Various azo compounds(Modified dyes)have been synthesised by chemical modification of areca nut extract(epicate-chin),a plant-based Polyphenolic compound to get semi-synthetic dyes.Three different primary amines namel...Various azo compounds(Modified dyes)have been synthesised by chemical modification of areca nut extract(epicate-chin),a plant-based Polyphenolic compound to get semi-synthetic dyes.Three different primary amines namely p-nitro aniline,p-anisidine and aniline,were diazotized to form their corresponding diazonium salts which were further coupled with an areca nut extract.Preliminary characterization of the areca nut extract and the resultant azo compounds(Modified dyes)was carried out in terms of melting point,solubility tests,thin layer chromatography,UV-Visible and FTIR spectroscopy.These modified dyes were further applied on polyester and nylon fabrics and%dye exhaustion was evaluated.Dyed fabrics were further tested for their fastness properties such as wash fastness,rubbing fastness,light fastness and sublimation fastness.The results of the fastness tests indicate that,all the three modified dyes have good dyeability for polyester and nylon fabrics.The dyed fabrics were also tested for ultraviolet protection factor which showed very good ultraviolet protection.展开更多
Cellulose nanocrystals(CNCs) have been widely applied in biomaterials and show great biocompatibility and mechanical strength. In this review, the chemical reactions applied in CNC surface modification and their appli...Cellulose nanocrystals(CNCs) have been widely applied in biomaterials and show great biocompatibility and mechanical strength. In this review, the chemical reactions applied in CNC surface modification and their application in CNC based biomaterials are introduced. Furthermore, the conjugation of different functional molecules and nanostructures to the surface of CNCs are discussed, with focus on the binding modes, reaction conditions, and reaction mechanisms. With this introduction, we hope to provide a clear view of the strategies for surface modification of CNCs and their application in biomaterials, thus providing an overall picture of promising CNC-based biomaterials and their production.展开更多
Layered double hydroxides are one class or kind of 2 D layered materials that are considered promising for use in the supercapacitor.Although there have been many studies on the structure,composition,properties,and el...Layered double hydroxides are one class or kind of 2 D layered materials that are considered promising for use in the supercapacitor.Although there have been many studies on the structure,composition,properties,and electrode fabrication of layered double hydroxides,none summarize the effects of various modification methods on the structure and performance of layered double hydroxides in the supercapacitor.In a bid to fill this gap,in this review,we summarize the progress of modification methods such as exfoliation,intercalation,vacancy,doping,phase transformation,and composition regulation of layered double hydroxides in the field of the supercapacitor and put forward some opinions regarding the progress of research on the methods used in modifying the layered double hydroxides.展开更多
In the phosphate buffer solution of pH＞7,the cysteine sensitized the electrochemiluminescence (ECL) of luminol.It could be modified on the surface of platinum electrode and furthermore adsorbing the luminol on its e...In the phosphate buffer solution of pH＞7,the cysteine sensitized the electrochemiluminescence (ECL) of luminol.It could be modified on the surface of platinum electrode and furthermore adsorbing the luminol on its exterior to construct an ECL sensor.The ECL intensity of this sensor was strong enough and very stable.There wasn't obvious decrease of ECL intensity for thirty times of using in 48 hours with the relative standard deviation (RSD) of 0.98%.It could be used to determine some quenching effective molecules such as superoxide dismutase (SOD) with negative response upon the concentration range from 4.8 IU/ml to 57.6 IU/ml.展开更多
In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate...In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na<sub>2</sub>O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na<sub>2</sub>O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.展开更多
Acylation has been shown to be an effective toolfor improving surface functional properties of plant proteins.Soy bean protein has been extensively modified throughchemical and enzvmatic treatments.Their effectiveness...Acylation has been shown to be an effective toolfor improving surface functional properties of plant proteins.Soy bean protein has been extensively modified throughchemical and enzvmatic treatments.Their effectiveness lies intheir high nutritional value and low cost,which promotetheir use as ingredients for the formulation of food products.This paper reports a complete review of chemical modificationof various proteins from plant and animal sources,The nutri-tive and toxicological aspects through in vitro and in vivotests are also described.展开更多
This study aimed to explore the adsorption performance of sludge-based activated carbon(SBC)towards dissolved organic matters(DOMs)removal from sewage,and investigated the modification effect of different types of che...This study aimed to explore the adsorption performance of sludge-based activated carbon(SBC)towards dissolved organic matters(DOMs)removal from sewage,and investigated the modification effect of different types of chemicals on the structure of synthesized SBC.Waste activated sludge(WAS)was used as a carbon source,and HCl,HNO 3,and Na OH were used as different types of chemicals to modify the SBC.With the aid of chemical activation,the modified SBC showed higher adsorption performances on DOMs removal with maximum adsorption of 29.05 mg/g and second-order constant(k)of 0.1367(L/mol/sec)due to the surface elution of ash and minerals by chemicals.The surface elemental composition of MSBC suggested that the content of C-C and C-O functional groups on the surface of modified sludge-based activated carbon(MSBC)played an important role on the adsorption capacities of MSBC towards DOMs removal in sewage.Additionally,the residual molecular weight of DOMs in sewage was investigated using a 3-dimension fluorescence excitationemission matrix(3 D-EEM)and high-performance size exclusion chromatography(HP-SEC).Results showed that the chemical modification significantly improved the adsorption capacity of MSBC on humic acids(HA)and aromatic proteins(APN),and both of Na OH-MSBC and HCl-MSBC were effective for a wide range of different AMW DOMs removal from sewage,while the HNO 3-MSBC exhibited poorly on AMW organics of 2,617 Da and 409 Da due to the reducing content of macropore.In brief,this study provides reference values for the impact of the chemicals of the activation stage before the SBCs application.展开更多
Global environmental concerns on the toxicity of lead-based piezoelectrics impel the great mass fervor on investigations of lead-free alternatives.Barium titanate(BaTiO3,BT)ceramics,the first discovered perovskite fer...Global environmental concerns on the toxicity of lead-based piezoelectrics impel the great mass fervor on investigations of lead-free alternatives.Barium titanate(BaTiO3,BT)ceramics,the first discovered perovskite ferroelectrics,were widely employed to fabricate dielectric capacitors from 1950s.Since a piezoelectric breakthrough was achieved via chemical modification,intensive researches have been performed embracing lead-free BT-based piezoelectrics and their extensional functionalities.In this review,we encompass the stateof-the-art progress on chemical modification tuning phase structure toward advanced electrical properties in BT-based ceramics.Generally,modulated regularity of cations substitution on phase transition is summarized and clarified.Then,we highlight the common methodologies of phase structure(phase boundary,relaxor phase,room-temperature phase transition,etc.)design for optimizing piezoelectricity,electrostrictive strain,electrocaloric,dielectric energy storage or permittivity performances,and cover the noticeable developments and relevant physical mechanisms.Finally,perspectives and challenges on future research issues are featured.This review proposes to exert the significant guidance and service for material design of BT-based and other lead-free perovskite materials with superior functionalities.展开更多
Silk extracted from the cocoon of silkworm has been used as textile materials for thousands of years.Recently,silk has been redefined as a protein-based biomaterial with great potential in biomedical applications owin...Silk extracted from the cocoon of silkworm has been used as textile materials for thousands of years.Recently,silk has been redefined as a protein-based biomaterial with great potential in biomedical applications owing to its excellent mechanical properties,biocompatibility,and biodegradability.With the advances in silk processing technologies,a broad range of intriguing silk-based functional biomaterials have been made and applied for various biomedical uses.However,most of these materials are based on natural silk proteins without chemical modification,leading to limited control of properties and functions(e.g.,biodegradability and bioactivity).A chemical toolbox for modifying the silk proteins is required to achieve versatile silk-based materials with precisely designed properties or functions for different applications.Furthermore,inspired by the traditional fine chemical industry based on synthetic chemistry,developing silk-based fine chemicals with special functions can significantly extend the applications of silk materials,particularly in biomedical fields.This review summarizes the recent progress on chemical modification of silk proteins,focusing on the methodologies and applications.We also discuss the challenges and opportunities of these chemically modified silk proteins.展开更多
Cutting fluid is crucial in ensuring surface quality and machining accuracy during machining.However,traditional mineral oil-based cutting fluids no longer meet modern machining’s health and environmental protection ...Cutting fluid is crucial in ensuring surface quality and machining accuracy during machining.However,traditional mineral oil-based cutting fluids no longer meet modern machining’s health and environmental protection require-ments.As a renewable,pollution-free alternative with excellent processing characteristics,vegetable oil has become an inevitable replacement.However,vegetable oil lacks oxidation stability,extreme pressure,and antiwear proper-ties,which are essential for machining requirements.The physicochemical characteristics of vegetable oils and the improved methods’application mechanism are not fully understood.This study aims to investigate the effects of viscosity,surface tension,and molecular structure of vegetable oil on cooling and lubricating properties.The mechanisms of autoxidation and high-temperature oxidation based on the molecular structure of vegetable oil are also discussed.The study further investigates the application mechanism and performance of chemical modification and antioxidant additives.The study shows that the propionic ester of methyl hydroxy-oleate obtained by epoxidation has an initial oxidation temperature of 175℃.The application mechanism and extreme pressure performance of conventional extreme pressure additives and nanoparticle additives were also investigated to solve the problem of insufficient oxidation resistance and extreme pressure performance of nanobiological lubricants.Finally,the study discusses the future prospects of vegetable oil for chemical modification and nanoparticle addition.The study provides theoretical guidance and technical support for the industrial application and scientific research of vegetable oil in the field of lubrication and cooling.It is expected to promote sustainable development in the manufacturing industry.展开更多
To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB...To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB by adopting appropriate synthesis strategies.By replacing 10% of HTPB binder in the propellant formulation,it can effectively enhance the interfacial bond strength between the propellant binder matrix and solid fillers(AP(ammonium perchlorate)and RDX(cyclotrimethylene-trinitramine)),the mechanical properties of the HTPB/AP/RDX/Al propellant were superior to blank control propellant with an improvement of 35.4% in tensile strength,62.0% enhancement in elongation at break,and reduce the propellant burn rate by 10.7% with any energy loss.The function mechanism of AEHTPB-CN was systematically elucidated through experiments and computer simulation techniques.The results show that the tertiary amine group in AEHTPB-CN can react with AP to form ammonium ionic bonds,and the hydroxyl and cyano groups can form hydrogen bonding interactions with AP,which enables AEHTPB-CN to be firmly adsorbed on the AP surface through chemical and physical interactions.For RDX,the interfacial bonding effect of AEHTPB-CN is attributed to their ability to form C-H···N≡C weak hydrogen bonding interaction between the cyano group and RDX methylene group.展开更多
Cellulose,a natural polymer material with abundant natural sources,is non-toxic,renewable,and biodegradable,making it one of the most promising green materials.Its inherent hydrophilicity dramatically limits the devel...Cellulose,a natural polymer material with abundant natural sources,is non-toxic,renewable,and biodegradable,making it one of the most promising green materials.Its inherent hydrophilicity dramatically limits the development and application of cellulose products.Hydrophobic modification can significantly change cellulose properties and endow it with additional functions depending on the types of modifying molecules.Controlled modification of cellulose by long-chain hydrophobic molecules is challenging.Significant advances took advantage of new reaction systems and copolymerization.This paper reviews recent innovations in long-chain cellulose hydrophobic modification.A brief value-adding assessment provides a reference for green changes of cellulose to make it fit for future applications.展开更多
This paper evaluates the adsorption capacity of chemically sugarcane bagasses with sodium hydroxide(SHS),citric acid(CAS),tartaric acid(TAS)and unmodified sugarcane bagasse(SB)for cadmium adsorption in water environme...This paper evaluates the adsorption capacity of chemically sugarcane bagasses with sodium hydroxide(SHS),citric acid(CAS),tartaric acid(TAS)and unmodified sugarcane bagasse(SB)for cadmium adsorption in water environment.The results prove adsorption capacity for Cd(II)increases after chemical modification and the adsorption fits perfectly with the Langmuir isotherm.CAS had the highest maximum adsorption capacity of 45.45 mg/g followed by TAS with 38.46 mg/g and SHS with 29.41 at optimum pH 5.0 and 120 minutes equilibrium time while 1 g SB removed 18.8 mg Cd(II)in the same conditions.The kinetics study of the process followed a pseudo-secondorder rate expression,that indicated a strong interaction between the biosorbents and adsorbate.The sugarcane bagasse and modified sugarcane bagasse were characterized by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)analysis.The chemical modification was confirmed by the presence of carboxyl and esters groups created at 1,738 cm-1.The estimation of acid groups in modified materials shows the enhancement of this group after modification.On the other hand,desorption studies showed the high leaching of cadmium ion from the biosorbent leading to the efficient reutilization of materials.展开更多
Tung oil(TO)/ultraviolet(UV)photo-composite curing material possesses the characteristics of low curing temperature,low material shrinkage and low environmental pollution.Accordingly,this material must be developed an...Tung oil(TO)/ultraviolet(UV)photo-composite curing material possesses the characteristics of low curing temperature,low material shrinkage and low environmental pollution.Accordingly,this material must be developed and utilized with the conjugated double bonds contained in the long chain of the main structure(α-tung acid)molecules in the refined TO.The aforementioned material can be chemically modified using a variety of chemical methods to develop a new TO-based UV photocurable material due to its unique chemical properties.This work reviews the research progress of TO/UV photo-composite curing materials in recent years.Firstly,the chemical structure and application of TO and UV Photocatalysis Technology were briefly introduced.Secondly,the research status of novel TO/UV photo-composite curing materials developed by the Diels-Alder reaction was discussed.The method and curing effect of the UVcuring system constructed by other chemically modified TO were also discussed.Thereafter,the application of TO in industrial production is introduced from four directions:the application of TO in biodiesel,the application in synthetic resin,the application in self-healing coating and microcapsules and other applications.Finally,the research and application prospects of TO/UV photo-composite curing materials were presented.展开更多
A facile "click chemistry" approach to functionalize 2D macromolecules of graphene oxide nanosheets with poly(ethylene glycol) of different molecular weights,polystyrene,palmitic acid and various amino acids...A facile "click chemistry" approach to functionalize 2D macromolecules of graphene oxide nanosheets with poly(ethylene glycol) of different molecular weights,polystyrene,palmitic acid and various amino acids was presented.FTIR,TGA,Raman spectroscopy,XPS,XRD,TEM,AFM and SEM were utilized to characterize the products.High degree of functionalization was achieved on the flat surfaces of graphene oxide,affording polymer-grafted 2D brushes and amino acids-immobilized nanosheets,which show improved solubility in organic solvents.The click chemistry strategy reported herein provides a facile and general method for functionalization of graphene oxide with macromolecules and desired biomolecules.展开更多
The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid...The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid waste in mining areas,coal gangue occupies a large area and pollutes the surrounding environment during the stacking process.Developing a method of resource utilization is thus a research hotspot.In this study,we modified spontaneous combustion gangue using NaOH,NaCl,and HCl by chemically modifying the minerals.We determined the optimal conditions for treating Fe^(2+) and Mn^(2+) in acid mine drainage with spontaneous combustion gangue and modified coal gangue using the single factor test method.Based on results of the static test,two dynamic test columns,column No.1(spontaneous combustion gangue)and column No.2(NaOH modified spontaneous combustion gangue),were constructed,and the repair effects of acid mine drainage were compared and analyzed using dynamic experiments.The results show that overall,NaOH modified spontaneous combustion gangue is the most efficient at removing the Fe^(2+) and Mn^(2+) in acid mine drainage.The optimal conditions for NaOH modification are an NaOH concentration of 3 mol/L,a liquid to solid ratio of 2 L/kg,and a modification time of 8 h.The overall efficiency of column No.2 at removing Fe^(2+) and Mn^(2+) from acid mine drainage is better than that of column No.1.Among them,the average removal efficiency of Fe^(2+)and Mn^(2+) from acid mine drainage in column No.2 were 97.73%and 44.82%,respectively.The above results show that NaOH modified spontaneous combustion gangue is a good adsorbent,which has application potential in wastewater remediation,as it can achieve the purpose of“treating dust with waste”.展开更多
To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes(SWNTs)growth at high temperature is the key for controlling the diameter of the SWNTs.In this letter,a facile app...To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes(SWNTs)growth at high temperature is the key for controlling the diameter of the SWNTs.In this letter,a facile approach to control the diameter and distribution of the SWNTs by improving the dispersion of the uniform Fe/Mo nanoparticles on silicon wafers with silica layer chemically modified by 1,1,1,3,3,3-hexamethyldisilazane under different conditions is reported.It is found that the dispersion of the catalyst nanoparticles on Si wafer surface can be improved greatly from hydrophilic to hydrophobic,and the diameter and distribution of the SWNTs depend strongly on the dispersion of the catalyst on the substrate surface.Well dispersion of the catalyst results in relatively smaller diameter and narrower distribution of the SWNTs due to the decrease of aggregation and enhancement of dispersion of the catalyst nanoparticles before growth.It is also found that the diameter of the superlong aligned SWNTs is smaller with more narrow distribution than that of random nanotubes.展开更多
Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some...Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some transition metals have been proved to catalyze the electrochemical conversion reaction of sulfur species.In this study,carbon encapsulated nickel nanoparticles(Ni@C)with a specific surface area of 146 m^(2)/g are shown to play a definitive electrocatalytic role for the sulfur cathode.With Ni@C incorporated,the Ni@C/G-S electrode achieved a better electrochemical performance than the G-S electrode.Moreover,the reversible capacity and cycle stability were further improved through chemical modifications of the carbon shell.The influence of doping with different elements on the Li-S battery performance was also investigated in detail.Higher specific capacities of 1229 mA·h/g,927 mA·h/g,and 830 mA·h/g were achieved at 0.2 C,0.5 C,and 1.0 C for the N-Ni@C-G/S electrode.Besides,the B-Ni@C-G/S electrode possessed a best cycle stability.展开更多
Limonoid bitterness is a serious problem in the citrus industry worldwide. Limonoid glucosyltransferase is an enzyme that catalyzes the conversion of bitter limonoid into non-bitter limonoid glucoside while retaining ...Limonoid bitterness is a serious problem in the citrus industry worldwide. Limonoid glucosyltransferase is an enzyme that catalyzes the conversion of bitter limonoid into non-bitter limonoid glucoside while retaining the health benefit of limonoids in the juice. The immobilization of this enzyme in a column can solve the juice bitterness problem. More information about the catalytic residues of the enzyme is needed in this immobilization process. Glutamate/aspartate,histidine,lysine,tryptophan,serine,and cysteine residues were chemi-cally modified to investigate their roles in the catalytic function of limonoid glucosyltransferase. Inactivation of the enzyme following modi-fication of carboxyl and imidazole moieties was a consequence of a loss in substrate binding and catalysis in the glucosyltransfer reaction. The modification of a single histidine residue completely destroyed the ability of limonoid glucosyltransferase to transfer the D-glucopyranosyl unit. Tryptophan seemed to have some role in maintaining the active conformation of the catalytic site. Lysine also seemed to have some direct or indirect role in this catalysis but the modification of serine and cysteine did not have any effect on catalysis. Therefore,we conclude that the carboxyl and imidazole groups containing amino acids are responsible for the catalytic action of the enzyme.展开更多
Organics of the phthalocyanine category have very good nonlinear optical properties. The single-walled carbon nanotubes were modified by using the phenoxy phthalocyanine. Characterization analysis was made by means of...Organics of the phthalocyanine category have very good nonlinear optical properties. The single-walled carbon nanotubes were modified by using the phenoxy phthalocyanine. Characterization analysis was made by means of the transmission electron microscope (TEM), ultraviolet visible absorptive spectra, fluorescent spectra and Raman spectra. Under the TEM, it was observed that the composite looked like sugarcoated haws. By comparing the ultraviolet visible absorptive spectra before and after absorption, it was disclosed that the spectral intensity and the intensity of the peaks in the fluorescent spectra dropped remarkably. This shows that the single-walled carbon nanotubes have absorbed a large number of phenoxy phthalocyanines. Raman analysis revealed that in the Raman spectra, the position of the main peaks of the single-walled carbon nanotubes after absorption moved in the direction of long waves. The analysis suggests that the movement of the Raman spectra results from the change in the state of the single-walled carbon nanotubes before and after absorption.展开更多
基金We highly acknowledge the University Grants Commission-Special Assistance Programme(UGC-SAP)-BSR SECTION for fellowship.
文摘Various azo compounds(Modified dyes)have been synthesised by chemical modification of areca nut extract(epicate-chin),a plant-based Polyphenolic compound to get semi-synthetic dyes.Three different primary amines namely p-nitro aniline,p-anisidine and aniline,were diazotized to form their corresponding diazonium salts which were further coupled with an areca nut extract.Preliminary characterization of the areca nut extract and the resultant azo compounds(Modified dyes)was carried out in terms of melting point,solubility tests,thin layer chromatography,UV-Visible and FTIR spectroscopy.These modified dyes were further applied on polyester and nylon fabrics and%dye exhaustion was evaluated.Dyed fabrics were further tested for their fastness properties such as wash fastness,rubbing fastness,light fastness and sublimation fastness.The results of the fastness tests indicate that,all the three modified dyes have good dyeability for polyester and nylon fabrics.The dyed fabrics were also tested for ultraviolet protection factor which showed very good ultraviolet protection.
基金National Natural Science Foundation of China(51373131)Fundamental Research Funds for the Central Universities(XDJK2016A017,XDJK2016C033,and WUT-2014-II-009)+1 种基金Project of Basic Science and Advanced Technology Research,Chongqing Science and Technology Commission(cstc2016,jcyjA0796)the Talent Project of Southwest University(SWU115034)
文摘Cellulose nanocrystals(CNCs) have been widely applied in biomaterials and show great biocompatibility and mechanical strength. In this review, the chemical reactions applied in CNC surface modification and their application in CNC based biomaterials are introduced. Furthermore, the conjugation of different functional molecules and nanostructures to the surface of CNCs are discussed, with focus on the binding modes, reaction conditions, and reaction mechanisms. With this introduction, we hope to provide a clear view of the strategies for surface modification of CNCs and their application in biomaterials, thus providing an overall picture of promising CNC-based biomaterials and their production.
基金The authors gratefully acknowledge the financial support provided by the project of Technological Innovation and Application Development in Chongqing(cstc2019jscxmsxm0378)the National Natural Science Foundation of China(Grant No.21576034 and 51908092)+1 种基金the State Education Ministry and Fundamental Research Funds for the Central Universities(2019CDQYCL042,2019CDXYCL0031,106112017CDJXSYY0001,2018CDYJSY0055,106112017CDJQJ138802,106112017CDJSK04XK11,and 2018CDQYCL0027)the Joint Funds of the National Natural Science Foundation of China-Guangdong(Grant No.U1801254).
文摘Layered double hydroxides are one class or kind of 2 D layered materials that are considered promising for use in the supercapacitor.Although there have been many studies on the structure,composition,properties,and electrode fabrication of layered double hydroxides,none summarize the effects of various modification methods on the structure and performance of layered double hydroxides in the supercapacitor.In a bid to fill this gap,in this review,we summarize the progress of modification methods such as exfoliation,intercalation,vacancy,doping,phase transformation,and composition regulation of layered double hydroxides in the field of the supercapacitor and put forward some opinions regarding the progress of research on the methods used in modifying the layered double hydroxides.
文摘In the phosphate buffer solution of pH＞7,the cysteine sensitized the electrochemiluminescence (ECL) of luminol.It could be modified on the surface of platinum electrode and furthermore adsorbing the luminol on its exterior to construct an ECL sensor.The ECL intensity of this sensor was strong enough and very stable.There wasn't obvious decrease of ECL intensity for thirty times of using in 48 hours with the relative standard deviation (RSD) of 0.98%.It could be used to determine some quenching effective molecules such as superoxide dismutase (SOD) with negative response upon the concentration range from 4.8 IU/ml to 57.6 IU/ml.
文摘In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na<sub>2</sub>O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na<sub>2</sub>O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.
文摘Acylation has been shown to be an effective toolfor improving surface functional properties of plant proteins.Soy bean protein has been extensively modified throughchemical and enzvmatic treatments.Their effectiveness lies intheir high nutritional value and low cost,which promotetheir use as ingredients for the formulation of food products.This paper reports a complete review of chemical modificationof various proteins from plant and animal sources,The nutri-tive and toxicological aspects through in vitro and in vivotests are also described.
基金the National Natural Science Foundation of China(Nos.51678546 and 41630318)the Chinese Universities Scientific Fund for Gradle plan of the China University of Geosciences(Wuhan)the National water pollution control and management technology major projects(Nos.2018ZX07105003 and 2018ZX 07110004)。
文摘This study aimed to explore the adsorption performance of sludge-based activated carbon(SBC)towards dissolved organic matters(DOMs)removal from sewage,and investigated the modification effect of different types of chemicals on the structure of synthesized SBC.Waste activated sludge(WAS)was used as a carbon source,and HCl,HNO 3,and Na OH were used as different types of chemicals to modify the SBC.With the aid of chemical activation,the modified SBC showed higher adsorption performances on DOMs removal with maximum adsorption of 29.05 mg/g and second-order constant(k)of 0.1367(L/mol/sec)due to the surface elution of ash and minerals by chemicals.The surface elemental composition of MSBC suggested that the content of C-C and C-O functional groups on the surface of modified sludge-based activated carbon(MSBC)played an important role on the adsorption capacities of MSBC towards DOMs removal in sewage.Additionally,the residual molecular weight of DOMs in sewage was investigated using a 3-dimension fluorescence excitationemission matrix(3 D-EEM)and high-performance size exclusion chromatography(HP-SEC).Results showed that the chemical modification significantly improved the adsorption capacity of MSBC on humic acids(HA)and aromatic proteins(APN),and both of Na OH-MSBC and HCl-MSBC were effective for a wide range of different AMW DOMs removal from sewage,while the HNO 3-MSBC exhibited poorly on AMW organics of 2,617 Da and 409 Da due to the reducing content of macropore.In brief,this study provides reference values for the impact of the chemicals of the activation stage before the SBCs application.
基金Key Technologies Research and Development Program of Sichuan Province,Grant/Award Number:2018JY0007National Natural Science Foundation of China,Grant/Award Number:51722208。
文摘Global environmental concerns on the toxicity of lead-based piezoelectrics impel the great mass fervor on investigations of lead-free alternatives.Barium titanate(BaTiO3,BT)ceramics,the first discovered perovskite ferroelectrics,were widely employed to fabricate dielectric capacitors from 1950s.Since a piezoelectric breakthrough was achieved via chemical modification,intensive researches have been performed embracing lead-free BT-based piezoelectrics and their extensional functionalities.In this review,we encompass the stateof-the-art progress on chemical modification tuning phase structure toward advanced electrical properties in BT-based ceramics.Generally,modulated regularity of cations substitution on phase transition is summarized and clarified.Then,we highlight the common methodologies of phase structure(phase boundary,relaxor phase,room-temperature phase transition,etc.)design for optimizing piezoelectricity,electrostrictive strain,electrocaloric,dielectric energy storage or permittivity performances,and cover the noticeable developments and relevant physical mechanisms.Finally,perspectives and challenges on future research issues are featured.This review proposes to exert the significant guidance and service for material design of BT-based and other lead-free perovskite materials with superior functionalities.
基金This work was supported by National Natural Science Foundation of China(No.52103129)Foundation of Westlake University.
文摘Silk extracted from the cocoon of silkworm has been used as textile materials for thousands of years.Recently,silk has been redefined as a protein-based biomaterial with great potential in biomedical applications owing to its excellent mechanical properties,biocompatibility,and biodegradability.With the advances in silk processing technologies,a broad range of intriguing silk-based functional biomaterials have been made and applied for various biomedical uses.However,most of these materials are based on natural silk proteins without chemical modification,leading to limited control of properties and functions(e.g.,biodegradability and bioactivity).A chemical toolbox for modifying the silk proteins is required to achieve versatile silk-based materials with precisely designed properties or functions for different applications.Furthermore,inspired by the traditional fine chemical industry based on synthetic chemistry,developing silk-based fine chemicals with special functions can significantly extend the applications of silk materials,particularly in biomedical fields.This review summarizes the recent progress on chemical modification of silk proteins,focusing on the methodologies and applications.We also discuss the challenges and opportunities of these chemically modified silk proteins.
基金Supported by National Key Research and Development Program of China(Grant No.2020YFB2010500)National Natural Science Foundation of China(Grant Nos.51975305,52105457)Shandong Provincial Natural Science Foundation of China(Grant No.ZR2020KE027).
文摘Cutting fluid is crucial in ensuring surface quality and machining accuracy during machining.However,traditional mineral oil-based cutting fluids no longer meet modern machining’s health and environmental protection require-ments.As a renewable,pollution-free alternative with excellent processing characteristics,vegetable oil has become an inevitable replacement.However,vegetable oil lacks oxidation stability,extreme pressure,and antiwear proper-ties,which are essential for machining requirements.The physicochemical characteristics of vegetable oils and the improved methods’application mechanism are not fully understood.This study aims to investigate the effects of viscosity,surface tension,and molecular structure of vegetable oil on cooling and lubricating properties.The mechanisms of autoxidation and high-temperature oxidation based on the molecular structure of vegetable oil are also discussed.The study further investigates the application mechanism and performance of chemical modification and antioxidant additives.The study shows that the propionic ester of methyl hydroxy-oleate obtained by epoxidation has an initial oxidation temperature of 175℃.The application mechanism and extreme pressure performance of conventional extreme pressure additives and nanoparticle additives were also investigated to solve the problem of insufficient oxidation resistance and extreme pressure performance of nanobiological lubricants.Finally,the study discusses the future prospects of vegetable oil for chemical modification and nanoparticle addition.The study provides theoretical guidance and technical support for the industrial application and scientific research of vegetable oil in the field of lubrication and cooling.It is expected to promote sustainable development in the manufacturing industry.
文摘To simplify the composite propellant formulation and address the current issue of the single-functionality present in existing additives,the multi-cyano,amine-based polybutadiene(AEHTPB-CN)was prepared based on AEHTPB by adopting appropriate synthesis strategies.By replacing 10% of HTPB binder in the propellant formulation,it can effectively enhance the interfacial bond strength between the propellant binder matrix and solid fillers(AP(ammonium perchlorate)and RDX(cyclotrimethylene-trinitramine)),the mechanical properties of the HTPB/AP/RDX/Al propellant were superior to blank control propellant with an improvement of 35.4% in tensile strength,62.0% enhancement in elongation at break,and reduce the propellant burn rate by 10.7% with any energy loss.The function mechanism of AEHTPB-CN was systematically elucidated through experiments and computer simulation techniques.The results show that the tertiary amine group in AEHTPB-CN can react with AP to form ammonium ionic bonds,and the hydroxyl and cyano groups can form hydrogen bonding interactions with AP,which enables AEHTPB-CN to be firmly adsorbed on the AP surface through chemical and physical interactions.For RDX,the interfacial bonding effect of AEHTPB-CN is attributed to their ability to form C-H···N≡C weak hydrogen bonding interaction between the cyano group and RDX methylene group.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(No.51673072)the Fundamental Research Funds for the Central Universities and South China University of Technology(Nos.2019ZD31 and 2019PY13).
文摘Cellulose,a natural polymer material with abundant natural sources,is non-toxic,renewable,and biodegradable,making it one of the most promising green materials.Its inherent hydrophilicity dramatically limits the development and application of cellulose products.Hydrophobic modification can significantly change cellulose properties and endow it with additional functions depending on the types of modifying molecules.Controlled modification of cellulose by long-chain hydrophobic molecules is challenging.Significant advances took advantage of new reaction systems and copolymerization.This paper reviews recent innovations in long-chain cellulose hydrophobic modification.A brief value-adding assessment provides a reference for green changes of cellulose to make it fit for future applications.
文摘This paper evaluates the adsorption capacity of chemically sugarcane bagasses with sodium hydroxide(SHS),citric acid(CAS),tartaric acid(TAS)and unmodified sugarcane bagasse(SB)for cadmium adsorption in water environment.The results prove adsorption capacity for Cd(II)increases after chemical modification and the adsorption fits perfectly with the Langmuir isotherm.CAS had the highest maximum adsorption capacity of 45.45 mg/g followed by TAS with 38.46 mg/g and SHS with 29.41 at optimum pH 5.0 and 120 minutes equilibrium time while 1 g SB removed 18.8 mg Cd(II)in the same conditions.The kinetics study of the process followed a pseudo-secondorder rate expression,that indicated a strong interaction between the biosorbents and adsorbate.The sugarcane bagasse and modified sugarcane bagasse were characterized by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)analysis.The chemical modification was confirmed by the presence of carboxyl and esters groups created at 1,738 cm-1.The estimation of acid groups in modified materials shows the enhancement of this group after modification.On the other hand,desorption studies showed the high leaching of cadmium ion from the biosorbent leading to the efficient reutilization of materials.
基金funded by Major Landmark Innovation Demonstration Project,2019XK2002Changsha Functional Oil Technology Innovation Center,KH2101007Hunan Forestry Bureau Outstanding Training Research Project,XLK202108-2.
文摘Tung oil(TO)/ultraviolet(UV)photo-composite curing material possesses the characteristics of low curing temperature,low material shrinkage and low environmental pollution.Accordingly,this material must be developed and utilized with the conjugated double bonds contained in the long chain of the main structure(α-tung acid)molecules in the refined TO.The aforementioned material can be chemically modified using a variety of chemical methods to develop a new TO-based UV photocurable material due to its unique chemical properties.This work reviews the research progress of TO/UV photo-composite curing materials in recent years.Firstly,the chemical structure and application of TO and UV Photocatalysis Technology were briefly introduced.Secondly,the research status of novel TO/UV photo-composite curing materials developed by the Diels-Alder reaction was discussed.The method and curing effect of the UVcuring system constructed by other chemically modified TO were also discussed.Thereafter,the application of TO in industrial production is introduced from four directions:the application of TO in biodiesel,the application in synthetic resin,the application in self-healing coating and microcapsules and other applications.Finally,the research and application prospects of TO/UV photo-composite curing materials were presented.
基金financially supported by the National Natural Science Foundation of China (No.50773038,and No.20974093)National Basic Research Program of China (973 Program) (No.2007CB936000)+2 种基金Qianjiang Talent Foundation of Zhejiang Province (2010R10021)the Fundamental Research Funds for the Central Universities (2009QNA4040)the Foundation for the Author of National Excellent Doctoral Dissertation of China (No.200527)
文摘A facile "click chemistry" approach to functionalize 2D macromolecules of graphene oxide nanosheets with poly(ethylene glycol) of different molecular weights,polystyrene,palmitic acid and various amino acids was presented.FTIR,TGA,Raman spectroscopy,XPS,XRD,TEM,AFM and SEM were utilized to characterize the products.High degree of functionalization was achieved on the flat surfaces of graphene oxide,affording polymer-grafted 2D brushes and amino acids-immobilized nanosheets,which show improved solubility in organic solvents.The click chemistry strategy reported herein provides a facile and general method for functionalization of graphene oxide with macromolecules and desired biomolecules.
基金This work was supported by the National Natural Science Foundation of China(Nos.51304114,41672247)the Scientific Research Fund of the Liaoning Provincial Education Department(No.LJ2017FAL016).
文摘The high concentrations of Fe^(2+) and Mn^(2+) in acid mine drainage make it difficult and expensive to treat.It is urgent that we find a cheap and efficient adsorption material to treat Fe^(2+) and Mn^(2+).As a solid waste in mining areas,coal gangue occupies a large area and pollutes the surrounding environment during the stacking process.Developing a method of resource utilization is thus a research hotspot.In this study,we modified spontaneous combustion gangue using NaOH,NaCl,and HCl by chemically modifying the minerals.We determined the optimal conditions for treating Fe^(2+) and Mn^(2+) in acid mine drainage with spontaneous combustion gangue and modified coal gangue using the single factor test method.Based on results of the static test,two dynamic test columns,column No.1(spontaneous combustion gangue)and column No.2(NaOH modified spontaneous combustion gangue),were constructed,and the repair effects of acid mine drainage were compared and analyzed using dynamic experiments.The results show that overall,NaOH modified spontaneous combustion gangue is the most efficient at removing the Fe^(2+) and Mn^(2+) in acid mine drainage.The optimal conditions for NaOH modification are an NaOH concentration of 3 mol/L,a liquid to solid ratio of 2 L/kg,and a modification time of 8 h.The overall efficiency of column No.2 at removing Fe^(2+) and Mn^(2+) from acid mine drainage is better than that of column No.1.Among them,the average removal efficiency of Fe^(2+)and Mn^(2+) from acid mine drainage in column No.2 were 97.73%and 44.82%,respectively.The above results show that NaOH modified spontaneous combustion gangue is a good adsorbent,which has application potential in wastewater remediation,as it can achieve the purpose of“treating dust with waste”.
基金financial support from NSFC(2117315951420105002)
文摘To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes(SWNTs)growth at high temperature is the key for controlling the diameter of the SWNTs.In this letter,a facile approach to control the diameter and distribution of the SWNTs by improving the dispersion of the uniform Fe/Mo nanoparticles on silicon wafers with silica layer chemically modified by 1,1,1,3,3,3-hexamethyldisilazane under different conditions is reported.It is found that the dispersion of the catalyst nanoparticles on Si wafer surface can be improved greatly from hydrophilic to hydrophobic,and the diameter and distribution of the SWNTs depend strongly on the dispersion of the catalyst on the substrate surface.Well dispersion of the catalyst results in relatively smaller diameter and narrower distribution of the SWNTs due to the decrease of aggregation and enhancement of dispersion of the catalyst nanoparticles before growth.It is also found that the diameter of the superlong aligned SWNTs is smaller with more narrow distribution than that of random nanotubes.
基金This work was financially supported by the China Petrochemical Corporation(218025-9).
文摘Lithium sulfur(Li-S)batteries are poised to be the next generation of high-density energy storage devices.In recent years,the concept of“electrocatalysis”has been introduced into the field of Li-S batteries,and some transition metals have been proved to catalyze the electrochemical conversion reaction of sulfur species.In this study,carbon encapsulated nickel nanoparticles(Ni@C)with a specific surface area of 146 m^(2)/g are shown to play a definitive electrocatalytic role for the sulfur cathode.With Ni@C incorporated,the Ni@C/G-S electrode achieved a better electrochemical performance than the G-S electrode.Moreover,the reversible capacity and cycle stability were further improved through chemical modifications of the carbon shell.The influence of doping with different elements on the Li-S battery performance was also investigated in detail.Higher specific capacities of 1229 mA·h/g,927 mA·h/g,and 830 mA·h/g were achieved at 0.2 C,0.5 C,and 1.0 C for the N-Ni@C-G/S electrode.Besides,the B-Ni@C-G/S electrode possessed a best cycle stability.
基金Supported by Ministry of Education,Culture,Sports,Science and Technology of Japan
文摘Limonoid bitterness is a serious problem in the citrus industry worldwide. Limonoid glucosyltransferase is an enzyme that catalyzes the conversion of bitter limonoid into non-bitter limonoid glucoside while retaining the health benefit of limonoids in the juice. The immobilization of this enzyme in a column can solve the juice bitterness problem. More information about the catalytic residues of the enzyme is needed in this immobilization process. Glutamate/aspartate,histidine,lysine,tryptophan,serine,and cysteine residues were chemi-cally modified to investigate their roles in the catalytic function of limonoid glucosyltransferase. Inactivation of the enzyme following modi-fication of carboxyl and imidazole moieties was a consequence of a loss in substrate binding and catalysis in the glucosyltransfer reaction. The modification of a single histidine residue completely destroyed the ability of limonoid glucosyltransferase to transfer the D-glucopyranosyl unit. Tryptophan seemed to have some role in maintaining the active conformation of the catalytic site. Lysine also seemed to have some direct or indirect role in this catalysis but the modification of serine and cysteine did not have any effect on catalysis. Therefore,we conclude that the carboxyl and imidazole groups containing amino acids are responsible for the catalytic action of the enzyme.
文摘Organics of the phthalocyanine category have very good nonlinear optical properties. The single-walled carbon nanotubes were modified by using the phenoxy phthalocyanine. Characterization analysis was made by means of the transmission electron microscope (TEM), ultraviolet visible absorptive spectra, fluorescent spectra and Raman spectra. Under the TEM, it was observed that the composite looked like sugarcoated haws. By comparing the ultraviolet visible absorptive spectra before and after absorption, it was disclosed that the spectral intensity and the intensity of the peaks in the fluorescent spectra dropped remarkably. This shows that the single-walled carbon nanotubes have absorbed a large number of phenoxy phthalocyanines. Raman analysis revealed that in the Raman spectra, the position of the main peaks of the single-walled carbon nanotubes after absorption moved in the direction of long waves. The analysis suggests that the movement of the Raman spectra results from the change in the state of the single-walled carbon nanotubes before and after absorption.
