Confined water has been proven to be of great importance due to its pervasiveness and contribution to life and many fields of scientific research.However,the control and characterization of confined water are a challe...Confined water has been proven to be of great importance due to its pervasiveness and contribution to life and many fields of scientific research.However,the control and characterization of confined water are a challenge.Herein,a confined space is constructed by flexibly changing the pH of a graphene oxide dispersion under the self-assembly process of a graphene hydrogel(GH),and the confined space is adjusted with variation from 10.04 to 3.52 nm.Confined water content in GH increases when the pore diameter of the confined space decreases;the corresponding adsorption capacity increases from 243.04 to 442.91 mg g−1.Moreover,attenuated total reflectance Fourier transform infrared spectroscopy and Raman spectroscopy are utilized to analyze the hydrogen bonding structure qualitatively and quantitatively,and correlation analysis reveals that the improvement in the adsorption capacity is caused by incomplete hydrogen bonding in the confined water.Further,confined water is assembled into four typical porous commercial adsorbents,and a remarkable enhancement of the adsorption capacity is achieved.This research demonstrates the application potential for the extraordinary properties of confined water and has implications for the development of highly effective confined water-modified adsorbents.展开更多
Uniform dispersion of two-dimensional(2 D) graphene materials in polymer matrices remains challenging. In this work, a novel layer-by-layer assembly strategy was developed to prepare a sophisticated nanostructure with...Uniform dispersion of two-dimensional(2 D) graphene materials in polymer matrices remains challenging. In this work, a novel layer-by-layer assembly strategy was developed to prepare a sophisticated nanostructure with highly dispersed 2 D graphene oxide in a three-dimensional matrix consisting of onedimensional bacterial cellulose(BC) nanofibers. This method is a breakthrough, with respect to the conventional static culture method for BC that involves multiple in situ layer-by-layer assembly steps at the interface between previously grown BC and the culture medium. In the as-prepared BC/GO nanocomposites, the GO nanosheets are mechanically bundled and chemically bonded with BC nanofibers via hydrogen bonding,forming an intriguing nanostructure. The sophisticated nanostructure of the BC/GO leads to greatly enhanced mechanical properties compared to those of bare BC. This strategy is versatile, facile, scalable, and can be promising for the development of high-performance BC-based nanocomposite hydrogels.展开更多
A novel magnetic hydrogel loaded with graphene oxide(GO)was developed in this study.Firstly,GO was prepared from bagasse through a single step via oxidation in the presence of ferrocene under muffled atmospheric condi...A novel magnetic hydrogel loaded with graphene oxide(GO)was developed in this study.Firstly,GO was prepared from bagasse through a single step via oxidation in the presence of ferrocene under muffled atmospheric conditions,followed by the loading of different amounts of magnetite onto GO via co-precipitation reaction of iron onto GO sheets.Finally,the 2-acrylamido-2-methyl-1-propane sulfonic acid was grafted onto carboxymethyl cellulose in the presence of magnetite GO and N,N′-methylenebisacrylamide as crosslinker yielded hydrogel.The structure,morphological,and thermal behavior of the prepared hydrogels were investigated.In addition,the adsorption performance of Ni(Ⅱ)ions from aqueous media by the prepared hydrogels was investigated as a function of temperature,time,and concentration of adsorbate in a batch system.The results demonstrated a remarkable enhancement in the adsorption process of Ni(Ⅱ)(Removal efficiency=98.82%).All isotherms were found to fit the Langmuir model best.The adsorption properties of both magnetic GO and magnetic hydrogel showed promising properties as green and cheap adsorbents.展开更多
The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,...The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,which posed a challenge to the conventional techniques. In this work,the batch experiments on TC adsorption in aqueous solution of hydrogel( HG) consisting of graphene oxide( GO) and TiO_2 nanotubes( TN) were successfully conducted. HG composite( HG-TN-GO) was prepared with TN and GO with self-assembly method during the oxidation-reduction reaction,and criogel( CG) with TN and GO was characterized by pH at point of zero charge( pH_(pzc)), transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy( XPS). The adsorption capacity of HG-TN-GO on TC was evaluated by analyzing its isotherms. The maximum adsorption capacity reached 751. 3 mg/g. Besides,the adsorption isotherms were well fitted by the Langmuir model, with the theoretical maximum( q_m) of 797. 0 mg/g. The adsorption process was systematically studied by varying pH during the whole adsorption process. The adsorption occurred probably via π-π interaction and cation-π bonding between TC and the HG-TN-GO surface. The composite could be regenerated in 50% ethanol aqueous solution,without significant capacity loss. After 6 recycles,the decrease of adsorption capacity was less than 10%.展开更多
A novel composites hydrogel adsorbent was facilely synthesized for efficient removal of acid dyes from aqueous solution.The composite hydrogel consisting of TiO_2 nanotubes(TN) and graphene oxide(GO)(H-TN-GO) was char...A novel composites hydrogel adsorbent was facilely synthesized for efficient removal of acid dyes from aqueous solution.The composite hydrogel consisting of TiO_2 nanotubes(TN) and graphene oxide(GO)(H-TN-GO) was characterized by BrunauerEmmett-Teller(BET),transmission electron microscope(TEM),scanning electron microscope(SEM),Raman spectra and X-ray photoelectron spectroscope(XPS).Experimental results elucidated that columnar hydrogel could be tunably prepared with self-assembly by adjusting the proportion of GO/TN,mixing time and pH.The properties of adsorption and regeneration on methyl orange(MO)onto H-TN-GO were investigated respectively.The maximal adsorption capacity of H-TN-GO for MO reached 933.8 and 513.7mg/g under the pH of 4.0 and 6.8,respectively.The adsorption capacity of MO reached the maximum when pH was equivalent to4.0,which attributed to increasing electrostatic attraction.Besides,the adsorption behavior was fitted reasonably better with Freundlich isotherm model than Langmuir model;the adsorption speed was rapid and the removal ratio almost reached 99.5% when the concentration of MO was less than 100 mg/L.After the used adsorbent was irradiated with the ultraviolet ray of 500 W for 3 h,its adsorption capacity could be recovered without significant loss.展开更多
Poly(vinyl alcohol)(PVA)/reduced graphene oxide(rGO)nanocomposites is prepared by the immersion of PVA/graphene oxide(GO)nanocomposites in the reducing agent aqueous solution.The PVA/graphene nanocomposites can be use...Poly(vinyl alcohol)(PVA)/reduced graphene oxide(rGO)nanocomposites is prepared by the immersion of PVA/graphene oxide(GO)nanocomposites in the reducing agent aqueous solution.The PVA/graphene nanocomposites can be used as scaffold after treatment by chemical crosslinking agents.The surface hydrophilicity of the nanocomposite scaffolds decreased with the addition of GO or rGO by measuring the contact angles of scaffolds.The electrical conductivity of PVA/rGO nanocomposite scaffold increased with rGO content increased.The highest conductivity of PVA/rGO nanocomposite scaffolds with 10 wt%rGO could reach to 12.16×10^(−3)S/m.The NIH-3T3 fibroblasts attach and grow well on the surface of PVA/rGO nanocomposite scaffolds with increasing the content of rGO.The number of cells obviously increases on the PVA/rGO nanocomposite scaffolds,especially,at 5 wt%and 10 wt%rGO.Furthermore,a good level of conductivity and a variation in the surface property of the PVA/rGO nanocomposite scaffolds have affected NIH-3T3 fibroblasts grow.展开更多
Water pollution is a global environmental issue with multi-dimensional infl uences on human life.Some strategies,such as photo-Fenton reaction,have been employed to remove recalcitrant pollutants.Two-dimensional(2D)gr...Water pollution is a global environmental issue with multi-dimensional infl uences on human life.Some strategies,such as photo-Fenton reaction,have been employed to remove recalcitrant pollutants.Two-dimensional(2D)graphene and its threedimensional(3D)confi gurations have attracted considerable attention as emerging carbon-based catalysts in photo-Fenton fi elds owing to their alluring properties in electron transfer,reactant adsorption,and light response.This review summarizes the recent developments in 2D and 3D graphene-based catalysts for photo-Fenton reactions.Their structures,characteristics,activity,and mechanisms are discussed.The conclusions and outlooks are proposed for the profound understanding of challenges and future directions.展开更多
Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor ...Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy density.In this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom source.Nanocellulose(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing density.Subsequently,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 cycles.Besides,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.展开更多
A novel hydrogel,consisting of titanium dioxide nanotubes and graphene oxide(H-TN-GO),was fabricated to remove ciprofloxacin(CIP)from aqueous solution.The adsorbent was characterized by scanning electron microscope(SE...A novel hydrogel,consisting of titanium dioxide nanotubes and graphene oxide(H-TN-GO),was fabricated to remove ciprofloxacin(CIP)from aqueous solution.The adsorbent was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy.Batch adsorption experiments systematically investigated the effect of contact time,temperature and pH on the capacity of H-TN-GO for CIP.Adsorption property of H-TN-GO and its regeneration performance was evaluated.H-TN-GO exhibited high adsorption capacity of 530 mg/g and Langmuir model was more suitable for fitting adsorption behavior.The removal ratio of CIP was more than 99%when initial concentrations were less than 100 mg/L.Besides,the initial pH of CIP solution had a distinct influence on the removal ratio,and adsorption capacity of adsorbance could be recovered by regeneration with mild alkaline condition.Large pore size and abundant oxygen-containing groups on the surface further improved its adsorption performance.The enhancing effect of H-TN-GO mainly attributed to the immobilization of TiO 2 onto graphene oxide andπ-πinteractions stacking between H-TN-GO and graphene oxide.As potential adsorbents,H-TN-GO exhibited remarkable regeneration capacity for water treatment.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 21777118)
文摘Confined water has been proven to be of great importance due to its pervasiveness and contribution to life and many fields of scientific research.However,the control and characterization of confined water are a challenge.Herein,a confined space is constructed by flexibly changing the pH of a graphene oxide dispersion under the self-assembly process of a graphene hydrogel(GH),and the confined space is adjusted with variation from 10.04 to 3.52 nm.Confined water content in GH increases when the pore diameter of the confined space decreases;the corresponding adsorption capacity increases from 243.04 to 442.91 mg g−1.Moreover,attenuated total reflectance Fourier transform infrared spectroscopy and Raman spectroscopy are utilized to analyze the hydrogen bonding structure qualitatively and quantitatively,and correlation analysis reveals that the improvement in the adsorption capacity is caused by incomplete hydrogen bonding in the confined water.Further,confined water is assembled into four typical porous commercial adsorbents,and a remarkable enhancement of the adsorption capacity is achieved.This research demonstrates the application potential for the extraordinary properties of confined water and has implications for the development of highly effective confined water-modified adsorbents.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51572187, 51563008, 51662009, 31660264)the Provincial Natural Science Foundation of Jiangxi (Grant No. 20161BAB206149)the Key Project of Natural Science Foundation of Jiangxi Province (Grant No. 20161ACB20018)
文摘Uniform dispersion of two-dimensional(2 D) graphene materials in polymer matrices remains challenging. In this work, a novel layer-by-layer assembly strategy was developed to prepare a sophisticated nanostructure with highly dispersed 2 D graphene oxide in a three-dimensional matrix consisting of onedimensional bacterial cellulose(BC) nanofibers. This method is a breakthrough, with respect to the conventional static culture method for BC that involves multiple in situ layer-by-layer assembly steps at the interface between previously grown BC and the culture medium. In the as-prepared BC/GO nanocomposites, the GO nanosheets are mechanically bundled and chemically bonded with BC nanofibers via hydrogen bonding,forming an intriguing nanostructure. The sophisticated nanostructure of the BC/GO leads to greatly enhanced mechanical properties compared to those of bare BC. This strategy is versatile, facile, scalable, and can be promising for the development of high-performance BC-based nanocomposite hydrogels.
文摘A novel magnetic hydrogel loaded with graphene oxide(GO)was developed in this study.Firstly,GO was prepared from bagasse through a single step via oxidation in the presence of ferrocene under muffled atmospheric conditions,followed by the loading of different amounts of magnetite onto GO via co-precipitation reaction of iron onto GO sheets.Finally,the 2-acrylamido-2-methyl-1-propane sulfonic acid was grafted onto carboxymethyl cellulose in the presence of magnetite GO and N,N′-methylenebisacrylamide as crosslinker yielded hydrogel.The structure,morphological,and thermal behavior of the prepared hydrogels were investigated.In addition,the adsorption performance of Ni(Ⅱ)ions from aqueous media by the prepared hydrogels was investigated as a function of temperature,time,and concentration of adsorbate in a batch system.The results demonstrated a remarkable enhancement in the adsorption process of Ni(Ⅱ)(Removal efficiency=98.82%).All isotherms were found to fit the Langmuir model best.The adsorption properties of both magnetic GO and magnetic hydrogel showed promising properties as green and cheap adsorbents.
基金Environmental Engineering,Natural Science Foundation of China(No.51522805)Innovation Foundation of Nanjing Institute of Technology,China(No.CKJB201410)
文摘The detection on tetracycline( TC) in drinking water poses an environmental issue since TC has been widely used to prevent animal disease and promote their growth. In addition,TC was difficult to remove or biodegrade,which posed a challenge to the conventional techniques. In this work,the batch experiments on TC adsorption in aqueous solution of hydrogel( HG) consisting of graphene oxide( GO) and TiO_2 nanotubes( TN) were successfully conducted. HG composite( HG-TN-GO) was prepared with TN and GO with self-assembly method during the oxidation-reduction reaction,and criogel( CG) with TN and GO was characterized by pH at point of zero charge( pH_(pzc)), transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy( XPS). The adsorption capacity of HG-TN-GO on TC was evaluated by analyzing its isotherms. The maximum adsorption capacity reached 751. 3 mg/g. Besides,the adsorption isotherms were well fitted by the Langmuir model, with the theoretical maximum( q_m) of 797. 0 mg/g. The adsorption process was systematically studied by varying pH during the whole adsorption process. The adsorption occurred probably via π-π interaction and cation-π bonding between TC and the HG-TN-GO surface. The composite could be regenerated in 50% ethanol aqueous solution,without significant capacity loss. After 6 recycles,the decrease of adsorption capacity was less than 10%.
基金National Natural Science Foundation of China(No.51522805)
文摘A novel composites hydrogel adsorbent was facilely synthesized for efficient removal of acid dyes from aqueous solution.The composite hydrogel consisting of TiO_2 nanotubes(TN) and graphene oxide(GO)(H-TN-GO) was characterized by BrunauerEmmett-Teller(BET),transmission electron microscope(TEM),scanning electron microscope(SEM),Raman spectra and X-ray photoelectron spectroscope(XPS).Experimental results elucidated that columnar hydrogel could be tunably prepared with self-assembly by adjusting the proportion of GO/TN,mixing time and pH.The properties of adsorption and regeneration on methyl orange(MO)onto H-TN-GO were investigated respectively.The maximal adsorption capacity of H-TN-GO for MO reached 933.8 and 513.7mg/g under the pH of 4.0 and 6.8,respectively.The adsorption capacity of MO reached the maximum when pH was equivalent to4.0,which attributed to increasing electrostatic attraction.Besides,the adsorption behavior was fitted reasonably better with Freundlich isotherm model than Langmuir model;the adsorption speed was rapid and the removal ratio almost reached 99.5% when the concentration of MO was less than 100 mg/L.After the used adsorbent was irradiated with the ultraviolet ray of 500 W for 3 h,its adsorption capacity could be recovered without significant loss.
基金financially supported by the Wisconsin Institute for Discovery(WID)at the University of Wisconsin-Madison and the China Scholarship Council.
文摘Poly(vinyl alcohol)(PVA)/reduced graphene oxide(rGO)nanocomposites is prepared by the immersion of PVA/graphene oxide(GO)nanocomposites in the reducing agent aqueous solution.The PVA/graphene nanocomposites can be used as scaffold after treatment by chemical crosslinking agents.The surface hydrophilicity of the nanocomposite scaffolds decreased with the addition of GO or rGO by measuring the contact angles of scaffolds.The electrical conductivity of PVA/rGO nanocomposite scaffold increased with rGO content increased.The highest conductivity of PVA/rGO nanocomposite scaffolds with 10 wt%rGO could reach to 12.16×10^(−3)S/m.The NIH-3T3 fibroblasts attach and grow well on the surface of PVA/rGO nanocomposite scaffolds with increasing the content of rGO.The number of cells obviously increases on the PVA/rGO nanocomposite scaffolds,especially,at 5 wt%and 10 wt%rGO.Furthermore,a good level of conductivity and a variation in the surface property of the PVA/rGO nanocomposite scaffolds have affected NIH-3T3 fibroblasts grow.
文摘Water pollution is a global environmental issue with multi-dimensional infl uences on human life.Some strategies,such as photo-Fenton reaction,have been employed to remove recalcitrant pollutants.Two-dimensional(2D)graphene and its threedimensional(3D)confi gurations have attracted considerable attention as emerging carbon-based catalysts in photo-Fenton fi elds owing to their alluring properties in electron transfer,reactant adsorption,and light response.This review summarizes the recent developments in 2D and 3D graphene-based catalysts for photo-Fenton reactions.Their structures,characteristics,activity,and mechanisms are discussed.The conclusions and outlooks are proposed for the profound understanding of challenges and future directions.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(No.52072191)Heilongjiang Provincial Natural Science Foundation of China(No.LH2020E126)the Fundamental Research Fund of Heilongjiang Provincial University(No.135509204).
文摘Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy density.In this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom source.Nanocellulose(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing density.Subsequently,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 cycles.Besides,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.
基金Practical Innovation Training Program for College Students,China(No.201811276115H)
文摘A novel hydrogel,consisting of titanium dioxide nanotubes and graphene oxide(H-TN-GO),was fabricated to remove ciprofloxacin(CIP)from aqueous solution.The adsorbent was characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy.Batch adsorption experiments systematically investigated the effect of contact time,temperature and pH on the capacity of H-TN-GO for CIP.Adsorption property of H-TN-GO and its regeneration performance was evaluated.H-TN-GO exhibited high adsorption capacity of 530 mg/g and Langmuir model was more suitable for fitting adsorption behavior.The removal ratio of CIP was more than 99%when initial concentrations were less than 100 mg/L.Besides,the initial pH of CIP solution had a distinct influence on the removal ratio,and adsorption capacity of adsorbance could be recovered by regeneration with mild alkaline condition.Large pore size and abundant oxygen-containing groups on the surface further improved its adsorption performance.The enhancing effect of H-TN-GO mainly attributed to the immobilization of TiO 2 onto graphene oxide andπ-πinteractions stacking between H-TN-GO and graphene oxide.As potential adsorbents,H-TN-GO exhibited remarkable regeneration capacity for water treatment.
