Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer...Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes,both restricted by the current collectors.Herein,a new tip-array current collector(designated as T-CC)was developed to replace the conventional planar current collectors,which intensifies both the charge transfer and ion transport significantly.The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy,which revealed the reduction of ion transport barrier,charge transport barrier and internal resistance.With the voltage increased from 1.0 to 1.5 and 2.0 V,the T-CC-based FCDI system(T-FCDI)exhibited average salt removal rates(ASRR)of 0.18,0.50,and 0.89μmol cm^(-2) min^(-1),respectively,which are 1.82,2.65,and 2.48 folds higher than that of the conventional serpentine current collectors,and 1.48,1.67,and 1.49 folds higher than that of the planar current collectors.Meanwhile,with the solid content in flow electrodes increased from 1 to 5 wt%,the ASRR for T-FCDI increased from 0.29 to 0.50μmol cm^(-2) min^(-1),which are 1.70 and 1.67 folds higher than that of the planar current collectors.Additionally,a salt removal efficiency of 99.89%was achieved with T-FCDI and the charge efficiency remained above 95%after 24 h of operation,thus showing its superior long-term stability.展开更多
Hybrid capacitive deionization(HCDI)shows promise for desalinating brackish and saline water by utilizing the pseudocapacitive properties of faradaic electrodes.Organic materials,with their low environmental impact an...Hybrid capacitive deionization(HCDI)shows promise for desalinating brackish and saline water by utilizing the pseudocapacitive properties of faradaic electrodes.Organic materials,with their low environmental impact and adaptable structures,are attractive for this application.However,their scarcity of active sites and tendency to dissolve in water-based solutions remain significant challenges.Herein,we synthesized a polynaphthalenequinoneimine(PCON)polymer with stable long-range ordered framework and rough three-dimensional floral surface morphology,along with high-density active sites provided by C=O and C=N functional groups,enabling efficient redox reactions and achieving a high Na^(+)capture capability.The synthesized PCON polymer showcases outstanding electroadsorption characteristics and notable structural robustness,attaining an impressive specific capacitance of 500.45 F g^(-1) at 1 A g^(-1) and maintaining 86.1%of its original capacitance following 5000 charge–discharge cycles.Benefiting from the superior pseudocapacitive properties of the PCON polymer,we have developed an HCDI system that not only exhibits exceptional salt removal capacity of 100.8 mg g^(-1) and a remarkable rapid average removal rate of 3.36 mg g^(-1) min-1 but also maintains 97%of its initial desalination capacity after 50 cycles,thereby distinguishing itself in the field of state-ofthe-art desalination technologies with its comprehensive performance that significantly surpasses reported organic capacitive deionization materials.Prospectively,the synthesis paradigm of the double active-sites PCON polymer may be extrapolated to other organic electrodes,heralding new avenues for the design of high-performance desalination systems.展开更多
Flow-electrode capacitive deionization(FCDI)is a newly developed desalination technology with a high electrode loading for superior salt removal efficiency,even with high feed salinity.However,the improvement in FCDI ...Flow-electrode capacitive deionization(FCDI)is a newly developed desalination technology with a high electrode loading for superior salt removal efficiency,even with high feed salinity.However,the improvement in FCDI performance could be restricted by obstacles such as poor charge transfer in the electrode slurry and agglomeration of the electrode particles.Therefore,various FCDIelectrode materials have been studied to overcome these bottlenecks through various mechanisms.Herein,a minireview is conducted to summarize the relevant information and provide a comprehensive view of the progress in FCDI electrode materials.Flow-electrode materials can be classified into three main groups:carbon materials,metalbased materials,and carbon-metal composites.Carbonbased capacitive materials with outstanding conductivities can facilitate charge transfer in FCDI,whereas metal-based materials and carbon-metal composites with ion-intercalative behaviors exhibit high ion adsorption abilities.Additionally,carbon materials with surface function groups can enhance electrode dispersion and reach a high electrode loading by electrostatic repulsion,further upgrading the conductive network of FCDI.Moreover,magnetic carbon-metal composites can be easily separated,and the salt removal performance can be improved with magnetic fields.Different electrode materials exhibit disparate features during FCDI development.Thus,combining these materials to obtain FCDI electrodes with multiple functions may be reasonable,which could be a promising direction for FCDI research.展开更多
Since conventional photocatalytic technology fails to achieve complete elimination of chlorophenol contaminants from aqueous environments,this study presents a synergistic photocatalysis-capacitive deionization(PC-CDI...Since conventional photocatalytic technology fails to achieve complete elimination of chlorophenol contaminants from aqueous environments,this study presents a synergistic photocatalysis-capacitive deionization(PC-CDI)system as an advanced solution for industrial chlorophenol wastewater remediation.The PC-CDI system,employing boron nitride/carbon nitride(BN/CN)heterojunction electrodes,demonstrates exceptional degradation performance toward chlorophenols.The high-surface-area porous BN/CN heterojunction facilitates electro-adsorption and charge carrier separation,thereby synergistically optimizing both photocatalytic(PC)and capacitive deionization(CDI)functionalities.Remarkably,the integrated system achieves a 2,4-DCP degradation efficiency of 97.15%and a 2,4,6-TCP degradation efficiency of 100%in 2 h.The CDI component enables spatial separation through the electro-adsorption of Cl^(-)ions at the anode,effectively mitigating their interference and suppressing chlorinated byproduct formation.Concurrently,the electro-adsorption of positively charged chlorophenol pollutants accelerates their diffusion to catalytic sites,promoting the reactive oxygen species(ROS)-driven degradation of chlorophenol pollutants.The PC-CDI system exhibits robust stability(>95%efficiency retention over five cycles)and broad applicability across various chlorophenol derivatives.By circumventing Cl^(-)-induced side reactions and inhibiting chlorine radical generation during photocatalysis,this strategy minimizes the environmental risks associated with chlorinated byproducts during chlorophenol wastewater treatment.These findings establish the PC-CDI system as a sustainable and eco-friendly technology for industrial wastewater treatment.展开更多
Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is cruci...Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.展开更多
The adsorption and desorption behavior of Cr(Ⅵ) in membrane capacitive deionization(MCDI) was investigated systematically in the presence of bovine serum albumin(BSA) and KCl with different concentrations, respective...The adsorption and desorption behavior of Cr(Ⅵ) in membrane capacitive deionization(MCDI) was investigated systematically in the presence of bovine serum albumin(BSA) and KCl with different concentrations, respectively. Results revealed that Cr(Ⅵ) absorption was enhanced and the adsorption amount for Cr(Ⅵ) increased from 155.7 to 190.8 mg/g when KCl concentration increased from 100 to 200 mg/L in the adsorption process, which was attributed to the stronger driving force. However, the adsorption amount sharply decreased to 90.2 mg/g when KCl concentration reached up to 1000 mg/L suggesting the negative effect for Cr(Ⅵ) removal that high KCl concentration had. As for the effect of BSA on ion adsorption, the amount for Cr(Ⅵ) significantly declined to 78.3 mg/g and p H was found to be an important factor contributing to this significant reduction. Then, the desorption performance was also conducted and it was obtained that the presence of KCl had negligible effect on Cr(Ⅵ) desorption, while promoted by the addition of BSA. The incomplete desorption was obtained and the residual chromium ions onto the electrode after desorption was detected via energy-dispersive X-ray spectroscopy(EDS). Based on above analysis, the enhanced removal mechanism for Cr(Ⅵ) in MCDI was found to be consisted of ion adsorption onto electrode surface, the redox reaction of Cr(Ⅵ) into Cr(III)and precipitation, which was demonstrated by X-ray photoelectron spectroscopy(XPS) and scanning electron microscope(SEM).展开更多
Flow-electrode capacitive deionization(FCDI)represents a promising approach for ion separation from aqueous solutions.However,the optimization of spacer,particularly for nitrate-contaminated groundwa-ter systems,has o...Flow-electrode capacitive deionization(FCDI)represents a promising approach for ion separation from aqueous solutions.However,the optimization of spacer,particularly for nitrate-contaminated groundwa-ter systems,has often been overlooked.This research comprehensively investigates the influence of using a conductive(carbon cloth,CC)spacer on nitrate removal performance within FCDI system,comparing it to a non-conductive(nylon net,NN)spacer.In both CC and NN FCDI systems,it is unsurprisingly that nitrate removal efficiency improved notably with the increasing current density and hydraulic retention time(HRT).Interestingly,the specific energy consumption(SEC)for nitrate removal did not show obvious fluctuations when the current density and HRT varied in both systems.Under the auspiciously optimized process parameters,CC-FCDI attained a 20%superior nitrate removal efficiency relative to NN-FCDI,ac-companied by a notably diminished SEC for CC-FCDI,registering at a mere 28%of NN-FCDI.This great improvement can be primarily attributed to the decrement in FCDI internal resistance after using con-ductive spacer,which further confirmed by electrochemical tests such as linear sweep voltammetry(LSV)and electrochemical impedance spectroscopy(EIS).Upon prolonged continuous nitrate removal at the optimized conditions,the CC-FCDI system achieved a consistent 90%nitrate removal efficiency with a low SEC of 2.7-7.8 kWh/kg NO_(3)-N,underscoring its steady performance.Overall,this study highlights the pivotal importance of careful spacer design and optimization in realizing energy-efficient groundwater treatment via FCDI.展开更多
Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;howe...Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;however, it is a process of intense energy. Membrane Capacitive Deionization (MCDI) has received considerable interest as a promising desalination technology, and MCDI research has increased significantly over the last 10 years. In addition, there are no guidelines for the design of Capacitive Deionization (CDI) implementation strategies for individual applications. This study, therefore;provides an alternative of CDI’s recent application developments, with emphasis placed on hybrid systems to address the technological needs of different relevant fields. The MCDI’s energy consumption is compared with the reverse osmosis literature data based on experimental data from laboratory-scale system. The study demonstrates that MCDI technology is a promising technology in the next few years with an extreme competition in water recovery, energy consumption and salt removal for reverse osmosis.展开更多
The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration an...The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration and pulverization,achieving precise size control,suppression of aggregation,and uniform dispersion of Ag nanoparticles remains challenging.Herein,the metal-organic frameworks(MOF)-assisted pyrolysis-galvanic replacement method was employed to construct ultrafine Ag particles uniformly anchored within a three-dimensional(3D)-ordered porous carbon skeleton composite(3D Ag@NC).By utilizing the potential difference between the elements,spontaneous replacement reactions occur,effectively preventing particle agglomeration usually caused by high-temperature reduction.The in situ constructed 3D porous carbon skeleton not only promotes electron transfer and electrolyte penetration but also mitigates the volume expansion of Ag particles during electrochemical cycling.Consequently,3D Ag@NC demonstrates outstanding dechlorination performance(105.29 mg g^(-1)),high charge efficiency(0.95),and exceptional cycling stability(84.12% after 100 cycles).This galvanic replacement strategy offers valuable insights into the fabrication of other small-sized,highly dispersed metal electrode materials.展开更多
As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC...As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC)were synthesized as CDI electrode material for removing Na^(+)and Cl^(−)in salty water.Results showed that the average diameter of HC was approximately 180 nm,and the infrared spectrum showed that its surface was successfully modified with sulfonic and amino groups,respectively.The sulfonic acid functionalized HC(HC-S)showed better electrochemical and desalting performance than the amino-functionalized HC(HC–N),with a maximum Faradic capacity of 287.4 F/g and an adsorptive capacity of 112.97 mg/g for NaCl.Additionally,92.63%capacity retention after 100 adsorption/desorption cycles demonstrates the excellent stability of HC-S.The main findings prove that HC-S is viable as an electrodematerial for desalination by high-performance CDI applications.展开更多
Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yi...Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.展开更多
Because of the low energy requirement and the environmentally safe byproducts, the capacitive deionization water desalination technology has attracted the attention of many researchers. The important requirements for ...Because of the low energy requirement and the environmentally safe byproducts, the capacitive deionization water desalination technology has attracted the attention of many researchers. The important requirements for electrode materials are good electrical conductivity, high surface area, good chemical stability and high specific capacitance. In this study, metallic nanoparticles that are encapsulated in a graphite shell(Cd doped Co/C NPs) are introduced as the new electrode material for the capacitive deionization process because they have higher specific capacitance than the pristine carbonaceous materials. Cd doped Co/C NPs perform better than graphene and the activated carbon. The introduced nanoparticles were synthesized using a simple sol gel technique. A typical sol gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol)was prepared based on the polycondensation property of the acetates. The physiochemical characterizations that were used confirmed that the drying, grinding and calcination in an Ar atmosphere of the prepared gel produced the Cd doped Co nanoparticles, which were encapsulated in a thin graphite layer. Overall, the present study suggests a new method to effectively use the encapsulated bimetallic nanostructures in the capacitive deionization technology.展开更多
Chromium(Cr)is a common heavy metal that has severe impacts on the ecosystem and human health.Capacitive deionization(CDI)is an environment-friendly and energy-efficient electrochemical purification technology to remo...Chromium(Cr)is a common heavy metal that has severe impacts on the ecosystem and human health.Capacitive deionization(CDI)is an environment-friendly and energy-efficient electrochemical purification technology to remove Cr from polluted water.The performance of CDI systems relies primarily on the properties of electrodes.Carbon-nanotubes(CNTs)membranes are promising candidates in creating advanced CDI electrodes and processes.However,the low electrosorption capacity and high hydrophobicity of CNTs greatly impede their applications in water systems.In this study,we employ atomic layer deposition(ALD)to deposit TiO_(2) nanoparticulates on CNTs membranes for preparing electrodes with hydrophilicity.The TiO_(2)-deposited CNTs membranes display preferable electrosorption performance and reusability in CDI processes after only 20 ALD cycles deposition.The total Cr and Cr(VI)removal efficiencies are significantly improved to 92.1%and 93.3%,respectively.This work demonstrates that ALD is a highly controllable and simple method to produce advanced CDI electrodes,and broadens the application of metal oxide/carbon composites in the electrochemical processes.展开更多
Capacitance for electrostatic adsorption forms primarily within a Debye length of the electrode surface. Capacitive carbon electrodes were derivatized with ionic groups by means of adsorbing a surfactant in order to t...Capacitance for electrostatic adsorption forms primarily within a Debye length of the electrode surface. Capacitive carbon electrodes were derivatized with ionic groups by means of adsorbing a surfactant in order to test the theory that attached ionic groups would exclude co-ions and increase coulombic efficiency without the need for an added charge barrier membrane. It has been discovered that capacitive electrodes surface derivatized with ionic groups become polarized and intrinsically more coulombically efficient.展开更多
Nitrogenization is an effective method for improving the capacitive deionization(CDI)performance of porous carbon materials.In particular,polymer organic frameworks with heteroatom doping,containing an ordered pore st...Nitrogenization is an effective method for improving the capacitive deionization(CDI)performance of porous carbon materials.In particular,polymer organic frameworks with heteroatom doping,containing an ordered pore structure and excellent electrochemical stability,are ideal precursors for carbon materials for high-performance CDI.In this study,a nitrogen-enriched micro-mesoporous carbon(NMC)electrode was fabricated by carbonizing a Schiff base network-1 at 500,600,and 700℃.Scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,N_(2) adsorption-desorption,the contact angle of water,cyclic voltammetry,and electrochemical impedance spectroscopy were used to characterize the morphological structure,wettability,Brunauer–Emmett–Teller surface areas,and electrochemical performance of the NMCs.The results showed that the NMC carbonized at 600℃ achieved the best specific capacitance(152.33 F/g),as well as a high electrosorption capacity(25.53 mg/g)because of its chemical composition(15.57%N)and surface area(312 m^(2)/g).These findings prove that NMC is viable as an electrode material for desalination by high-performance CDI applications.展开更多
Carbon materials have the advantages of good electrical conductivity and excellent chemical stability, so many carbon materials have been introduced as electrodes for the capacitive deionization (CDI) process. Due to ...Carbon materials have the advantages of good electrical conductivity and excellent chemical stability, so many carbon materials have been introduced as electrodes for the capacitive deionization (CDI) process. Due to the low surface area compared to the other nanocarbonaceous materials, CNFs performance as electrode in the CDI units is comparatively low. This problem has been overcome by preparing high surface area carbon nanofibers and by creating numerous long pores on the nanofibers surface. The modified CNFs have been synthesized using low cost, high yield and facile method;electrospinning technique. Stabilization and graphitization of electrospun nanofiber mats composed of polyacrylonitrile (PAN) and poly (methyl methacrylate) (PMMA) leads form longitudinal pores CNFs. The utilized characterizations indicated that the CNFs obtained from electrospun solution having 50% PMMA have surface area of 181 m2/g which are more than the conventional CNFs. Accordingly, these nanofibers revealed salt removal efficiency of ~90% and specific capacitance of 237 F/g.展开更多
Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconduct...Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconductivity,commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage.Despite this,its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity.Herein,a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers.The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites,and continuous graphitized carbon core ensuring rapid electrons transport.The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time.When directly evaluated as a current collector-free capacitive deionization electrode,the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers,and remarkable cyclic stability up to 20 h with negligible degeneration.Particularly,the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm^(−2) among carbon microfibers.Moreover,monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance(0.051 mg cm^(−2)).This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.展开更多
The“battery type”inorganic electrode has been demonstrated the highly efficient sodium ion intercalation capacity for capacitive deionization.In this work,the CoMn_(2)O_(4)(CMO)microspheres with porous core-shell st...The“battery type”inorganic electrode has been demonstrated the highly efficient sodium ion intercalation capacity for capacitive deionization.In this work,the CoMn_(2)O_(4)(CMO)microspheres with porous core-shell structure are prepared via co-precipitation and followed by annealing.The effects of annealing temperatures on the morphology,pore structure,valence state,and electrochemical behavior of CMO are explored.As electrode for capacitive deionization,the salt removal capacity and current efficiency of optimized AC||CMO device reaches up to 60.7 mg g^(−1) and 97.6%,respectively,and the capacity retention rate is 74.1%after 50 cycles.Remarkably,both the in-situ X-ray diffraction and ex-situ X-ray diffraction analysis features that the intercalation/de-intercalation of sodium ions are governed by(103)and(221)crystal planes of CMO.Accordingly,the density functional theory calculations realize that the adsorption energies of Na+onto(103)and(221)crystal planes are higher than that of any other crystal planes,manifesting the priorities in adsorption of sodium atoms.Furthermore,the X-ray photoelectron spectra of pristine and post-CMO electrode highlights that the reversible conversion of Mn^(3+)/Mn^(4+)couple is resulted from the intercalation/de-intercalation of Na^(+),while this is irreversible for Co^(3+)/Co^(2+)couple.Beyond that,the CMO electrode has been proven the selectivity removal of Na^(+) over K^(+)and Mg^(2+)in a multi-cation stream.展开更多
MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F spe...MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F species),as a typical structural MXene,always shows better chemical-physical characteristics than multilayer-Ti_(3)C_(2)T_(x).Thus,we prepared monolayer-Ti_(3)C_(2)T_(x) electrode by HF etching method and absolute ethyl alcohol intercalationdelamination treatment for capacitive deionization(CDI).The prepared monolay-Ti_(3)C_(2)T_(x) shows a higher specific surface area(235.6 m^(2)/g)and a thinner thickness(0.8 nm).Moreover,a series of systematic investigation demonstrated that monolayer-Ti_(3)C_(2)T_(x) has obvious promotional phenomenon on electrochemical properties(e.g.,mass specific capacitance increased from 52.1 F/g to 144.7 F/g).The NaCl adsorption capacity of monolayer-Ti_(3)C_(2)T_(x),is 30.7 mg/g in 1000 mg/L NaCl solution at 1.2 V.We concluded that the electro-sorption mechanism could be expressed as double electric layer and monolayer coverage by a good fitting of Langmuir isotherms and the pseudo-second-order kinetics equation.This work would provide a new strategy for the application of monolayer-Ti_(3)C_(2)T_(x) material in wastewater treatment in the future.展开更多
基金supported by the Shenzhen Science and Technology Program(JCYJ20230808105111022,JCYJ20220818095806013)Natural Science Foundation of Guangdong(2023A1515012267)+1 种基金the National Natural Science Foundation of China(22178223)the Royal Society/NSFC cost share program(IEC\NSFC\223372).
文摘Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes,both restricted by the current collectors.Herein,a new tip-array current collector(designated as T-CC)was developed to replace the conventional planar current collectors,which intensifies both the charge transfer and ion transport significantly.The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy,which revealed the reduction of ion transport barrier,charge transport barrier and internal resistance.With the voltage increased from 1.0 to 1.5 and 2.0 V,the T-CC-based FCDI system(T-FCDI)exhibited average salt removal rates(ASRR)of 0.18,0.50,and 0.89μmol cm^(-2) min^(-1),respectively,which are 1.82,2.65,and 2.48 folds higher than that of the conventional serpentine current collectors,and 1.48,1.67,and 1.49 folds higher than that of the planar current collectors.Meanwhile,with the solid content in flow electrodes increased from 1 to 5 wt%,the ASRR for T-FCDI increased from 0.29 to 0.50μmol cm^(-2) min^(-1),which are 1.70 and 1.67 folds higher than that of the planar current collectors.Additionally,a salt removal efficiency of 99.89%was achieved with T-FCDI and the charge efficiency remained above 95%after 24 h of operation,thus showing its superior long-term stability.
基金supported by the National Key R&D Program of China(Grant Nos.2023YFC3009900)National Natural Science Foundation of China(Grant Nos.61904116)+1 种基金Natural Science Foundation of Jiangsu Province(Grant Nos.BK20211029)the young scientific talent lifting project of Jiangsu Association for Science and Technology(Grant Nos.JSTJ-2023-018).
文摘Hybrid capacitive deionization(HCDI)shows promise for desalinating brackish and saline water by utilizing the pseudocapacitive properties of faradaic electrodes.Organic materials,with their low environmental impact and adaptable structures,are attractive for this application.However,their scarcity of active sites and tendency to dissolve in water-based solutions remain significant challenges.Herein,we synthesized a polynaphthalenequinoneimine(PCON)polymer with stable long-range ordered framework and rough three-dimensional floral surface morphology,along with high-density active sites provided by C=O and C=N functional groups,enabling efficient redox reactions and achieving a high Na^(+)capture capability.The synthesized PCON polymer showcases outstanding electroadsorption characteristics and notable structural robustness,attaining an impressive specific capacitance of 500.45 F g^(-1) at 1 A g^(-1) and maintaining 86.1%of its original capacitance following 5000 charge–discharge cycles.Benefiting from the superior pseudocapacitive properties of the PCON polymer,we have developed an HCDI system that not only exhibits exceptional salt removal capacity of 100.8 mg g^(-1) and a remarkable rapid average removal rate of 3.36 mg g^(-1) min-1 but also maintains 97%of its initial desalination capacity after 50 cycles,thereby distinguishing itself in the field of state-ofthe-art desalination technologies with its comprehensive performance that significantly surpasses reported organic capacitive deionization materials.Prospectively,the synthesis paradigm of the double active-sites PCON polymer may be extrapolated to other organic electrodes,heralding new avenues for the design of high-performance desalination systems.
基金financially supported by the National Natural Science Foundation of China(No.52374423)the Science and Technology Innovation Program of Hunan Province(No.2021RC4010)the Science and Technology Major Project of Changsha(No.kh2401030)
文摘Flow-electrode capacitive deionization(FCDI)is a newly developed desalination technology with a high electrode loading for superior salt removal efficiency,even with high feed salinity.However,the improvement in FCDI performance could be restricted by obstacles such as poor charge transfer in the electrode slurry and agglomeration of the electrode particles.Therefore,various FCDIelectrode materials have been studied to overcome these bottlenecks through various mechanisms.Herein,a minireview is conducted to summarize the relevant information and provide a comprehensive view of the progress in FCDI electrode materials.Flow-electrode materials can be classified into three main groups:carbon materials,metalbased materials,and carbon-metal composites.Carbonbased capacitive materials with outstanding conductivities can facilitate charge transfer in FCDI,whereas metal-based materials and carbon-metal composites with ion-intercalative behaviors exhibit high ion adsorption abilities.Additionally,carbon materials with surface function groups can enhance electrode dispersion and reach a high electrode loading by electrostatic repulsion,further upgrading the conductive network of FCDI.Moreover,magnetic carbon-metal composites can be easily separated,and the salt removal performance can be improved with magnetic fields.Different electrode materials exhibit disparate features during FCDI development.Thus,combining these materials to obtain FCDI electrodes with multiple functions may be reasonable,which could be a promising direction for FCDI research.
文摘Since conventional photocatalytic technology fails to achieve complete elimination of chlorophenol contaminants from aqueous environments,this study presents a synergistic photocatalysis-capacitive deionization(PC-CDI)system as an advanced solution for industrial chlorophenol wastewater remediation.The PC-CDI system,employing boron nitride/carbon nitride(BN/CN)heterojunction electrodes,demonstrates exceptional degradation performance toward chlorophenols.The high-surface-area porous BN/CN heterojunction facilitates electro-adsorption and charge carrier separation,thereby synergistically optimizing both photocatalytic(PC)and capacitive deionization(CDI)functionalities.Remarkably,the integrated system achieves a 2,4-DCP degradation efficiency of 97.15%and a 2,4,6-TCP degradation efficiency of 100%in 2 h.The CDI component enables spatial separation through the electro-adsorption of Cl^(-)ions at the anode,effectively mitigating their interference and suppressing chlorinated byproduct formation.Concurrently,the electro-adsorption of positively charged chlorophenol pollutants accelerates their diffusion to catalytic sites,promoting the reactive oxygen species(ROS)-driven degradation of chlorophenol pollutants.The PC-CDI system exhibits robust stability(>95%efficiency retention over five cycles)and broad applicability across various chlorophenol derivatives.By circumventing Cl^(-)-induced side reactions and inhibiting chlorine radical generation during photocatalysis,this strategy minimizes the environmental risks associated with chlorinated byproducts during chlorophenol wastewater treatment.These findings establish the PC-CDI system as a sustainable and eco-friendly technology for industrial wastewater treatment.
文摘Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.
基金financially supported by the National Natural Science Fund of China (No. 51508153)the Natural Science Fund of Jiangsu (No. BK20150813)+1 种基金the Fundamental Research Funds for the Central UniversitiesA Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The adsorption and desorption behavior of Cr(Ⅵ) in membrane capacitive deionization(MCDI) was investigated systematically in the presence of bovine serum albumin(BSA) and KCl with different concentrations, respectively. Results revealed that Cr(Ⅵ) absorption was enhanced and the adsorption amount for Cr(Ⅵ) increased from 155.7 to 190.8 mg/g when KCl concentration increased from 100 to 200 mg/L in the adsorption process, which was attributed to the stronger driving force. However, the adsorption amount sharply decreased to 90.2 mg/g when KCl concentration reached up to 1000 mg/L suggesting the negative effect for Cr(Ⅵ) removal that high KCl concentration had. As for the effect of BSA on ion adsorption, the amount for Cr(Ⅵ) significantly declined to 78.3 mg/g and p H was found to be an important factor contributing to this significant reduction. Then, the desorption performance was also conducted and it was obtained that the presence of KCl had negligible effect on Cr(Ⅵ) desorption, while promoted by the addition of BSA. The incomplete desorption was obtained and the residual chromium ions onto the electrode after desorption was detected via energy-dispersive X-ray spectroscopy(EDS). Based on above analysis, the enhanced removal mechanism for Cr(Ⅵ) in MCDI was found to be consisted of ion adsorption onto electrode surface, the redox reaction of Cr(Ⅵ) into Cr(III)and precipitation, which was demonstrated by X-ray photoelectron spectroscopy(XPS) and scanning electron microscope(SEM).
基金supported by Shanxi Province Basic Research Program(Free Exploration Category)(No.202203021221041)National Natural Science Foundation of China(No.52300016)+1 种基金China Postdoctoral Science Foundation(No.2023M733379)Students Innovation and Entrepreneurship Foundation of USTC(No.CY2022G12).
文摘Flow-electrode capacitive deionization(FCDI)represents a promising approach for ion separation from aqueous solutions.However,the optimization of spacer,particularly for nitrate-contaminated groundwa-ter systems,has often been overlooked.This research comprehensively investigates the influence of using a conductive(carbon cloth,CC)spacer on nitrate removal performance within FCDI system,comparing it to a non-conductive(nylon net,NN)spacer.In both CC and NN FCDI systems,it is unsurprisingly that nitrate removal efficiency improved notably with the increasing current density and hydraulic retention time(HRT).Interestingly,the specific energy consumption(SEC)for nitrate removal did not show obvious fluctuations when the current density and HRT varied in both systems.Under the auspiciously optimized process parameters,CC-FCDI attained a 20%superior nitrate removal efficiency relative to NN-FCDI,ac-companied by a notably diminished SEC for CC-FCDI,registering at a mere 28%of NN-FCDI.This great improvement can be primarily attributed to the decrement in FCDI internal resistance after using con-ductive spacer,which further confirmed by electrochemical tests such as linear sweep voltammetry(LSV)and electrochemical impedance spectroscopy(EIS).Upon prolonged continuous nitrate removal at the optimized conditions,the CC-FCDI system achieved a consistent 90%nitrate removal efficiency with a low SEC of 2.7-7.8 kWh/kg NO_(3)-N,underscoring its steady performance.Overall,this study highlights the pivotal importance of careful spacer design and optimization in realizing energy-efficient groundwater treatment via FCDI.
文摘Water and energy shortages came due to rapid population growth, living standards and rapid development in the agriculture and industrial sectors. Desalination tends to be one of the most promising water solutions;however, it is a process of intense energy. Membrane Capacitive Deionization (MCDI) has received considerable interest as a promising desalination technology, and MCDI research has increased significantly over the last 10 years. In addition, there are no guidelines for the design of Capacitive Deionization (CDI) implementation strategies for individual applications. This study, therefore;provides an alternative of CDI’s recent application developments, with emphasis placed on hybrid systems to address the technological needs of different relevant fields. The MCDI’s energy consumption is compared with the reverse osmosis literature data based on experimental data from laboratory-scale system. The study demonstrates that MCDI technology is a promising technology in the next few years with an extreme competition in water recovery, energy consumption and salt removal for reverse osmosis.
基金financially supported by the Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)the National Natural Science Foundation of China(52374423)+1 种基金the Major Science and Technology Programs of Yunnan Province(202302AB080016)the Hunan Provincial Natural Science Youth Fund(2024JJ6726)。
文摘The capacitive deionization(CDI)performance of silver(Ag)electrodes is limited by electrochemical failure induced by volumetric expansion.While carbon encapsulation and Ag size control mitigate stress concentration and pulverization,achieving precise size control,suppression of aggregation,and uniform dispersion of Ag nanoparticles remains challenging.Herein,the metal-organic frameworks(MOF)-assisted pyrolysis-galvanic replacement method was employed to construct ultrafine Ag particles uniformly anchored within a three-dimensional(3D)-ordered porous carbon skeleton composite(3D Ag@NC).By utilizing the potential difference between the elements,spontaneous replacement reactions occur,effectively preventing particle agglomeration usually caused by high-temperature reduction.The in situ constructed 3D porous carbon skeleton not only promotes electron transfer and electrolyte penetration but also mitigates the volume expansion of Ag particles during electrochemical cycling.Consequently,3D Ag@NC demonstrates outstanding dechlorination performance(105.29 mg g^(-1)),high charge efficiency(0.95),and exceptional cycling stability(84.12% after 100 cycles).This galvanic replacement strategy offers valuable insights into the fabrication of other small-sized,highly dispersed metal electrode materials.
基金supported by the National Science Foundation of China(No.21606191)the Natural Science Foundation of Shandong Province(No.ZR2020ME024).
文摘As a new electrochemical technology,capacitive deionization(CDI)has been increasingly applied in environmental water treatment and seawater desalination.In this study,functional groups modified porous hollow carbon(HC)were synthesized as CDI electrode material for removing Na^(+)and Cl^(−)in salty water.Results showed that the average diameter of HC was approximately 180 nm,and the infrared spectrum showed that its surface was successfully modified with sulfonic and amino groups,respectively.The sulfonic acid functionalized HC(HC-S)showed better electrochemical and desalting performance than the amino-functionalized HC(HC–N),with a maximum Faradic capacity of 287.4 F/g and an adsorptive capacity of 112.97 mg/g for NaCl.Additionally,92.63%capacity retention after 100 adsorption/desorption cycles demonstrates the excellent stability of HC-S.The main findings prove that HC-S is viable as an electrodematerial for desalination by high-performance CDI applications.
基金financially supported by research grants from the Natural Science Foundation of China(52173235,22265010,12204071,62074022)National Key Research and Development Program of China(2022YFB3803300)+2 种基金Youth Talent Support Program of Chongqing(CQYC2021059206)Hainan Province Science and Technology Special Fund(ZDYF2024SHFZ038)Science and Technology Innovation and Improving Project of Army Medical University(No.2021XJS24)。
文摘Solar-driven interface evaporation with high solar-to-steam conversion efficiency has shown great potential in seawater desalination.However,due to the influence of latent heat and condensation efficiency,the water yield from solar-driven interface evaporation remains insufficient,posing a significant challenge that requires resolution.In this work,we designed a dual-mode high-flux seawater desalination device that combines solar-driven interface evaporation and capacitive desalination.By utilizing coupled desalination materials exhibiting both photothermal conversion and capacitance activity,the device demonstrated photothermal evaporation rates of 1.41 and 0.97 kg m^(-2)h^(-1)for condensate water yield under one-sun irradiation.Additionally,the device exhibited a salt adsorption capacity of up to48 mg g^(-1)and a salt adsorption rate of 2.1 mg g^(-1)min-1.In addition,the salt adsorption capacity increased by approximately 32%under one-sun irradiation.Furthermore,photo-enhanced capacitive desalination performance was explored through numerical simulations and theoretical calculations.Theoretical calculations and characterizations confirmed that the defect energy levels formed by the introduction of sulfur vacancies can effectively widen the light absorption range,improve photothermal conversion performance,and stimulate more photoelectrons to participate in capacitive desalination.Concurrently,the electron distribution state of molybdenum disulfide with sulfur vacancies and surface defect sites contributes to ion/electron transport at the solid-liquid interface.This work provides a novel pathway for integrating solar vapor generation with other low-energy desalination technologies.
基金financially supported by the National Plan for Science & Technology (NPST), King Saud University Project No. 11-NAN1460-02
文摘Because of the low energy requirement and the environmentally safe byproducts, the capacitive deionization water desalination technology has attracted the attention of many researchers. The important requirements for electrode materials are good electrical conductivity, high surface area, good chemical stability and high specific capacitance. In this study, metallic nanoparticles that are encapsulated in a graphite shell(Cd doped Co/C NPs) are introduced as the new electrode material for the capacitive deionization process because they have higher specific capacitance than the pristine carbonaceous materials. Cd doped Co/C NPs perform better than graphene and the activated carbon. The introduced nanoparticles were synthesized using a simple sol gel technique. A typical sol gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol)was prepared based on the polycondensation property of the acetates. The physiochemical characterizations that were used confirmed that the drying, grinding and calcination in an Ar atmosphere of the prepared gel produced the Cd doped Co nanoparticles, which were encapsulated in a thin graphite layer. Overall, the present study suggests a new method to effectively use the encapsulated bimetallic nanostructures in the capacitive deionization technology.
基金Financial supports from the Jiangsu Natural Science Foundation(BK20190677)National Natural Science Foundation of China(21908096)+2 种基金Scientific Research Foundation of Chuzhou University(2020qd06)support from the Program of Excellent Innovation Teams of Jiangsu Higher Education Institutionsthe Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Chromium(Cr)is a common heavy metal that has severe impacts on the ecosystem and human health.Capacitive deionization(CDI)is an environment-friendly and energy-efficient electrochemical purification technology to remove Cr from polluted water.The performance of CDI systems relies primarily on the properties of electrodes.Carbon-nanotubes(CNTs)membranes are promising candidates in creating advanced CDI electrodes and processes.However,the low electrosorption capacity and high hydrophobicity of CNTs greatly impede their applications in water systems.In this study,we employ atomic layer deposition(ALD)to deposit TiO_(2) nanoparticulates on CNTs membranes for preparing electrodes with hydrophilicity.The TiO_(2)-deposited CNTs membranes display preferable electrosorption performance and reusability in CDI processes after only 20 ALD cycles deposition.The total Cr and Cr(VI)removal efficiencies are significantly improved to 92.1%and 93.3%,respectively.This work demonstrates that ALD is a highly controllable and simple method to produce advanced CDI electrodes,and broadens the application of metal oxide/carbon composites in the electrochemical processes.
文摘Capacitance for electrostatic adsorption forms primarily within a Debye length of the electrode surface. Capacitive carbon electrodes were derivatized with ionic groups by means of adsorbing a surfactant in order to test the theory that attached ionic groups would exclude co-ions and increase coulombic efficiency without the need for an added charge barrier membrane. It has been discovered that capacitive electrodes surface derivatized with ionic groups become polarized and intrinsically more coulombically efficient.
基金supported by the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the National Natural Science Foundation of China(No.21577027)the 2017 Central Special Fund for Soil,Preliminary Study on Harmless Treatment and Comprehensive Utilization of Tailings in Dabao Mountain(No.18HK0108)。
文摘Nitrogenization is an effective method for improving the capacitive deionization(CDI)performance of porous carbon materials.In particular,polymer organic frameworks with heteroatom doping,containing an ordered pore structure and excellent electrochemical stability,are ideal precursors for carbon materials for high-performance CDI.In this study,a nitrogen-enriched micro-mesoporous carbon(NMC)electrode was fabricated by carbonizing a Schiff base network-1 at 500,600,and 700℃.Scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,N_(2) adsorption-desorption,the contact angle of water,cyclic voltammetry,and electrochemical impedance spectroscopy were used to characterize the morphological structure,wettability,Brunauer–Emmett–Teller surface areas,and electrochemical performance of the NMCs.The results showed that the NMC carbonized at 600℃ achieved the best specific capacitance(152.33 F/g),as well as a high electrosorption capacity(25.53 mg/g)because of its chemical composition(15.57%N)and surface area(312 m^(2)/g).These findings prove that NMC is viable as an electrode material for desalination by high-performance CDI applications.
文摘Carbon materials have the advantages of good electrical conductivity and excellent chemical stability, so many carbon materials have been introduced as electrodes for the capacitive deionization (CDI) process. Due to the low surface area compared to the other nanocarbonaceous materials, CNFs performance as electrode in the CDI units is comparatively low. This problem has been overcome by preparing high surface area carbon nanofibers and by creating numerous long pores on the nanofibers surface. The modified CNFs have been synthesized using low cost, high yield and facile method;electrospinning technique. Stabilization and graphitization of electrospun nanofiber mats composed of polyacrylonitrile (PAN) and poly (methyl methacrylate) (PMMA) leads form longitudinal pores CNFs. The utilized characterizations indicated that the CNFs obtained from electrospun solution having 50% PMMA have surface area of 181 m2/g which are more than the conventional CNFs. Accordingly, these nanofibers revealed salt removal efficiency of ~90% and specific capacitance of 237 F/g.
基金We gratefully acknowledge financial supports from the Natural Science Founda-tion of Shandong Province (No.ZR2020QE066)Taishan Scholar Project (No.ts201511080)+1 种基金the fellowship of China Postdoctoral Science Foundation (No.2020M672081)Opening Project of State Key Laboratory of Advanced Tech-nology for Float Glass (No.2020KF08).
文摘Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconductivity,commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage.Despite this,its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity.Herein,a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers.The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites,and continuous graphitized carbon core ensuring rapid electrons transport.The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time.When directly evaluated as a current collector-free capacitive deionization electrode,the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers,and remarkable cyclic stability up to 20 h with negligible degeneration.Particularly,the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm^(−2) among carbon microfibers.Moreover,monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance(0.051 mg cm^(−2)).This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.
基金This work was supported by the National Natural Science Foundation of China (No.21862016)Project of Ningxia key R&D plan (No.2017BY064).
文摘The“battery type”inorganic electrode has been demonstrated the highly efficient sodium ion intercalation capacity for capacitive deionization.In this work,the CoMn_(2)O_(4)(CMO)microspheres with porous core-shell structure are prepared via co-precipitation and followed by annealing.The effects of annealing temperatures on the morphology,pore structure,valence state,and electrochemical behavior of CMO are explored.As electrode for capacitive deionization,the salt removal capacity and current efficiency of optimized AC||CMO device reaches up to 60.7 mg g^(−1) and 97.6%,respectively,and the capacity retention rate is 74.1%after 50 cycles.Remarkably,both the in-situ X-ray diffraction and ex-situ X-ray diffraction analysis features that the intercalation/de-intercalation of sodium ions are governed by(103)and(221)crystal planes of CMO.Accordingly,the density functional theory calculations realize that the adsorption energies of Na+onto(103)and(221)crystal planes are higher than that of any other crystal planes,manifesting the priorities in adsorption of sodium atoms.Furthermore,the X-ray photoelectron spectra of pristine and post-CMO electrode highlights that the reversible conversion of Mn^(3+)/Mn^(4+)couple is resulted from the intercalation/de-intercalation of Na^(+),while this is irreversible for Co^(3+)/Co^(2+)couple.Beyond that,the CMO electrode has been proven the selectivity removal of Na^(+) over K^(+)and Mg^(2+)in a multi-cation stream.
基金Project(2018YFC1900300)supported by the National Key R&D Program of ChinaProject(51825403)supported by the National Science Fund for Distinguished Young Scholars,ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,China。
文摘MXene materials have got great attention from researchers of environmental treatment for the great electrochemical performance.Monolayer-Ti_(3)C_(2)T_(x)(T_(x) is the surface terminal groups such as-O,-OH and/or-F species),as a typical structural MXene,always shows better chemical-physical characteristics than multilayer-Ti_(3)C_(2)T_(x).Thus,we prepared monolayer-Ti_(3)C_(2)T_(x) electrode by HF etching method and absolute ethyl alcohol intercalationdelamination treatment for capacitive deionization(CDI).The prepared monolay-Ti_(3)C_(2)T_(x) shows a higher specific surface area(235.6 m^(2)/g)and a thinner thickness(0.8 nm).Moreover,a series of systematic investigation demonstrated that monolayer-Ti_(3)C_(2)T_(x) has obvious promotional phenomenon on electrochemical properties(e.g.,mass specific capacitance increased from 52.1 F/g to 144.7 F/g).The NaCl adsorption capacity of monolayer-Ti_(3)C_(2)T_(x),is 30.7 mg/g in 1000 mg/L NaCl solution at 1.2 V.We concluded that the electro-sorption mechanism could be expressed as double electric layer and monolayer coverage by a good fitting of Langmuir isotherms and the pseudo-second-order kinetics equation.This work would provide a new strategy for the application of monolayer-Ti_(3)C_(2)T_(x) material in wastewater treatment in the future.
