Deposition Behavior Research Articles

Numerical and experimental approach for dust dispersion and deposition behavior for safe decommissioning activities

ABSTRACT The use of high-fidelity modeling is a promising technique for studying the mechanisms of dust dispersion and deposition in safe decommissioning operations. Detailed multiphysics models for poly-dispersed turbulent flow, particle-laden flow, and particle surface interaction were coupled with a Reynolds Averaged Navier Stokes method for numerical simulation of dust dispersion and deposition. A model that considered the critical viscosity was utilized to estimate the interaction between particles and substrate. The deposition behavior of particles was a result of the competition between adhesion and rebound probabilities during the impact process, and only when the critical viscosity exceeded that of the impacting particles could they attach to the surfaces. To validate the accuracy of the simulation results, deposition experiments using zirconia particles were conducted. The experimental setup included a 3.2 m polycarbonate pipe, a fan regulated by an inverter to control the flow, an ultra-low penetration air filter capable of capturing particles with a minimum diameter of 120 nanometers. An air pump connected to a particle tank and a mixing tank was used for homogenizing the injection of particles. Particle concentration was measured during the experiments using a light scattering spectrometer system, WELASⓇ 2000, from the manufacturer PalasⓇ. This optical measurement technique functioned with a white light source and scattered light detection. The scattered light was collected via optical fibers, which led to the control and evaluation point, and results were displayed through special software. The numerical simulation results were compared with the experimental data and used to validate the numerical approach for flow with zirconia particles deposited on various material surfaces, including iron, titanium, stainless steel 304, and stainless steel 316, for airflow rates ranging from 54 L/min to 124 L/min.

Dry Reforming of Methane on Ni/LaZrO2 Catalyst under External Electric Fields: A Combined First-Principles and Microkinetic Modeling Study.

Dry reforming of methane (DRM) reaction has great potential in reducing the greenhouse effect and solving energy problems. Herein, the DRM reaction mechanism and activity on Ni16/LaZrO2 catalyst under electric fields were comprehensively investigated by combining density functional theory calculations with microkinetic modeling. The results showed that La doping increases the interaction between Ni and ZrO2 by Ni cluster transfer of more electrons. The adsorption strength of species followed the order Ni16/ZrO2 > Ni16/LaZrO2, which is consistent with the results for the d-band center but opposite to the metal-support interaction. The best DRM reaction path on Ni16/LaZrO2 was the CH2-O pathway, which is different from the CH-O pathway on Ni(111) and Ni16/ZrO2. Both positive and negative electric fields of strong and weak metal-support interactions reduced the energy barrier of DRM reaction. Importantly, our results showed that the more dispersed and smaller Ni12/LaZrO2 model by considering the dispersing effect induced by La doping, which displayed very different results from that of Ni16/LaZrO2: reduced the energy barrier for methane decomposition, thereby promoting DRM reaction activity. Microkinetic results showed that the carbon deposition behavior of DRM becomes weaker on Ni16/LaZrO2 due to the suppression of methane decomposition in the presence of La doping compared to Ni16/ZrO2, but the opposite result is obtained on Ni12/LaZrO2. The order of DRM reactivity was Ni16/LaZrO2 < Ni16/ZrO2 < Ni12/LaZrO2, which is consistent with the experiment observations. The conversion of methane and CO2 was higher in positive electric fields than in negative electric fields at low temperatures, but the results were opposite at high temperature. Negative electric fields can improve the carbon deposition resistance of Ni-based catalysts compared to positive electric fields. The degree of rate control analysis showed that CHx* oxidation also plays an important role in the DRM reaction. We envision that this study could provide a deeper understanding for guiding the widespread application of electric field catalysis.

Influence of the PET-PTFE Separator Pore Structure on the Performance of Lithium Metal Batteries.

The separator is a crucial component in lithium batteries, as it physically separates the cathode and the anode while allowing ion transfer through the internal channel. The pore structure of the separator significantly influences the performance of lithium batteries, particularly lithium metal batteries. In this study, we investigate the use of a Janus separator composed of poly(ethylene terephthalate) (PET)-polytetrafluoroethylene (PTFE) fibers in lithium metal batteries. This paper presents a comprehensive analysis of the impact of this asymmetric material on the cycling performance of the battery alongside an investigation into the influence of two different substrates on lithium-ion deposition behavior. The research findings indicate that when the rigid PET side faces the lithium metal anode and the soft PTFE side faces the cathode, it significantly extends the cycling lifespan of lithium metal batteries, with an impressive 82.6% capacity retention over 2000 cycles. Furthermore, this study demonstrates the versatility of this separator type in lithium metal batteries by assembling the lithium metal electrode with high cathode-loading capacities (4 mA h/cm2). In conclusion, the results suggest that the design of asymmetric separators can serve as an effective engineering strategy with substantial potential for enhancing the lifespan of lithium metal batteries.

Interfacial Layers with Desolvation Function Induced Stable Deposition of Lithium Metal for Long-Cycling Lithium Metal Batteries.

The unstable solid electrolyte interface (SEI) formed by uncontrollable electrolyte degradation, which leads to dendrite growth and Coulombic efficiency decay, hinders the development of Li metal anodes. A controllable desolvation process is essential for the formation of stable SEI and improved lithium metal deposition behavior. Here, we show a functional artificial interface protective layer comprised of chondroitin sulfate-reduced graphene oxide (CrG), on which polar functional groups are distributed to effectively reduce the energy barrier for desolvation of Li+ and effectively alienate solvent molecules to avoid solvent involvement in SEI formation, thus promoting the formation of a LiF-rich SEI. Consequently, stable Coulombic efficiencies of 98.4% were achieved after 500 cycles in a Li//Cu cell. Moreover, the LiFePO4 full cells achieve steady circulation (470 cycles at 80%, 1 C) with a negative/positive electrode capacity ratio of 2.87. Our multifunctional artificial interface protective layer provides a new way to advance Li metal batteries.

Numerical simulation of ash deposition behavior in radiant syngas cooler coupled with impact surface temperature

Radiant syngas cooler (RSC) is a crucial heat recovery device for entrained-flow coal gasification technology. However, ash deposition in an RSC can severely affect operating efficiency and safety. An ash deposition model coupled with the impact surface temperature was established based on the ash particle deposition morphology. The effects of different operating conditions on ash deposition characteristics are discussed. The simulated data agreed well with the industrial data. The results indicate that ash particles were primarily deposited in the collision deposition zone. The maximum deposition thickness of radiation screen and cylinder membrane wall is 9.82 mm and 1.88 mm, respectively. The ash deposition hindered heat transfer process and the highest heat flux was observed in the middle part of the RSC. Ash deposition around 5.3 m increases significantly with an increase in the inlet syngas temperature. Increasing the load increased probability of ash particle collision and the area of influence.

Regulating Sodium Deposition Behavior by a Triple-Gradient Framework for High-Performance Sodium Metal Batteries.

An efficient method for the synthesis of a self-supporting carbon framework (denoted Gra-GC-MoSe2) is proposed with a triple-gradient structure-in sodiophilic sites, pore volume, and electrical conductivity-which facilitates the highly efficient regulation of Na deposition. In situ and ex situ measurements, together with theoretical calculations, reveal that the gradient distribution of Se heteroatoms in MoSe2, and its derivatives tailor the sodiophilicity, while the gradient distribution of porous nanostructures homogenizes the Na+ diffusion. Therefore, Na deposition occurs from the bottom to the top of the Gra-GC-MoSe2 framework without dendrite formation. In addition, the gradient in electrical conductivity ensures the stripping process does not lead to dead Na. As a result, a Gra-GC-MoSe2 modified Na anode (Na@Gra-GC-MoSe2) shows impressive cycling stability with a high average Coulombic efficiency in an asymmetric cell. In symmetric cells, it also exhibits a long cycling life of 2000h with a low polarization voltage and works stably even under a large capacity of 10mAhcm-2. Moreover, a Na@Gra-GC-MoSe2|| Na3V2(PO4)3 full cell delivers a high energy density with an excellent cycling performance.

Experimental determination of deposition velocity of CsOH aerosols on CaCO3 at temperature range 170 - 290 °C

A field assessment at the Fukushima-Daiichi Nuclear Power Station revealed high radioactivity on the concrete shield plugs, which is estimated above 20 PBq for Cs-137 at units 2 and 3. This leads to significant interest in the retention of Cs on concrete during severe accidents (SA). However, the interaction of CsOH, as one of the main Cs forms released in SA, with concrete surfaces at elevated temperatures remains poorly researched. In this study, we have experimentally investigated the deposition behavior of CsOH on CaCO3, which is the primary phase existing on the surface of concrete, under humid atmosphere. As a result, the chemical reaction enhanced deposition rate (N), and increased linearly with CsOH concentration (Cg), as following expression:N(µg/cm2.s)=vdCg, where vd is temperature-dependent deposition velocity as given by lnvd(cm/s) = -3785.8/T + 3.766, for T in the range of 170 and 290 °C.This empirical model can be integrated into severe accident codes to quantify the chemical trapping of cesium on concrete surfaces during ex-vessel release. Moreover, it can contribute to understanding the reasons behind the high dose rate on concrete shield plugs at the Fukushima Daiichi Nuclear power stations and aid in developing effective decommissioning practices for concrete structures.

Erosion, deposition and breach evolution of landslide dams composed of various dam material types based on flume tests

The accurate and rapid prediction of breach outflow rates of landslide dams is crucial for effective risk assessment and mitigation strategies. However, challenges arise due to the complexities associated with breaching mechanisms. In this study, 12 flume tests were conducted on landslide dams composed of various material types, including fine-grained, coarse-grained, well-graded, and gap-graded materials, each with two dry densities. This study comprehensively investigated erosion, deposition, and breach evolution, providing the foundation for the development of breach evolution models. A comprehensive logic diagram, focusing on shear stress and grain size distribution, was proposed to forecast the failure modes of landslide dams. The study also suggested a method to assess the longitudinal breach evolution based on the prediction of the Erosion Point (EP) and Deposition Point (DP), and to assess the lateral breach evolution by considering both steep and gentle breach side slopes. Our findings indicate that fine-grained materials undergo layer erosion, coarse-grained materials remain stable, well-graded materials develop erosion pits, and gap-graded materials are prone to piping. The existence of an interface can result in piping channels, even when the overall hydraulic gradient is insufficient to initiate piping. Incorporating the longitudinal slope angle and its influence on both driving and resisting forces into the traditional erosion rate equation can significantly enhance its accuracy, especially when coarse particles are present. Coarse particles play a pivotal role in erosion and deposition behavior and reshaping the breach evolution as the initiation of coarse particles is dominated by rolling instead of slipping in fine particles. Deposition on the downstream slope of a dam can significantly influence the longitudinal breach process, leading to changes in the downstream topography and grain size distribution. The proposed method for assessing longitudinal breach evolution unifies the previous methodologies by predicting the positions of EP and DP based on erosion and deposition.

Constructing Reversible Li Deposition Interfaces by Tailoring Lithiophilic Functionalities of a Heteroatom-Doped Graphene Interlayer for Highly Stable Li Metal Anodes.

Lithium (Li) metal has been regarded as the ideal anode for rechargeable batteries due to its low reduction potential and high theoretical capacity. However, the formation of fatal Li dendrites during repeated cycling shortens the battery life and causes serious safety concerns. Functionalized separators with electrically conductive and lithiophilic coating layers potentially inhibit dendrite formation and growth on Li metal anodes by providing nucleation sites for reversible Li deposition/stripping. In this work, we propose functionalized separators incorporating heteroatom-doped (N or B) graphene interlayers to modulate the Li nucleation behavior. The electronegative N-doping and electropositive B-doping were investigated to understand their regulation of the Li deposition behavior. With the heteroatom-doped graphene-coated separators, we observe significantly improved cycling stability along with enhanced charge transfer kinetics and low Li nucleation overpotential. This is attributed to the heteroatom-doped graphene interlayer expanding the surface area of the Li metal anode while providing additional space for uniform Li deposition/stripping, thus preventing undesirable side reactions. As a result, the formation of dendrites and pits on the Li metal anode surface is suppressed, demonstrating the protective effect of the Li metal anode. Interestingly, N-doped graphene-coated separators exhibit lower Li nucleation overpotentials than B-doped graphene-coated separators but rather lower average Coulombic efficiencies and reduced cycling stability. This implies that adequate adsorption on B-based sites, as opposed to the strong adsorption on N-based sites, improves the reversibility. Notably, the Li adsorption strength of the lithiophilic functional groups critically affects the reversibility, as observed by Li nucleation barrier measurements and atomistic simulations. This work suggests that interface engineering using conductive and lithiophilic materials can be a promising strategy for controlling Li deposition in advanced Li metal batteries.

Self-regulating shielding layer induces (002) plane directional deposition of zinc metal anode

Rechargeable aqueous zinc batteries (AZIBs) are ideal for grid-scale energy storage due to their safety and economic characteristics. However, uncontrollable side reactions and dendrite growth severely affect the reversibility of zinc anodes. In the interfacial reaction, inducing smooth deposition of dominant planes is crucial for stabilizing the zinc anodes. Herein, we report a highly concentrated 1‑butyl‑3-methylimidazolium ion (BMIM+) modified electrolyte to improve the diffusion and deposition behavior of Zn2+. Thanks to the strong adsorption effect of BMIM+ at the zinc anode interface, the self-regulating shielding layer inhibits water-induced parasitic reactions. Under the action of BMIM+, Zn2+ has the lowest diffusion energy barrier towards the (002) plane, thus transforming the electrodeposition from a randomly stacked sheet to a dense deposited layer in the Zn(002) plane. The results showed that the symmetric cell composed of the modified electrolyte had a cycle life of 3200 h at 1 mA cm−2, and the average coulombic efficiency (CE) of the asymmetric cell was as high as 99.8 %. The full cell assembled with ZnxV2O5·nH2O still provided 86 % capacity retention at 2 A g−1 after 500 cycles. This electrolyte modification strategy provides a promising option for modulating the anode/electrolyte interface chemistry to achieve high-performance AZIBs.

Simulation of the dynamic processes of microplastic suspension and deposition in a lake sediment-water system.

The occurrence of microplastics in aquatic environments has attracted increasing interest from both the public and scientists, especially their migration behaviors. Although several environmental behaviors of microplastics have been studied, the issue of microplastic suspension and deposition in lake sediment-water systems remains to be elucidated. In this study, we built an indoor sediment-water system with input and output rivers that simulated the actual situations in lakes, and aimed to explore the suspension and deposition behavior of microplastics using eight group experiments. The abundance of microplastics in overlying water and sediments in different periods was analyzed, and the characteristics of hydrodynamic disturbance on microplastic suspension and deposition were identified. Importantly, the exchange of microplastics in sediments and water under dynamic flow conditions was assessed. The results showed that the middle-scale experiment designed in this study effectively simulated the dynamic transport process of microplastics in lakes, and the hydrodynamic force had a significant impact on the suspension and deposition behaviors of microplastics. The average abundance of polystyrene, polyethylene terephthalate and polyamide microplastics was 1.07, 0.60 and 0.83 particles/L in overlying water during the suspension experiments, respectively. This showed a pattern of first rising and then falling with the extension of suspension time. Even in the environment with the maximum input water volume (8000 ml/min) in this study, only microplastics at a depth of 0 to 2 cm from the sediment were suspended. The average abundance of microplastics was 313.02 particles/kg during the deposition experiments, which gradually increased with the extension of deposition time in sediments. Finally, microplastic sizes in water of the suspension experiments and in sediments of the deposition experiments were concentrated in the range of 500 to 1500 μm and 300 to 1000 μm, respectively.

Behavior of iron deposition on the surface structure and electrical properties of CrBr[formula omitted] by scanning tunneling microscopy and spectroscopy

Chromium Tribromide (CrBr3) is a well-known material due to its magnetic properties. However, the low Curie temperature of CrBr3 limited its development for electronic devices. Therefore, one possible solution to overcome this limitation is to introduce a heterostructure by incorporating metallic elements. In this study, we fabricate the CrBr3/HOPG heterostructure by mechanical exfoliation and dry transfer techniques, and we conduct the deposition of iron atoms onto the surface of the heterostructure. Investigating the surface morphology and electrical properties using scanning tunneling microscopy and scanning tunneling spectroscopy. Our result revealed the morphology of CrBr3 ranging from monolayer to multiple-layer thicknesses. Numerous irregular patterns with widths of 2–3 nm on the platform, and the atomic structure became highly resolved after iron deposition. The top-layer and bottom-layer bromine atoms surrounding the hexagonal arrangements formed by intermediate-layer chromium atoms are present. In terms of electrical properties, iron deposition caused significant changes to the energy band gap of CrBr3, which decreased abruptly from 1.837±0.058 eV to 0.148±0.024 eV, indicating that a transition from a p-type semiconductor to semi-metal occurred. Our research supports the simulation of density functional theory in describing the electrical properties of CrBr3 in previous research.

Electrolyte Engineering via Fluorinated Siloxane Solvent for Achieving High-Performance Lithium-Metal Batteries.

Advanced solvent is of important significance to develop an excellent electrolyte that simultaneously maintains a high ionic conductivity, wide electrochemical window, and good compatibility with electrodes for high-performance lithium-metal batteries (LMBs). To realize a stable electrode/electrolyte interface and a uniform lithium (Li) deposition process, an optimal fluorinated siloxane (3,3,3-trifluoropropyltrimethoxysilane, TFTMS) is proposed as a cosolvent with 1,2-dimethoxyethane (DME) and highly antioxidative fluoroethylene carbonate (FEC) to formulate a Li-metal compatibility electrolyte. The TFTMS-based electrolyte presents high oxidization stability, high Li+ conductivity, and high Li+ transfer number, contributing to the accelerated reaction kinetics, homogeneous Li deposition behavior, and stable interfacial chemistry. Therefore, high Li stripping/plating reversibility (∼99%) and stable cycling (1400 h) are achieved in the TFTMS-based electrolyte, giving rise to the excellent electrochemical performance of practical Li-metal full cells. Moreover, an industrial 4 Ah NCM811|Gr pouch cell with the TFTMS-based electrolyte is demonstrated to display similar cycling performance with the commercial carbonate electrolyte in 120 cycles at 1 C. This work offers an approach toward high-performance LMBs through rational electrolyte design with fluorinated siloxane solvent.

Promoting Li2S Nucleation/Dissolution Kinetics via Multiple Active Sites over TiVCrMoC3Tx Interface.

Lithium-sulfur batteries (LSBs) are still limited by some issues such as polysulfides shuttle and lithium dendrites. Recently, the concept "high-entropy" has been considered as the research hotspot and international frontier. Herein, a high entropy MXene (TiVCrMoC3Tx, HE-MXene) doped graphene is designed as the modified coating on commercial separators for LSBs. The HE-MXene affords multiple metal active sites, fast Li+ diffusion rate, and efficient adsorption toward polysulfide intermediates. Furthermore, strong lithophilic property is favorable for uniform Li+ deposition. The combination of in situ characterizations confirms TiVCrMoC3Tx effectively promotes the Li2S nucleation/dissolution kinetics, reduces the Li+ diffusion barrier, and exhibits favorable lithium uniform deposition behavior. This TiVCrMoC3Tx/G@PP provides a high-capacity retention rate after 1000 cycles at 1 C and 2 C, with a capacity decay rate of merely 0.021% and 0.022% per cycle. Surprisingly, the cell operates at a low potential of 48mV while maintaining at 5mA cm-2/5 mAh cm-2 for 4000h. Furthermore, it still maintains a high-capacity retention rate under a high sulfur loading of 4.8/6.4mg cm-2 and a low E/S ratio of 8.6/7.5µgmL-1. This work reveals a technical roadmap for simultaneously addressing the cathode and anode challenge, thus achieving potential commercially viable LSBs.

Spreading model of single droplet impacting the banana leaf surface and computational fluid dynamics simulation analysis

The droplet deposition behavior is an important indicator of precision agriculture and sustainable agriculture 4.0. Comprehensive analysis of the behavior and modeling of pesticide droplets impacting target leaves is an important basis for achieving efficient spray deposition. In this study, banana leaves were taken as the research object, the spreading model and computational fluid dynamics (CFD) model of single droplet impacting on the target leaf surface were studied from the micro and macro perspectives. The aim is to clarify and obtain the quantitative mapping relationship between droplet deposition performance and related operating parameters. The results showed that the pesticide droplets were asymmetrically spread and slipped on the surface of the inclined banana leaves. The maximum lateral spreading diameter Dnmax was only affected by the normal component of Weber number Wen, while the maximum tangential spreading diameter Dtmax and slip distance L were affected by the normal component of Weber number Wen and the inclination angle α. As the impact velocity increases, the pesticide droplets interact with the non-smooth morphology of the banana leaf surface to form a large number of pinning sites on the edge contact line. Combining the microscopic characteristics of banana leaves with the physicochemical characteristics of the droplets, a CFD model was established to carry out single-drop impact simulation verification. The impact velocity and inclination angle were set as variables to carry out CFD simulation of the dynamic process. The numerical simulation results are consistent with the spreading model obtained from the experimental study, which can quantitatively reflect the impact process of pesticide droplets. The spreading model and CFD model of pesticide droplets impacting on the banana leaf surface established in this study, can provide guidance for the selection of pesticide application for the spray droplet deposition behavior. At the same time, it can also provide methodological reference for other crop spray research and spray technology research in other fields.

Co-solvent and additive joint engineering enable long-life and wide-temperature Zn metal battery

The dendrite growth and interfacial side reactions pose significant threaten to the practical applications of aqueous zinc metal batteries (AZMBs), especially at subzero temperature environments. To this end, co-solvent and additive joint engineering is proposed to design hybrid electrolyte, which consists of a mixture of 1,2-propanediol (1,2-PG) solvent and H2O with trace amounts of 18-crown-6 molecules, for constructing stable wide-temperature AZMBs. Notably, the 18-crown-6 and 1,2-PG molecules can both disturb the original hydrogen-bond network of H2O molecules. Interestingly, the 18-crown-6 molecules predominantly tends to absorb on the Zn anode surface and form favorable organic-inorganic hybrid SEI layer to regulate Zn deposition behaviors. The 1,2-PG molecules are responsible for reconstructing the solvation structure of Zn2+ and lowering the solid-liquid transition temperature of aqueous electrolyte, suppressing the H2O-induced side reactions and improving the antifreezing capability of electrolyte. Furthermore, the hybrid electrolyte induces the preferential Zn(002) plane deposition under the low temperature environments due to the synergistic effect of 18-crown-6 and 1,2-PG molecules, enhancing the Zn2+ transport and deposition kinetics. Consequently, the hybrid electrolyte endows the assembled cells with enhanced cycling lifespan and reversibility within the wide temperature range from -50 to 25 °C, expanding the application range of AZMBs.

Breakthrough in atmospheric plasma spraying of high-density composite electrolytes: Deposition behavior and performance of plasma-sprayed GDC-LSGM on porous metal-supported solid oxide fuel cells

The potential application of plasma spraying in the preparation of ceramic electrolyte for porous metal-supported solid oxide fuel cells (SOFCs) is highlighted by its ability to eliminate the need for a high-temperature sintering process. However, the challenge of achieving highly dense electrolytes through plasma spraying remains to be addressed. In this study, a novel electrolyte for porous metal-supported SOFCs (PMS-SOFCs) is developed. This involved the preparation of a highly dense structure of gadolinium-doped ceria (GDC)-lanthanum strontium gallium magnesium oxide (LSGM) composite coating using plasma spraying under atmospheric conditions. The composite electrolyte is prepared using atmospheric plasma spraying (APS). The addition of the low-melting-point LSGM phase enhanced the microstructural densification of the GDC-based composite coating and diminished electron loss in a reducing atmosphere, thereby improving the cell's open-circuit voltage. At 36 kW plasma arc power, the single cell with composite electrolyte exhibited a maximum power density of 371 mw/cm2 at 750 °C and achieved the highest open-circuit voltage (1.03 V) at 600 °C. Moreover, the open-circuit voltage remained stable over a 100-h test. These findings suggest that using APS to deposit a composite electrolyte with added low-melting-point secondary phases presents a promising approach for achieving relatively high OCV in PMS-SOFCs based on cerium oxide electrolytes.

Understanding dilution effects on particle-containing pesticide droplets deposition on rice leaf via developing CFD-VOF-DPM model.

Pesticide dilution is one of the essential aspects of plant protection. However, the effect of dilution on the deposition characteristics of pesticide droplets containing particulate additives on crop leaf surfaces remains unclear and warrants further research. Herein, a validated computational fluid dynamics (CFD)-volume of fluid (VOF)-discrete phase model (DPM) numerical model was developed to analyze the influence of particle content on the deposition behavior of droplets on the leaf surface comparatively, taking into account the particle content of different diluted thifluzamide solutions. Additionally, the study aimed to analyze further the kinetic behavior of pesticide droplets landing on rice leaves across different dilution conditions. Pesticide droplets diluted 100-fold had a lower retraction rate during spreading than particle-free droplets, so the solution is more easily deposited in the leaves. Moreover, the low dilution (high concentration) increased the critical adhesion rate between droplets and rice leaves, inhibiting the bouncing of droplets on the leaf surface, thus promoting their effective deposition on the surface. In addition, low dilution (high concentration) is not conducive to spreading droplets when the impact velocity is high, and it also results in a large amount of pesticide use. The actual application process can be through understanding the dilution factor of the configured pesticide solution, and reasonable adjustment of the nozzle pressure can effectively improve the utilization rate of pesticides and reduce the pollution brought by pesticides to the environment. These results provide an essential reference for studying pesticide droplet deposition characteristics, including rice plant protection and spraying technology. © 2024 Society of Chemical Industry.

Effect of particle density on microplastics transport in artificial and natural porous media

The occurrence and persistence of microplastics (MPs) in natural environments are of increasing concern. Along with this, the transport of MPs in sediments has been investigated mainly focusing on the effect of plastic size and shape, media size effect, and solution chemistry. Yet, the influence of particle density is only partially understood. Therefore, column experiments on the transport of variably buoyant MPs in saturated natural sediments and glass beads were conducted, and transport parameters were quantified using a two-site kinetic transport model with a depth-dependent blocking function (the amount of retained MPs does not decrease at a constant rate with increasing depth, the majority of MPs were retained near the column inlet). Neutral, sinking, and buoyant MPs within the same size range were selected, with stable water isotope applied as conservative tracer to explore water and MP movement in the tested sediments. The results showed that 95.5 ± 1.4% of sinking MPs remained in columns packed with gravel, followed by buoyant and neutral MPs, thus indicating that particle density does affect MP mobility. Similar recovered amounts of MPs were found in columns packed with glass beads, indicating that tested sediment types do not affect the deposition behavior of MPs. The breakthrough curves of MPs were accurately described by the selected model. However, the simulated retention profiles overestimated the observed MP amount in layers closest to the column inlet. The coupled experimental and modeled results suggest an enhanced retention of sinking MPs, while neutrally and buoyant MPs exhibit a higher mobility in comparison. Thus, neutral or buoyant MPs can potentially pose a higher contamination risk to subsurface porous media environments compared to sinking MPs. Discrepancies between observed and simulated retention profiles indicate that future model development is needed for advancing the MP deposition as affected by particle density.

In situ designing an implanted hetero-interface of high adsorption energy in composite lithium anode towards high−rate lithium metal batteries

Lithium metal is considered as the ultimate anode material for next-generation Li based battery chemistries. The constituted lithium metal batteries (LMBs) specialize in high energy density, but the inherent dendritic lithium growth as well as the serious proliferation of native solid electrolyte interphase (SEI) have been impeding their practical application, in particular under the high-rate conditions of a more concentrated Li+ flux. Herein, we report a composite anode design, in which LiF/LiC as the products of the in situ spontaneous reductive defluorination between Li and poly(tetrafluoroethylene) (PTFE) are uniformly implanted in bulk metallic Li via facile mechanical kneading. The macroscopical composite anode creates a dispersion of lithiophilic nanodomains microscopically in bulk. The built-in LiF/LiC doping of high Li adsorption energy improves the affinity towards Li+ flux and avoids the Li+-adhesion-induced Li aggregation. The construction facilitates a dense while large granular plating as well as the generation of a thin, inorganic-rich SEI to synergistically ensure a dendrite-free Li deposition behavior. The improved plating reversibility and cycling stability are verified in forms of both symmetric cell under harsh conditions up to 30 mA cm−2@30 mAh cm−2 and high-areal-capacity Li||LiFeO4 full cell for 500 cycles at 3 C. This not only expands the state-of-the-art LMBs under high-loading and power-intensive scenarios, but also preliminarily evidences its scalable and industry-adaptable potential.