A series of lanthanum doped meosoporous MCM-41(LaxM41,x is Si/La molar ratio) was prepared by sol-gel method.The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption ...A series of lanthanum doped meosoporous MCM-41(LaxM41,x is Si/La molar ratio) was prepared by sol-gel method.The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique.The content of La in the materials was determined by ICP.It was found that the La content of La25M41,La50M41 and La100M41 was 7.53%,3.89% and 2.32%,respectively.The phosphate adsorption capacities increased with increasing amount of La incorporation.With 0.40 g La25M41 99.7% phosphate could be removed.The effects of Si/La molar ratio,LaxM41 dose,pH,initial concentration of phosphate solution,co-ions on phosphate adsorption were also evaluated.The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model,and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.展开更多
In this study,the dredged river sediment,soft texture and fine particles,is mixed with other materials and transformed into eco-friendly autoclaved aerated concrete(hereinafter referred to as AAC)blocks.The results in...In this study,the dredged river sediment,soft texture and fine particles,is mixed with other materials and transformed into eco-friendly autoclaved aerated concrete(hereinafter referred to as AAC)blocks.The results indicated the bricks produced under the conditions of 30%–34%dredged river sediment,24%cement,10%quick lime,30%fly ash,2%gypsum and 0.09%aluminum powder with 0.5 water to material ratio,2.2 MPa autoclave pressure and 6 h autoclave time,the average compressive strength of 4.5 MPa and average dry density of 716.56 kg/m³were obtained,the two parameters(strength&density)both met the requirement of national industry standard.At the same time,the contents of dredged river sediment,cement,lime,fly ash,gypsum and aluminum powder were 15%,48%,20%,15%,2%and 0.09%,respectively,and the non-AAC block made of 0.5 water to material ratio,the average compressive strength of 3.1 MPa and average dry density of 924.19 kg/m³were obtained,the two parameters(strength&density)also met the requirement of national industry standard.In addition,the AAC block’s phase composition and morphology were micro-analyzed by SEM and XRD,the main substances in AAC block were found to be tobermorite and CSH,Among them,the chemical bond between Si-O-Si and Al-O-Al is broken,Al-O-Si is regenerated,Al substituted tobermorite with better strength is formed,and the compressive strength of AAC is further improved.展开更多
The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic,thereby increasing the demands for the development of disinfectants base...The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic,thereby increasing the demands for the development of disinfectants based on natural products,with low health risks and low aquatic toxicity.In the present study,a few natural naphthoquinones and their derivatives bearing the 1,4-naphthoquinone skeleton were synthesized,and their antibacterial activity against selected bacterial strains was evaluated.In vitro antibacterial activities of the compounds were investigated against Escherichia coli and Staphylococcus aureus.Under the minimum inhibitory concentration(MIC)of≤0.125μmol/L for juglone(1a),5,8-dimethoxy-1,4-naphthoquinone(1f),and 7-methyl-5-acetoxy-1,4-naphthoquinone(3),a strong antibacterial activity against S.aureus was observed.All 1,4-naphthoquinone derivatives exhibited a strong antibacterial activity,with MIC values ranging between 15.625 and 500μmol/Land ECso values rangingbetween10.56 and248.42μmol/L.Most of the synthesized compounds exhibited strong antibacterial activities against S.aureus.Among these compounds,juglone(la)showed the strongest antibacterial activity.The results from mechanistic investigations indicated that juglone,a natural naphthoquinone,caused cell death by inducing reactive oxygen species production in bacterial cells,leading to DNA damage.In addition,juglone could reduce the self-repair ability of bacterial DNA by inhibiting RecA expression.In addition to having a potent antibacterial activity,juglone exhibited low cytotoxicity in cell-based investigations.In conclusion,juglone is a strong antibacterial agent with low toxicity,indicating that its application as a bactericidal agent may be associated with low health risks and aquatic toxicity.展开更多
A novel microvibration hammerhead consists of a piezoelectric actuator and a double cross-shape compliant mechanism(DCCM)is presented in this paper.The output force of the piezoelectric actuator can be detected in rea...A novel microvibration hammerhead consists of a piezoelectric actuator and a double cross-shape compliant mechanism(DCCM)is presented in this paper.The output force of the piezoelectric actuator can be detected in real time by an insideinstalled pressure sensor.A theoretical model including the stiffness,first natural frequency,and stress of the DCCM and the displacement output of the piezoelectric actuator are established,and then they are further analyzed using the finite element analysis method.The effects of the beam thickness on the static and dynamic properties are deeply analyzed and compared.A prototype micro hammering system is constructed by integrating the microvibration hammerhead assembly and controlling system.Various experiments are also carried out to verify the basic performance of the micro hammering system.展开更多
To study how global warming and eutrophication affect water ecosystems,a multiplicative growth Monod model,modified by incorporating the Arrhenius equation,was applied to Lake Taihu to quantitatively study the relatio...To study how global warming and eutrophication affect water ecosystems,a multiplicative growth Monod model,modified by incorporating the Arrhenius equation,was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data.To qualitatively assess which factor was a limitation of the improved model,temperature variables were calculated using annual mean air temperature (AT),water temperature (WT),and their average temperature (ST),while substrate variables were calculated using annual mean total nitrogen (TN),total phosphorus (TP),and their weighted aggregate (R),respectively.The nine fitted curves showed that TN and AT were two important factors influencing algal growth;AT limited growth as algal photosynthesis is mainly carried out near the water surface;N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model.The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0°C.Results also showed that the more eutrophic the lake,the greater the effect AT had on algal growth.Subsequently,the long-term joint effect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.展开更多
Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water.A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was...Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water.A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was synthesized by a post-grafting and metal cation incorporation process.The surface structure of the adsorbent was characterized by X-ray diffraction,N2 adsoropion/desoprotion technique,and Fourier transform infrared spectroscopy.The experimental results showed that the adsorption equilibrium data were well fitted to the Langmuir equation.The maximum adsorption capacity of the modified silicate material was 51.8 mg/g.The kinetic data from the adsorption of phosphate were fitted to pseudo second-order model.The phosphate adsorption was highly pH dependent and the relatively high removal of phosphate fell within the pH range 3.0-6.0.The coexistence of other anions in solutions has an adverse effect on phosphate adsorption;a decrease in adsorption capacity followed the order of exogenous anions:F > SO2-4 > NO-3 > Cl-.In addition,the adsorbed phosphate could be desorbed by NaOH solutions.This silicate adsorbent with a large adsorption capacity and relatively high selectivity could be utilized for the removal of phosphate from aqueous waste streams or in aquatic environment.展开更多
To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process(SCWO), oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO rea...To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process(SCWO), oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve(imax) was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds(imax > 0.25) can be completely oxidized when the reactor temperature reaches 500℃. However, some compounds(imax > 0.25) need a higher temperature for complete oxidation, up to 560℃. To analyze the correlation coefficients between imax and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure.展开更多
Fenton oxidation is a promising water treatment method to degrade organic pollutants. In this study, 30 different organic compounds were selected and their reaction rate constants(k) were determined for the Fenton oxi...Fenton oxidation is a promising water treatment method to degrade organic pollutants. In this study, 30 different organic compounds were selected and their reaction rate constants(k) were determined for the Fenton oxidation process. Gaussian09 and Material Studio software sets were used to carry out calculations and obtain values of 10 different molecular descriptors for each studied compound. Ferric-oxyhydroxide coagulation experiments were conducted to determine the coagulation percentage. Based upon the adsorption capacity,all of the investigated organic compounds were divided into two groups(Group A and Group B). The percentage adsorption of organic compounds in Group A was less than 15%(wt./wt.)and that in the Group B was higher than 15%(wt./wt.). For Group A, removal of the compounds by oxidation was the dominant process while for Group B, removal by both oxidation and coagulation(as a synergistic process) took place. Results showed that the relationship between the rate constants(k values) and the molecular descriptors of Group A was more pronounced than for Group B compounds. For the oxidation-dominated process,EHOMOand Fukui indices(f(0)_x, f(-)_x, f(+)_x) were the most significant factors. The influence of bond order was more significant for the synergistic process of oxidation and coagulation than for the oxidation-dominated process. The influences of all other molecular descriptors on the synergistic process were weaker than on the oxidation-dominated process.展开更多
基金supported by the National Natural Science Foundation of China (21347006, 21576175, 51478285, 51403148)the Opening Project of Key Laboratory of Jiangsu Province Environmental Science and Engineering of Suzhou University of Science and Technology (zd131205)the Collaborative Innovation Center of Technology and Material of Water Treatment~~
基金supported by the National Natural Science Foundation of China (21347006, 21576175, 51478285, 51403148)the Opening Project of Key Laboratory of Jiangsu Province environmental science and engineering of Suzhou University of Science and Technology (zd131205)Collabora‐tive Innovation Center of Technology and Material of Water Treatment and Suzhou Key Lab of Separation and Purification Materials & Technologies (SZS201512)~~
基金supported by the National Major Research Plan for Water Pollution Control and Treatment of China (No.2008ZX07101-015)
文摘A series of lanthanum doped meosoporous MCM-41(LaxM41,x is Si/La molar ratio) was prepared by sol-gel method.The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique.The content of La in the materials was determined by ICP.It was found that the La content of La25M41,La50M41 and La100M41 was 7.53%,3.89% and 2.32%,respectively.The phosphate adsorption capacities increased with increasing amount of La incorporation.With 0.40 g La25M41 99.7% phosphate could be removed.The effects of Si/La molar ratio,LaxM41 dose,pH,initial concentration of phosphate solution,co-ions on phosphate adsorption were also evaluated.The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model,and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.
基金the National Natural Science Foundation of China(NSFC)(Nos.21876025,42177119).
文摘In this study,the dredged river sediment,soft texture and fine particles,is mixed with other materials and transformed into eco-friendly autoclaved aerated concrete(hereinafter referred to as AAC)blocks.The results indicated the bricks produced under the conditions of 30%–34%dredged river sediment,24%cement,10%quick lime,30%fly ash,2%gypsum and 0.09%aluminum powder with 0.5 water to material ratio,2.2 MPa autoclave pressure and 6 h autoclave time,the average compressive strength of 4.5 MPa and average dry density of 716.56 kg/m³were obtained,the two parameters(strength&density)both met the requirement of national industry standard.At the same time,the contents of dredged river sediment,cement,lime,fly ash,gypsum and aluminum powder were 15%,48%,20%,15%,2%and 0.09%,respectively,and the non-AAC block made of 0.5 water to material ratio,the average compressive strength of 3.1 MPa and average dry density of 924.19 kg/m³were obtained,the two parameters(strength&density)also met the requirement of national industry standard.In addition,the AAC block’s phase composition and morphology were micro-analyzed by SEM and XRD,the main substances in AAC block were found to be tobermorite and CSH,Among them,the chemical bond between Si-O-Si and Al-O-Al is broken,Al-O-Si is regenerated,Al substituted tobermorite with better strength is formed,and the compressive strength of AAC is further improved.
基金the Startup Fund for Youngman Research at SJTU(No.19X100040082)the Medical and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University(No.20X190020002).
文摘The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic,thereby increasing the demands for the development of disinfectants based on natural products,with low health risks and low aquatic toxicity.In the present study,a few natural naphthoquinones and their derivatives bearing the 1,4-naphthoquinone skeleton were synthesized,and their antibacterial activity against selected bacterial strains was evaluated.In vitro antibacterial activities of the compounds were investigated against Escherichia coli and Staphylococcus aureus.Under the minimum inhibitory concentration(MIC)of≤0.125μmol/L for juglone(1a),5,8-dimethoxy-1,4-naphthoquinone(1f),and 7-methyl-5-acetoxy-1,4-naphthoquinone(3),a strong antibacterial activity against S.aureus was observed.All 1,4-naphthoquinone derivatives exhibited a strong antibacterial activity,with MIC values ranging between 15.625 and 500μmol/Land ECso values rangingbetween10.56 and248.42μmol/L.Most of the synthesized compounds exhibited strong antibacterial activities against S.aureus.Among these compounds,juglone(la)showed the strongest antibacterial activity.The results from mechanistic investigations indicated that juglone,a natural naphthoquinone,caused cell death by inducing reactive oxygen species production in bacterial cells,leading to DNA damage.In addition,juglone could reduce the self-repair ability of bacterial DNA by inhibiting RecA expression.In addition to having a potent antibacterial activity,juglone exhibited low cytotoxicity in cell-based investigations.In conclusion,juglone is a strong antibacterial agent with low toxicity,indicating that its application as a bactericidal agent may be associated with low health risks and aquatic toxicity.
基金supported by“National Natural Science Foundation of China(No.52205138)”“the Fundamental Research Funds for the Central Universities,CAUC(No.3122019095)”+1 种基金Science and Technology Planning Project of Tianjin Science and Technology Bureau,China(No.KJZ40420220150)Natural Science Foundation of Tianjin,China(No.21JCQNJC00860).
文摘A novel microvibration hammerhead consists of a piezoelectric actuator and a double cross-shape compliant mechanism(DCCM)is presented in this paper.The output force of the piezoelectric actuator can be detected in real time by an insideinstalled pressure sensor.A theoretical model including the stiffness,first natural frequency,and stress of the DCCM and the displacement output of the piezoelectric actuator are established,and then they are further analyzed using the finite element analysis method.The effects of the beam thickness on the static and dynamic properties are deeply analyzed and compared.A prototype micro hammering system is constructed by integrating the microvibration hammerhead assembly and controlling system.Various experiments are also carried out to verify the basic performance of the micro hammering system.
基金supported by the State Technology Major Special Project on Water Pollution Control(No.2008ZX07101-009,2009ZX07101-015)the National Natural Science Foundation of China(No. 90510009)
文摘To study how global warming and eutrophication affect water ecosystems,a multiplicative growth Monod model,modified by incorporating the Arrhenius equation,was applied to Lake Taihu to quantitatively study the relationships between algal biomass and both nutrients and temperature using long-term data.To qualitatively assess which factor was a limitation of the improved model,temperature variables were calculated using annual mean air temperature (AT),water temperature (WT),and their average temperature (ST),while substrate variables were calculated using annual mean total nitrogen (TN),total phosphorus (TP),and their weighted aggregate (R),respectively.The nine fitted curves showed that TN and AT were two important factors influencing algal growth;AT limited growth as algal photosynthesis is mainly carried out near the water surface;N leakage of phytoplankton and internal phosphorus load from sediment explains why TN was the best predictor of peak biomass using the Monod model.The fitted results suggest that annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0°C.Results also showed that the more eutrophic the lake,the greater the effect AT had on algal growth.Subsequently,the long-term joint effect of annual temperature increase and eutrophication to water ecosystems can be quantitatively assessed and predicted.
基金supported by the National Major Research Plan for Water Pollution Control and Treatment of China(No. 2009ZX07101-015,2009ZX07105-003)
文摘Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water.A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was synthesized by a post-grafting and metal cation incorporation process.The surface structure of the adsorbent was characterized by X-ray diffraction,N2 adsoropion/desoprotion technique,and Fourier transform infrared spectroscopy.The experimental results showed that the adsorption equilibrium data were well fitted to the Langmuir equation.The maximum adsorption capacity of the modified silicate material was 51.8 mg/g.The kinetic data from the adsorption of phosphate were fitted to pseudo second-order model.The phosphate adsorption was highly pH dependent and the relatively high removal of phosphate fell within the pH range 3.0-6.0.The coexistence of other anions in solutions has an adverse effect on phosphate adsorption;a decrease in adsorption capacity followed the order of exogenous anions:F > SO2-4 > NO-3 > Cl-.In addition,the adsorbed phosphate could be desorbed by NaOH solutions.This silicate adsorbent with a large adsorption capacity and relatively high selectivity could be utilized for the removal of phosphate from aqueous waste streams or in aquatic environment.
基金supported by the National Natural Science Foundation of China(No.21177083,20937003)the Program for New Century Excellent Talents in University
文摘To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process(SCWO), oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve(imax) was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds(imax > 0.25) can be completely oxidized when the reactor temperature reaches 500℃. However, some compounds(imax > 0.25) need a higher temperature for complete oxidation, up to 560℃. To analyze the correlation coefficients between imax and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure.
基金supported by the National Natural Science Funds of China (No. NSFC21177083)the Shanghai Municipal Commission of Economy and Informatization Project (No. CXY-2013-52)
文摘Fenton oxidation is a promising water treatment method to degrade organic pollutants. In this study, 30 different organic compounds were selected and their reaction rate constants(k) were determined for the Fenton oxidation process. Gaussian09 and Material Studio software sets were used to carry out calculations and obtain values of 10 different molecular descriptors for each studied compound. Ferric-oxyhydroxide coagulation experiments were conducted to determine the coagulation percentage. Based upon the adsorption capacity,all of the investigated organic compounds were divided into two groups(Group A and Group B). The percentage adsorption of organic compounds in Group A was less than 15%(wt./wt.)and that in the Group B was higher than 15%(wt./wt.). For Group A, removal of the compounds by oxidation was the dominant process while for Group B, removal by both oxidation and coagulation(as a synergistic process) took place. Results showed that the relationship between the rate constants(k values) and the molecular descriptors of Group A was more pronounced than for Group B compounds. For the oxidation-dominated process,EHOMOand Fukui indices(f(0)_x, f(-)_x, f(+)_x) were the most significant factors. The influence of bond order was more significant for the synergistic process of oxidation and coagulation than for the oxidation-dominated process. The influences of all other molecular descriptors on the synergistic process were weaker than on the oxidation-dominated process.
