Engineering Multi‑field‑coupled Synergistic Ion Transport System Based on the Heterogeneous Nanofluidic Membrane for High‑Efficient Lithium Extraction

The global carbon neutrality strategy brings a wave of rechargeable lithium‐ion batteries technique development and induces an ever-growing consumption and demand for lithium(Li).Among all the Li exploitation,extracting Li from spent LIBs would be a strategic and perspective approach,especially with the low energy consumption and eco-friendly membrane separation method.However,current membrane separation systems mainly focus on monotonous membrane design and structure optimization,and rarely further consider the coordination of inherent structure and applied external field,resulting in limited ion transport.Here,we propose a heterogeneous nanofluidic membrane as a platform for coupling multi-external fields(i.e.,lightinduced heat,electrical,and concentration gradient fields)to construct the multi-field-coupled synergistic ion transport system(MSITS)for Li-ion extraction from spent LIBs.The Li flux of the MSITS reaches 367.4 mmol m^(−2)h^(−1),even higher than the sum flux of those applied individual fields,reflecting synergistic enhancement for ion transport of the multi-field-coupled effect.Benefiting from the adaptation of membrane structure and multi-external fields,the proposed system exhibits ultrahigh selectivity with a Li^(+)/Co^(2+)factor of 216,412,outperforming previous reports.MSITS based on nanofluidic membrane proves to be a promising ion transport strategy,as it could accelerate ion transmembrane transport and alleviate the ion concentration polarization effect.This work demonstrated a collaborative system equipped with an optimized membrane for high-efficient Li extraction,providing an expanded strategy to investigate the other membrane-based applications of their common similarities in core concepts.

Intensification of chemical separation engineering by nanostructured channels and nanofluidics: From theories to applications

With the development of manufacturing technology on the nanoscale, the precision of nano-devices is rapidly increasing with lower cost. Different from macroscale or microscale fluids, many specific phenomena and advantages are observed in nanofluidics. Devices and process involving and utilizing these phenomena play an important role in many fields in chemical engineering including separation, chemical analysis and transmission.In this article, we summarize the state-of-the-art progress in theoretical studies and manufacturing technologies on nanofluidics. Then we discuss practical applications of nanofluidics in many chemical engineering fields,especially in separation and encountering problems. Finally, we are looking forward to the future of nanofluidics and believe it will be more important in the separation process and the modern chemical industry.

Heat transfer of nanofluidics in hydrophilic pores: Insights from molecular dynamics simulations

Nanofluidics in hydrophilic nanopores is a common issue in many natural and industrial processes. Among all,the mass transport of nanofluidics is most concerned. Besides that, the heat transfer of a fluid flow in nano or micro channels is always considered with adding nanoparticles into the flow, so as to enhance the heat transfer by convection between the fluid and the surface. However, for some applications with around 1 nm channels such as nano filtration or erosion of rocks, there should be no nanoparticles included. Hence, it is necessary to figure out the heat transfer mechanism in the single phase nanofluidics. Via non-equilibrium molecular dynamics simulations, we revealed the heat transfer inside nanofluidics and the one between fluid and walls by setting simulation into extremely harsh condition. It was found that the heat was conducted by molecular motion without temperature gradient in the area of low viscous heat, while it was transferred to the walls by increasing the temperature of fluids. If the condition back to normal, it was found that the viscous heat of nanofluidics could be easily removed by the fluid-wall temperature drop of less than 1 K.

Exosome Nanoporator:An Innovative Nanofluidic Device to Develop Exosome-based Drug Delivery Vehicles

The research group of Prof.YANG Hui in Shenzhen Institute of Advanced Technology(SIAT)of the Chinese Academy of Sciences,has recently presented a novel nanofluidic device for high-throughput preparation of exosome-based drug delivery vehicles.Their latest results were published in Small,entitled“A High-Throughput Nanofluidic Device for Exosome Nanoporation to Develop Cargo Delivery Vehicles”,and featured on the back cover.

Bioinspired nanofluidic iontronics for brain-like computing

The human brain performs computations via a highly interconnected network of neurons.Taking inspiration from the information delivery and processing mechanism of the human brain in central nervous systems,bioinspired nanofluidic iontronics has been proposed and gradually engineered to overcome the limitations of the conventional electron-based von Neumann architecture,which shows the promising potential to enable efficient brain-like computing.Anomalous and tunable nanofluidic ion transport behaviors and spatial confinement show promising controllability of charge carriers,and a wide range of structural and chemical modification paves new ways for realizing brain-like functions.Herein,a comprehensive framework of mechanisms and design strategy is summarized to enable the rational design of nanofluidic systems and facilitate the further development of bioinspired nanofluidic iontronics.This review provides recent advances and prospects of the bioinspired nanofluidic iontronics,including ion-based brain computing,comprehension of intrinsic mechanisms,design of artificial nanochannels,and the latest artificial neuromorphic functions devices.Furthermore,the challenges and opportunities of bioinspired nanofluidic iontronics in the pioneering and interdisciplinary research fields are proposed,including brain–computer interfaces and artificial neurons.

Supramolecular flow chemistry: Construction of multiscale supramolecular assemblies by micro/nanofluidic techniques

The rapid and precise fabrication of multiscale supramolecular assemblies using micro/nanofluidic techniques has emerged as a dynamic area of research in supramolecular chemistry, materials chemistry, and organic chemistry. This review summarizes the application of micro/nanofluidic techniques in constructing supramolecular assemblies, including nanoscale supramolecular assemblies such as macrocycles and cages, microscale supramolecular assemblies such as metal organic frameworks (MOFs) and covalent organic frameworks (COFs), and macroscale supramolecular assemblies such as supramolecular hydrogels. Compared to conventional synthesis methods, micro/nanofluidic techniques for the production of supramolecular assemblies have significant advantages, including enhanced safety, high reaction rates, improved selectivity/yield, and scalability. Additionally, micro/nanofluidic systems facilitate the creation of precisely controllable micro/nanoconfined environments, allowing for a unique flow behavior that improves our understanding of the supramolecular self-assembly process. Such systems may also lead to the development of novel supramolecular assemblies that differ from those generated via traditional methods.

3D-printed mechanically strong and extreme environment adaptable boron nitride/cellulose nanofluidic macrofibers

Fibrous nanofluidic materials are ideal building blocks for implantable electrode,biomimetic actuator,wearable electronics due to their favorable features of intrinsic flexibility and unidirectional ion transport.However,the large-scale preparation of fibrous nanofluidic materials with desirable mechanical strength and good environment adaptability for practical use remains challenging.Herein,by fully taking advantage of the attractive mechanical,structural,chemical features of boron nitride(BN)nanosheet and nanofibrillated cellulose(NFC),a scalable and cost-effective three-dimensional(3D)printed macrofiber featuring abundant vertically aligned nanofluidic channels is demonstrated to exhibit a good combination of high tensile strength of 100 MPa,thermal stability of up to 230℃,ionic conductivity of 1.8×10^(−4)S/cm at low salt concentrations(<10^(−3)M).In addition,the versatile surface chemistry of cellulose allows us to stabilize the macrofiber at the molecular level via a facile postcross-linking method,which eventually enables the stable operation of the modified macrofiber in various extreme environments such as strong acidic,strong alkaline,high temperature.We believe this work implies a promising guideline for designing and manufacturing fibrous nanodevices towards extreme environment operations.

Photothermal regulated ion transport in nanofluidics:From fundamental principles to practical applications

Light regulated ion transport across membranes is central to nature.Based on this,artificial nanofluidics with light driven ion transport behaviors has been developed for both fundamental study and practical applications.Here,we focus on recent progress in photothermal controlled ion transport systems and review the corresponding construction strategies in diverse photothermal nanofluidics with various dimensions and structures.We systematically emphasize the three underlying working principles including temperature gradient,water evaporation induced ion transport blockage,and evaporation gradient.On the basis of these fundamental research,photothermal regulated ion transport has been mainly introduced into ionic devices,desalination,and energy conversion.Furthermore,we provide some perspectives for the current challenges and future developments of this promising research field.We believe that this review could encourage further understanding and open the minds to develop new advances in this fertile research field.

Osmotic-Enhanced-Photoelectrochemical Hydrogen Production Based on Nanofluidics

Harvesting clean energy such as solar energy and salinity gradient energy directly from the surrounding environment has attracted great attention.A promising proof-of-concept combination of cation-selective membrane-based osmotic energy with photoelectrochemical-based solar energy has been developed,highlighting the great potential for the direct conversion of osmotic energy to hydrogen energy.With the help of a 50-fold concentration gradient,the MXene-CdSe quantum dots system exhibits the highest photocurrent enhancement ratio(Δ/_(L-H)/Δ/_(L-L)),and the hydrogen production is increased by about 33%at a bias of 0 V versus reversible hydrogen electrode.Directly converting osmotic energy and solar energy into hydrogen energy suggests the possibility of coupling osmotic energy with other renewable energy sources.

Nanofluidic osmotic power generation from CO_(2) with cellulose membranes

The diffusion of chemical species down concentration gradient is a ubiquitous phenomenon that releases Gibbs free energy.Nanofluidic materials have shown great promise in harvesting the energy from ionic diffusion via the reverse electrodialysis process.In principle,any chemicals that can be converted to ions can be used for nanofluidic power generation.In this work,we demonstrate the power generation from the diffusion of CO_(2) into air using nanofluidic cellulose membranes.By dissolving CO_(2) in water,a power density of 87 mW/m^(2) can be achieved.Using monoethanolamine solutions to dissolve CO_(2),the power density can be increased to 2.6 W/m^(2).We further demonstrate that the waste heat released in industrial and carbon capture processes,can be simultaneously harvested with our nanofluidic membranes,increasing the power density up to 16 W/m^(2) under a temperature difference of 30°C.Therefore,our work should expand the application scope of nanofluidic osmotic power generation and contribute to carbon utilization and capture technologies.

Fabrication of all-transparent polymer-based and encapsulated nanofluidic devices using nano-indentation lithography

In this paper,we describe a novel and simple process for the fabrication of all-transparent and encapsulated polymeric nanofluidic devices using nano-indentation lithography.First,a nanomechanical probe is used to‘scratch’nanoscale channels on polymethylmethacrylate(PMMA)substrates with sufficiently high hardness.Next,polydimethylsiloxane(PDMS)is used twice to duplicate the nanochannels onto PDMS substrates from the‘nano-scratched’PMMA substrates.A number of experiments are conducted to explore the relationships between the nano-indentation parameters and the nanochannel dimensions and to control the aspect ratio of the fabricated nanochannels.In addition,traditional photolithography combined with soft lithography is employed to fabricate microchannels on another PDMS‘cap’substrate.After manually aligning the substrates,all uncovered channels on two separate PDMS substrates are bonded to achieve a sealed and transparent nanofluidic device,which makes the dimensional transition from microscale to nanoscale feasible.The smallest dimensions of the achievable nanochannels that we have demonstrated thus far are of~20 nm depth and~800 nm width,with lengths extendable beyond 100μm.Fluid flow experiments are performed to verify the reliability of the device.Two types of colloidal solution are used to visualize the fluid flow through the nanochannels,that is,ethanol is mixed with gold colloid or fluorescent dye(fluorescein isothiocyanate),and the flow rate and filling time of liquid in the nanochannels are estimated based on time-lapsed image data.The simplicity of the fabrication process,bio-compatibility of the polymer substrates,and optical transparency of the nanochannels for flow visualization are key characteristics of this approach that will be very useful for nanofluidic and biomolecular research applications in the future.

Redox switch of ionic transport in conductive polypyrrole-engineered unipolar nanofluidic diodes

Controlling ion transport in nanoconfined spaces is a key task for the creation of smart nanofluidic devices.In this work,redox-active polypyrrole （PPy） polymers are introduced into anodic aluminum oxide （AAO） nanochannels to form smart unipolar nanofluidic diodes （UNDs） for the first time.The ionic transport behavior of the present polypyrrole-engineered UNDs can be controlled through the redox reactions of PPy.Under an applied oxidation potential,conductive PPy exhibits several redox states carrying different charges,following the formation of polarons and bipolarons with different oxidation states.Combined with the asymmetric distribution of PPy in the AAO nanochannels,the UNDs investigated here exhibit redox-switchable ion rectification and ion-gating properties.The influence of the charge asymmetry of the UNDs on their ionic transport behavior is assessed by precisely controlling the length of oxidized PPy segments in the AAO nanochannels and by carrying out theoretical simulations based on the Poisson and Nernst-Planck （PNP） equations.

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is investigated.The DarcyBrinkman model is used to characterize the fluid flow dynamics in porous materials.The analytical solutions are obtained for the unidirectional and completely developed flow.Based on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is solved.The eigenvalue problem is then solved by the spectral method.Finally,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing parameters.The results show that increasing the Darcy number,the Lewis number,the Dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the flow.Besides,the flow is the most unstable when the channel is vertically oriented.

Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

Cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry applications.In this study,we investigate the three-dimensional flow of a water-based Ag-Mg O hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid properties.How the variable fluid properties affect the dynamics and heat transfer features is studied by Reynolds's linearized model for variable viscosity and Chiam's model for variable thermal conductivity.The single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids,incorporating the experimental data.This model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressibility condition.A self-similar model is developed by the Lie-group scaling transformations,and the subsequent self-similar equations are then solved numerically.The influence of variable fluid parameters on both swirling and non-swirling flow cases is analyzed.Additionally,the Nusselt number for the disk surface is calculated.It is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked sheet.With the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is illustrated.The resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity transformations.The transformed differential equations are solved analytically.Impacts of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted graphically.The skin friction and Nusselt number were also evaluated.In addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching one.Further,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O nanofluid.Furthermore,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

Functional thermal fluids and their applications in battery thermal management:A comprehensive review

With the increasing requirements for fast charging and discharging,higher requirements have been put forward for the thermal management of power batteries.Therefore,there is an urgent need to develop efficient heat transfer fluids.As a new type of heat transfer fluids,functional thermal fluids mainly includ-ing nanofluids(NFs)and phase change fluids(PCFs),have the advantages of high heat carrying density,high heat transfer rate,and broad operational temperature range.However,challenges that hinder their practical applications remain.In this paper,we firstly overview the classification,thermophysical prop-erties,drawbacks,and corresponding modifications of functional thermal fluids.For NFs,the high ther-mal conductivity and high convective heat transfer performance were mainly elaborated,while the stability and viscosity issues were also analyzed.And then for PCFs,the high heat carrying density was mainly elaborated,while the problems of supercooling,stability,and viscosity were also analyzed.On this basis,the composite fluids combined NFs and PCFs technology,has been summarized.Furthermore,the thermal properties of traditional fluids,NFs,PCFs,and composite fluids are compared,which proves that functional thermal fluids are a good choice to replace traditional fluids as coolants.Then,battery thermal management system(BTMS)based on functional thermal fluids is summarized in detail,and the thermal management effects and pump consumption are compared with that of water-based BTMS.Finally,the current technical challenges that parameters optimization of functional thermal fluids and structures optimization of BTMS systematically are presented.In the future,it is necessary to pay more attention to using machine learning to predict thermophysical properties of functional thermal fluids and their applications for BTMS under actual vehicle conditions.

Unsteady MHD Casson Nanofluid Flow Past an Exponentially Accelerated Vertical Plate:An Analytical Strategy

In this study,the characteristics of heat transfer on an unsteady magnetohydrodynamic(MHD)Casson nanofluid over an exponentially accelerated vertical porous plate with rotating effects were investigated.The flow was driven by the combined effects of the magnetic field,heat radiation,heat source/sink and chemical reaction.Copper oxide(CuO)and titanium oxide(TiO2)are acknowledged as nanoparticle materials.The nondimensional governing equations were subjected to the Laplace transformation technique to derive closed-form solutions.Graphical representations are provided to analyze how changes in physical parameters,such as the magnetic field,heat radiation,heat source/sink and chemical reaction,affect the velocity,temperature and concentration profiles.The computed values of skin friction,heat and mass transfer rates at the surface were tabulated for various sets of input parameters.It is perceived that there is a drop in temperature due to the rise in the heat source/sink and the Prandtl number.It should be noted that a boost in the thermal radiation parameter prompts an increase in temperature.An increase in the Prandtl number,heat source/sink parameter,time and a decrease in the thermal radiation parameter result in an increase in theNusselt number.The computed values of the skin friction,heat andmass transfer rates at the surface were tabulated for various values of the flow parameters.The present results were compared with those of previously published studies andwere found to be in excellent agreement.This research has practical applications in areas such as drug delivery,thermal medicine and cancer treatment.

Visual experimental study of nanofluids application to promote CO_(2) absorption in a bubble column

The addition of dispersed-phase nanoparticles in the liquid phase can enhance the gas-liquid transfer process as the suspended nanoparticles affect the transfer process inside the fluid through microdisturbance or micro-convection effects.In this article,a high-speed digital camera was used to visualize the bubble behavior of CO_(2) in pure water and nanofluids to examine the effects of CO_(2) gas flow rate,nanoparticle solid content and type on the bubble behavior in the fluids.The CO_(2) absorption performance in three water-based nanofluids were compared in a bubbler.And the mass transfer characteristics during CO_(2) bubble absorption and the reasons for the enhanced gas-liquid mass transfer effect of nanoparticles were analyzed.The results showed that the presence of nanoparticles affected the formation process of bubbles in the fluid,shortened the bubble detachment time,reduced the detachment diameter,effectively increased the gas-liquid contact area,and improved the bubbles detachment frequency.The system with MCM-41 corresponded to a higher overall mass transfer coefficient.Uncalined MCM-41 contained surfactant that enhanced foaming behavior in water.This prevented the transfer of CO_(2) to some extent,and the CO_(2) absorption by uncalined MCM-41/H_(2)O was 5.34%higher than that by pure water.Compared with SiO_(2) nanoparticles with the same particle size and the same composition,MCM-41 had a higher adsorption capacity and better hydrophilicity due to its larger specific surface area and rich porous structure,which was more favorable to accelerate the collision between nanoparticles and CO_(2) bubbles to cause micro-convection.Under the condition of 0.1%(mass)solid content,the enhancement of CO_(2) absorption process by MCM-41 nanoparticles was more significant and improved by 16.9%compared with pure water.

Numerical investigation on MHD Jeffery-Hamel nanofluid flow with different nanoparticles using fuzzy extension of generalized dual parametric homotopy algorithm

This study considers an MHD Jeffery-Hamel nanofluid flow with distinct nanoparticles such as copper,Al_(2)O_(3)and SiO_(2)between two rigid non-parallel plane walls with the fuzzy extension of the generalized dual parametric homotopy algorithm.The nanofluids have been formulated to enhance the thermophysical characteristics of fluids,including thermal diffusivity,conductivity,convective heat transfer coefficients and viscosity.Due to the presence of distinct nanofluids,a change in the value of volume fraction occurs that influences the velocity profiles of the flow.The short value of nanoparticles volume fraction is considered an uncertain parameter and represented in a triangular fuzzy number range among[0.0,0.1,0.2].A novel generalized dual parametric homotopy algorithm with fuzzy extension is used here to study the fuzzy velocities at various channel positions.Finally,the effectiveness of the proposed approach has been demonstrated through a comparison with the available results in the crisp case.

Radiative Blood-Based Hybrid Copper-Graphene Nanoliquid Flows along a Source-Heated Leaning Cylinder

Variant graphene,graphene oxides(GO),and graphene nanoplatelets(GNP)dispersed in blood-based copper(Cu)nanoliquids over a leaning permeable cylinder are the focus of this study.These forms of graphene are highly beneficial in the biological and medical fields for cancer therapy,anti-infection measures,and drug delivery.The non-Newtonian Sutterby(blood-based)hybrid nanoliquid flows are generalized within the context of the Tiwari-Das model to simulate the effects of radiation and heating sources.The governing partial differential equations are reformulated into a nonlinear set of ordinary differential equations using similar transformational expressions.These equations are then transformed into boundary value problems through a shooting technique,followed by the implementation of the bvp4c tool in MATLAB.The influences of various parameters on the model’s nondimensional velocity and temperature profiles,reduced skin friction,and reduced Nusselt number are presented for detailed discussions.The results indicated that Cu-GNP/blood and Cu-GO/blood hybrid nanofluids exhibit the lowest and highest velocity distributions,respectively,for increased nanoparticles volume fraction,curvature parameter,Sutterby fluid parameter,Hartmann number,and wall permeability parameter.Conversely,opposite trends are observed for the temperature distribution for all considered parameters,except the mixed convection parameter.Increases in the reduced skin friction magnitude and the reduced Nusselt number with higher values of graphene/GO/GNP nanoparticle volume fraction are also reported.Finally,GNP is identified as the superior heat conductor,with an average increase of approximately 5%and a peak of 7.8%in the reduced Nusselt number compared to graphene and GO nanoparticles in the Cu/blood nanofluids.