Water Molecules Research Articles

Manganese pyrophosphate with multiple coordinated water molecules for electrocatalytic water oxidation

Manganese pyrophosphate with multiple coordinated water molecules for electrocatalytic water oxidation

Methanol-water manipulated polymorphic nucleation of L-Ornithine-L-Aspartate

Screening for a suitable polymorph is crucial in pharmaceutical engineering. Here we reported the polymorphic nucleation of L-Ornithine-L-Aspartate (LOLA) in a methanol–water binary solvent. A new metastable form named monohydrate was discovered, which was found affected the nucleation of LOLA anhydrate. The antisolvent crystallization experiments showed that when the molar fraction of methanol was less than 0.387 or more than 0.448, the anhydrate LOLA nucleated, while it was between 0.390–0.416, the monohydrate appeared. Specifically, the isolated water molecules were the key parameter for polymorphic nucleation of LOLA. When methanol was less or more, it was insufficient to break the water hydrogen bonding network or enough to form methanol–water network, both could cause less isolated water, thus the anhydrate nucleated. On the contrary, when the methanol content was 0.390–0.416, methanol molecules could occupy some spatial sites in the water network resulting in more isolated water, thus the monohydrate appeared.

Effects of pH and temperature on the properties of acid-induced commercial soy protein isolate gel

The goals of this study were to investigate the effect of preheating conditions on the formation of thermal aggregates of commercial soy isolate protein (SPI) and to characterize the textural properties and microstructure of acid-induced SPI gels. SPI was subjected to preheating treatments at different temperatures (85 °C, 95 °C) and pH values (7.0, 7.5, 8.5, 9.5), and the treated SPI was then used to form acid-induced gels. Characterization of the different gels showed that lower temperatures and pH values favored protein aggregation and the formation of larger aggregates, while higher temperatures and pH values led to a lower degree of aggregation and the formation of smaller aggregates. The lowest average particle size (340.77 nm) and turbidity (0.063), and the highest solubility (81.79 %) were obtained when the preheating temperature of the thermal aggregates was 95 °C and the pH was 9.5. Higher preheating temperature and pH values caused the unfolding of SPI’s tertiary structure, decreased the content of β-sheet structure, and increased the exposure of hydrophobic groups and free sulfhydryl groups. These exposed groups facilitated protein–protein interactions during network assembly, resulting in denser and stronger gel networks. Notably, SPI subjected to higher temperatures and pH values exhibited greater binding capacity for water molecules, higher water holding capacity, and gel strength. Overall, the results showed that modification of preheating temperature and pH can control the formation state of SPI thermal aggregates, ultimately impacting the properties of SPI acid-induced gels.

The Effect of Irradiation on Meat Products.

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

Unveil the Triple Roles of Water Molecule on Power Generation of MXene Derived TiO2 based Moisture Electric Generator (Adv. Energy Mater. 27/2024)

Unveil the Triple Roles of Water Molecule on Power Generation of MXene Derived TiO₂ based Moisture Electric Generator (Adv. Energy Mater. 27/2024)

Bio-inspired super-wetting coatings constructed from interfacial mineralization of rare earth phosphate for oil/water separation applications

The oil fouling problem of lipophilic polymer matrix causes severe decline of separation performance, becoming one of the most serious challenges for oil/water separation. A chemical-stable and mechanical-strong anti-fouling coating is highly emerged. Herein, to achieve anti-fouling performance on diverse polymer substrates, a biomimic super-wetting coating is fabricated by interfacial mineralization of lanthanum phosphate (LaPO4). The strong interaction between ions makes LaPO4 very stable against acid, base, oil and mechanical impact, while the dense charges on the surface of LaPO4 attract water molecules and create a hydration layer to repulse oil under water. The membranes and meshes modified by such mineralized coating exhibit good separation efficiency (>99 %) and high permeation flux for oil-in-water emulsions and oil/water mixtures, respectively. In addition, notable cyclic flux recovery ability was fulfilled by water rinsing. The fabrication of such mineralized coating is easily operated through solution process and no harmful byproducts will be generated. Basically, the low-cost and eco-friendly mineralized coating is promising for oily water treatment in the practical complicated environment.

Molecular-scale insights into nanoconfined water-CO2 interactions in geological carbon storage

Understanding the nanoconfined water-CO2 interactions at the molecular scale is of great importance for the fluid transport in confined porous media. Here, a series typical water film and water bridge scenarios are determined, and the associated impacts on nanoconfined water-CO2 interactions as well as the geological hydrocarbon recovery and CO2 storage are investigated in nanopores. Our results confirm either in water film or water bridge scenarios, the competitive adsorptions of nanoconfined water and CO2 reduce the adsorbed water amount and derive the new water bridge with CO2 additions. Such a phenomenon indicates the substrate surface shifts from water-wet to partially CO2-wet, with lower fluid molecule diffusions and illite-water-CO2 sandwich-structured adsorption layer. Overall, our work investigates the mechanism of CO2 effects on distributions and aggregations of nanoconfined water molecules in nanopores, which also provides molecular-scale insights into the nanoconfined water-CO2 interactions in the processes of geological CO2 storage and utilization.

Comparative analysis of amine-functionalized silica for direct air capture (DAC): Material characterization, performance, and thermodynamic efficiency

Direct air capture (DAC) technology faces challenges due to energy-intensive processes and limited CO2 capture capacity under atmospheric concentration. Utilizing adsorption techniques with solid sorbents offers a sustainable solution. This study investigates the performance, efficiency, and regeneration energy of various amines (TEPA, low and high molecular weights PEI and APTES) functionalized mesoporous silica (SBA-15) for DAC. Comprehensive investigations, including characterization and thermodynamic efficiency evaluation, are conducted for CO2 adsorption under dry and humid conditions (50 % RH). Functionalizing SBA-15 with TEPA, PEI-L and PEI-H, and TEPA significantly improves CO2 adsorption, increasing capacities to 2.1, 1.36, and 1.11 mmol/g, respectively, and introduction of humidity further increases CO2 capacities to 3.17, 2.87, and 1.68 mmol/g, respectively. However, there’s a trade-off in thermodynamic efficiency due to energy consumed in desorbing water molecules. S-TEP exhibits the highest thermodynamic efficiency in dry conditions, while S-PEI-L achieves the highest efficiency in humid conditions. Stability tests of all material in addition to, the commercial material, lewatit demonstrate robust regenerability over 10 cycles under both dry and humid conditions (50 % RH). This study provides insights into functionalized SBA-15 performance in CO2 adsorption, with implications for efficient and sustainable indoor DAC processes.

One-pot fabrication of highly permeable P84/UiO-66-NH2-PEI membrane for the efficient removal of heavy metals from wastewater

Heavy metal pollution threatens water bodies and public health, necessitating the exploration of advanced technologies to effectively remove heavy metals from wastewater. In this study, a one-pot approach was employed to fabricate a positively charged membrane using P84 as the substrate, and UiO-66-NH2 nanoparticles and PEI as crosslinkers. Introducing UiO-66-NH2 with inherent porous structures can create nanopores and gaps within the PA layer, providing extra pathways for water molecules to permeate the membrane. Moreover, the UiO-66-NH2 nanoparticles imparted hydrophilicity and a positive charge to the resulting membrane. Compared to the blank membrane without UiO-66-NH2 nanoparticles, the optimal membrane demonstrated a significant increase of 44 % in water flux (52.4 L m−2h−1) while maintaining a remarkable removal performance for CuCl2 (99.5 %), PbCl2 (99.4 %), Ni(NO3)2 (98.6 %), and ZnCl2 (98.4 %) at 4 bar. Furthermore, the UiO-66-NH2 nanoparticles can cross-link with the P84 polymer, ensuring a stable attachment between the polyamide (PA) layer and the P84 substrate by covalent bonds, preventing the potential conventional nanoparticle leakage. Additionally, three different fabrication methods were employed to explore the optimal approach for incorporating UiO-66-NH2 nanoparticles, with each method resulting in a distinct distribution of nanoparticles within the membrane. This study highlights the potential of the resultant membranes in addressing the challenges of wastewater treatment, offering a facile and promising avenue for heavy metal removal.

Electrosynthesis of Unusual Nonfcc Palladium Hydride Nanoparticles.

Intercalation of hydrogen into the palladium atomic layers during the growth of Pd nanoparticles can lead to the synthesis of unique palladium hydride phases. Here, we discover an unusual nonfcc palladium hydride nanoparticle, a structure that is not face-centered cubic (fcc), formed through coreduction of water molecules and Pd ions in solution. Crystal structure determination based on atomic electron tomography points to potential triclinic unit cells, indicating the presence of more than one nonfcc phase, with some of those being a stack of loosened and distorted close-packed layer of atoms. The probability of finding the nonfcc phase in single-crystalline particles varies depending on the number and distribution of contact area with other particles. Roughly half of the isolated and one side-coalesced single-crystal particles exhibit a nonfcc structure, while fcc dominates multiple side-coalesced single crystals as well as polycrystal particles. These observations suggest a coalescence-induced phase transition from a nonfcc to a stable fcc structure, due to the metastable nature of the nonfcc phases. While hydrogen is proven to be a key component for the synthesis of the nonfcc structure, there was limited formation of the unusual phase in a H2 gas bubbling system. Thus, electrochemical pathways can be promising for the in situ creation and study of unique metastable nanomaterials.

Enhancement in Heat Transfer Performance of Water Vapor Condensation on Graphene-Coated Copper Surfaces: A Molecular Dynamics Study.

The condensation of water vapor plays a crucial role in various applications, including combating water scarcity. In this study, by employing molecular dynamics simulations, we delved into the impact of graphene coatings on water vapor condensation on copper surfaces. Unique to this work was the exploration of various levels of graphene coverage and distribution, a facet largely unexplored in prior investigations. The findings demonstrated a notable increase in the rate of water vapor condensation and heat transfer performance as the graphene coverage was reduced. Using graphene coverages of 84%, 68%, and 52%, the numbers of condensed water molecules were 664, 735, and 880 molecules/ns, respectively. One of the most important findings was that when using the same graphene coverage of 68%, the rate of water vapor condensation and heat transfer performance increased as the graphene coating became more distributed. The overall performance of the water condensation correlated well with the energy and vibrational interaction between the graphene and the copper. This phenomenon suggests how a hybrid surface can enhance the nucleation and growth of a droplet, which might be beneficial for tailoring graphene-coated copper surfaces for applications demanding efficient water vapor condensation.

Zwitterionic nanospheres engineered co-polymer composite membrane for precise protein-protein separation via dynamic self-assembly micelle deposition

The accurate protein-protein separation is important but technically challenging. Achieving such a precise separation using membrane requires the selective channels with appropriate pore geometry structure and high anti-fouling property. In this study, polyethersulfone-b-poly(sulfobetaine methyl methacrylate) (PES-b-PSBMA) was synthesized and engineered onto polysulfone (PSF) ultrafiltration (UF) membrane to fabricate zwitterionic nanospheres engineered co-polymer (ZN-e-CoP) composite membrane via dynamic self-assembly micelle deposition. On the one hand, self-assembly zwitterionic nanospheres were used as blocks to construct hydrophilic layers with size-dependent sieving channels, endowing ZN-e-CoP composite membranes with enhanced permselectivity and protein-protein separation abilities, meanwhile zwitterionic groups from nanospheres reinforced the structure stability of nanospheres/nanospheres and nanospheres/membrane via multiple intermolecular interactions. On the other hand, zwitterionic nanospheres can induce to produce the hydration layer enveloping themselves by binding water molecules, where hydration layer acts as a protective barrier on the membrane surface, impeding the protein adhesion. Hence, ZN-e-CoP_1a composite membrane exhibited superior separation properties with Lysozyme/Bovine Serum Albumin (BSA) separation factor of 18.1 and 95.4 % rejection against BSA, 10.1 and 2.3 times, respectively, higher these of pristine PSF membrane (1.8 and 42.1 %), without obviously sacrificing water flux. Simultaneously, hydration layer enables the ZN-e-CoP_1a membrane with enhanced anti-fouling performance and durability during the long-term operations. The proposed approach opens new pathways to fabricate excellent anti-fouling membranes for precise protein-protein separation.

Improving the Water Resistance of Bi‐Based Perovskite‐Inspired Materials for Vapor‐Phase Photocatalytic Overall Water Splitting

Lead halide perovskites are well known for their exceptional photophysical and electronic properties, which have placed them at the forefront of challenging optoelectronic applications and solar‐to‐fuel conversion. However, their air/water instability, combined with their toxicity, is still a critical problem that has slowed down their commercialization. In this sense, bismuth‐based halide derivatives attract much interest as a potentially safer, air‐stable alternative. Herein, a novel Bi‐based perovskite‐inspired material, IEF‐19 (IEF stands for IMDEA Energy Framework), which contains a bulky aromatic cation (1,5‐diammonium naphthalene), is prepared. Additionally, an N‐alkylation strategy is successfully employed to achieve four water‐stable perovskite‐inspired materials, which contains diammonium naphthalene cations that are tetra‐alkylated by methyl, ethyl, propyl, and butyl groups. Moreover, computational studies are performed to gain a deeper understanding of the intrinsic structural stability and affinity of water molecules for Bi‐based perovskite‐inspired materials. Importantly, the air‐ and water‐stable IEF‐19‐Et (i.e., stable at least 12 months under ambient conditions and 3 weeks in contact with water) is found to be an active photocatalyst for vapor‐phase overall water splitting in the absence of any sacrificial agent under both ultraviolet–visible or simulated sunlight irradiation. This material exhibits an estimated apparent quantum yield of 0.08% at 400 nm, partially explained by its adequate energy band level diagram.

Wettability behavior of DTMS modified SiO2: Experimental and molecular dynamics study

In this research, the wetting behavior of SiO2 modified with dodecyltrimethoxysilane (DTMS) was explored using both experimental and molecular dynamics (MD) simulation approaches. The experimental results reveal that DTMS can chemically bond to the SiO2 surface, and the contact angle (CA) reaches the maximum value of 157.7° when the mass of DTMS is twice that of SiO2. The different wetting behaviors caused by DTMS grafting were analyzed by CA fitting, ionic pairs, concentration distribution, molecule orientation, and interfacial interaction energy. The results demonstrate that a 25% DTMS grafting rate resulted in a maximum CA of 158.2°, which is ascribed to the disruption of interfacial hydrogen bonding and changes in the hydration structure caused by DTMS grafting. Moreover, the above hydrophobic SiO2 model shows a slight decrease in CA as the water temperature increases, which is consistent with the experimental findings. In contrast, an opposite change was observed for the pristine SiO2 model. Although the higher water temperature enhances the diffusion capacity of water molecules in both models, the difference in interfacial interactions is responsible for the change in CA. We hope this finding will contribute to a deeper understanding of the wetting adjustment of SiO2.

Influence of carbon quantum dots on foam stability: a molecular dynamics study

Abstract Carbon quantum dots are employed in foam for enhanced oil recovery. This study focuses on the impact of carbon quantum dots on the stability of oil displacement foam. Molecular dynamics simulations are conducted to investigate commonly used models of carbon quantum dots and surfactant foams in oil displacement. The research delves into the interfacial properties of the foam film, the flow characteristics of water molecules, and the interaction between carbon quantum dots and surfactants. Insights gained from these three aspects reveal the influence of carbon quantum dots on surfactant foam films. This work provides theoretical guidance for the utilization of carbon nanomaterials in foam-assisted oil recovery.

Research on microscopic wetting mechanism of talcum powder by compounded surfactant for spraying dust reduction

Adding surfactant is an effective method to improve the dust removal efficiency of talcum powder dust. Based on the optimization of surfactants, this paper proposed an efficient compound surfactant scheme by calculating interaction parameters, adsorption simulation, and wettability test experiments. Molecular dynamics simulation was used to analyze the interaction mechanism between compound surfactant and talcum powder. Tests of spraying talcum powder with compound surfactants under different pressures were carried out. The results show that the combination of anionic surfactants SDS and SDBS with nonionic surfactants Tween 80 and AEO9 has a positive synergistic effect. The better the wetting effect of the compound system, the more ordered the surfactant molecules are arranged. Meanwhile, the diffusion ability of water molecules is stronger, and the thickness of the solid-liquid interface is larger. The wetting effect of compound surfactant on talcum powder is mainly influenced by van der Waals force. The dust removal efficiency test shows that SDS-Tween 80 compound surfactant with a pressure of 1.5MPa and molar ratio of 0.4:0.6 is the best spray dust removal scheme. The research results are helpful to guide the application of compound surfactants in talcum powder dust control.

Atomistic understanding of Ti3C2 MXene membrane performance for separation of nitrate ions from aqueous solutions

Water desalination, which is a reliable method for providing drinking water and a suitable solution, as well as the membrane filtration method in wastewater treatment, has increased significantly in recent years. In this research, the separation of nitrite and nitrate ions from aqueous solutions was done using the MXene membrane of the Ti3C2 type using molecular dynamics simulation. In this study, various parameters, such as pore size MXene structure, characteristics of cavities, applied pressure, and flux were investigated. To investigate the removal of toxic pollutants from water, water flux, potential mean force, distribution of water molecules, and density were investigated. The results showed that the amount of penetration through the membrane increased with the increase in pressure. It was observed that by applying pressure to the system, the number of water molecules accumulated in front of the membrane decreases because they quickly pass through the membrane, which indicates the positive effect of increasing pressure on the separation rate of molecules. The permeability of this membrane was several times higher than the existing membranes in the industry. So that Mexene membranes, which consist of at least two layers, can repel ions with 100% success.

Role of heads and tails on tetrahydrofuran- and dimethyl sulfoxide-water separation by glycerol and sucrose esters

Tetrahydrofuran (THF) and dimethylsulfoxide (DMSO) are miscible in water due to hydrogen (H) bonding. Amphiphilic glycerol and sucrose esters with a different number of tails and heads separate them, depending on the organic solvent concentration. Separation is worse in solutions where amphiphiles are most soluble. Separation occurs due to interactions between the amphiphiles and either organic solvents or water, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Separation is best with glycerol esters with more heads and tails. Multiple tails hamper interactions between glycerol ester heads, thereby facilitating interactions with organic solvents or water to promote solvent–water separation. THF interacts with the glycerol ester tails, while water H bonds with the glycerol ester heads, as indicated by activity coefficients estimated with conductor-like screening model for real solvents. In THF, amphiphiles self-assemble into micelles, as shown by small angle x ray scattering (SAXS). Without water, THF is likely both inside and outside the micelles. SAXS shows that micelles shrink with 4% water in THF because water molecules partition inside them and are smaller than THF. With additional water, micelles swell into emulsions. Dissimilar to THF, DMSO preferentially interacts with the glycerol ester heads rather than their tails. ATR-FTIR shows that the proportion of free vs bonded S=O groups of DMSO decreases upon mixing with glycerol esters. DMSO and glycerol esters primarily accept H bonds, as indicated by their sigma profile. This leads to competition for interactions with water, displacing DMSO.

Stabilization of flake Zn powder anodes via designing functional additives in electrolytes for aqueous Zn ion batteries

Zn powder anodes have attracted much attention in aqueous Zn ion battery applications due to advantages such as low cost and processability. However, the high-activity Zn powder anode faces problems such as side reactions, hydrogen evolution, and dendrites, which limit the cycling stability of the cell. In this work, the high activity of Zn powder is weakened by introducing low-cost erythritol as a functional additive in the ZnSO4 electrolyte to improve the cycle life of the cell. Both theoretical calculations and empirical evidence demonstrate that the incorporation of erythritol alters the coordination sphere of Zn2+ and modifies the local molecular architecture of the electrolyte. This modification serves to diminish the reactivity of water molecules, thereby efficaciously suppressing dendrite formation and deleterious ancillary reactions on the zinc powder anode surfaces. Concurrently, erythritol functions as an interfacial cationic captor, enhancing reaction dynamics and facilitating the development of a favorable protective layer throughout the zinc plating/stripping process. Consequently, the symmetric cell paired with an erythritol-containing electrolyte manifests stable cycling performance for an extended duration of 850 h at a current density of 0.288 mA cm−2 and areal capacity of 0.144 mAh cm−2. Notably, it maintains a cycling life of 400 h even under intensified conditions (2.88 mA cm−2/1.44 mAh cm−2). Furthermore, the constructed Na2V6O16·3H2O full cell illustrated remarkable capacity retention of 155.8 mAh g−1 following 800 cycles at a high rate of 5 A g−1.

Direct Evidence of the Effect of Water Molecules Position in the Spectroscopy, Dynamics, and Lighting Performance of an Eco‐Friendly Mn‐Based Organic–Inorganic Metal Halide Material for High‐Performance LEDs and Solvent Vapor Sensing (Adv. Sci. 26/2024)

Direct Evidence of the Effect of Water Molecules Position in the Spectroscopy, Dynamics, and Lighting Performance of an Eco‐Friendly Mn‐Based Organic–Inorganic Metal Halide Material for High‐Performance LEDs and Solvent Vapor Sensing (Adv. Sci. 26/2024)