Nanoparticles(NPs)have already been widely used in catalysis,antibacterial and coating fields.Compared with the traditional toxic and harmful reducing reagents,green synthesis of NPs by using plant extracts is not onl...Nanoparticles(NPs)have already been widely used in catalysis,antibacterial and coating fields.Compared with the traditional toxic and harmful reducing reagents,green synthesis of NPs by using plant extracts is not only environmental-friendly and cost-effective but also conducive to the multi-level and efficient utilization of wild plant resources.In this study,the aqueous extracts from Sorbus pohuashanensis(SP)and Aronia melanocarpa(AM)fruits were used as the reducing and protective reagents for synthesizing Au/AgNPs,with the characteristics of originality operation and high repeatability.The SP/AM fruit extracts functionalized Au/AgNPs were characterized by UV-vis spectroscopy(UV-vis),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).UV-vis spectrums showed the NPs peaks verified by the presence between 400–550 nm;TEM and SEM demonstrated NPs displayed approximately spherical structures;EDS confirmed the existence of Au/Ag elements;XRD measurements confirmed that the obtained NPs showed highly crystalline structures;FTIR demonstrated the fruits extracts were adsorbed on the surface of NPs.Primary experiments indicated that SP/AM fruit extracts functionalized-NPs could be used as the reagents for removing the organic dyes efficiently;Zone of inhibition tests(ZOI)explained that NPs have slow-release antibacterial activity.展开更多
Activated carbon made from the shells of Ricinodendron heudelotii was used to remove the remazol black dye in aqueous solution. The results of the characterization of this carbon revealed that it is microporous, with ...Activated carbon made from the shells of Ricinodendron heudelotii was used to remove the remazol black dye in aqueous solution. The results of the characterization of this carbon revealed that it is microporous, with a basic global surface (0.337 mmol/L) and a specific surface of 612 m<sup>2</sup>/g. The prepared carbon therefore has excellent adsorbent properties. Kinetic and thermodynamic studies were carried out to describe the adsorption mechanism of remazol black on this carbon. It appears from this study that the pseudo-second-order kinetic model is the best suited to describe this adsorption phenomenon with an equilibrium time of 200 min. The adsorption equilibrium study revealed that Langmuir and Freundlich models can help to describe the adsorption process. We note that the optimum pH and optimum mass for the removal of 20 mg/L of remazol black are 3 and 0.25 g, respectively. This carbon made it possible to eliminate more than 98% of the remazol dye in aqueous solution. The thermodynamic study revealed that the adsorption is of the physisorption type, spontaneous and endothermic.展开更多
Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic.Herein,a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG)with a nanoporous 3 D network structure prep...Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic.Herein,a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG)with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes.The Cu-MOG exhibited high efficiency,with an adsorption capacity of up to 650.32 mg/g,and rapid adsorption efficiency,with the ability to adsorb 80%of Neutral Red within 1 min.The high adsorption efficiency was attributed to its large specific surface area,which enabled it to massively bind cationic dyes through electrostatic interaction,and a nanoporous structure that promoted intra-pore diffusion.Remarkably,the Cu-MOG displayed size-selective adsorption,based on adsorption studies concerning dyes of different sizes as calculated by density functional theory.Additionally,the adsorption performance of the Cu-MOG still maintained removal efficiency of 100%after three regeneration cycles.These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.展开更多
We report the preparation of poly(3,4-ethylene dioxythiophene)(PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange(MO...We report the preparation of poly(3,4-ethylene dioxythiophene)(PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange(MO)from aqueous media.This novel adsorbent material can be used to selectively remove MO on a wide p H range(3.0-10.0),with a maximum capacity of 143.8 mg/g at p H 3.0.When used in a recirculating filtration system,the maximum absorption capacity was reached in a shorter time(20 min)than that observed for batch mode experiments(360 min).Based on the analyses of the kinetics and adsorption isotherm data,one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic.Besides,considering the estimated values for the Gibbs energy,and entropy and enthalpy changes,it was established that the adsorption process is spontaneous and occurs in an endothermic manner.The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles,without significant loss of their characteristics.We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems.展开更多
Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy...Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy recy-clable adsorbents via a facile route is still a challenge.In this work,ZIF-67/cotton fibers as adsorbents for dye removal were prepared in a large-scale using a simple coordination replication method.The successful fabrication of the ZIF-67/cotton fibers was confirmed by FTIR,XRD,XPS,SEM and BET analysis,respectively.As expected,the as-prepared ZIF-67/cotton fibers exhibited high adsorption capacity of 3787 mg/g towards malachite green(MG).Meanwhile,the adsorption kinetics and isotherm obeyed the pseudo-second-order kinetics and Langmuir model,respectively.Moreover,its removal efficiency towards MG was not significantly influenced by the pH and ionic strength of aque-ous solution.Most importantly,the ZIF-67/cotton fibers can remove MG from synthetic effluents,and it can be easily regenerated without filtration or centrifugation processes,with the regeneration efficiency remaining over 90%even after 10 cycles.Additionally,the ZIF-67/cotton fibers presented excellent antimicrobial performance against E.coli and S.aureus.Hence,the distinctive features of the as-prepared ZIF-67/cotton fibers make it promisingly applicable for the colored wastewater treatment.展开更多
Dyeing wastewater treatment remains a challenge.Although effective,the in-series process using electrochemical oxidation as the pre-or post-treatment of biodegradation is long.This study proposes a compact dual-chambe...Dyeing wastewater treatment remains a challenge.Although effective,the in-series process using electrochemical oxidation as the pre-or post-treatment of biodegradation is long.This study proposes a compact dual-chamber electrocatalytic biofilm reactor(ECBR)to complete azo dye decolorization and mineralization in a single unit via anodic oxidation on a MnO_(x)/Ti flow-through anode followed by cathodic biodegradation on carbon felts.Compared with the electrocatalytic reactor with a stainlesssteel cathode(ECR-SS)and the biofilm reactor(BR),the ECBR increased the chemical oxygen demand(COD)removal efficiency by 24%and 31%(600 mg/L Acid Orange 7 as the feed,current of 6 mA),respectively.The COD removal efficiency of the ECBR was even higher than the sum of those of ECR-SS and BR.The ECBR also reduced the energy consumption(3.07 kWh/kg COD)by approximately half compared with ECR-SS.The advantages of the ECBR in azo dye removal were attributed to the synergistic effect of the MnO_(x)/Ti flow-through anode and cathodic biofilms.Catalyzed by MnIV=O generated on the MnO_(x)/Ti anode under a low applied current,azo dyes were oxidized and decolored.The intermediate products with improved biodegradability were further mineralized by the cathodic aerobic heterotrophic bacteria(non-electrochemically active)under the stimulation of the applied current.Taking advantage of the mutual interactions among the electricity,anode,and bacteria,this study provides a novel and compact process for the effective and energyefficient treatment of azo dye wastewater.展开更多
Functional carbon nanomaterials have become the stars of many active research fields,such as electronics,energy,catalysis,imaging,sensing and biomedicine.Herein,a facile and one-pot strategy for generating ferromagnet...Functional carbon nanomaterials have become the stars of many active research fields,such as electronics,energy,catalysis,imaging,sensing and biomedicine.Herein,a facile and one-pot strategy for generating ferromagnetic nanoparticles loaded on N-doped carbon nanosheets(Fe-N-CNS)is presented by salt-assisted high-temperature carbonization of natural silk proteins.Due to their graphitic structures,N-doping and ferromagnetic nanoparticles(FeN_(x),FeO_(y),FeC_(z)),the silk-derived Fe-N-CNS can act as excellent mimics of both peroxidase and oxidase.Benefiting from the combined character of the graphene-like structures and enzyme-like activities,Fe-N-CNS can be further applied to highly efficient dye removal via synergistic adsorption and degradation.Meanwhile,the as-prepared Fe-N-CNS with intrinsic magnetism and electrical conductivity can also serve as an efficient electromagnetic wave absorption agent.The broadest effective absorption bandwidth(EAB)of as-obtained absorbing material yields a 6.73 GHz with 1 mm thickness,with a maximum reflection loss of-37.33 dB(11.41 GHz).The EAB can cover2~18 GHz with a tunable absorber thickness from 1.0 mm to 5.0 mm.Collectively,Fe-N-CNS,as a dualfunctional material,can tackle the aggravating environmental pollution issues of both dyes and electromagnetic waves.展开更多
Water pollution has become a serious problem owing to the development of society.Photocatalysis is a promising approach to remove various pollutants in water,such as organic pollutants and antibiotic resistance bacter...Water pollution has become a serious problem owing to the development of society.Photocatalysis is a promising approach to remove various pollutants in water,such as organic pollutants and antibiotic resistance bacteria.Meanwhile,the design of heterojunction between two semiconductors is an effective path to improve photocatalytic properties due to its potential in improving separation and transfer of photoinduced carriers.In this study,Nb_(2)O_(5)/g-C_(3)N_(4)(NO/CN)composite materials were prepared through a one-step heating method.Characterizations confirmed successful preparation of NO/CN heterojunction structure and better optical properties than pure g-C_(3)N_(4) and Nb_(2)O_(5).NO/CN composite materials showed excellent photocatalytic efficiency for Escherichia coli(E.coli)inactivation(95%)compared with the pure Nb_(2)O_(5)(10%) and g-C_(3)N_(4)(77%).Meanwhile,NO/CN exhibited better organic pollutants removal(Rh B for94%,methyl orange(MO)for 15%and methylene blue(MB)for 87%)under visible light,which is likely owing to the heterojunction structure between g-C_(3)N_(4) and Nb_(2)O_(5) that leads to the good separation of photogenerated electron-hole pair.Free radical scavenging and electron spin resonance(ESR)experiments demonstrated that superoxide radicals(·O_(2)^(-)) and holes(h^(+)) were the dominant radicals.Therefore,the NO/CN was proposed to be a promising material for effective disinfection and removal of organic contaminants in water treatment.展开更多
The introduction of mesoporosity into the microporous metal-organic frameworks(MOFs)is expected to expand their applications.Herein,we report a green and facile method to obtain hierarchically porous MOF structures by...The introduction of mesoporosity into the microporous metal-organic frameworks(MOFs)is expected to expand their applications.Herein,we report a green and facile method to obtain hierarchically porous MOF structures by using an air-steam etching process.By virtue of the protonation reaction between the imidazole moiety and water vapor,the protonated imidazole related linkers leave the framework,resulting in the formation of mesopores in the zeolitic imidazolate frameworks(ZIFs),as exemplified by ZIF-8.Given the mild etching process,the materials'structural integrity and crystallinity are well maintained.Accordingly,the hierarchical porous ZIF-8 exhibited enhanced performance in the dye removal as well as CO_(2) cycloaddition reaction with epichlorohydrin in comparison with microporous ZIF-8,owing to the accelerated mass transfer arising from mesoporous structures.Remarkably,the proposed steam etching approach is generally applicable,which can be readily extended to other ZIFs,such as ZIF-14,ZIF-69,and ZIF-71,thus representing a powerful strategy to construct hierarchically porous MOF materials.展开更多
Hydrogen peroxide(H_(2)O_(2))disproportionation,iron precipitation,and narrow pH range are the drawbacks of traditional Fenton process.To surmount these barriers,we proposed a ferric ion(Fe^(3+))-ascorbic acid(AA)comp...Hydrogen peroxide(H_(2)O_(2))disproportionation,iron precipitation,and narrow pH range are the drawbacks of traditional Fenton process.To surmount these barriers,we proposed a ferric ion(Fe^(3+))-ascorbic acid(AA)complex catalyzed calcium peroxide(CaO_(2))Fenton-like system to remove organic dyes in water.This collaborative Fe^(3+)/AA/CaO_(2)system presented an obvious improvement in the methyl orange(MO)decolorization,and also effectively eliminated other dyes.Response surface method was employed to optimize the running parameters for this coupling process.Under the optimized arguments(2.76 mmol/L Fe^(3+),0.68 mmol/L AA,and 4 mmol/L CaO_(2)),the MO removal achieved 98.90%after 15 min at pH 6.50,which was close to the computed outcome of 99.30%.Furthermore,this Fenton-like system could perform well in a wide range of pH(3-11),and enhance the H_(2)O_(2)decomposition and Fe ions recycle.The scavenger experiment result indicated that hydroxyl radical,superoxide anion free radical,and singlet oxygen were acted on the dye elimination.Moreover,electron spin resonance analysis corroborated that the existences of these active species in the Fe^(3+)/AA/CaO_(2)system.This study could advance the development of Fenton-like technique in organic effluent disposal.展开更多
To valorize kraft lignin,hydroxymethylation and sulfonation were applied on this under-utilized,but vastly available,material.The hydroxymethylation pretreatment was conducted as means to improve the reactivity of lig...To valorize kraft lignin,hydroxymethylation and sulfonation were applied on this under-utilized,but vastly available,material.The hydroxymethylation pretreatment was conducted as means to improve the reactivity of lignin.The sulfonation of hydroxymethylated kraft lignin was investigated by sulfuric acid and sodium sulfite treatments under various conditions.The modified lignin samples were characterized for their charge density,solubility,elemental components,and molecular weights.The results showed that the hydroxymethylation facilitated the sulfonation by sodium sulfite,yielding a product(SSH-lignin)with the charge density of-1.2 meq/g and water solubility of 10 g/L under the conditions of Ns_(2)SO_(3)/lignin molar ratio of 0.49 mol/mol,95℃and 3 h.On the other hand,hydroxymethylation hindered the sulfonation of lignin by sulfuric acid,yielding a product(SAH-lignin)with the charge density of–0.46 meq/g and solubility of 0.9 g/L under the conditions of H_(2)SO_(4)/lignin molar ratio of 14.8 mol/mol,80℃and 1 h.The SSH-lignin had a high adsorption on kaolinite(17 mg/g)at a lignin concentration of 40 g/L.The sulfonated lignins were also found to be effective coagulant for the cationic dye ethyl violet.展开更多
基金support from the Fundamental Research Funds for the Central Universities(2572020DR07)Natural Science Fund of Heilongjiang Province(LH2019B001)+1 种基金the 111 Project(B20088)Heilongjiang Touyan Innovation Team Program(Tree Genetics and Breeding Innovation Team).
文摘Nanoparticles(NPs)have already been widely used in catalysis,antibacterial and coating fields.Compared with the traditional toxic and harmful reducing reagents,green synthesis of NPs by using plant extracts is not only environmental-friendly and cost-effective but also conducive to the multi-level and efficient utilization of wild plant resources.In this study,the aqueous extracts from Sorbus pohuashanensis(SP)and Aronia melanocarpa(AM)fruits were used as the reducing and protective reagents for synthesizing Au/AgNPs,with the characteristics of originality operation and high repeatability.The SP/AM fruit extracts functionalized Au/AgNPs were characterized by UV-vis spectroscopy(UV-vis),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS),scanning electron microscope(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR).UV-vis spectrums showed the NPs peaks verified by the presence between 400–550 nm;TEM and SEM demonstrated NPs displayed approximately spherical structures;EDS confirmed the existence of Au/Ag elements;XRD measurements confirmed that the obtained NPs showed highly crystalline structures;FTIR demonstrated the fruits extracts were adsorbed on the surface of NPs.Primary experiments indicated that SP/AM fruit extracts functionalized-NPs could be used as the reagents for removing the organic dyes efficiently;Zone of inhibition tests(ZOI)explained that NPs have slow-release antibacterial activity.
文摘Activated carbon made from the shells of Ricinodendron heudelotii was used to remove the remazol black dye in aqueous solution. The results of the characterization of this carbon revealed that it is microporous, with a basic global surface (0.337 mmol/L) and a specific surface of 612 m<sup>2</sup>/g. The prepared carbon therefore has excellent adsorbent properties. Kinetic and thermodynamic studies were carried out to describe the adsorption mechanism of remazol black on this carbon. It appears from this study that the pseudo-second-order kinetic model is the best suited to describe this adsorption phenomenon with an equilibrium time of 200 min. The adsorption equilibrium study revealed that Langmuir and Freundlich models can help to describe the adsorption process. We note that the optimum pH and optimum mass for the removal of 20 mg/L of remazol black are 3 and 0.25 g, respectively. This carbon made it possible to eliminate more than 98% of the remazol dye in aqueous solution. The thermodynamic study revealed that the adsorption is of the physisorption type, spontaneous and endothermic.
基金supported by the National Natural Science Foundation of China (No. 21575117)
文摘Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic.Herein,a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG)with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes.The Cu-MOG exhibited high efficiency,with an adsorption capacity of up to 650.32 mg/g,and rapid adsorption efficiency,with the ability to adsorb 80%of Neutral Red within 1 min.The high adsorption efficiency was attributed to its large specific surface area,which enabled it to massively bind cationic dyes through electrostatic interaction,and a nanoporous structure that promoted intra-pore diffusion.Remarkably,the Cu-MOG displayed size-selective adsorption,based on adsorption studies concerning dyes of different sizes as calculated by density functional theory.Additionally,the adsorption performance of the Cu-MOG still maintained removal efficiency of 100%after three regeneration cycles.These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.
文摘We report the preparation of poly(3,4-ethylene dioxythiophene)(PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange(MO)from aqueous media.This novel adsorbent material can be used to selectively remove MO on a wide p H range(3.0-10.0),with a maximum capacity of 143.8 mg/g at p H 3.0.When used in a recirculating filtration system,the maximum absorption capacity was reached in a shorter time(20 min)than that observed for batch mode experiments(360 min).Based on the analyses of the kinetics and adsorption isotherm data,one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic.Besides,considering the estimated values for the Gibbs energy,and entropy and enthalpy changes,it was established that the adsorption process is spontaneous and occurs in an endothermic manner.The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles,without significant loss of their characteristics.We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems.
基金This work is financially supported by the National Natural Science Founda-tion of China(No.52003171)Fundamental Research Funds for the Central Universities,China(No.YJ201823+2 种基金YJ201959)Sichuan Province Science and Technology Support Program,China(No.2020YJ0316,2021YJ0290)the Science and Technology Cooperation Project between Sichuan University and Zigong City(No:2019CDZG-23).
文摘Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy recy-clable adsorbents via a facile route is still a challenge.In this work,ZIF-67/cotton fibers as adsorbents for dye removal were prepared in a large-scale using a simple coordination replication method.The successful fabrication of the ZIF-67/cotton fibers was confirmed by FTIR,XRD,XPS,SEM and BET analysis,respectively.As expected,the as-prepared ZIF-67/cotton fibers exhibited high adsorption capacity of 3787 mg/g towards malachite green(MG).Meanwhile,the adsorption kinetics and isotherm obeyed the pseudo-second-order kinetics and Langmuir model,respectively.Moreover,its removal efficiency towards MG was not significantly influenced by the pH and ionic strength of aque-ous solution.Most importantly,the ZIF-67/cotton fibers can remove MG from synthetic effluents,and it can be easily regenerated without filtration or centrifugation processes,with the regeneration efficiency remaining over 90%even after 10 cycles.Additionally,the ZIF-67/cotton fibers presented excellent antimicrobial performance against E.coli and S.aureus.Hence,the distinctive features of the as-prepared ZIF-67/cotton fibers make it promisingly applicable for the colored wastewater treatment.
基金This work was supported by the National Key Research and Development Program of China(No.2020YFA0211003)the National Natural Science Foundation of China(Nos.51978465,21878230,and 51878646)the Natural Science Foundation of Tianjin of China(Nos.19JCQNJC07500 and 19JCZDJC39800).
文摘Dyeing wastewater treatment remains a challenge.Although effective,the in-series process using electrochemical oxidation as the pre-or post-treatment of biodegradation is long.This study proposes a compact dual-chamber electrocatalytic biofilm reactor(ECBR)to complete azo dye decolorization and mineralization in a single unit via anodic oxidation on a MnO_(x)/Ti flow-through anode followed by cathodic biodegradation on carbon felts.Compared with the electrocatalytic reactor with a stainlesssteel cathode(ECR-SS)and the biofilm reactor(BR),the ECBR increased the chemical oxygen demand(COD)removal efficiency by 24%and 31%(600 mg/L Acid Orange 7 as the feed,current of 6 mA),respectively.The COD removal efficiency of the ECBR was even higher than the sum of those of ECR-SS and BR.The ECBR also reduced the energy consumption(3.07 kWh/kg COD)by approximately half compared with ECR-SS.The advantages of the ECBR in azo dye removal were attributed to the synergistic effect of the MnO_(x)/Ti flow-through anode and cathodic biofilms.Catalyzed by MnIV=O generated on the MnO_(x)/Ti anode under a low applied current,azo dyes were oxidized and decolored.The intermediate products with improved biodegradability were further mineralized by the cathodic aerobic heterotrophic bacteria(non-electrochemically active)under the stimulation of the applied current.Taking advantage of the mutual interactions among the electricity,anode,and bacteria,this study provides a novel and compact process for the effective and energyefficient treatment of azo dye wastewater.
基金funded by the National Nature Science Foundation(Nos.21901110,52001265 and 12274356)Natural Science Foundation of Fujian Province(No.2021J01847)+3 种基金Fujian Provincial Department of Education Fund(No.JAT190337)Fujian Provincial Department of Science and Technology(No.2019J06001)the Open Fund of Xiamen Key Laboratory of Marine Corrosion and Smart Protective Materialsthe 111 Project(No.B16029)。
文摘Functional carbon nanomaterials have become the stars of many active research fields,such as electronics,energy,catalysis,imaging,sensing and biomedicine.Herein,a facile and one-pot strategy for generating ferromagnetic nanoparticles loaded on N-doped carbon nanosheets(Fe-N-CNS)is presented by salt-assisted high-temperature carbonization of natural silk proteins.Due to their graphitic structures,N-doping and ferromagnetic nanoparticles(FeN_(x),FeO_(y),FeC_(z)),the silk-derived Fe-N-CNS can act as excellent mimics of both peroxidase and oxidase.Benefiting from the combined character of the graphene-like structures and enzyme-like activities,Fe-N-CNS can be further applied to highly efficient dye removal via synergistic adsorption and degradation.Meanwhile,the as-prepared Fe-N-CNS with intrinsic magnetism and electrical conductivity can also serve as an efficient electromagnetic wave absorption agent.The broadest effective absorption bandwidth(EAB)of as-obtained absorbing material yields a 6.73 GHz with 1 mm thickness,with a maximum reflection loss of-37.33 dB(11.41 GHz).The EAB can cover2~18 GHz with a tunable absorber thickness from 1.0 mm to 5.0 mm.Collectively,Fe-N-CNS,as a dualfunctional material,can tackle the aggravating environmental pollution issues of both dyes and electromagnetic waves.
基金Financial support from the Fundamental Research Funds for the Central Universities(No.2019MS041)Postdoctoral Science Foundation of China(No.2021M690208)。
文摘Water pollution has become a serious problem owing to the development of society.Photocatalysis is a promising approach to remove various pollutants in water,such as organic pollutants and antibiotic resistance bacteria.Meanwhile,the design of heterojunction between two semiconductors is an effective path to improve photocatalytic properties due to its potential in improving separation and transfer of photoinduced carriers.In this study,Nb_(2)O_(5)/g-C_(3)N_(4)(NO/CN)composite materials were prepared through a one-step heating method.Characterizations confirmed successful preparation of NO/CN heterojunction structure and better optical properties than pure g-C_(3)N_(4) and Nb_(2)O_(5).NO/CN composite materials showed excellent photocatalytic efficiency for Escherichia coli(E.coli)inactivation(95%)compared with the pure Nb_(2)O_(5)(10%) and g-C_(3)N_(4)(77%).Meanwhile,NO/CN exhibited better organic pollutants removal(Rh B for94%,methyl orange(MO)for 15%and methylene blue(MB)for 87%)under visible light,which is likely owing to the heterojunction structure between g-C_(3)N_(4) and Nb_(2)O_(5) that leads to the good separation of photogenerated electron-hole pair.Free radical scavenging and electron spin resonance(ESR)experiments demonstrated that superoxide radicals(·O_(2)^(-)) and holes(h^(+)) were the dominant radicals.Therefore,the NO/CN was proposed to be a promising material for effective disinfection and removal of organic contaminants in water treatment.
基金National Key Projects for Fundamental Research and Development of China(No.2016YFB0600901)the National Natural Science Foundation of China(Nos.22038010,21536001,21878229 and 21978212)the Science and Technology Plans of Tianjin(Nos.19PTSYJC00020 and 20ZYJDJC00110).
文摘The introduction of mesoporosity into the microporous metal-organic frameworks(MOFs)is expected to expand their applications.Herein,we report a green and facile method to obtain hierarchically porous MOF structures by using an air-steam etching process.By virtue of the protonation reaction between the imidazole moiety and water vapor,the protonated imidazole related linkers leave the framework,resulting in the formation of mesopores in the zeolitic imidazolate frameworks(ZIFs),as exemplified by ZIF-8.Given the mild etching process,the materials'structural integrity and crystallinity are well maintained.Accordingly,the hierarchical porous ZIF-8 exhibited enhanced performance in the dye removal as well as CO_(2) cycloaddition reaction with epichlorohydrin in comparison with microporous ZIF-8,owing to the accelerated mass transfer arising from mesoporous structures.Remarkably,the proposed steam etching approach is generally applicable,which can be readily extended to other ZIFs,such as ZIF-14,ZIF-69,and ZIF-71,thus representing a powerful strategy to construct hierarchically porous MOF materials.
基金the financial support from the Natural Science Foundation of China(No.51908485)the Natural Science Foundation of Hebei province(Nos.E2020203185,B2020203033,B2018203331)the University Science and Technology Program Project of Hebei Provincial Department of Education(No.QN2020143).
文摘Hydrogen peroxide(H_(2)O_(2))disproportionation,iron precipitation,and narrow pH range are the drawbacks of traditional Fenton process.To surmount these barriers,we proposed a ferric ion(Fe^(3+))-ascorbic acid(AA)complex catalyzed calcium peroxide(CaO_(2))Fenton-like system to remove organic dyes in water.This collaborative Fe^(3+)/AA/CaO_(2)system presented an obvious improvement in the methyl orange(MO)decolorization,and also effectively eliminated other dyes.Response surface method was employed to optimize the running parameters for this coupling process.Under the optimized arguments(2.76 mmol/L Fe^(3+),0.68 mmol/L AA,and 4 mmol/L CaO_(2)),the MO removal achieved 98.90%after 15 min at pH 6.50,which was close to the computed outcome of 99.30%.Furthermore,this Fenton-like system could perform well in a wide range of pH(3-11),and enhance the H_(2)O_(2)decomposition and Fe ions recycle.The scavenger experiment result indicated that hydroxyl radical,superoxide anion free radical,and singlet oxygen were acted on the dye elimination.Moreover,electron spin resonance analysis corroborated that the existences of these active species in the Fe^(3+)/AA/CaO_(2)system.This study could advance the development of Fenton-like technique in organic effluent disposal.
文摘To valorize kraft lignin,hydroxymethylation and sulfonation were applied on this under-utilized,but vastly available,material.The hydroxymethylation pretreatment was conducted as means to improve the reactivity of lignin.The sulfonation of hydroxymethylated kraft lignin was investigated by sulfuric acid and sodium sulfite treatments under various conditions.The modified lignin samples were characterized for their charge density,solubility,elemental components,and molecular weights.The results showed that the hydroxymethylation facilitated the sulfonation by sodium sulfite,yielding a product(SSH-lignin)with the charge density of-1.2 meq/g and water solubility of 10 g/L under the conditions of Ns_(2)SO_(3)/lignin molar ratio of 0.49 mol/mol,95℃and 3 h.On the other hand,hydroxymethylation hindered the sulfonation of lignin by sulfuric acid,yielding a product(SAH-lignin)with the charge density of–0.46 meq/g and solubility of 0.9 g/L under the conditions of H_(2)SO_(4)/lignin molar ratio of 14.8 mol/mol,80℃and 1 h.The SSH-lignin had a high adsorption on kaolinite(17 mg/g)at a lignin concentration of 40 g/L.The sulfonated lignins were also found to be effective coagulant for the cationic dye ethyl violet.
