Pure Water System Research Articles

Water-based Silicalite-1 porous liquid facilitates adsorption and absorption for CH4 capture

As the key to open the Pandora’s box of gas efficient capture, water-based porous liquids have doubled the popular attention. Nevertheless, the synthesis of water-based porous liquids is a significant challenge due to the inherent limitation in the wettability of nanoporous hosts. In this work, Silicalite-1 was prepared by hydrothermal synthesis, based on which a water-based porous liquid of S-1-PL was successfully prepared, and CH4 capture in the porous liquid via adsorption-absorption synergistic approach was evaluated. It was demonstrated that S-1-PL exhibited excellent stability and flowability, with a pore opening ratio up to 90 %. CH4 capture capacity in S-1-PL with the solid content of 15 wt% was 0.57 mol/L, which was 2.6 times that in pure water system, demonstrating excellent CH4 physisorption performance. When the adsorption-absorption synergistic approach was employed, CH4 capture capacity increases to 1.88 mol/L with an increase by 229.8 %. In addition, a hydrate nano-promoter of −SO3-@PSNS was prepared to enhance hydration efficiency, which resulted in a notable enhancement in the hydration conversion rate, and it increases from 12.54 % to 61.99 % in the system of S-1-PL15wt%, giving rise to a significant increase in CH4 capture to 6.22 mol/L, which is 12.67 times that in the system of −SO3-@PSNS solution. These findings provide clear evidence for the first time on the exceptional adaptability of water-based porous liquid for the capture of CH4 by adsorption-absorption synergistic approach, offering a new strategy for the emission reduction of CH4.

Cyano-modified molecular cage silica gel stationary phase: Multi-functional chromatographic performance by high-performance liquid chromatography

This study successfully prepared different loading levels of cyano-functionalized RCC3 molecular cage silica gel stationary phase (RCC3-CN@SiO2) through aldehyde-amine condensation reaction and subsequent modification strategies. Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption-desorption, and scanning electron microscopy confirmed the successful synthesis of RCC3-CN@SiO2 chromatographic stationary phase. The research demonstrates that due to hydrophobic/hydrophilic interactions, π-π interactions, hydrogen bonding, and size-selective porous structure, the stationary phase effectively separates moderately polar and weakly polar compounds in reversed-phase liquid chromatography (RPLC) mode, exhibiting hydrophobic selectivity comparable to the commercial DaisoC18-RP columns. Additionally, the tertiary amine and cyanogen groups on the molecular cage surface enhance the interaction with polar compounds, successfully separating nucleosides, sulfonamides, amino acids, and sugars in hydrophilic interaction chromatography (HILIC) mode. Further applications in the separation analysis of acidic drugs, alkaline drugs, cinnamic acid natural products, and chiral compounds demonstrate the multifunctional chromatographic capabilities for diverse compound types. Compared to Unitary Diol commercial columns, the prepared stationary phase showed significant advantages in wide polarity range separation performance. Moreover, through nucleoside compound separation mode switching analysis, RCC3-CN@SiO2 stationary phase further validates its favorable performance in both RPLC and HILIC modes, demonstrating extensive potential applications in the field of analytical chemistry. Importantly, the stationary phase exhibits efficient separation of nucleoside compounds in pure water systems, aligning with the principles of green analysis.

Enhanced CO2 photoreduction in pure water systems by surface-reconstructed asymmetric Mn–Cu sites

Metal-organic frameworks (MOFs) with abundant pores are excellent adsorbents for metal ions. However, the subsequent treatment of used MOFs and their reutilization still lack promising solutions. Herein, the surface-restructured Mn-doped Cu2O (RM-Cu2O) catalyst containing asymmetric Mn−Cu sites is prepared by glucose reduction using the spent Cu-based MOF (HKUST-1) as the precursor. The RM-Cu2O catalyst shows good potential in tunable photocatalytic syngas (CO and H2) production in a pure water system. The syngas ratios can be tuned from ∼1:2 to ∼1:1 by increasing CO production. DFT calculations and photoelectrochemical tests confirm that the asymmetric Mn−Cu sites on the RM-Cu2O catalyst accelerate the photogenerated charge transport and optimize CO2 adsorption and activation. In situ irradiation X-ray photoelectron spectroscopy is conducted to investigate the dynamic charge transport and reactions on the RM-Cu2O catalyst. Based on in situ Fourier transform infrared spectroscopy and simulations, the mechanism of photocatalytic syngas production is elucidated. This work provides a promising solution for the resource utilization of the spent MOFs-based adsorbents and photocatalytic energy development.

Precisely Regulating Asymmetric Charge Distribution by Single‐Atom Central Doped Ag‐Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels

AbstractHigh efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe‐N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry‐breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24‐FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24‐FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol ⋅ gcat−1 ⋅ h−1 in H2O‐CO2 system under visible light irradiation, ~1.65/1.25‐fold, 1.83/1.37‐fold, and 3.60/1.61‐fold higher than that of Au1Ag24‐FePPc, Ag25‐FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry‐breaking sites of cluster‐based catalysts for effective CO2 conversion.

Aggregation-induced C–C bond formation on an electrode driven by the surface tension of water

Electrochemical organic synthesis is typically conducted in organic media. The solvent and related supporting electrolytes negatively affect the greenness of electrosynthesis. In this work, with 100% water used as the solvent, we realize aggregation-driven electrochemical radical cross coupling of unsaturated compounds driven by water tension. A key finding is that aggregation of the substrate at the electrode confined the radical intermediate and prevented side reactions, thus providing a way to regulate radical reactions in addition to their native properties. The reaction provides up to 90% yields with almost quantitative chemoselectivity. The pure water system readily yields the products via cold filtration, and the solvent is recycled repeatedly. In particular, the life span of the radical species generated in the reaction increase significantly because of the confined environment in the aggregation state. The greenness of this protocol is further enhanced with readily separation of product from media using cooling and filtration.

Phase equilibrium data for semiclathrate hydrates formed with n-propyl, tri-n-butylammonium bromide and tri-n-butyl, n-pentylammonium bromide under methane, carbon dioxide and nitrogen gas pressure

Semiclathrate hydrates are water-based materials formed from aqueous solutions of ionic substances. To enhance the gas capture performance of these materials, it is necessary to direct focus on the cation, which is a key part of construction of the hydrogen-bonding framework. In this paper, we focus on the partly-asymmetric cations, i.e., the n-propyl, tri-n-butylammonium bromide (N3444Br) and tri-n‑butyl, n-pentylammonium bromide (N4445Br), which are yet to be subjected to gas hydrate formation. The three phase equilibrium (gas–hydrate–liquid) conditions for the systems of (N3444Br or N4445Br) + H2O + (CH4, CO2 or N2) in the range of the pressure and mass fractions of the aqueous solutions between 1 and 11 MPa and 0.10–0.40, respectively, are reported. In all the systems, the semiclathrate hydrates were successfully formed under gas pressure. It was demonstrated that both the N3444Br and N4445Br salts promoted hydrate formation under these gases, while in the case with lean aqueous solutions N3444Br acted as an inhibitor of methane hydrate formation in pure water system. The present data are compared with the literature data, and the effect of the side chain length on the phase behavior of the semiclathrate hydrate phase is discussed.

Molecular dynamics simulation on the variations in characteristics of aqueous solution with diverse additives: Inspirations for binary ice preparation

Ice slurry, as a novel energy storage medium, possesses the superiority of high energy storage density. The freezing point inhibitors are employed to regulate the supercooling phenomenon of water, while the macroscopic experiments are complicated to elucidate the action mechanism. Consequently, this paper adopts molecular dynamic simulation method to investigate the mean square displacement, radial distribution function, hydrogen bonds types, hydrogen bonds number and length of water at various concentrations of ethanol, NaCl, and SiO2 additives. The results indicate that the average number of hydrogen bonds of the system composed with 600 pure water molecules is 1127.24, and the average length of hydrogen bonds is 2.33 Å. Moreover, the addition of alcoholics and chlorides inhibits the hydrogen bonds between water and water molecules, and promotes the generation of hydrogen bonds, thus weakening the diffusion motion of water molecules. Whereas, it is observed that the addition of nanoparticles leads to agglomeration in pure water system, resulting an increase in the viscosity and a decrease in the diffusion rate of the system. The proposed microscopic model can effectively depict the potential interaction mechanisms of additives and water, which is contributing to develop effective freezing point inhibitors and improve the energy utilization efficiency.

Bimetallic NiCu catalyst derived from spent MOF adsorbent for efficient photocatalytic CO2 reduction

The metal–organic frameworks (MOFs) rich in porous structures and their derivatives have been widely developed and applied to heavy metal adsorption. However, little attention has been paid to the subsequent treatment and reutilization of spent MOFs adsorbents. A potential feasible strategy is to develop MOFs-derived bimetallic catalysts for energy conversion. Herein, a bimetallic Ni-Cu2O-Cu/C nanocomposite (Ni-Cu/C) derived from spent Cu-based MOFs (CuBTC) adsorbents was fabricated and applied to improve the performance of photocatalytic CO2 reduction. The results demonstrate that Ni doping could improve the charge transfer dynamics. The synthesized Ni-Cu/C catalyst exhibits a high CO yield (12.45 μmol g−1 h−1) in the pure water system in the absence of other photosensitizers and sacrificial agents, which is 2.05 folds higher compared to Cu/C. The CO2 conversion selectivity of the synthesized Ni-Cu/C catalyst reaches up to 99.0%. The mechanism of photocatalytic CO2 reduction reaction was further investigated by in-situ experiments and density functional theory calculation. The in-situ FT-IR characterization show that photogenerated electrons could effectively adsorb CO2 to produce CO2− and optimize *CO immediate. This work not only emphasizes the unique design of bimetallic catalyst derived from spent MOFs adsorbent, but also contributes a feasible solution to its reutilization for enhanced CO2 conversion.

Formation and decomposition characteristics of CO2+TBAB hydrate for a safer CO2 storage

CO2 hydrate caps can effectively reduce the leakage risk from subsea CO2 sequestration. TBAB (tetrabutylammonium bromide) affects temperature and pressure required for the CO2 hydrate formation, which improves hydrate cap application. This study analyzes hydrate formation and decomposition characteristics in TBAB + CO2 system under different initial pressures and TBAB concentrations. The results show that the addition of TBAB effectively expand CO2 hydrate stable area and prevent CO2 leakage. 5 wt% TBAB not only provides crystal nucleus for hydrate formation and shortens the induction period, but also increases CO2 hydrate cap temperature to 290.3 K. The hydrate decomposition process in TBAB system is divided into CO2 ·nCO2 and TBAB·26H2O·nCO2 decomposition stage. Comparing with hydrate decomposition process in pure water system, it is found that TBAB mainly affects the second stage of hydrate decomposition process. In 5 wt% TBAB system, the hydrate decomposition process was affected by TBAB after more than 68 % hydrate decomposition. It is found that the hydrate decomposition rate with TBAB is almost 1/7 of that without TBAB. This study provides experimental support for expanding the application of CO2 hydrate caps, and provides a basis for determining the geological storage area of CO2 in sediments.

Precisely Regulating Asymmetric Charge Distribution by Single-Atom Central Doped Ag-Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels.

High efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe-N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry-breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24-FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24-FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol·gcat-1·h-1 in H2O-CO2 system under visible light irradiation, ~ 1.65/1.25-fold, 1.83/1.37-fold, and 3.6/1.61-fold higher than that of Au1Ag24-FePPc, Ag25-FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry-breaking sites of cluster-based catalysts for effective CO2 conversion.

Rapid nucleation and growth of tetrafluoroethane hydrate enhanced by bubble and gas cycling

The application of hydrate technology is predominantly limited by the rapid nucleation and stable formation of hydrates, which could be promoted by the disturbance of bubbles. In this study, the effect of bubble generation and different bubble sizes on the nucleation and growth characteristics of R134a hydrates were investigated. The impact of three methods (depressurization-induced R134a vaporization, depressurization combined with stirring and gas cycling bubbling) of bubble effect and size on the nucleation, growth characteristics, and stability of R134a hydrate formation were explored. The research results indicate that utilizing only the depressurization method to induce R134a vaporization and bubble formation leads to a gas consumption rate of 19.6 mmol/min, which is 868 times higher than that in a pure water system. Furthermore, refining bubble size through stirring under depressurization conditions further augments the gas conversion rate by 8.6 %, and the optimal temperature for R134a hydrate formation is identified to be as low as 4 °C. Importantly, utilizing gas cycling as a means to generate bubbles enables uniform and rapid nucleation and growth of hydrates. Within a short 10 min, R134a hydrates was rapidly and stably formed, achieving a formation rate 35 times faster compared to the boiling-condensation method. In comparison to stirring-depressurization, the gas cycling method further increases the gas consumption rate by 10 %. The drawback of slow nucleation and growth rates in hydrates, as well as the need to enhance their stability, is addressed by the gas cycling method.

In situ visualization of salt crystallization in sub-/supercritical water environments

Elevated temperature and pressure conditions in sub-/supercritical water environments hinder the direct observation of salt crystallization phenomena, resulting in indeterminate salt crystal morphologies. In this study, an innovative experimental apparatus has been developed to conduct in situ investigations into the crystal morphology of various types of inorganic salts. The results indicate that the critical temperature of the water-salt system is higher than that of pure water systems, with phase transition thresholds for saturated NaCl-H2O and KCl-H2O systems 671.4 K and 728.1 K, respectively. A distinct “flash crystallization” phenomenon is observed during the crystallization of inorganic salts, accompanied by different crystal morphologies. KCl crystals exhibit a dispersed particle form, NaCl crystals manifest in a finely fragmented accumulation form, and Na2SO4 crystals present transparent feather-like structures. The size of NaCl crystals formed on the surface of a Ni wire at 622.8 K through heterogeneous nucleation ranges from 200.4 μm to 450.9 μm. The crystallization characteristics of salt in sub-/supercritical water are influenced by various factors, including electric dipole moment interactions, common ion effect, the effect of type I salts on type II salts, and homo/heterogeneous nucleation.

Experimental study on gas separation from the oil–water-emulsion mixture via hydrate method

The gas separation technology based on hydrate method offers several advantages, including a short process flow, simple equipment, no pollution, less corrosion, and lower energy consumption. It has a broad application prospect in the acid gas purification, biogas purification and CO2 sequestration., etc. However, demanding hydrate formation conditions and lower gas separation effects constrain its application. Oil-water emulsion shows promise in improving mass and heat transfer efficiency, enhancing hydrate slurry fluidity, and reducing hydrate aggregates. Thus, this study investigates the effects of different oil–water ratios, promoter concentrations, and surfactants on hydrate formation and separation efficiency in an oil–water emulsion system. At an oil–water ratio of 1:1, the purification rate increased to 6.06, five times higher than in a pure water system. The addition of 1,3-Dioxolane (DIOX) facilitated bidirectional growth properties of hydrate formation on droplet surfaces, enhancing hydrate nucleation and formation, leading to a CO2 recovery increase to 87% with 1.5 wt% DIOX. Furthermore, lipophilic surfactants were more likely to promote hydrate slurry fluidization. The addition of Span80 reduced hydrate agglomeration and increased the rate of hydrate formation as concentration rose. The results suggest that adding DIOX and increasing the concentration of Span80 could improve the hydrate method’s separation efficiency at an oil–water ratio of 1:1.

Molecular insight into the decomposition mechanism and stability of CO2 hydrate in the symmetric non-flat double-plate porous media system

Unveiling the decomposition mechanism and stability of hydrate in porous media sediments is the fundamental issue related to hydrate-based CO2 capture and sequestration. In this work, Molecular Dynamics (MD) simulations were performed to study the decomposition mechanism and stability of CO2 hydrate in the porous media of symmetric non-flat double-plate system and explore its mass transfer process. The model of CO2 hydrate in porous media possessing symmetric non-flat double-plate structure was constructed using square quartz (SiO2) as the single crystal material of porous media, illustrating the decomposition mechanism and stability law of CO2 hydrate in such media system. Simulation results indicate that there exists no pretty noteworthy discrepancy between CO2 hydrate in the symmetric non-flat double-plate porous media system and pure CO2 hydrate at the aspect of the decomposition process and sequence. The decomposition process can be divided into two stages: initial cage destruction and CO2 bubble evolution. The decomposition order proceeds in an outside to inside manner generally, with CO2 hydrate decomposition in the middle layer and diagonal region taking priority. Furthermore, the distance between media layers exerts a prominent influence on CO2 hydrate decomposition, which larger distance motivates the decomposition of CO2 hydrate easier. The results also indicated that, compared with pure water system, the stability of CO2 hydrate is greater in the symmetric non-flat double-plate porous media system, with the extreme values of DC reaching 0.64 times only than pure water system. Additionally, CO2 hydrate displayed a stronger stability in the confined space. These findings are beneficial for understanding the decomposition mechanism and stability of CO2 hydrate and provide an interesting insight into geological CO2 sequestration in sediments.

Photosynthesis of H2O2 in pure water over 2D metal-organic frameworks film by co-doping Ga and porphyrin

Hydrogen peroxide (H2O2) is a clean oxidizing agent and potential energy carrier. Photocatalytic H2O2 production has garnered increased attention due to its green and energy-saving process. However, existing photocatalysts face several challenges, such as limited response to visible light, the requirement for sacrificial reagents, and complications in powder recycling. In this work, we synthesized two-dimensional (2D) NH2-MIL-53(Al) films co-modified with Ga and tetrakis (4-carboxyphenyl) porphyrin (TCPP) with enhanced photocatalytic activity of 268.7 µmol∙g−1∙h−1 from only O2 and pure H2O, reaching 3.5 times higher than pure NH2-MIL-53(Al). Notably, in comparison with other reported MOF photocatalysts, NMA-Ga5%-L30 stands out with the highest photocatalytic H2O2 generation activity in a pure water system under visible light. Moreover, this sample film was readily recovered from a photocatalytic system and exhibits significant cycling stability. The heightened photocatalytic activity is attributed to the dual modification, which not only reduces the photogenerated band gap but also promotes the charge carrier’s separation and transfer. This work provides a strategy for the design of MOFs-based photocatalysts with easy recycle properties for artificial photosynthesis of H2O2.

Analysis of factors affecting the formation characteristics of carbon dioxide hydrates in pure water system

As the oilfield fully enters the late stage of exploitation, the water content in the oil and gas transportation pipelines is rising. Meanwhile, the high-pressure and low-temperature environment inside the pipeline facilitate the formation of hydrates, which will seriously block the mixing pipeline and cause a series of production safety problems. Therefore, it is necessary to control the risk under the high water content system. In this paper, a high-pressure flow loop device with a viewable window was used to study the formation characteristics of carbon dioxide hydrate in a pure water system, and the effects of the liquid loading, pressure, volume flow rate, and two inhibitors, polyvinylpyrrolidone (PVP) and propylene glycol methyl ether (PM), on the induction time of carbon dioxide hydrate formation were investigated. The experimental results showed that the amount of liquid loading, pressure, volume flow rate, and inhibitor had a significant effect on the hydrate induction time. In addition, the ether compounds PM and PVP have inhibitory synergistic effects, which can significantly prolong the hydrate induction time, and the inhibitory synergistic effect is further enhanced with the increase of PM concentration, which further suggests the synergistic inhibition mechanism of the two. Based on the standard regression coefficient method, the factors affecting the induction time were subjected to sensitivity analysis, and it was found that the inhibitor was the most important factor affecting the induction time. Therefore, future research should also focus on finding better performance of inhibitors, synergists and their ratio.

Molecular simulation of the effect of anionic surfactant on methane diffusion in coal

Coal seam water injection is one of the important means of coal mine disaster prevention and control, which helps to reduce gas concentration. Anionic surfactants can change the hydrophilicity of coal to enhance the wetting effect of coal seam water injection and inhibit the diffusion of methane. However, the research on the effect of surfactants on the diffusion process of methane is still relatively weak. In order to explore the influence mechanism of anionic surfactant on coal surface wettability and methane diffusion from a microscopic point of view. Using wiser coal model and two commonly used anionic surfactants, sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS), the surfactant/water interface configuration, water/coal contact angle configuration and coal seam methane diffusion configuration were constructed. The interfacial stability of surfactant and water was discussed, and the wetting modification effect of surfactant on coal surface and the law of gas diffusion were analyzed. Finally, by studying the microscopic properties of each molecule in the simulation system, the adsorption mode of surfactants, the hydrophilicity of polar groups, the number of hydrogen bonds and the change of the pore volume in the coal seam system were analyzed, and the wetting modification mechanism of surfactants on coal surface and the inhibition effect of methane diffusion were discussed. The results show that with the increase of surfactant concentration, the interface formation energy is constantly enhanced, and the absolute value of electrostatic energy gradually increases, making the effect between surfactant and water stronger. The contact angle of coal surface under the action of SDS surfactant is the smallest, which is 36.230°, indicating that SDS surfactant has the best effect on the wettability of coal surface. The amount of methane diffusion in the surfactant action system decreased significantly compared with the pure water system, and the distribution of methane in the coal seam increased, indicating that the interaction between methane and coal is enhanced under the action of surfactant. With the increase of surfactant concentration, surfactant molecules are easier to spread on the surface of coal seam, and the wettability of coal surface increases. The research results can provide some research ideas and reference significance for anionic surfactants in the prevention and control of coal mine gas disasters.

Study of the Formation of Hydrates with NaCl, Methanol Additive, and Quartz Sand Particles

During deepwater drilling, testing, production, or hydrate mining, the circulating medium in the wellbore may contain solid particles, such as rock chips and sand, in addition to drilling fluids, gas, and water. In the high-pressure, low-temperature conditions of deep water, gas intrusion can easily combine with free water in the drilling fluid to form hydrates, increasing the drilling risk. Therefore, understanding the formation patterns of hydrates in drilling fluids is of significant importance for the prevention and control of hydrates. This study utilized a small-scale high-pressure reactor to investigate the impact of the stirring rate, NaCl, and methanol additives, as well as the sand content on the hydrate formation process and gas consumption. The results indicate that the hydrate formation process can be divided into an induction stage, a rapid formation stage, and a slow formation stage. The induction stage and rapid formation stage durations are significantly reduced under stirring conditions. In NaCl and methanol solutions, hydrate formation is inhibited, with the induction stage duration increasing with higher concentrations of NaCl and methanol. There was no apparent rapid formation stage observed. The final gas consumption decreases substantially with increasing concentrations of NaCl and methanol, reaching no significant hydrate formation at a 20% concentration. The sand content has a significant impact on the slow formation stage, with the final gas consumption increasing within a certain range (in this work, at a sand content of 20%), and being notably higher than in the pure water system under the same conditions.

Effects of reverse osmosis membrane replacement of pure water system on clinical chemistry and immunoassay in clinical laboratory.

Reverse osmosis (RO) membrane, key component of water-purifying equipment, is often stored in protection fluid containing substances such as glycerol, which may contaminate the water at replacement. This study aims to explore the effects of RO membrane replacement on clinical chemistry and immunoassay, particularly triglyceride (TG), providing reference for managing test interference caused by RO membrane replacement. The RO membrane of water-purifying equipment A, which provided water to C16000 biochemistry analyzer (Abbott Laboratories, Abbott Park, USA) and E801 electrochemiluminescence analyzer (Roche, Basel, Switzerland), was replaced. Water resistivity was recorded, and quality control (QC) tests were performed on C16000 and E801. Moreover, TG was measured in 29 of selected serum samples on C16000 at 0.5h and 10.5h after RO membrane replacement and on reference biochemistry analyzer BS2000M (Mindray Biomedical Electronics Co., Shenzhen, China), which was connected to water-purifying equipment B without RO membrane replacement. Finally, blank, calibrator 1 and calibrator 2 of TG reagent were measured on C16000 before and at 0.5h, 2.5h and 10.5h after RO membrane replacement. All statistical analyses of data were done using GraphPad Prism (GraphPad Software Inc., San Diego, USA), and a value of P < 0.05 was considered statistically significant. After RO membrane replacement, all QC results of clinical chemistry and immune tests passed except TG that showed positive bias of 536% and 371% at two levels, respectively. Moreover, TG results of the same serum samples were significantly higher at 0.5h than 10.5h after RO membrane replacement. Meanwhile, there was worse agreement and correlation of TG results between C16000 and BS2000M at 0.5h than 10.5h after replacement. Furthermore, the absorbance of TG blank, calibrator 1 and calibrator 2 was significantly higher at 0.5h and 2.5h after replacement than before replacement, and the absorbance gradually returned to normal value at 10.5h after replacement. Replacement of RO membrane could cause significant interference to TG test while have no effects on other laboratory tests performed in the study, which may be due to glycerol contamination. Our data provides important reference for management of test interference caused by RO membrane replacement. Clinical laboratory should observe the effects of RO membrane replacement on laboratory tests through both water quality monitoring and QC detection.

Energy stable scheme for random batch molecular dynamics.

The computational bottleneck of molecular dynamics is pairwise additive long-range interactions between particles. The random batch Ewald (RBE) method provides a highly efficient and superscalable solver for long-range interactions, but the stochastic nature of this algorithm leads to unphysical self-heating effect during the simulation. We propose an energy stable scheme (ESS) for particle systems by employing a Berendsen-type energy bath. The scheme removes the notorious energy drift, which exists due to the force error even when a symplectic integrator is employed. Combining the RBE with the ESS, the new method provides a perfect solution to the computational bottleneck of molecular dynamics at the microcanonical ensemble. Numerical results for a primitive electrolyte and all-atom pure water systems demonstrate the attractive performance of the algorithm, including its dramatically high accuracy, linear complexity, and overcoming the energy drift for long-time simulations.