Evaporation Behavior Research Articles

1D Mn coordination polymer derived from sulfanilic acid: Synthesis, structure, adsorption properties and Hirshfeld surfaces analysis

A one-dimensional Mn coordination polymer formulated; [Mn2(C6H7NO3S)2Cl4O4]n (1) (where = C6H7NO3S is sulfanilic acid) was synthesized via the hydrothermal method by reacting aqueous solutions of MnCl2·4H2O and sulfanilic acid. The X-ray studies demonstrate layered arrangement of monomers in the coordination polymer interconnected by weak hydrogen bonds. The vibrational frequencies of functional groups and bonds within the polymer were analyzed using infrared spectroscopy. The thermal degradation of the coordination polymer structure was studied under non-isothermal conditions in an argon atmosphere using thermogravimetric (TG) and differential thermal analysis (DTA), revealing a decomposition process occurring in four to five distinct stages. The sorption properties of the coordination polymer were investigated using N2 gas in an Autosorb IQ device at 77 K, resulting in a surface area of 318.4642 m²/g. Additionally, the sorption behavior of benzene and water vapor on the polymer was investigated at room temperature, yielding a result of 70.82 m²/g for benzene vapor and 172.66 m²/g for water vapor. The molecular fragment, [Mn2(C6H7NO3S)2Cl4O4] as the monomer unit are used for calculating the Hirshfeld surface of this compound that reveals strong N-H∙∙∙Cl intermolecular hydrogen bonding and π–π interactions.

Impact of High Temperature and Water Vapor on the Oxidation Behavior of Chemical Vapor Infiltration-SiCf/SiC Composite

Impact of High Temperature and Water Vapor on the Oxidation Behavior of Chemical Vapor Infiltration-SiCf/SiC Composite

Role of equation of state and clusterization algorithms on nuclear vaporization

By using the Quantum Molecular Dynamics (QMD) model, a study on the nuclear vaporization in [Formula: see text] collision is presented for different nuclear equations of state along with a systematic comparison of different clusterization methods based on simple spatial correlations, spatial-momentum correlations, mass dependent binding energy cuts and Simulated Annealing Clusterization Algorithm (SACA). The effect of different nuclear equations of state i.e., Soft, Hard and Soft with Momentum Dependent (SMD) interactions on the energy of onset of vaporization for [Formula: see text] collisions is predicted by investigating gas/liquid content and probability of vaporization versus incident energy behavior. These two observables probe the critical point of nuclear vaporization very well. Further outcome of different clusterization algorithms on the energy of onset of nuclear vaporization is also probed and a comparison of calculations with the experimental data for [Formula: see text] and [Formula: see text] collisions is carried out for different clusterization algorithms.

Low-temperature conformal vacuum deposition of OLED devices using close-space sublimation

Close-space sublimation (CSS) has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes (OLEDs). CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200 °C. CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media. The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources. The low temperature and conformal nature of CSS, along with its high material utilization and short process time, make it a promising method for fabricating flexible OLED displays.

Influence of Temperature and Water Vapour on the High-Temperature Oxidation and Cr Evaporation Behaviour of High-Cr Alloys for SOFC Cathode Air Pre-Heaters

Chromium evaporation and oxide scale growth are among the key degradation mechanisms associated with Solid Oxide Fuel Cells (SOFCs). It is often underestimated how the cathode air pre-heater (CAPH) made of high Cr-containing alloys in SOFC systems can contribute to cathode degradation. This study examines the effect of exposure temperature and water content on both degradation mechanisms in Inconel 625, SS309 and AluChrom 318. For the influence of water content, samples of Inconel 625, SS309 and AluChrom 318 were isothermally exposed at 850°C in dry air and air containing 1%, 3% and 9% of H2O at a high flow rate for 168 hours. For the influence of temperature, samples of Inconel 625, SS309 and AluChrom 318 were isothermally exposed at 650°C, 750°C and 850°C in a 6.0 L/min air stream containing 3% H2O for 168 hours. The evaporated Cr (VI) species were collected using the denuder technique. The formed oxide scales were subsequently analysed using XRD and SEM/EDX. The results of the surface characterisation indicated that the oxide scales formed on Inconel 625, SS309 and AluChrom 318 at high temperatures were Cr2O3, (Cr,Mn)3O4 spinel and Al2O3, respectively.The results of this study show that Cr evaporation and oxidation rates were dramatically reduced at the lower temperature used for Inconel 625 and SS309. AluChrom 318 exhibited an increased oxidation rate with increasing temperature, but it demonstrated a reverse trend to the temperature dependent Cr evaporation compared to Inconel 625 and SS309. It was also found that the amount of Cr evaporated from an alloy solely depended on the partial pressure of Cr presented on the oxide surface. At 850°C, the total mass of evaporated Cr(VI) species was found as follows: Cr2O3 (Inconel 625) > (Cr,Mn)3O4 spinel (SS309) >> Al2O3 (AluChrom 318). However, at 650 and 750°C, the total mass of evaporated Cr(VI) species was found to be: (Cr,Mn)3O4 spinel (SS309) > Cr2O3 (Inconel 625) > > Al2O3 (AluChrom 318). The significant effect of water vapour on the three tested materials appeared to be the further enhancement of Cr2O3 evaporation. At 850°C, the amount of evaporated Cr2O3 from the alloys exposed at the same humidity level corresponded to the Cr partial pressure on the surface, as follows: Cr2O3 (Inconel 625) > (Cr,Mn)3O4 spinel (SS309) > Al2O3 (AluChrom 318). The water vapour slightly increased the growth rate of Cr2O3 and (Cr,Mn)3O4 spinel formed on the Inconel 625 and SS309 surface, respectively. However, no evidence of change in the growth rate of the alumina on AluChrom 318 under the influence of water vapour in oxidising atmosphere was observed for the tested period in this study. Figure 1

Dynamic adsorption behavior of 1.1.1.2-tetrafluoroethane (R134a) on activated carbon beds under different humidity and moisture levels

1.1.1.2-Tetrafluoroethane (R134a) is developed as a tracer for mechanical leakage detection in military chemistry. Due to the weaker physical adsorption properties, water vapor competitive adsorption limits the use of tracer R134a. Thus, it is urgent to the analyze dynamic competitive adsorption behavior of R134a and water vapor on the activated carbon. In this study, R134a breakthrough curves on the fixed beds packed with activated carbons under different relative humidity and moisture content levels were systematically measured. Combining mass spectrometry, gas chromatography, and a novel fiber Bragg grating temperature sensor, the dynamic competitive adsorption processes and axial temperature of fixed beds were first reported. Interestingly, with increasing moisture content, R134a breakthrough time decreased, but dynamic adsorption capacity increased. This was attributed to the fact that the residual water vapor could increase the specific surface area and pore volume of activated carbon to enhance R134a dynamic adsorption capacity. Using the R134a as the standard, the dynamic competitive adsorption process was first revealed and could be divided into four stages including Co-adsorption, Co-breakthrough, Competitive Adsorption (“Rolling Up” and “Adsorption Platform”), and Dynamic Adsorption Equilibrium. “Rolling Up” and “Adsorption Platform” phenomena are mainly determined by the strength of intermolecular interactions, the concentration difference of adsorbate, and the thermal effect induced by water vapor adsorption/desorption.

Evaporative wicking in thin porous media

Evaporation cooling as an environment-friendly and energy-saving cooling option is usually realized by using porous medium to enhance the transport process, where the evaporation and wicking emerge simultaneously. Thin porous media are commonly applied in the evaporative wicking process. However, the evaporation on thin porous medium imposes significant impact on flow and heat transfer performance of evaporative wicking, which makes the prediction of evaporative wicking behavior more difficult. In this work, experimental studies of evaporative wicking of ethanol in Dutch Twill Weave (DTW) screens are carried out, where the evolution of wicking front and temperature distribution are captured by infrared thermography. Moreover, the numerical model that describes capillary rise, evaporation and heat transfer during evaporative wicking is built, which agrees well with the experimental results. Further investigation suggests that considering the evaporative cooling effect is indispensable for accurately predicting the evaporative wicking behavior in DTW screens. In addition, it is found that there is a rapid increase in temperature difference between the liquid and metal wires around the wicking front based on the local non-thermal equilibrium model.

An experimental and numerical study on the brine droplet evaporation considering salt precipitation

Spray evaporation is a promising and highly efficient desalination technology for treating high-salinity wastewater. However, the existing numerical studies on brine spray evaporation are mainly based on pure water assumption and ignore salt precipitation for simplicity. In the present study, the evaporation process of a single brine droplet considering salt precipitation was experimentally investigated using the pendent droplet method. The variation in brine droplet mass during the evaporation and crystallization process was measured for the first time. Based on the experimental data, a reaction engineering approach model for the brine droplets was developed and incorporated into ANSYS Fluent. The obtained reaction engineering approach model was proven compatible with the numerical simulation of brine spray evaporation. Thus, the numerical model was used to compare the spray evaporation behavior between pure water and NaCl solution. Results indicate that brine droplets have larger falling velocities and shorter residence time in the dryer than pure water droplets. The short residence time and large mass transfer resistance of brine droplets lead to a large axial dimension requirement of the dryer. The present study offers a new technological route for the numerical simulation of brine spray evaporation by considering salt precipitation.

Experimental study of Gas-To-Liquid (GTL) and diesel fuel blends evaporation behaviour and droplet lifetime through Leidenfrost effect

Gas to Liquid (GTL) fuel is considered a clean alternative fuel and has been given much attention to replacing conventional fuel. Evaporation behaviour and droplet lifetime are critical aspects that need to be determined as these aspects can affect the fuel spray properties and improve the combustion process. In this study, a set of GTL–diesel fuel blends are prepared, which are G20, G50, G80, and G100 (the number represents the GTL percentage fuel ratio in the fuel blends). Subsequently, using a single droplet drop test on the hot plate (Leidenfrost effect), the GTL fuel blends droplet lifetime and evaporation behaviour are visualised using a high-speed camera connected to long-distance microscopy. An image processing system and a MatLab were used to measure and analyse the droplet evaporation data. Comparing the fuel characterisation of the GTL fuel and conventional diesel fuel, the GTL fuel shows a lower value in all properties tested except for the calorific value, cetane number, and vapour pressure. The qualitative results through the Leidenfrost effect have shown that increasing the GTL fuel ratio (20% to 100%) decreases the heating phase duration (37.3 % to 14.4 %) and evaporation rate (1.29 mm 2/s to 1.10 mm 2/s) while increasing their steady evaporation phase duration and droplet lifetime. The shorter period to achieve steady evaporation is beneficial as the spray inside the chamber has a limited time to evaporate for combustion.

In situ characterization of particle formation in spray flame synthesis using wide-angle light scattering

Wide-angle light scattering (WALS) was used for in situ measurements of droplet and nanoparticle size distributions during the synthesis of titania and iron oxide particles from liquid precursor solutions in the standardized SpraySyn burner for spray flame synthesis. Titania was synthesized from titanium tetraisopropoxide (TTIP) and iron oxide from iron(III) nitrate nonahydrate (INN) using ethanol (EtOH) as solvent. Scattering images were taken at heights up to 120 mm above the burner surface and classified into droplet and particle scattering. Droplet size distributions were derived from a sequential analysis of scattering data containing the oscillating Mie pattern, the lognormal size distribution parameters for spherical and fractal particle fractions from a multivariate approach on averaged particle scattering data. The results show that the precursor addition leads to altered evaporation behavior and even droplet disruption probably induced by puffing or micro-explosions compared to pure EtOH. In the case of TTIP (a hygroscopic alkoxide), the synthesis of a large fraction of spheres was observed, while the nitrate INN leads to the formation of mostly fractal aggregates.

Tensiometry-based sensing of aggregation and of evaporation behavior of a volatile amphiphile in mixed solutions with ionic and nonionic surfactants

Mixed surfactants solutions containing volatile amphiphiles, e.g. fragrances, are envisaged to exhibit correlations between aggregation behavior, molecular interactions, composition of the mixed adsorbed layers and the concentration of the volatile component in the vapors. These issues are addressed with tensiometric methods by considering dynamic and steady-state interfacial adsorption-evaporation behavior at both sides of air-liquid interface in mixed solutions of geraniol and micelle-forming ionic and non-ionic surfactants. Pendant drop tensiometry proved to be a sensitive method in assessing the concentration of geraniol in the vapors above mixed solutions. Differences in the release of the fragrance from the mixed interfacial layers are explained by competitive contributions of specific barrier mechanisms and concentration-dependent aggregation in bulk solutions. Synergetic effect in reducing surface tension was evident for mixtures of geraniol with anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB) surfactants. Dynamic anti-synergetic effect in SDS-geraniol mixtures is attributed to strong aggregation behavior, which was found to hinder the evaporation of geraniol. Measurements of the headspace concentration indicated weak interactions between geraniol and micelles of non-ionic highly surface active Brij-35 surfactant. The presented results extend the traditional analytical toolbox for evaluating factors which affect the mass transfer of volatile organic amphiphiles between aqueous and gas phases.

Pressure-driven distillation using air-trapping membranes for fast and selective water purification.

Membrane technologies that enable the efficient purification of impaired water sources are needed to address growing water scarcity. However, state-of-the-art engineered membranes are constrained by a universal, deleterious trade-off where membranes with high water permeability lack selectivity. Current membranes also poorly remove low-molecular weight neutral solutes and are vulnerable to degradation from oxidants used in water treatment. We report a water desalination technology that uses applied pressure to drive vapor transport through membranes with an entrapped air layer. Since separation occurs due to a gas-liquid phase change, near-complete rejection of dissolved solutes including sodium chloride, boron, urea, and N-nitrosodimethylamine is observed. Membranes fabricated with sub-200-nm-thick air layers showed water permeabilities that exceed those of commercial membranes without sacrificing salt rejection. We also find the air-trapping membranes tolerate exposure to chlorine and ozone oxidants. The results advance our understanding of evaporation behavior and facilitate high-throughput ultraselective separations.

Characterizing water vapor adsorption on coal by nuclear magnetic resonance: Influence of coal pore structure and surface properties

Steam injection is a novel and promising technology for enhancing coalbed methane (CBM) recovery. Accurate descriptions of the migration and adsorption of water vapor on coal is crucial for determining the occurrence state of the CBM and improving CBM production. This study quantitatively characterized the dynamic transport and adsorption processes of water vapor in coal pores and fractures using nuclear magnetic resonance (NMR). The results demonstrated that water vapor was preferentially adsorbed in the coal micropores, which was mainly related to capillary condensation, whereas liquid water filled a wide range of pores and fractures. Due to the differences in the microstructure and surface properties among different coals, the water vapor adsorption behaviors varied significantly. Among the coals used in this study, water vapor was most easily adsorbed on the bitumite with the biggest specific surface area, pore volume, pore area, the highest content of oxygen-containing functional groups, and the strongest wettability. Additionally, the coal pore structure had a greater impact on the water vapor adsorption capacity than the oxygen functional groups and the wettability. This research is of great significance for understanding the flow behaviors of water vapor in porous media and the interactions between coal and water.

Experimental study of butanol droplet evaporation in a turbulent, high-pressure environment

An experimental investigation is conducted to study the vaporization behavior of butanol droplets in a turbulent environment at elevated pressure. A single droplet of butanol, with a diameter of 500 µm, is suspended at the intersection point of two micro-fibers positioned in the center of a fan-stirred spherical chamber. The latter is equipped with eight axial fans to generate an isotropic and homogeneous turbulent flow field with nearly zero-mean velocity. In this experiment, turbulence intensity and ambient pressure were varied from 0 to 1.5 m/s and from 1 to 10 bar, respectively, while ambient temperature was kept at room conditions. The experimental findings revealed that the butanol droplet squared diameter exhibited a linear relationship with time for the majority of the droplet lifetime. This observation suggests that the d2-law is applicable across all the test conditions explored in this study. Results showed that the vaporization rate of a butanol droplet decreases with ambient pressure and increases with turbulence intensity. The vaporization rate of butanol falls between that of heptane and decane, with closer proximity to decane. Furthermore, the comparison of these fuels indicates that the influence of turbulence on the vaporization rate is more significant for fuels with lower vapor mass diffusivity. Finally, published correlations based on Damköhler and Reynolds numbers are verified and found to hold for the butanol droplet vaporization data.

Chemical potential of different phases inside the pyramid stepped basin solar still through Gibbs free energy

Chemical potentials of the temperature components of the pyramid stepped basin solar distiller (PSBSD) have been evaluated to illustrate the behavior of the water vapor and condensed water droplets during the process of solar distillation. Chemical potential is one of the main criteria in terms of chemical and phase equilibrium which is obtained from the Gibbs phase rule. The application of the Gibbs phase rule established a good relationship between the design, climatic and experimental parameters of the PSBSD. The internal heat transfer coefficients of the distiller are influenced by the intensity of solar radiation and ambient temperature which in turn explains the intensive state of the PSBSD. It is found that the chemical potentials and the intensive states of the different phases of the system established a relation between the equilibrium of liquid and vapor mixture with specifications of temperature components of the PSBSD. It is also found that the efficiency of the PSBSD is 38.135% with a distillate yield of 4.280 l/m2day over 24 h cycle.

A Quantification of Heat Storage Change-Based Evaporation Behavior in Middle–Large-Sized Lakes in the Inland of the Tibetan Plateau and Their Temporal and Spatial Variations

A large number of different-sized lakes exist in the inland area of the Tibetan Plateau (TP), which are examples of the important connection between the atmosphere and hydrosphere through the analysis of lake surface convergence and evaporation processes. The evaporation level changes that occur in middle–large-sized lakes (surface area > 50 km2) in the area directly influence the regional mass and energy balance values, atmospheric boundary layer heat and humidity structures, and weather processes occurring in the lower-reach areas. The studies conducted in the literature at present, concerning lake evaporation processes, generally overlook the differences in lake heat storage behavior due to the reduced amount of data in the literature concerning lake bathymetry. According to the in situ bathymetric data obtained for 68 middle–large-sized lakes in the inner basin of the TP, in this study, we calculated their heat storage (G) change values by using the different vertical-depth water-temperature-change integral method, and we established a regression equation for the heat storage and lake surface net radiation values for 68 lakes. The evaporation rates of 134 middle–large-sized lakes larger than 50 km2 in the inland are of the TP were calculated by obtaining the G regression result and adopting it into the Penman model, as well as estimating the evaporation losses of theses 134 lakes from 2002 to 2018. The result shows that the annual average evaporation rate for these lakes is 927.39 mm/year, with an insignificant upward trend (0.10 mm/year). This method achieved good accuracy compared with the Bowen ratio method, which estimates the evaporation rate during the ice-free season, with a high correlation coefficient (R) value of 0.95 and least root mean square error (RMSE) value of 61 mm. The annual mean evaporation rate can be divided into the southern and northern lake groups along a 34°N line with a difference of 314.41 mm/year. The annual average evaporation volume of these lakes was 25.02 km3 and showed an upward trend of 0.35 km3/year. Among them, the annual average evaporation volume contribution ratio of level-1 lakes (50 km2 ≤ lake’s area < 100 km2, 61 lakes) was 14.04%, showing an upward trend, and the contribution of level-3 lakes (lake’s area ≥ 500 km2, 10 lakes) was 41.50%, showing a downward trend. There were no obvious changes in the level-2 lakes (100 km2 ≤ lake’s area < 500 km2, 63 lakes), which maintained at the same level in approximately 44.46%. Air temperature is the most important factor affecting the evaporation rate of lakes, while the lake surface area is the main factor affecting lake evaporation volume. Our study, considering the actual lake heat storage value, provides a useful reference for further improving lake water budget balance values and watershed hydrologic features in the inland closed lakes located in the TP.

Experimental investigation on the heat transfer characteristics of argon space containing sodium vapor

A large quantity of argon is typically provided at the top of the main vessel of a sodium-cooled fast reactor (SFR) to serve as covering gas. The sodium coolant in an SFR evaporates and mixes with the argon covering gas during reactor operation. This mixed gas has a critical influence on the heat transfer at the top of the main vessel, particularly the temperature of the roof slab. The temperature distribution in the roof slab significantly affects reactor safety as it serves as the pressure boundary of the main vessel. Research on the behavior of sodium vapor has typically employed numerical simulations, and any experimental verifications have generally used simplified experimental models. To study the heat transfer characteristics of sodium vapor and eliminate the influence of simplifications on the results, the Heat transfer Experimental Facility for Argon space at the top of the main vessel (HEFA) was established based on a scaled-down top of the main vessel. The HEFA was employed to analyze influence of sodium vapor on the heat transfer characteristics of the reactor space by evaluating the effects of various heating temperatures with and without liquid sodium on the temperature distributions in the argon and roof slab. Furthermore, the emissivity of the liquid sodium surface was measured. The results show that the radiative absorption effect of sodium vapor primarily occurs near the liquid sodium surface. When the heating temperature was less than 400 °C, the presence of sodium vapor increased the temperature of the main vessel. When the heating temperature was 540 °C, the radiative absorption effect of the sodium vapor was enhanced, reducing the roof slab temperature. The observed phenomena can be considered to ensure reactor safety during the design of SFRs.

Magnetic regulation on evaporation behavior of ferrofluid sessile droplets.

Active magnetic regulation is an emerging subject due to the special and programmable wettability of the sessile ferrofluid droplet. The interaction between liquid and externally applied magnetic field gives rise to controllable spreading and thus evaporation. This work reports the experimental and numerical results of the natural evaporation of a ferrofluid droplet under the effect of a nonuniform magnetic field. The evaporation process of droplets is described into two stages in terms of the geometric distortion and the appearance of the deposition pattern. The presence of the magnetic field leads to a transition of droplet drying from the disk shape with a ring to multiple peaks. A numerical model is established to simulate the evaporation process of ferrofluid droplets with the arbitrary Lagrangian-Eulerian method for tracking droplet deformation. The increasing magnetic flux could effectively enlarge the contact radius and enhance the internal flow of the ferrofluid droplet, thus promoting the evaporation process. The numerical results are verified by comparing the droplet geometry deformation with the experimental results. In both the numerical and experimental investigations, the externally applied magnetic field shortens the process of ferrofluid droplet evaporation. The design and optimization of the magnetic field play an important role in regulating ferrofluid droplet evaporation, which in turn facilitates technological advances in industries such as evaporative cooling and inkjet printing.

Multi-Component Evaporation and Uneven Aluminum Distribution during High-Power Vacuum Laser Welding of Ti-6Al-4V Titanium Alloy

Titanium alloy is an important material for the manufacture of key components of deep-sea submersibles. High-power vacuum laser welding is an important method for welding TC4 thick plate (40–120 mm) structures. However, due to the low melting point of aluminum, its uneven distribution in the weld caused by evaporation during welding affects the quality of joints. This paper conducted experimental and simulation studies to investigate the effect of process parameters on multi-component evaporation and uneven aluminum distribution. Based on a three-dimensional model of vacuum laser welding, the mechanism of the uneven distribution of aluminum in the weld is explained. The results show that the uneven distribution of aluminum in the weld is mainly related to the metal vapor behavior and keyhole morphology. As the welding speed rises from 1 m/min to 3 m/min, the proportion of aluminum in the metal vapor and the degree of compositional unevenness increase. When the laser power increases from 6 kW to 18 kW, the proportion of aluminum in the metal vapor and degree of unevenness increase, peak at 12 kW, and then decrease. This work facilitates the selection of suitable process parameters to reduce aluminum evaporation during the high-power vacuum welding of Ti-6Al-4V alloys. Joints with a more stable performance can be obtained by avoiding the uneven distribution of aluminum.

Thermodynamic behavior of water vapor adsorption in shale and its dependence on organic matter and clay minerals

Isothermal adsorption experiments of water vapor in shale samples with differing TOC (total organic carbon content) and differing clay content were conducted at three set temperatures to reveal the adsorption mechanism, and to determine the thermodynamic dependence of primary and secondary adsorption processes on the content of organic matter and clay minerals. The adsorption of water vapor in shale is spontaneous with the Gibbs free energy change is minus ranging from −0.28 - −5.15 KJ/mol, the adsorption changes from entropy driven to enthalpy driven as the adsorption amount increases (enthalpy change turns from plus to minus ranging from −1.25–––6.72 KJ/mol, and the entropy change is opposite ranging from −0.0031–––0.035 KJ/mol), and the primary adsorption amount increases with higher experimental temperature but secondary adsorption amount decreases. Fitting results and their relying theories indicate that micropore filling and monolayer adsorption occur in primary adsorption mainly though strong hydrogen bonding and electrostatic forces between water vapor and the pore surface, and multilayer adsorption and capillary condensation dominate secondary adsorption mainly through weak hydrogen bonding among water vapor. There are positive correlations of adsorption amount versus both clay content and TOC. Clay minerals are strongly hydrophilic because of their exchangeable cations and polar groups, providing primary and secondary adsorption sites, and enhancing the spontaneity of adsorption. OFGs (oxygen functional groups) in organic matter are hydrophilic, other pore surfaces are hydrophobic or weak hydrophilic, which also develop many adsorption sites. Results from this work provide new insights about the influence of organic matter and clay minerals on the adsorption thermodynamic behavior of water vapor in shale.