Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaO...Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.展开更多
The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an effic...The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an efficient methodology via the co-reaction of K-feldspar and phosphogypsum for the extraction of soluble potassium salts and recovery of SO_2 with reduced CO_2 emission and energy consumption. The results of characterization and reactivity evaluation indicated that the partial melting of K-feldspar and phosphogypsum in the hightemperature co-reaction significantly facilitated the reduction of phosphogypsum to SO_2 and the exchange of K^+(K-feldspar) with Ca^(2+)(CaSO_4 in phosphogypsum). The reaction parameters were systematically investigated with the highest sulfur recovery ratio of ~ 60% and K extraction ratio of ~ 87.7%. This novel methodology possesses an energy consumption reduction of ~ 28% and CO_2 emission reduction of ~ 55% comparing with the present typical commercial technologies for utilization of K-feldspar and the treatment of phosphogypsum.展开更多
Post-combustion CO_2 capture(PCC) process faces significant challenge of high regeneration energy consumption.Biphasic absorbent is a promising alternative candidate which could significantly reduce the regeneration e...Post-combustion CO_2 capture(PCC) process faces significant challenge of high regeneration energy consumption.Biphasic absorbent is a promising alternative candidate which could significantly reduce the regeneration energy consumption because only the CO_2-concentrated phase should be regenerated. In this work, aqueous solutions of triethylenetetramine(TETA) and N,N-diethylethanolamine(DEEA) are found to be efficient biphasic absorbents of CO_2. The effects of the solvent composition, total amine concentration, and temperature on the absorption behavior, as well as the effect of temperature on the desorption behavior of TETA–DEEA–H2 O system were investigated. An aqueous solution of 1 mol·L-1 TETA and 4 mol·L-1 DEEA spontaneously separates into two liquid phases after a certain amount of CO_2 is absorbed and it shows high CO_2 absorption/desorption performance.About 99.4% of the absorbed CO_2 is found in the lower phase, which corresponds to a CO_2 absorption capacity of 3.44 mol·kg-1. The appropriate absorption and desorption temperatures are found to be 30 °C and 90 °C,respectively. The thermal analysis indicates that the heat of absorption of the 1 mol·L-1 TETA and 4 mol·L-1 DEEA solution is-84.38 kJ·(mol CO_2)-1 which is 6.92 kJ·(mol CO_2)-1 less than that of aqueous MEA. The reaction heat, sensible heat, and the vaporization heat of the TETA–DEEA–H2 O system are lower than that of the aqueous MEA, while its CO_2 capacity is higher. Thus the TETA–DEEA–H2 O system is potentially a better absorbent for the post-combustion CO_2 capture process.展开更多
An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtaine...An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 ℃(ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 ℃ for30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Bronsted acid sites ratio for ST-450 induced by bidentate ligands between SO4^2-and TiO2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm^3·g^-1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 ℃ exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO4^2-and TiO2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.展开更多
Food allergy is one of the most important food safety problems that has attracted increasing attention.The food allergy experimental models provide not only the accurate allergen detection and evaluation methods but a...Food allergy is one of the most important food safety problems that has attracted increasing attention.The food allergy experimental models provide not only the accurate allergen detection and evaluation methods but also the powerful approaches for mechanism investigations.In this paper,we reviewed the common food allergy cell models including mast cell,basophil granulocyte and basophil,as well as the animal models of BALB/c mouse,C3H/HeJ mouse,and BN rat.We also introduced zebrafish,a promising model organism for investigating immunity though lacking direct applications in food allergy to date,and focused on traumatic inflammation,bacterial infection and viral infection models.In addition,we also summarized the clinical diagnostic research methods for food allergy.The elucidation of these topics will help researchers to understand the characteristics and mechanisms of various models and thus select the proper models for particular study,so as to support further investigations of food allergy.展开更多
The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantl...The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.展开更多
Kiln phosphoric acid(KPA)technology could produce P2O5 with high purity and has been applied in thermal phosphoric acid industry;however the formation of fouling in the high-temperature rotary kiln restricts the stabl...Kiln phosphoric acid(KPA)technology could produce P2O5 with high purity and has been applied in thermal phosphoric acid industry;however the formation of fouling in the high-temperature rotary kiln restricts the stable and long-term operation.In this paper,the reaction of phosphate ores with gaseous P2O5 was investigated in a high-temperature reactor,and the Ca O-SiO2-P2O5 ternary phase diagram was analyzed to understand the fouling formation mechanism.The results showed that the low-melting-point products,such as Ca(PO3)2and Ca2P2O7,are responsible for the fouling in the KPA process.In addition,a small amount of impurities,e.g.,aluminum and iron,could facilitate the generation of the low-melting-point products and cause serious fouling.Based on the high-temperature SiO2-P2O5 and CaO-SiO2-P2O5 phase diagram analysis,the control of Si/Ca molar ratio(e.g.,Si/Ca=2.0)was found to avoid fouling formation in the kiln.These results could provide the operation parameters of reaction temperature and feeds composition to suppress the fouling in the kiln reactor for the phosphoric acid production in industry.展开更多
TiO2 pigments are typically coated with inert layers to suppress the photocatalytic activity and improve the weatherability. However, the traditional inert layers have a lower refractive index compared to TiO2, and th...TiO2 pigments are typically coated with inert layers to suppress the photocatalytic activity and improve the weatherability. However, the traditional inert layers have a lower refractive index compared to TiO2, and therefore reduce the lightening power of TiO2. In the present work, a uniform, amorphous, 2.9-nm-thick TiO2 protective layer was deposited onto the surface of anatase TiO2 pigments according to pulsed chemical vapor deposition at room temperature, with Ti Cl4 as titanium precursor. Amorphous TiO2 coating layers exhibited poor photocatalytic activity, leading to a boosted weatherability. Similarly, this coating method is also effective for TiO2 coating with amorphous SiO2 and SnO2 layers. However, the lightening power of amorphous TiO2 layer is higher than those of amorphous SiO2 and SnO2 layers. According to the measurements of photoluminescence lifetime, surface photocurrent density, charge-transfer resistance, and electron spin resonance spectroscopy, it is revealed that the amorphous layer can prevent the migration of photogenerated electrons and holes onto the surface, decreasing the densities of surface electron and hole, and thereby suppress the photocatalytic activity.展开更多
Gas–liquid mass transfer of rotating disk reactor was studied in CO2 absorption using 1,8-diazabicyclo-[5.4.0]-undec-7-ene(DBU)-glycerol solution as solvent. Effects of the rotating disk structure and various operati...Gas–liquid mass transfer of rotating disk reactor was studied in CO2 absorption using 1,8-diazabicyclo-[5.4.0]-undec-7-ene(DBU)-glycerol solution as solvent. Effects of the rotating disk structure and various operation parameters on the CO2 absorption rate and CO2 removal efficiency were investigated. The rotating disk with optimal holes is conducive to mass transfer of CO2 and the formation of thin liquid film at the opening increases the gas–liquid contact area. With the increase of rotating speed, the liquid flow pattern on the rotating disk surface changes from thin film flow to separated streams and creates extra liquid lines attached to the rim of the disk,which leads to a very complicated change on the CO2 absorption rate and CO2 removal efficiency. The overall gas-phase mass transfer coefficient increases 138% as the rotating speed increasing from 250 to 1400 r·min^-1.Increasing temperature from 298 to 338 K can enhance the CO2 absorption rate due to lowering the viscosity of the solvent. The rate-determined step for the absorption is focused on the gas side. The rotating disk reactor can effectively enhance the absorption of CO2 with viscous DBU-glycerol solvents.展开更多
The commercial sulfate process for pigment production uses concentrated sulfuric acid(N 85 wt% H_2SO_4) as feeding material and discharges 8–10 tons of spend dilute acid(20 wt% H_2SO_4) per ton of product. Re-using s...The commercial sulfate process for pigment production uses concentrated sulfuric acid(N 85 wt% H_2SO_4) as feeding material and discharges 8–10 tons of spend dilute acid(20 wt% H_2SO_4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO_2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model(SCM), incorporation of particle size distribution(PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid(60 wt% H_2 SO_4) practicable and the re-use of spend acid becomes possible and economical.展开更多
CO_(2)capture with a low energy consumption is of important application significance for reducing CO_(2)emission.The phase-change absorbent developed in recent years shows its potential for low-energy CO_(2)capture.Th...CO_(2)capture with a low energy consumption is of important application significance for reducing CO_(2)emission.The phase-change absorbent developed in recent years shows its potential for low-energy CO_(2)capture.The unclear phase-splitting rule hinders the efficient development of CO_(2)phase-change absorbents.To predict phase-splitting behaviors of mono/poly-amine-organic solvent-water system with various concentrations,a quasi-activity coefficient was developed based on Debye&Mc Aulay equation and some Density function theory descriptors.Six models based on Debye&Mc Aulay equation were developed with different ion radius,descriptors or poly-amine-CO_(2)products.The phase-splitting boundary was drawn on the model with the best predictability.This quasi-activity coefficient would provide guidance for the phase-splitting systems development,especially for polyamines.展开更多
The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene(DBU)is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO_2(DGC)ionic compounds reacts directly with dimethyl carbonat...The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene(DBU)is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO_2(DGC)ionic compounds reacts directly with dimethyl carbonate(DMC)to produce high value-added glycerol carbonate(GC)catalyzed by DBU and DGC.The catalytic performance of DBU and DGC,as well as the kinetics of the reaction catalyzed by DBU,were investigated.The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC.When the temperature is higher than 60°C,DGC catalyzes the reaction jointly with DBU,which is produced from the decomposition of DGC.DBU has a good catalytic effect on the reaction between glycerol and DMC,with 90%conversion of glycerol and 84%selectivity to GC under the following conditions:DMC-to-glycerol molar ratio of 3:1,4.0%DBU(based on glycerol mass),reaction time of 60 min,and reaction temperature of 40°C.The apparent kinetics results show that the activation energies are 30.95 kJ·mol^(-1)and 55.16 kJ·mol^(-1)for the forward and reverse GC generation reactions,respectively,and the activation energy of the decomposition reaction of GC to glycidol(GD)is 26.58 kJ·mol^(-1).展开更多
Pulsed chemical vapor deposition(P-CVD)is a promising technology for the surface modification of TiO_(2) particles.For the scale-up application of P-CVD,a custom-designed rotary reactor and corresponding coating proce...Pulsed chemical vapor deposition(P-CVD)is a promising technology for the surface modification of TiO_(2) particles.For the scale-up application of P-CVD,a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work.The obtained SiO_(2)-coated TiO_(2) particles were characterized by various measures including high-resolution transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,etc.The results illustrated that the SiO_(2) films with a thickness of(3.7±0.7)nm were successfully deposited onto the surface of TiO_(2) particles.According to the dye degradation tests and acid solubility measurement,the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO_(2) particles.Zeta potential measurements showed that the SiO_(2)-coated TiO_(2) is possible to be stably dispersed in the pH range of 6.9–11.6.The coating process made the whiteness of TiO_(2) particles decreased slightly but still sufficient(97.3±0.1)for application.Furthermore,the properties of the TiO_(2) particles coated by PCVD were compared with the particles coated by traditional wet chemical deposition.It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance.The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO_(2)-coated TiO_(2) via P-CVD.展开更多
In our daily life, accident would happen with arterial haemorrhage,and death would be brought out by continuous arterial bleeding for little time if emergency has not been implemented in time. This paper presents a hu...In our daily life, accident would happen with arterial haemorrhage,and death would be brought out by continuous arterial bleeding for little time if emergency has not been implemented in time. This paper presents a humerus arterial bleeding simulation model (HABSM) for hemostasia,which has a high-fidelity, practical model for the humerus arterial hemostasia operation that is not only for the surgeons and nurses, but also for commons in urgent bleeding accident. The functional components of HABSM are arm model, fluid circulated pipeline and circuit controlling system. The arm model is made of elastic material as human muscle. Fluid circulated pipeline contains wiggly pump, inlet pipe and outlet pipe. And circuit controlling system has single chip micyoco system (SCM), keyboard, pressure sensor and vision circuit. SCM controls pump and valve to realize humerus arterial blood circulation. Both surgeons and commons thought well of HABSM which provided a task trainer for humerus arterial hemostasia.展开更多
Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the domi...Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the dominant epidemic strain in China. We developed an attenuated aMPV subtype B strain by serial passaging in Vero cells and evaluated its safety and efficacy as a vaccine candidate. The safety test showed that after the 30th passage, the LN16-A strain was fully attenuated, as clinical signs of infection and histological lesions were absent after inoculation.The LN16-A strain did not revert to a virulent strain after five serial passages in chickens. The genomic sequence of LN16-A differed from that of the parent wild-type LN16(wtLN16) strain and had nine amino acid mutations. In chickens, a single immunization with LN16-A induced robust humoral and cellular immune responses, including the abundant production of neutralizing antibodies, CD4^(+) T lymphocytes, and the Th1(IFN-γ) and Th2(IL-4 and IL-6)cytokines. We also confirmed that LN16-A provided 100% protection against subtype B aMPV and significantly reduced viral shedding and turbinate inflammation. Our findings suggest that the LN16-A strain is a promising live attenuated vaccine candidate that can prevent infection with subtype B aMPV.展开更多
基金the support from the National Natural Science Foundation of China (22008157,21978178)。
文摘Rotating packed bed(RPB) is one of the most effective gas–liquid mass transfer enhancement reactors, its effective specific mass transfer area(ae) is critical to understand the mass transfer process. By using the NaOH–CO_(2) chemical absorption method, the aevalues of three RPB reactors with different rotor sizes were measured under different operation conditions. The results showed that the high gravity factor and liquid flow rate were major affecting factors, while the gas flow rate exhibited minor influence.The radius of packing is the dominant equipment factor to affect aevalue. The results indicated that the contact area depends on the dispersion of the liquid phase, thus the centrifugal force of rotating packed bed greatly influenced the aevalue. Moreover, the measured ae/ap(effective specific mass transfer area/specific surface area of packing) values were fitted with dimensionless correlation formulas. The unified correlation formula with dimensionless bed size parameter can well predict the experimental data and the prediction errors were within 15%.
基金received financial supports from Innovation Seedling Projects of Zigong City (2017CXM02)Key R&D Program of Sichuan Province (2017GZ0391)National Key Research and Development Program (2016YFE0102600)
基金Supported by the National Natural Science Foundation of China(21336004)the State Key Research Plan of the Ministry of Science and Technology(2013BAC12B03)
文摘The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an efficient methodology via the co-reaction of K-feldspar and phosphogypsum for the extraction of soluble potassium salts and recovery of SO_2 with reduced CO_2 emission and energy consumption. The results of characterization and reactivity evaluation indicated that the partial melting of K-feldspar and phosphogypsum in the hightemperature co-reaction significantly facilitated the reduction of phosphogypsum to SO_2 and the exchange of K^+(K-feldspar) with Ca^(2+)(CaSO_4 in phosphogypsum). The reaction parameters were systematically investigated with the highest sulfur recovery ratio of ~ 60% and K extraction ratio of ~ 87.7%. This novel methodology possesses an energy consumption reduction of ~ 28% and CO_2 emission reduction of ~ 55% comparing with the present typical commercial technologies for utilization of K-feldspar and the treatment of phosphogypsum.
基金Supported by the National Natural Science Foundation of China(21606154)
文摘Post-combustion CO_2 capture(PCC) process faces significant challenge of high regeneration energy consumption.Biphasic absorbent is a promising alternative candidate which could significantly reduce the regeneration energy consumption because only the CO_2-concentrated phase should be regenerated. In this work, aqueous solutions of triethylenetetramine(TETA) and N,N-diethylethanolamine(DEEA) are found to be efficient biphasic absorbents of CO_2. The effects of the solvent composition, total amine concentration, and temperature on the absorption behavior, as well as the effect of temperature on the desorption behavior of TETA–DEEA–H2 O system were investigated. An aqueous solution of 1 mol·L-1 TETA and 4 mol·L-1 DEEA spontaneously separates into two liquid phases after a certain amount of CO_2 is absorbed and it shows high CO_2 absorption/desorption performance.About 99.4% of the absorbed CO_2 is found in the lower phase, which corresponds to a CO_2 absorption capacity of 3.44 mol·kg-1. The appropriate absorption and desorption temperatures are found to be 30 °C and 90 °C,respectively. The thermal analysis indicates that the heat of absorption of the 1 mol·L-1 TETA and 4 mol·L-1 DEEA solution is-84.38 kJ·(mol CO_2)-1 which is 6.92 kJ·(mol CO_2)-1 less than that of aqueous MEA. The reaction heat, sensible heat, and the vaporization heat of the TETA–DEEA–H2 O system are lower than that of the aqueous MEA, while its CO_2 capacity is higher. Thus the TETA–DEEA–H2 O system is potentially a better absorbent for the post-combustion CO_2 capture process.
基金Supported by the Key Program of National Natural Science Foundation of China(No.21336008).
文摘An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 ℃(ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 ℃ for30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Bronsted acid sites ratio for ST-450 induced by bidentate ligands between SO4^2-and TiO2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm^3·g^-1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 ℃ exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO4^2-and TiO2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.
基金the State key research and development plan(2017YFD0400203).
文摘Food allergy is one of the most important food safety problems that has attracted increasing attention.The food allergy experimental models provide not only the accurate allergen detection and evaluation methods but also the powerful approaches for mechanism investigations.In this paper,we reviewed the common food allergy cell models including mast cell,basophil granulocyte and basophil,as well as the animal models of BALB/c mouse,C3H/HeJ mouse,and BN rat.We also introduced zebrafish,a promising model organism for investigating immunity though lacking direct applications in food allergy to date,and focused on traumatic inflammation,bacterial infection and viral infection models.In addition,we also summarized the clinical diagnostic research methods for food allergy.The elucidation of these topics will help researchers to understand the characteristics and mechanisms of various models and thus select the proper models for particular study,so as to support further investigations of food allergy.
基金Supported by the National Natural Science Foundation of China(21406146)
文摘The selective oxidation of cyclopentene by aqueous H2O2 using H3PW12O40 and tetrabutyl ammonium bromide(TBAB) as a phase transfer catalyst has been investigated. The results show that the presence of TBAB significantly improved the oxidation selectivity of cyclopentene. The effects of the reaction conditions on the conversion of cyclopentene were investigated in detail. The optimal reaction conditions are as follows: the H3PW12O40 to TBAB molar ratio, 1:1–1:3;H3PW12O40 to cyclopentene molar ratio,0.54:100–0.64:100;and molar ratio of H2O2 to cyclopentene, 1.6:1. The conversion reached to 59.8% in 4h at 35.0 ℃, while the selectivity of glutaraldehyde was 38.0% and the selectivity of 1,2-cyclopentanediol was 55.6%. In addition, a route for oxidation of cyclopentene by aqueous H2O2 using a heteropoly acid and quaternary ammonium salt as a phase transfer catalyst was proposed.
基金support from the National Key R&D Program of China(2018YFC1900201)the Provincial Key R&D Program of Shanxi(201603D31212003)。
文摘Kiln phosphoric acid(KPA)technology could produce P2O5 with high purity and has been applied in thermal phosphoric acid industry;however the formation of fouling in the high-temperature rotary kiln restricts the stable and long-term operation.In this paper,the reaction of phosphate ores with gaseous P2O5 was investigated in a high-temperature reactor,and the Ca O-SiO2-P2O5 ternary phase diagram was analyzed to understand the fouling formation mechanism.The results showed that the low-melting-point products,such as Ca(PO3)2and Ca2P2O7,are responsible for the fouling in the KPA process.In addition,a small amount of impurities,e.g.,aluminum and iron,could facilitate the generation of the low-melting-point products and cause serious fouling.Based on the high-temperature SiO2-P2O5 and CaO-SiO2-P2O5 phase diagram analysis,the control of Si/Ca molar ratio(e.g.,Si/Ca=2.0)was found to avoid fouling formation in the kiln.These results could provide the operation parameters of reaction temperature and feeds composition to suppress the fouling in the kiln reactor for the phosphoric acid production in industry.
基金Supported by the National Key R&D Program of China(2018YFB0605700).
文摘TiO2 pigments are typically coated with inert layers to suppress the photocatalytic activity and improve the weatherability. However, the traditional inert layers have a lower refractive index compared to TiO2, and therefore reduce the lightening power of TiO2. In the present work, a uniform, amorphous, 2.9-nm-thick TiO2 protective layer was deposited onto the surface of anatase TiO2 pigments according to pulsed chemical vapor deposition at room temperature, with Ti Cl4 as titanium precursor. Amorphous TiO2 coating layers exhibited poor photocatalytic activity, leading to a boosted weatherability. Similarly, this coating method is also effective for TiO2 coating with amorphous SiO2 and SnO2 layers. However, the lightening power of amorphous TiO2 layer is higher than those of amorphous SiO2 and SnO2 layers. According to the measurements of photoluminescence lifetime, surface photocurrent density, charge-transfer resistance, and electron spin resonance spectroscopy, it is revealed that the amorphous layer can prevent the migration of photogenerated electrons and holes onto the surface, decreasing the densities of surface electron and hole, and thereby suppress the photocatalytic activity.
基金Supported by the National Natural Science Foundation of China(21606154,21878190).
文摘Gas–liquid mass transfer of rotating disk reactor was studied in CO2 absorption using 1,8-diazabicyclo-[5.4.0]-undec-7-ene(DBU)-glycerol solution as solvent. Effects of the rotating disk structure and various operation parameters on the CO2 absorption rate and CO2 removal efficiency were investigated. The rotating disk with optimal holes is conducive to mass transfer of CO2 and the formation of thin liquid film at the opening increases the gas–liquid contact area. With the increase of rotating speed, the liquid flow pattern on the rotating disk surface changes from thin film flow to separated streams and creates extra liquid lines attached to the rim of the disk,which leads to a very complicated change on the CO2 absorption rate and CO2 removal efficiency. The overall gas-phase mass transfer coefficient increases 138% as the rotating speed increasing from 250 to 1400 r·min^-1.Increasing temperature from 298 to 338 K can enhance the CO2 absorption rate due to lowering the viscosity of the solvent. The rate-determined step for the absorption is focused on the gas side. The rotating disk reactor can effectively enhance the absorption of CO2 with viscous DBU-glycerol solvents.
基金Supported by the National Natural Science Foundation of China(21236004)
文摘The commercial sulfate process for pigment production uses concentrated sulfuric acid(N 85 wt% H_2SO_4) as feeding material and discharges 8–10 tons of spend dilute acid(20 wt% H_2SO_4) per ton of product. Re-using spend acid to leach ilmenite can cut the waste emission and save fresh feeding acid. However, the leaching reaction with dilute acid is very slow and the digestion efficiency is fairly low. This paper describes a wet-milling process to enhance the dilute-acid leaching of ilmenite that makes it possible to produce TiO_2 pigment in a more environmentally benign routine. The leaching kinetic study of unmilled ilmenite, dry milled 60 min ilmenite and wet milled 60 min ilmenite was conducted by revision of the shrinking core model(SCM), incorporation of particle size distribution(PSD) into SCM. The results revealed that mechano-chemical activation method significantly increased the leaching efficiency of titanium from 36% to 76% by reducing the particle size and increasing the reaction contact area. On the other hand, the milling process increased the lattice deformation and amorphization of crystalline, which lowered the activation energies in the leaching process. Compared with dry milling operation, wet milling is more effective, the particle size distribution of wet-milled ilmenite was much narrower, smaller, and more uniform. Wet milling of ilmenite makes the leaching reaction with dilute acid(60 wt% H_2 SO_4) practicable and the re-use of spend acid becomes possible and economical.
基金financial support from National Natural Science Foundation of China(21878190)China Petrochemical Corporation(419033-1)the Engineering Experimental Teaching Center,School of Chemical Engineering,Sichuan University for the Nuclear Magnetic Resonance(NMR,JNM-ECZ400S/L1,JEOL Ltd.)support and the compute server support。
文摘CO_(2)capture with a low energy consumption is of important application significance for reducing CO_(2)emission.The phase-change absorbent developed in recent years shows its potential for low-energy CO_(2)capture.The unclear phase-splitting rule hinders the efficient development of CO_(2)phase-change absorbents.To predict phase-splitting behaviors of mono/poly-amine-organic solvent-water system with various concentrations,a quasi-activity coefficient was developed based on Debye&Mc Aulay equation and some Density function theory descriptors.Six models based on Debye&Mc Aulay equation were developed with different ion radius,descriptors or poly-amine-CO_(2)products.The phase-splitting boundary was drawn on the model with the best predictability.This quasi-activity coefficient would provide guidance for the phase-splitting systems development,especially for polyamines.
基金Supported by the National Natural Science Foundation of China(No.21476150)
文摘The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene(DBU)is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO_2(DGC)ionic compounds reacts directly with dimethyl carbonate(DMC)to produce high value-added glycerol carbonate(GC)catalyzed by DBU and DGC.The catalytic performance of DBU and DGC,as well as the kinetics of the reaction catalyzed by DBU,were investigated.The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC.When the temperature is higher than 60°C,DGC catalyzes the reaction jointly with DBU,which is produced from the decomposition of DGC.DBU has a good catalytic effect on the reaction between glycerol and DMC,with 90%conversion of glycerol and 84%selectivity to GC under the following conditions:DMC-to-glycerol molar ratio of 3:1,4.0%DBU(based on glycerol mass),reaction time of 60 min,and reaction temperature of 40°C.The apparent kinetics results show that the activation energies are 30.95 kJ·mol^(-1)and 55.16 kJ·mol^(-1)for the forward and reverse GC generation reactions,respectively,and the activation energy of the decomposition reaction of GC to glycidol(GD)is 26.58 kJ·mol^(-1).
基金supported by the National Key Research and Development Program of China(2018YFB0605700)National Natural Science Foundation of China(21908150)China Postdoctoral Science Foundation(2019M653404)。
文摘Pulsed chemical vapor deposition(P-CVD)is a promising technology for the surface modification of TiO_(2) particles.For the scale-up application of P-CVD,a custom-designed rotary reactor and corresponding coating process at room temperature was developed in the present work.The obtained SiO_(2)-coated TiO_(2) particles were characterized by various measures including high-resolution transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,etc.The results illustrated that the SiO_(2) films with a thickness of(3.7±0.7)nm were successfully deposited onto the surface of TiO_(2) particles.According to the dye degradation tests and acid solubility measurement,the deposited film can effectively inhibit the photocatalytic activity and enhance the weatherability of the TiO_(2) particles.Zeta potential measurements showed that the SiO_(2)-coated TiO_(2) is possible to be stably dispersed in the pH range of 6.9–11.6.The coating process made the whiteness of TiO_(2) particles decreased slightly but still sufficient(97.3±0.1)for application.Furthermore,the properties of the TiO_(2) particles coated by PCVD were compared with the particles coated by traditional wet chemical deposition.It is shown that the P-CVD can produce thinner but denser films with better photoactivity suppression performance.The developed coating process within the rotary reactor was proved practically feasible and convenient for the scale-up production of SiO_(2)-coated TiO_(2) via P-CVD.
文摘In our daily life, accident would happen with arterial haemorrhage,and death would be brought out by continuous arterial bleeding for little time if emergency has not been implemented in time. This paper presents a humerus arterial bleeding simulation model (HABSM) for hemostasia,which has a high-fidelity, practical model for the humerus arterial hemostasia operation that is not only for the surgeons and nurses, but also for commons in urgent bleeding accident. The functional components of HABSM are arm model, fluid circulated pipeline and circuit controlling system. The arm model is made of elastic material as human muscle. Fluid circulated pipeline contains wiggly pump, inlet pipe and outlet pipe. And circuit controlling system has single chip micyoco system (SCM), keyboard, pressure sensor and vision circuit. SCM controls pump and valve to realize humerus arterial blood circulation. Both surgeons and commons thought well of HABSM which provided a task trainer for humerus arterial hemostasia.
基金supported by the National Key Research and Development Program of China (2022YFD1800604)the China Agricultural Research System (CARS-41)the Heilongjiang Touyan Innovation Team Program of China
文摘Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the dominant epidemic strain in China. We developed an attenuated aMPV subtype B strain by serial passaging in Vero cells and evaluated its safety and efficacy as a vaccine candidate. The safety test showed that after the 30th passage, the LN16-A strain was fully attenuated, as clinical signs of infection and histological lesions were absent after inoculation.The LN16-A strain did not revert to a virulent strain after five serial passages in chickens. The genomic sequence of LN16-A differed from that of the parent wild-type LN16(wtLN16) strain and had nine amino acid mutations. In chickens, a single immunization with LN16-A induced robust humoral and cellular immune responses, including the abundant production of neutralizing antibodies, CD4^(+) T lymphocytes, and the Th1(IFN-γ) and Th2(IL-4 and IL-6)cytokines. We also confirmed that LN16-A provided 100% protection against subtype B aMPV and significantly reduced viral shedding and turbinate inflammation. Our findings suggest that the LN16-A strain is a promising live attenuated vaccine candidate that can prevent infection with subtype B aMPV.
