turkey through a comparison with long-term monthly precipitation time series obtained from ground-based precipitation observations by the use of statistical performance indicators and Taylor diagrams. This is followed by a comparative evaluation of three ensemble methodologies, simple average of the models, multiple linear regression for superensemble, and artificial neural networks (ANN). The analysis results show that the overall performance of ensembled time series is better compared to individual RCMs. ANN generally provided the best performance when all RCMs are used as inputs. Improvement in the performance of ensembling due to the use of nonlinear models is further confirmed by fuzzy inference systems (FIS). Both ANN and FIS generated monthly precipitation time series with higher correlations with those of observations. However, extreme events are poorly represented in the ensembled time series, and this may result in inefficiency in the design of various water structures such as spillways and storm water drainage systems that are based on high return period events.

Dynamics of changes in the temperature coefficient of electrical conductivity of distilled water in conductometric cells during heating and cooling

The problem of taking into account the influence of air on the properties of distilled water is considered, namely the lack of a single generally accepted method for calculating such an influence. The sensitivity of the structure of water to the influence of external factors is described and the possibility of recording and studying such factors by changes in the temperature coefficient of electrical conductivity of water is shown. The dependences of the temperature coefficient of electrical conductivity of distilled water on the rate of change in water temperature, the degree of filling of conductometric cells, as well as on the intensity of the exchange of carbon dioxide between water and air across their interface have been studied. It is noted that these metabolic processes are currently insufficiently studied. A hardware-software measuring complex has been developed and manufactured to study the temperature coefficient of electrical conductivity of water when its temperature changes within the range of 20–55 °C. The temperature coefficient of electrical conductivity of water in sealed conductometric cells was measured at different degrees of filling the cells with distilled water and the rate of heating and cooling of water. The degree of filling of the cells varied within the range of 10–100 %, the rate of change in water temperature varied within the range of 0.04–2.00 °C/min. With a constant heating and cooling time of 15 minutes in all experiments, the change in speed was achieved by changing the temperature of the heating element. The integral temperature coefficient of electrical conductivity is calculated based on the initial and final values of electrical conductivity and water temperature in each measurement cycle. The dependences of the temperature coefficient of electrical conductivity on the rate of change in water temperature at several constant degrees of cell filling were obtained. It has been shown that with a constant ratio of the volumes of water and air in the cell and an increase in the rate of heating of water, the temperature coefficient of electrical conductivity of water decreases by 19–22 %. It has been established that at a constant rate of water heating, with a decrease in the volume of water in the cell, the temperature coefficient of electrical conductivity of water decreases by 40–42 %. The results obtained can be used to quantify the dissociation coefficient of carbonic acid, the mobility of hydrogen ions, as well as the intensity of the gas exchange process under various external influences on water. Refinement of data on the electrical conductive properties of water and processes at the water/air interface is necessary for the development of models of atmospheric phenomena and climate change, as well as for the creation of sensors for weak changes in environmental parameters for the purposes of both environmental monitoring and medical diagnostics.

Identification of local structures in water from supercooled to ambient conditions.

Studies of water thermodynamics have long been tied to the identification of two distinct families of local structures, whose competition could explain the origin of the many thermodynamic anomalies and the hypothesized liquid-liquid critical point in water. Despite the many successes and insights gained, the structural indicators proposed throughout the years were not able to unequivocally identify these two families over a wide range of conditions. We show that a recently introduced indicator, Ψ, which exploits information on the hydrogen bond network connectivity, can reliably identify these two distinct local environments over a wide range of thermodynamic conditions (188-300K and 0-13 kbar) and that close to the liquid-liquid critical point, the spatial correlations of density fluctuations are identical to those of the Ψ indicator. Our results strongly support the idea that water thermodynamic properties arise from the competition between two distinct and identifiable local environments.

Temperature Control of the Self-Assembly Process of 4-Aminoquinoline Amphiphile: Selective Construction of Perforated Vesicles and Nanofibers, and Structural Restoration Capability.

The construction of diverse and distinctive self-assembled structures in water, based on the control of the self-assembly processes of artificial small molecules, has received considerable attention in supramolecular chemistry. Cage-like perforated vesicles are distinctive and interesting self-assembled structures. However, the development of self-assembling molecules that can easily form perforated vesicles remains challenging. This paper reports a lower critical solution temperature (LCST) behavior-triggered self-assembly property of a 4-aminoquinoline (4-AQ)-based amphiphile with a tetra(ethylene glycol) chain, in HEPES buffer (pH 7.4). This property allows to form perforated vesicles after heating at 80 °C (> LCST). The self-assembly process of the 4-AQ amphiphile can be controlled by heating at 80 °C (> LCST) or 60 °C (< LCST). After cooling to room temperature, the selective construction of the perforated vesicles and nanofibers was achieved from the same 4-AQ amphiphile. Furthermore, the perforated vesicles exhibited slow morphological transformation into intertwined-like nanofibers but were easily restored by brief heating above the LCST.

The structure and physical properties of a packaged bacteriophage particle.

A string of nucleotides confined within a protein capsid contains all the instructions necessary to make a functional virus particle, a virion. Although the structure of the protein capsid is known for many virus species1,2, the three-dimensional organization of viral genomes has mostly eluded experimental probes3,4. Here we report all-atom structural models of an HK97 virion5, including its entire 39,732 base pair genome, obtained through multiresolution simulations. Mimicking the action of a packaging motor6, the genome was gradually loaded into the capsid. The structure of the packaged capsid was then refined through simulations of increasing resolution, which produced a 26 million atom model of the complete virion, including water and ions confined within the capsid. DNA packaging occurs through a loop extrusion mechanism7 that produces globally different configurations of the packaged genome and gives each viral particle individual traits. Multiple microsecond-long all-atom simulations characterized the effect of the packaged genome on capsid structure, internal pressure, electrostatics and diffusion of water, ions and DNA, and revealed the structural imprints of the capsid onto the genome. Our approach can be generalized to obtain complete all-atom structural models of other virus species, thereby potentially revealing new drug targets at the genome-capsid interface.

Experiment-based new insights into hydrogen bonds between alcohol and water through reduced-hydrogen-bonded plasmon-activated water

The molecular structure of water and alcohol connected by hydrogen bonds (HBs) remains unclear. In this study, innovative plasmon-activated water (PAW) with fewer HBs was produced from bulk deionized water (DIW). The HBs between pure ethanol and water were stronger than those of pure DIW, which was confirmed by analyses of measured densities and the spectra of nuclear magnetic resonance (NMR) T1 and Raman OH-stretching of PAW with fewer HBs for the first time. Moreover, the intrinsic HBs between hydrophilic alcohol molecules were destroyed by hot electron transfer, reducing the original HBs, such as in PAW. For extremely polar DIW, the degree of non–hydrogen-bonded water (DNHBW) was approximately 0.21. For alcohols, the non–hydrogen-bonded alcohol (DNHBA) was also first similarly defined. The calculated values of DNHBA are 0.48, 0.68, and 0.87 for methanol, ethanol, and propanol, respectively. These values were consistent with their corresponding solvent polarities and HB strength. Moreover, the relative intensity of weak HBs (RIWHBs) is first defined utilizing the Raman spectra of water and alcohol/water mixtures. The calculated values of RIWHBs were consistent with our recognized strength of HBs of alcohol/water mixtures, as illustrated by PAW with intrinsically reduced HBs.

Comparative study of inhibition mechanism and performance of kinetic hydrate inhibitors: Varying amide group orientation

In this work, the inhibition mechanisms of two kinetic hydrate inhibitors, poly(N-isopropyl acrylamide) (PNIPAM) and poly(N-vinyl isobutyramide) (PNVIBA), were investigated at the molecular level, and the influence of the orientation of the amide group on the inhibition performance was evaluated. The results show that two inhibitors have the similar inhibition behavior, and should have the comparable inhibition performance. However, PNIPAM is slightly better at decreasing the stability of gas clusters to inhibit hydrate nucleation, and PNVIBA is slightly better at disrupting liquid water structure and preventing hydrate nucleus from contacting with the surroundings.

Water structure at coal/water interface: Insights from SFG vibrational spectroscopy and MD simulation

The coal/water interface plays a significant role in coal processing and utilization, and hydrogen bonds (HBs) are the primary factors affecting the interfacial water structure. Sum frequency generation (SFG) vibrational spectroscopy was used in this study to analyze HBs at the coal/water interface, and molecular dynamics (MD) simulations were conducted to investigate the molecular dynamics properties of interfacial water. The results showed that water molecules formed strong HBs with the lignite surface using both oxygen and hydrogen atoms, whereas HBs at bituminous coal/water and anthracite/water interfaces mainly occurred through the hydrogen atoms of water molecules. Fewer HBs existed at the bituminous coal/water interface, resulting in more free hydroxyl groups of water molecules. HBs at the anthracite/water interface were weaker than those at the lignite/water interface but stronger than those at the bituminous coal/water interface. Stronger HBs facilitated the adsorption of water molecules onto coal surfaces, reducing the number density and diffusion coefficient of water molecules within the water layer. For both properties, the MD simulation results showed the following order of decreasing magnitude: bituminous coal/water interface > anthracite/water interface > lignite/water interface. The combination of SFG vibrational spectroscopy and MD simulation offers a scientific approach to understanding the coal/water interface.