Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen producti...Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen production at room-temperature is kinetically slow and requires precious metal catalysts.In this work,it is found that the prepared Raney Ni W-r treated with high concentration of NaOH(6.25 mol/L)at 110℃exhibited excellent catalytic performance for AB hydrolysis at room temperature.The Raney Ni W-r can promote the AB complete hydrolysis within 60 s under basic condition at small sized trials,even higher than that of the 20%Pt/C catalyst.Its apparent activation energy at room temperature is only 26.6 kJ/mol and the turnover frequency(TOF)value is as high as 51.42 min-1.Owing to its high density and magnetic properties,the catalyst is very easy for magnetic separation.Furthermore,possible mechanism of the hydrolytic reaction of AB based on experimental results is proposed.As a well-established industrial catalyst,Raney Ni has been prepared on a large scale at low cost.This study provides a promising pathway for the large-scale preparation of low-cost and recyclable catalysts for AB hydrolysis.展开更多
With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysi...With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.展开更多
In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymeriz...In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymerization rate of waste PET bottles and the yield of TPA were conducted to determine the optimized experimental conditions,in terms of reaction time,reaction temperature,dosage of ethylene glycol and sodium bicarbonate,amount of distilled water and stirring rate.Then IR spectra and elemental analysis were carried out for the characterization of obtained product.Under optimal experimental conditions,over 98%PET can be depolymerized into the target product(TPA)and the purity and yield of TPA are over 97%and 94%,respectively.Both the experimental and analytical results support a feasible process for the preparation of TPA from waste PET.It is expected that this alcohol alkali hydrolysis method can promise an effective way for the sustainable recycling of waste PET.展开更多
A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide （COS）. The influences of the calcination temperature, additive content （2.5%-10.0% Fe2O3, ...A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide （COS）. The influences of the calcination temperature, additive content （2.5%-10.0% Fe2O3, mass fraction） and the basic density of the activation process were thoroughly investigated. The surface of catalysts was characterized by Boehm titration. The products were characterized by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS）. The results show that catalysts with 2.5%-5.0% Fe2O3 after calcining at 500 ℃ have superior activity. The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon（AC）, and the activity follows the order： KOH〉Na2CO3 〉NaHCO3. Boehm titration data clearly show that the total acidity increases （from 0.06 to 0.48 mmol/g） and the basic groups decrease （from 0.78 to 0.56 mmol/g） after COS hydrolysis and H2S adsorption. The XPS results show that the product of HzS may be absorbed by the interaction with metal compounds and 02 to form sulfate （171.28 eV） and element sulfur （164.44 eV）, which lead to catalysts poisoning.展开更多
To study the stereostructure by X-ray and the technology of extracting acankoreanogenin from the leaves of Acanthopanax graeilistylus W. W. Smith （AGS）, the crystal structure was measured with a Bruker APEX-Ⅱ area-...To study the stereostructure by X-ray and the technology of extracting acankoreanogenin from the leaves of Acanthopanax graeilistylus W. W. Smith （AGS）, the crystal structure was measured with a Bruker APEX-Ⅱ area-detector diffractometer instrument and the technology of extracting in combination hydrolysis in situ （ECHS） was compared with these of traditional methods. The crystal belongs to the monoclinic system, space group P2b with unit cell parameters： a=（8.3652±0.0006） nm, b=（24.721±0.002） nm, and c=（14.5587±0.0011） nm, α=90°, β=97.850 （4） °, γ=90 °, V=2982.51 nm3, Dc= 1.179 mg/m3, and the molecular number （Z） of elementary structures was 2. The comparisons show that the extraction rate of acankoreanogenin with ECHS methods is much higher than that of traditional methods. Then, central composite design-response surface methodology （CCD-RSM） was adopted for optimizing the extraction rate of ECHS methods. The optimized values of extraction parameters are as follows： for the for extraction process of acid hydrolysis are that extraction time 110.8 min, solvent-herb ratio 11.5 and acid content 5.25%; the best extraction process of basic hydrolysis are that extract time 120 min, solvent-herb ratio 8.7 and the alkali content 8.79%. Finally, the extracts were purified with decolorizing carbon after alkali solution and acid-isolation and purity of acankoreanogenin was 98.7%.展开更多
The hydrolysis process for Silver carp by-products was studied. Protein hydrolysate was prepared with proteolytic enzyme, Alcalase. Hydrolysis conditions were optimized by the regression model of three factors five le...The hydrolysis process for Silver carp by-products was studied. Protein hydrolysate was prepared with proteolytic enzyme, Alcalase. Hydrolysis conditions were optimized by the regression model of three factors five levels quadratic rotation perpendicular regressive design. The optimum hydrolysis conditions of hydrolyzing the protein of Silver carp by-products were determined to be concentration of enzyme (E/S) 3.33%, pH 8.54, hydrolyzing temperature 58 ℃, reaction time 90 min, concentration of substrate 8%. Nitrogen recovery was more than 75%.展开更多
The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hyd...The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.展开更多
The conformational and functional changes of soybean protein after a hybrid extrusion-hydrolysis method were evaluated.Three extrusion temperatures(60,80,and 100℃)were used prior to enzymatic hydrolysis.The hydrolysi...The conformational and functional changes of soybean protein after a hybrid extrusion-hydrolysis method were evaluated.Three extrusion temperatures(60,80,and 100℃)were used prior to enzymatic hydrolysis.The hydrolysis degrees,molecular weight profiles,solubilities,surface hydrophobicities,sulphydryl contents,disulfide bound,water holding capacity,emulsion,and foam properties of the protein isolated from the enzyme-hydrolyzed extruded soybeans were analyzed.It shows that extrusion caused significant changes in the hydrophobicity,molecular weight distribution,solubility,surface hydrophobicity,emulsification activity,and stability of the protein.The increase of molecular weights could be attributed to the formation of protein aggregates during extrusion.Extrusion and enzymatic hydrolysis led to a sharp increase in the number of disulfide bonds with a decrease of the sulphydryl group.The water holding capacity and the solubility of protein increased with the increase of extrusion temperature and hydrolysis time.Extrusion improved the emulsifying activity but reduced the emulsifying stability of the recovered proteins.Extrusion improved the foam capacity but reduced the foam stability of the proteins.The data demonstrated that the extrusion-hydrolysis treatment significantly altered the conformational and functional properties of soybean protein,which may be further optimized for the development of new soy protein ingredient with desired functional properties.展开更多
Cod muscle protein was hydrolyzed by an alkaline protease in our study. The influences of hydrolysis temperature,fish protein concentration,and ratio of protease addition to protein amount on its degree of hy- drolysi...Cod muscle protein was hydrolyzed by an alkaline protease in our study. The influences of hydrolysis temperature,fish protein concentration,and ratio of protease addition to protein amount on its degree of hy- drolysis (DH) of protein were studied in details by applying dual quadratic rotary combinational design. The final results showed that more than 84% cod muscle protein could be hydrolyzed and recovered. Cod protein hydrolysate thus obtained had a balanced amino acid composition and mainly consisted of small peptides with molecule weight less than 6900 dalton.展开更多
Microsized single-crystalline Co3O4 has been synthesized by high-temperature hydrolysis of CoCD2H20 at 600℃. The samples were characterized by powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） an...Microsized single-crystalline Co3O4 has been synthesized by high-temperature hydrolysis of CoCD2H20 at 600℃. The samples were characterized by powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results reveal that the as-prepared powders are microsized single-crystalline CO3O4 with cubic spinel structure. An increase in the high-temperature hydrolysis time results in the evolution of particle shapes from cube to quasi-sphere, and then to octahedron. The effect of NaCl additive on the surface morphologies of Co3O4 particles was experimentally investigated. The results indicate that the NaCl additive acts as an inert disperse phase in the high-temperature hydrolysis, and prevents the aggregation of Co3O4 particles effectively.展开更多
Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to b...Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to be separated , and these process sometimes cause serious environmental problems in practical application of cellulose polymer degradation science.Herein , an efficient two-stage method for selective hydrolysis of lignocelluloses biomass is being developed in this paper by controlling of pH in an ionic liquid.The lignin-hemicelluloses matrix in corn stalk was hydrolyzed into xylose in 23.1% yield in the first stage ; and cellulose-rich residues from the first stage was by farther hydrolyzed to provide a glucose in 26.9%yield.Structure of the products were identified by 13 C NMR.It should be mentioned that , the ionic liquid which can be regenerated and reused throughout the process. The present work significantly opens an a new path to utilize each component of lignocellulose as raw materials producing biofuels , renewable energy and fine chemicals.展开更多
Limited enzymatic hydrolysis of skim milk by trypsin was investigated in this paper, and it was found that the degree of hydrolysis (DH) of milk proteins had a relationship of DH -1 =a+bt -1 with the time(t) o...Limited enzymatic hydrolysis of skim milk by trypsin was investigated in this paper, and it was found that the degree of hydrolysis (DH) of milk proteins had a relationship of DH -1 =a+bt -1 with the time(t) of hydrolysis at low enzyme concentrations, some properties of the protein such as NSI in PI or TCA were changed obviously. It was suggested that most milk proteins would be degraded into peptides by trypsin .展开更多
基金supported by the National Natural Science Foundation of China(21908135)Natural Science Foundation of Shanxi Datong University(2022K23)+1 种基金Graduate Research Innovation and Practice Innovation Projects of Shanxi Datong University(23CX31)Postgraduate Educational Reform and Research Program of Shanxi Datong University(23JG07)。
文摘Ammonia borane(AB)has received much attention as an environmentally friendly,non-toxic,room temperature stable hydrogen storage material with high hydrogen content of 19.6%.However,its hydrolysis for hydrogen production at room-temperature is kinetically slow and requires precious metal catalysts.In this work,it is found that the prepared Raney Ni W-r treated with high concentration of NaOH(6.25 mol/L)at 110℃exhibited excellent catalytic performance for AB hydrolysis at room temperature.The Raney Ni W-r can promote the AB complete hydrolysis within 60 s under basic condition at small sized trials,even higher than that of the 20%Pt/C catalyst.Its apparent activation energy at room temperature is only 26.6 kJ/mol and the turnover frequency(TOF)value is as high as 51.42 min-1.Owing to its high density and magnetic properties,the catalyst is very easy for magnetic separation.Furthermore,possible mechanism of the hydrolytic reaction of AB based on experimental results is proposed.As a well-established industrial catalyst,Raney Ni has been prepared on a large scale at low cost.This study provides a promising pathway for the large-scale preparation of low-cost and recyclable catalysts for AB hydrolysis.
文摘With the aim to effectively depolymerize polyethylene terephthalate(PET)under mild reaction conditions,PET methanolysis and dimethyl terephthalate(DMT)hydrolysis are integrated in a catalyst system.Firstly,methanolysis of PET to DMT is achieved over Cu-Mg-Al oxide catalyst.Next,terephthalic acid(TPA)is prepared by DMT hydrolysis.It is found that hydrolysis of DMT to TPA can be promoted by introducing trace amount of water in this catalyst system.CuO-MgO-4.5Al_2O_(3)catalyst demonstrates the excellent catalytic performance for the depolymerization of PET with high conversion rate and TPA yield(100%and 99.5%,respectively)after reaction at 160℃for 6 h,which provides a new idea for the depolymerization of PET.
基金Project(2016TP1007)supported by the Hunan Provincial Science and Technology Plan,China
文摘In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymerization rate of waste PET bottles and the yield of TPA were conducted to determine the optimized experimental conditions,in terms of reaction time,reaction temperature,dosage of ethylene glycol and sodium bicarbonate,amount of distilled water and stirring rate.Then IR spectra and elemental analysis were carried out for the characterization of obtained product.Under optimal experimental conditions,over 98%PET can be depolymerized into the target product(TPA)and the purity and yield of TPA are over 97%and 94%,respectively.Both the experimental and analytical results support a feasible process for the preparation of TPA from waste PET.It is expected that this alcohol alkali hydrolysis method can promise an effective way for the sustainable recycling of waste PET.
基金Project(50908110) supported by the National Natural Science Foundation of ChinaProject(2008AA062602) supported by the National High-Tech Research and Development Program of China+1 种基金Project(20090451431) supported by China Postdoctoral Science FoundationProject(2007PY01-10) supported by Young and Middle-aged Academic and Technical Back-up Personnel Program of Yunnan Province,China
文摘A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide （COS）. The influences of the calcination temperature, additive content （2.5%-10.0% Fe2O3, mass fraction） and the basic density of the activation process were thoroughly investigated. The surface of catalysts was characterized by Boehm titration. The products were characterized by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS）. The results show that catalysts with 2.5%-5.0% Fe2O3 after calcining at 500 ℃ have superior activity. The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon（AC）, and the activity follows the order： KOH〉Na2CO3 〉NaHCO3. Boehm titration data clearly show that the total acidity increases （from 0.06 to 0.48 mmol/g） and the basic groups decrease （from 0.78 to 0.56 mmol/g） after COS hydrolysis and H2S adsorption. The XPS results show that the product of HzS may be absorbed by the interaction with metal compounds and 02 to form sulfate （171.28 eV） and element sulfur （164.44 eV）, which lead to catalysts poisoning.
基金Project(11JJ2042)supported by the Natural Science Foundation of Hunan Province,ChinaProject supported by the "Twelfth Five-Year" Key Discipline of Hunan University of Chinese Medicine-Pharmaceutical Analysis Science,China+1 种基金Project(11K048)supported by the Innovation Platform and Open Foundation Program of Higher Colleges of Hunan Province,ChinaProject(K1207010-21)supported by the Changsha City Science and Technology Bureau Key Projects,China
文摘To study the stereostructure by X-ray and the technology of extracting acankoreanogenin from the leaves of Acanthopanax graeilistylus W. W. Smith （AGS）, the crystal structure was measured with a Bruker APEX-Ⅱ area-detector diffractometer instrument and the technology of extracting in combination hydrolysis in situ （ECHS） was compared with these of traditional methods. The crystal belongs to the monoclinic system, space group P2b with unit cell parameters： a=（8.3652±0.0006） nm, b=（24.721±0.002） nm, and c=（14.5587±0.0011） nm, α=90°, β=97.850 （4） °, γ=90 °, V=2982.51 nm3, Dc= 1.179 mg/m3, and the molecular number （Z） of elementary structures was 2. The comparisons show that the extraction rate of acankoreanogenin with ECHS methods is much higher than that of traditional methods. Then, central composite design-response surface methodology （CCD-RSM） was adopted for optimizing the extraction rate of ECHS methods. The optimized values of extraction parameters are as follows： for the for extraction process of acid hydrolysis are that extraction time 110.8 min, solvent-herb ratio 11.5 and acid content 5.25%; the best extraction process of basic hydrolysis are that extract time 120 min, solvent-herb ratio 8.7 and the alkali content 8.79%. Finally, the extracts were purified with decolorizing carbon after alkali solution and acid-isolation and purity of acankoreanogenin was 98.7%.
基金Heilongjiang Province Science and Technology Key Project
文摘The hydrolysis process for Silver carp by-products was studied. Protein hydrolysate was prepared with proteolytic enzyme, Alcalase. Hydrolysis conditions were optimized by the regression model of three factors five levels quadratic rotation perpendicular regressive design. The optimum hydrolysis conditions of hydrolyzing the protein of Silver carp by-products were determined to be concentration of enzyme (E/S) 3.33%, pH 8.54, hydrolyzing temperature 58 ℃, reaction time 90 min, concentration of substrate 8%. Nitrogen recovery was more than 75%.
文摘The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42,2.12 and 2.78 respectively based on the experimental data,in which the coefficients of diffusion resistance conform an exponential function. So,the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data,which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.
基金supported by the National Key Research and Development Program of China(2016YFD0401402)the National Natural Science Foundation of China(nos.3143000560,31301501,and 31571876)Fok Ying Tung Education Foundation(no.151032)
文摘The conformational and functional changes of soybean protein after a hybrid extrusion-hydrolysis method were evaluated.Three extrusion temperatures(60,80,and 100℃)were used prior to enzymatic hydrolysis.The hydrolysis degrees,molecular weight profiles,solubilities,surface hydrophobicities,sulphydryl contents,disulfide bound,water holding capacity,emulsion,and foam properties of the protein isolated from the enzyme-hydrolyzed extruded soybeans were analyzed.It shows that extrusion caused significant changes in the hydrophobicity,molecular weight distribution,solubility,surface hydrophobicity,emulsification activity,and stability of the protein.The increase of molecular weights could be attributed to the formation of protein aggregates during extrusion.Extrusion and enzymatic hydrolysis led to a sharp increase in the number of disulfide bonds with a decrease of the sulphydryl group.The water holding capacity and the solubility of protein increased with the increase of extrusion temperature and hydrolysis time.Extrusion improved the emulsifying activity but reduced the emulsifying stability of the recovered proteins.Extrusion improved the foam capacity but reduced the foam stability of the proteins.The data demonstrated that the extrusion-hydrolysis treatment significantly altered the conformational and functional properties of soybean protein,which may be further optimized for the development of new soy protein ingredient with desired functional properties.
文摘Cod muscle protein was hydrolyzed by an alkaline protease in our study. The influences of hydrolysis temperature,fish protein concentration,and ratio of protease addition to protein amount on its degree of hy- drolysis (DH) of protein were studied in details by applying dual quadratic rotary combinational design. The final results showed that more than 84% cod muscle protein could be hydrolyzed and recovered. Cod protein hydrolysate thus obtained had a balanced amino acid composition and mainly consisted of small peptides with molecule weight less than 6900 dalton.
基金Project(50704038) supported by the National Natural Science Foundation of ChinaProject(108170) supported by the Key Foundation of Ministry of Education,China
文摘Microsized single-crystalline Co3O4 has been synthesized by high-temperature hydrolysis of CoCD2H20 at 600℃. The samples were characterized by powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results reveal that the as-prepared powders are microsized single-crystalline CO3O4 with cubic spinel structure. An increase in the high-temperature hydrolysis time results in the evolution of particle shapes from cube to quasi-sphere, and then to octahedron. The effect of NaCl additive on the surface morphologies of Co3O4 particles was experimentally investigated. The results indicate that the NaCl additive acts as an inert disperse phase in the high-temperature hydrolysis, and prevents the aggregation of Co3O4 particles effectively.
文摘Although lots of basic studies , such as the hydrolysis and dissolution of lignocelluloses has made great progress in recent years , the hydrolysates containing complex mixture of pentose and hexose are very hard to be separated , and these process sometimes cause serious environmental problems in practical application of cellulose polymer degradation science.Herein , an efficient two-stage method for selective hydrolysis of lignocelluloses biomass is being developed in this paper by controlling of pH in an ionic liquid.The lignin-hemicelluloses matrix in corn stalk was hydrolyzed into xylose in 23.1% yield in the first stage ; and cellulose-rich residues from the first stage was by farther hydrolyzed to provide a glucose in 26.9%yield.Structure of the products were identified by 13 C NMR.It should be mentioned that , the ionic liquid which can be regenerated and reused throughout the process. The present work significantly opens an a new path to utilize each component of lignocellulose as raw materials producing biofuels , renewable energy and fine chemicals.
文摘Limited enzymatic hydrolysis of skim milk by trypsin was investigated in this paper, and it was found that the degree of hydrolysis (DH) of milk proteins had a relationship of DH -1 =a+bt -1 with the time(t) of hydrolysis at low enzyme concentrations, some properties of the protein such as NSI in PI or TCA were changed obviously. It was suggested that most milk proteins would be degraded into peptides by trypsin .
