The remediation of wastewater requires treatment technologies which are robust, efficient,simple to operate and affordable such as adsorption. Lately, three-dimensional(3D)graphene based materials have attracted signi...The remediation of wastewater requires treatment technologies which are robust, efficient,simple to operate and affordable such as adsorption. Lately, three-dimensional(3D)graphene based materials have attracted significant attention as effective adsorbents for wastewater treatment. The intrinsic properties of 3D graphene structure such as large surface area and interconnected porous structure can facilitate the transport of pollutants into the 3D network and provide abundant active sites for trapping the pollutants. For the synthesis of 3D graphene structure, ice-templating is commonly practiced due to its facile steps, cost effectiveness and high scalability potential. This review covers the icetemplating fabrication technique for 3D graphene based materials and their application as adsorbents in eliminating dyes and heavy metals from aqueous media. The assembly mechanisms of the ice-templating fsynthesis are comprehensively discussed. Further discussion on the fundamental principles, critical process parameters and characteristics of ice-templated 3D graphene structures is also included. A thorough review on the mechanisms for batch adsorption of dyes and heavy metals is presented based on the structures and properties of the 3D graphene materials. The review further evaluates the dynamic adsorption in packed columns and the regeneration of 3D graphene based materials.展开更多
A bulk Poly(vinyl alcohol)/ZIF-8(PVA/ZIF-8)porous composite with aligned porous structure was prepared by ice-templating method.The microstructure of PVA/ZIF-8 porous composites was characterized by scanning electron ...A bulk Poly(vinyl alcohol)/ZIF-8(PVA/ZIF-8)porous composite with aligned porous structure was prepared by ice-templating method.The microstructure of PVA/ZIF-8 porous composites was characterized by scanning electron microscopy(SEM).The results showed that the composites had regular pore structure and ZIF-8 nanoparticles were evenly distributed on the skeleton of PVA.X-ray diffraction(XRD)test results showed that the crystalline structure of ZIF-8 was well preserved in the composites.The specific surface area of the composite was characterized by nitrogen adsorption/desorption test.The specific surface area of the composite was up to 1160 m^2 g^1.PVA/ZIF-8 porous composites could also support a certain weight with almost no volume shrinkage.The carbon dioxide adsorption quantity of the composite was up to 11.3 cm^3 g^1,proving that PVA/ZIF-8 porous composite has a good application prospect in the field of carbon dioxide adsorption.展开更多
A poly vinyl alcohol（PVA） scaffold with aligned porous is strengthened by in-situ combining with TiO2. The increased freezing rate can be used to further increase the strength of aligned porous materials. The streng...A poly vinyl alcohol（PVA） scaffold with aligned porous is strengthened by in-situ combining with TiO2. The increased freezing rate can be used to further increase the strength of aligned porous materials. The strengthened porous PVA exhibits aligned interconnected porous structures and shows a significant enhancement in tensile testing and compression strength testing.展开更多
Ice-templating technique offers a viable means for constructing ordered macro-porous architectures in materials;nevertheless,it is generally limited by a low efficiency for fabrication,large difficulty for manipulatio...Ice-templating technique offers a viable means for constructing ordered macro-porous architectures in materials;nevertheless,it is generally limited by a low efficiency for fabrication,large difficulty for manipulation,along with the small dimension,and poor structural uniformity of icetemplated materials.Here,a new approach was exploited for continuous ice-templating of uniformly ordered macro-porous materials based on the establishment of a large,stable temperature gradient with specific bi-directional designs at the freezing front by descending the front toward the cooling medium to accommodate its upward growth.The freezing rate was markedly increased with the dimension of frozen body notably enlarged as compared with the case for conventional static ice-templating technique.The macro-porous architecture of materials,taking zirconia ceramics as an example,was made much finer and more uniform over the entire sample,and exhibited better ordering of alignment and enhanced inter-connectivity between lamellae.This led to an improvement in the compressive strength and its stability along the height direction for ice-templated materials than those made by the static ice-templating technique at a similar porosity.This study may facilitate the scale up of ice-templating techniques and promote the exploitation and application of new high-performance materials.展开更多
The structures of tungsten and tungsten carbide scaffolds play a key role in determining the properties of their infiltrated composites for multifunctional applications.However,it is challenging to construct and contr...The structures of tungsten and tungsten carbide scaffolds play a key role in determining the properties of their infiltrated composites for multifunctional applications.However,it is challenging to construct and control the architectures by means of self-assembly in W/WC systems because of their large densities.Here we present the development of unidirectionally porous architectures,with high porosities exceeding 65 vol.%,for W and WC scaffolds which in many respects reproduce the design motif of natural wood using a direct ice-templating technique.This was achieved by adjusting the viscosities of suspensions to retard sedimentation during freezing.The processing,structural characteristics and mechanical properties of the resulting scaffolds were investigated with the correlations between them explored.Quantitative relationships were established to describe their strengths based on the mechanics of cellular solids by taking into account both inter-and intra-lamellar pores.The fracture mechanisms were also identified,especially in light of the porosity.This study extends the effectiveness of the ice-templating technique for systems with large densities or particle sizes.It further provides preforms for developing new natureinspired multifunctional materials,as represented by W/WC-Cu composites.展开更多
We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly w...We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly with ice-templated 3DG and a tin source. The structure and morphology analyses showed that 3DG has an interconnected porous architecture with a large pore volume of 0.578 cm^3·g^-1 and a high surface area of 470.5 m^2·g^-1. In comparison, SnO2@3DG exhibited a pore volume of 0.321 cmg.g^-1 and a surface area of 237.7 m^2·g^-1 with a homogeneous distribution of ultrasmall SnO2 nanoparticles in a 3DG network. SnO2@3DG showed a discharge capacity of 1,155 mA-h·g^-1 in the initial cycle, a reversible capacity of 432 mA·h·g^-1 after 200 cycles at 100 mA·g^-1 （with capacity retention of 85.7% relative to that in the second cycle）, and a discharge capacity of 210 mAh·g^-1 at a high rate of 800 mA·g^-1 This is due to the high distribution of SnO2 nanoparticles in the 3DG network and the enhanced facilitation of electron/ion transport in the electrode.展开更多
Self-pumping dressings(SPDs)have been developed as a new type of effective material for the drainage of excessive wound exudates based on the structure of asymmetric wettability.However,current SPDs are easy to lose t...Self-pumping dressings(SPDs)have been developed as a new type of effective material for the drainage of excessive wound exudates based on the structure of asymmetric wettability.However,current SPDs are easy to lose their asymmetric wettability due to the weak interfacial mechanical stability between the hydrophobic and hydrophilic layers.Herein,we report an integrated self-pumping organohydrogel dressing with aligned microchannels(SPD-AM),prepared by an ice-templating-assisted wetting-enabled-transfer(WET)polymerization strategy,that can accelerate the healing process of diabetic wounds.The WET polymerization strategy enables strong interfacial mechanical stability between the hydrophobic organogel and hydrophilic hydrogel layers.The aligned microchannels greatly improve the draining capability of SPDs.Taking a diabetic rat model as an example,the SPD-AM can significantly reduce the bacterial colonization with low inflammatory responses,enhance dermal remodeling by about 47.31%,and shorten wound closure time by about 1/5 compared with other dressings,ultimately accelerating diabetic wound healing.This study is valuable for developing next-generation SPDs with stable mechanical performance for clinical applications.展开更多
基金support provided by the Ministry of Higher Education(MOHE)Malaysia under the Fundamental Research Grant Scheme(FRGS/1/2015/SG06/UNIM/02/1)
文摘The remediation of wastewater requires treatment technologies which are robust, efficient,simple to operate and affordable such as adsorption. Lately, three-dimensional(3D)graphene based materials have attracted significant attention as effective adsorbents for wastewater treatment. The intrinsic properties of 3D graphene structure such as large surface area and interconnected porous structure can facilitate the transport of pollutants into the 3D network and provide abundant active sites for trapping the pollutants. For the synthesis of 3D graphene structure, ice-templating is commonly practiced due to its facile steps, cost effectiveness and high scalability potential. This review covers the icetemplating fabrication technique for 3D graphene based materials and their application as adsorbents in eliminating dyes and heavy metals from aqueous media. The assembly mechanisms of the ice-templating fsynthesis are comprehensively discussed. Further discussion on the fundamental principles, critical process parameters and characteristics of ice-templated 3D graphene structures is also included. A thorough review on the mechanisms for batch adsorption of dyes and heavy metals is presented based on the structures and properties of the 3D graphene materials. The review further evaluates the dynamic adsorption in packed columns and the regeneration of 3D graphene based materials.
文摘A bulk Poly(vinyl alcohol)/ZIF-8(PVA/ZIF-8)porous composite with aligned porous structure was prepared by ice-templating method.The microstructure of PVA/ZIF-8 porous composites was characterized by scanning electron microscopy(SEM).The results showed that the composites had regular pore structure and ZIF-8 nanoparticles were evenly distributed on the skeleton of PVA.X-ray diffraction(XRD)test results showed that the crystalline structure of ZIF-8 was well preserved in the composites.The specific surface area of the composite was characterized by nitrogen adsorption/desorption test.The specific surface area of the composite was up to 1160 m^2 g^1.PVA/ZIF-8 porous composites could also support a certain weight with almost no volume shrinkage.The carbon dioxide adsorption quantity of the composite was up to 11.3 cm^3 g^1,proving that PVA/ZIF-8 porous composite has a good application prospect in the field of carbon dioxide adsorption.
基金Supported by the Northwestern Polytechnical University under Grant No 158-QP-2016the Natural Science Basic Research Plan of Shaanxi Province under Grant No 2017JM5112
文摘A poly vinyl alcohol（PVA） scaffold with aligned porous is strengthened by in-situ combining with TiO2. The increased freezing rate can be used to further increase the strength of aligned porous materials. The strengthened porous PVA exhibits aligned interconnected porous structures and shows a significant enhancement in tensile testing and compression strength testing.
基金financially supported by the National Key R&D Program of China(2020YFA0710404)the National Natural Science Foundation of China(52173269 and 51871216)+1 种基金the Youth Innovation Promotion Association CASand Liaoning Revitalization Talents Program。
文摘Ice-templating technique offers a viable means for constructing ordered macro-porous architectures in materials;nevertheless,it is generally limited by a low efficiency for fabrication,large difficulty for manipulation,along with the small dimension,and poor structural uniformity of icetemplated materials.Here,a new approach was exploited for continuous ice-templating of uniformly ordered macro-porous materials based on the establishment of a large,stable temperature gradient with specific bi-directional designs at the freezing front by descending the front toward the cooling medium to accommodate its upward growth.The freezing rate was markedly increased with the dimension of frozen body notably enlarged as compared with the case for conventional static ice-templating technique.The macro-porous architecture of materials,taking zirconia ceramics as an example,was made much finer and more uniform over the entire sample,and exhibited better ordering of alignment and enhanced inter-connectivity between lamellae.This led to an improvement in the compressive strength and its stability along the height direction for ice-templated materials than those made by the static ice-templating technique at a similar porosity.This study may facilitate the scale up of ice-templating techniques and promote the exploitation and application of new high-performance materials.
基金the National Natural Science Foundation of China(Grant Nos.51871216 and 51501190)the Opening Project of Jiangsu Province Key Laboratory of High-end Structural Materials(Grant No.hsm1801)provided by the U.S.Air Force Office of Scientific Research,under MURI grant AFSOR-FA9550-15-1-0009 to the University of California Riverside through a subcontract to the University of California Berkeley。
文摘The structures of tungsten and tungsten carbide scaffolds play a key role in determining the properties of their infiltrated composites for multifunctional applications.However,it is challenging to construct and control the architectures by means of self-assembly in W/WC systems because of their large densities.Here we present the development of unidirectionally porous architectures,with high porosities exceeding 65 vol.%,for W and WC scaffolds which in many respects reproduce the design motif of natural wood using a direct ice-templating technique.This was achieved by adjusting the viscosities of suspensions to retard sedimentation during freezing.The processing,structural characteristics and mechanical properties of the resulting scaffolds were investigated with the correlations between them explored.Quantitative relationships were established to describe their strengths based on the mechanics of cellular solids by taking into account both inter-and intra-lamellar pores.The fracture mechanisms were also identified,especially in light of the porosity.This study extends the effectiveness of the ice-templating technique for systems with large densities or particle sizes.It further provides preforms for developing new natureinspired multifunctional materials,as represented by W/WC-Cu composites.
文摘We report on the ice-templated preparation and sodium storage of ultrasmall SnO2 nanoparticles （3--4 nm） embedded in three-dimensional （3D） graphene （SnO2@3DG）. SnO2@3DG was fabricated by hydrothermal assembly with ice-templated 3DG and a tin source. The structure and morphology analyses showed that 3DG has an interconnected porous architecture with a large pore volume of 0.578 cm^3·g^-1 and a high surface area of 470.5 m^2·g^-1. In comparison, SnO2@3DG exhibited a pore volume of 0.321 cmg.g^-1 and a surface area of 237.7 m^2·g^-1 with a homogeneous distribution of ultrasmall SnO2 nanoparticles in a 3DG network. SnO2@3DG showed a discharge capacity of 1,155 mA-h·g^-1 in the initial cycle, a reversible capacity of 432 mA·h·g^-1 after 200 cycles at 100 mA·g^-1 （with capacity retention of 85.7% relative to that in the second cycle）, and a discharge capacity of 210 mAh·g^-1 at a high rate of 800 mA·g^-1 This is due to the high distribution of SnO2 nanoparticles in the 3DG network and the enhanced facilitation of electron/ion transport in the electrode.
基金supported by the National Natural Science Foundation of China(22035008,21972155,22002177,and 22205244)Youth Innovation Promotion Association,Chinese Academy of Sciences(CAS)(2022027)+1 种基金CAS-Croucher Funding Scheme for Joint LaboratoriesChina Postdoctoral Science Foundation(2022M713225)。
文摘Self-pumping dressings(SPDs)have been developed as a new type of effective material for the drainage of excessive wound exudates based on the structure of asymmetric wettability.However,current SPDs are easy to lose their asymmetric wettability due to the weak interfacial mechanical stability between the hydrophobic and hydrophilic layers.Herein,we report an integrated self-pumping organohydrogel dressing with aligned microchannels(SPD-AM),prepared by an ice-templating-assisted wetting-enabled-transfer(WET)polymerization strategy,that can accelerate the healing process of diabetic wounds.The WET polymerization strategy enables strong interfacial mechanical stability between the hydrophobic organogel and hydrophilic hydrogel layers.The aligned microchannels greatly improve the draining capability of SPDs.Taking a diabetic rat model as an example,the SPD-AM can significantly reduce the bacterial colonization with low inflammatory responses,enhance dermal remodeling by about 47.31%,and shorten wound closure time by about 1/5 compared with other dressings,ultimately accelerating diabetic wound healing.This study is valuable for developing next-generation SPDs with stable mechanical performance for clinical applications.
