Tumor angiogenesis is closely related to tumor development,immune escape,and drug resistance.Therefore,the development of effective anti-tumor angiogenesis drugs is of great research significance.Although the current ...Tumor angiogenesis is closely related to tumor development,immune escape,and drug resistance.Therefore,the development of effective anti-tumor angiogenesis drugs is of great research significance.Although the current clinical angiogenesis inhibitors have achieved certain efficacy,they also pose the problems of limited and short duration of efficacy,drug resistance,and intrinsic toxicity.Anti-tumor angiogenesis strategies targeting endothelial cells(ECs)have attracted widespread attention in the development of highly effective and low toxicity anti-angiogenesis inhibitors.Studies have verified that the trace element selenium(Se)can inhibit tumor growth by inhibiting tumor angiogenesis through different mechanisms.Nevertheless,it is unclear whether Se speciation has different effects on anti-tumor angiogenesis.Herein,we found that Se exhibited effective anti-angiogenic activity,and its mechanisms of activity were determined by its chemical speciation.Organic Se can significantly inhibit tumor angiogenesis by targeting thioredoxin reductase(TrxR)to trigger cell apoptosis and cell cycle arrest and by increasing reactive oxygen species(ROS)production in ECs.Inorganic Se can induce cell cycle arrest and increase ROS production in ECs,showing promising anti-angiogenic effects.Se nanoparticles(SeNPs)slightly inhibit tumor angiogenesis by inducing apoptosis and cell cycle arrest and by increasing the production of ROS.In summary,this study elucidates the anti-angiogenic activity of Se speciation control with a view to providing a scientific reference for the design and development of novel Se-based highly effective and low toxicity angiogenesis inhibitors.展开更多
Bamboo charcoal （BC） was used as starting material to prepare Co-Fe binary oxideloaded adsorbent （Co-Fe-MBC） through its impregnation in Co（NO3）2 , FeCl3 and HNO3 solutions simultaneously, followed by microwave ...Bamboo charcoal （BC） was used as starting material to prepare Co-Fe binary oxideloaded adsorbent （Co-Fe-MBC） through its impregnation in Co（NO3）2 , FeCl3 and HNO3 solutions simultaneously, followed by microwave heating. The low-cost composite was characterized and used as an adsorbent for Cr（VI） removal from water. The results showed that a cobalt and iron binary oxide （CoFe2O4 ） was uniformly formed on the BC through redox reactions. The composite exhibited higher surface area （331 m2/g） than that of BC or BC loaded with Fe alone （Fe-MBC）. The adsorption of Cr（VI） strongly depended on solution pH, temperature and ionic strength. The adsorption isotherms followed the Langmuir isotherm model well, and the maximum adsorption capacities for Cr（VI） at 288 K and pH 5.0 were 35.7 and 51.7 mg/g for Fe-MBC and Co-Fe-MBC, respectively. The adsorption processes were well fitted by the pseudo second-order kinetic model. Thermodynamic parameters showed that the adsorption of Cr（VI） onto both adsorbents was feasible, spontaneous, and exothermic under the studied conditions. The spent Co-Fe-MBC could be readily regenerated for reuse.展开更多
The mesoporous Cu/Mg/Fe layered double hydroxide（Cu/Mg/Fe-LDH） with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous solutions.The Cu/Mg/Fe-LDH was characterized by Fourier t...The mesoporous Cu/Mg/Fe layered double hydroxide（Cu/Mg/Fe-LDH） with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous solutions.The Cu/Mg/Fe-LDH was characterized by Fourier transform infrared spectrometry,X-ray diffraction crystallography,scanning electron microscopy,X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller.Effects of various physico-chemical parameters such as pH,adsorbent dosage,contact time and initial arsenate concentration on the adsorption of arsenate onto Cu/Mg/Fe-LDH were investigated.Results showed that it was efficient for the removal of arsenate,and the removal efficiency of arsenate increased with the increment of the adsorbent dosage,while the arsenate adsorption capacity decreased with increase of initial pH from 3 to 11.The adsorption isotherms can be well described by the Langmuir model with R 2 〉 0.99.Its adsorption kinetics followed the pseudo second-order kinetic model.Coexisting ions such as HPO42-,CO32-,SO42and NO3could compete with arsenate for adsorption sites on the Cu/Mg/Fe-LDH.The adsorption of arsenate on the adsorbent can be mainly attributed to the ion exchange process.It was found that the synthesized Cu/Mg/Fe-LDH can reduce the arsenate concentration down to a final level of 〈 10 μg/L under the experimental conditions,and makes it a potential material for the decontamination of arsenate polluted water.展开更多
The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts （DBPs） during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typica...The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts （DBPs） during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon （TOC） and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions, four trihalomethanes （THMs）, nine haloacetic acids （HAAs）, total organic halogen （TOX） and its halogen species fractions, including total organic chlorine （TOC1） and total organic bromide （TOBr）, were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species, which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.展开更多
For the system of water samples collected from Yangtze River,the effects of seasonal variation and Fe（III） concentrations on the formation and distribution of trihalomethanes （THMs） during chlorination have been i...For the system of water samples collected from Yangtze River,the effects of seasonal variation and Fe（III） concentrations on the formation and distribution of trihalomethanes （THMs） during chlorination have been investigated.The corresponding lifetime cancer risk of the formed THMs to human beings was estimated using the parameters and procedure issued by the US EPA.The results indicated that the average concentration of THMs （100.81 μg/L） in spring was significantly higher than that in other seasons,which was related to the higher bromide ion concentration resulted from the intrusion of tidal saltwater.The total cancer risk in spring reached 8.23 × 10 ？5 and 8.86 × 10 ？5 for males and females,respectively,which were about two times of those in summer under the experimental conditions.Furthermore,it was found that the presence of Fe（III） resulted in the increased level of THMs and greater cancer risk from exposure to humans.Under weak basic conditions,about 10% of the increment of THMs from the water samples in spring was found in the presence of 0.5 mg/L Fe（III） compared with the situation without Fe（III）.More attention should be given to the effect of the coexistence of Fe（III） and bromide ions on the risk assessment of human intake of THMs from drinking water should be paid more attention,especially in the coastland and estuaries.展开更多
Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be...Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be used as an adsorbent for Pb（Ⅱ） contaminants removal in water.The composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy（XRD）,scanning electron microscopy coupled with energy dispersive X-ray spectrometry（SEM-EDS）,Fourier transform infrared（FT-IR） and point of zero charge（pH pzc） measurements.Nitrogen adsorption analyses showed that the BET specific surface area and total pore volume increased with iron impregnation.The adsorbent with Fe molar concentration of 2 mol/L（2Fe-MBC） exhibited the highest surface area and produced the best pore structure.The Pb（Ⅱ） adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb（Ⅱ）.The adsorption of Pb（Ⅱ） strongly depended on solution pH,with maximum values at pH 5.0.The ionic strength had a significant effect on the adsorption at pH 〈 6.0.The adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb（Ⅱ） was 200.38 mg/g for 2Fe-MBC.The adsorption processes were well fitted by a pseudo second-order kinetic model.Thermodynamic parameters showed that the adsorption of Pb（Ⅱ） onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant role.These results have important implications for the design of low-cost and effective adsorbents in the removal of Pb（Ⅱ） from wastewater.展开更多
Natural zeolite was modified by loading cetylpyridinium bromide （CPB） to create more efficient sites for humic acid （HA） adsorption. The natural and CPB modified zeolites were characterized with X-ray diffraction,...Natural zeolite was modified by loading cetylpyridinium bromide （CPB） to create more efficient sites for humic acid （HA） adsorption. The natural and CPB modified zeolites were characterized with X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of various experimental parameters such as contact time, initial HA concentration, solution pH and coexistent Ca^2＋, upon HA adsorption onto CPB modified zeolites were evaluated. The results showed that natural zeolite had negligible affinity for HA in aqueous solutions, but CPB modified zeolites exhibited high adsorption efficiency for HA. A higher CPB loading on natural zeolites exhibited a larger HA adsorption capacity. Acidic pH and coexistent Ca^2＋ were proved to be favorable for HA adsorption onto CPB modified zeolite. The kinetic process was well described by pseudo second-order model. The experimental isotherm data fitted well to Langmuir and Sips models. The maximum monolayer adsorption capacity of CPB modified zeolite with surfactant bilayer coverage was found to be 92.0 mg/g.展开更多
Nitrogen removal performance and nitrifyingpopulation dynamics were investigated in a redox stratifiedmembrane biofilm reactor(RSMBR)under oxygen limitedcondition to treat ammonium-rich wastewater.When theNH_(4)^(+)-N...Nitrogen removal performance and nitrifyingpopulation dynamics were investigated in a redox stratifiedmembrane biofilm reactor(RSMBR)under oxygen limitedcondition to treat ammonium-rich wastewater.When theNH_(4)^(+)-N loading rate increased from 11.1±1.0 to 37:2±3:2 gNH_(4)^(+)-N·m^(-2)·d^(-1),the nitrogen removal inthe RSMBR system increased from 18.0±9.6 mgN·d^(-1)to 128.9±61.7 mgN·d^(-1).Shortcut nitrogen removal wasachieved with nitrite accumulation of about22:3±5:3 mgNO_(2)^(-)-N·L-1.Confocal micrographsshowed the stratified distributions of nitrifiers anddenitrifiers in the membrane aerated biofilms(MABs)atday 120,i.e.,ammonia and nitrite oxidizing bacteria(AOBand NOB)were dominant in the region adjacent to themembrane,while heterotrophic bacteria propagated at thetop of the biofilm.Real-time qPCR results showed that theabundance of amoA gene was two orders of magnitudehigher than the abundance of nxrA gene in the MABs.However,the nxrA gene was always detected during theoperation time,which indicates the difficulty of completewashout of NOB in MABs.The growth of heterotrophicbacteria compromised the dominance of nitrifiers inbiofilm communities,but it enhanced the denitrificationperformance of the RSMBR system.Applying a highammonia loading together with oxygen limitation wasfound to be an effective way to start nitrite accumulation inMABs,but other approaches were needed to sustain orimprove the extent of nitritation in nitrogen conversion inMABs.展开更多
A space experiment on bubble behavior and heat transfer in subcooled pool boiling phenomenon has been performedutilizing the temperature-controlled pool boiling (TCPB) device both in normal gravity in the laboratoryan...A space experiment on bubble behavior and heat transfer in subcooled pool boiling phenomenon has been performedutilizing the temperature-controlled pool boiling (TCPB) device both in normal gravity in the laboratoryand in microgravity aboard the 22^(nd) Chinese recoverable satellite. The fluid is degassed R113 at 0.1 MPa andsubcooled by 26℃ nominally. A thin platinum wire of 60 μm in diameter and 30 mm in length is simultaneouslyused as heater and thermometer. Only the dynamics of the vapor bubbles, particularly the lateral motion and thedeparture of discrete vapor bubbles in nucleate pool boiling are reported and analyzed in the present paper. It'sfound that these distinct behaviors can be explained by the Marangoni convection in the liquid surrounding vaporbubbles. The origin of the Marangoni effect is also discussed.展开更多
This paper presents a new set of experimental data of air-water flow patterns in a channel with a cross-section of 1×1 mm2. The ranges of the gas and liquid superficial velocities are 0.1-10 m/s and 0.2~7 m/s, re...This paper presents a new set of experimental data of air-water flow patterns in a channel with a cross-section of 1×1 mm2. The ranges of the gas and liquid superficial velocities are 0.1-10 m/s and 0.2~7 m/s, respectively. Bubble, bubble-slug, slug, and frothy flows are observed. The present data are compared with other data in mini-channels reported in literature, and also compared with those in normal channel at microgravity, in which the Bond number has the same order of magnitude. The slug-frothy boundary is in consistent with each other, but for the bubble-slug transition, a much smaller value for the transition quality in the drift-flux model is obtained in the present study than those predicted by the empirical relations for the case of microgravity. It’s shown that the mini-scale modeling may not be an effective way to anticipate the bubble-slug transition of two-phase flow at microgravity.展开更多
A novel composite adsorbent, hydroxyapatite/ manganese dioxide （HAp/MnO2）, has been developed for the purpose of removing lead ions from aqueous solutions. The combination of HAp with MnO2 is meant to increase its a...A novel composite adsorbent, hydroxyapatite/ manganese dioxide （HAp/MnO2）, has been developed for the purpose of removing lead ions from aqueous solutions. The combination of HAp with MnO2 is meant to increase its adsorption capacity. Various factors that may affect the adsorption efficiency, including solution pH, coexistent substances such as humic acid and competing cations （Ca2＋, Mg2＋）, initial solute concentration, and the duration of the reaction, have been investigated. Using this composite adsorbent, solution pH and coexistent calcium or magnesium cations were found to have no significant influence on the removal of lead ions under the experi- mental conditions. The adsorption equilibrium was described well by the Langmuir isotherm model, and the calculated maximum adsorption capacity was 769 mg. gl. The sorption processes obeyed the pseudo-second-order kinetics model. The experimental results indicate that HAp/MnO2 composite may be an effective adsorbent for the removal of lead ions from aqueous solutions.展开更多
The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the c...The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.展开更多
Exploiting a tissue diagnosis method to abstain the involuted operating and consume valuable reagents while realizing high-speed and inexpensive pathological grading technology to supply a better scheme for cancer the...Exploiting a tissue diagnosis method to abstain the involuted operating and consume valuable reagents while realizing high-speed and inexpensive pathological grading technology to supply a better scheme for cancer therapy is a significant method of cancers detection. A promising immuno-fluorescence strategy was rationally designed and synthesized by loading ruthenium complex into cervical cancer-targeted DNA-cage, which was well used to realize high-speed and inexpensive diagnosis of clinical cervical cancer tumor tissues avoiding the traditional multi-stage process, thus demonstrating high application potential in clinical pathological grading and surgical judgment. Moreover, it has been finding that Apts-DNA@Ru can enrichment in the tumor region, interestingly, no enrichment in normal cervical cancer tissue. It has the potential to realize the integration of in vivo diagnose and further synchronous treatment in the near future. Thence, this study demonstrates a strategy for integration of cancer-targeted DNA-cage and fluorescent Ru POP as alternative IHC reagents for next-generation more rapid convenient cancer detection.展开更多
The biosorption of Direct Black 38 by dried anaerobic granular sludge in a batch system under specific temperatures and initial pH was investigated.The adsorption reaction is pH dependent with higher removal at low pH...The biosorption of Direct Black 38 by dried anaerobic granular sludge in a batch system under specific temperatures and initial pH was investigated.The adsorption reaction is pH dependent with higher removal at low pH.The adsorption equilibrium data fit very well with both Langmuir and Freundlich models in the concentration range of Direct Black 38 at all chosen temperatures.The adsorption parameters show that the adsorption of Direct Black 38 is an endothermic and more effective process at high temperatures.The kinetics of adsorption was found to be second order and adsorption rate constants increased with increasing temperature.Activation energy was determined as 26.8 kJ/mol for the process.This suggests that the adsorption of Direct Black 38 by dried anaerobic granular sludge is chemically controlled.展开更多
The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time （EBCT）, and initial Cr（VI） concentration on Cr（VI） reductio...The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time （EBCT）, and initial Cr（VI） concentration on Cr（VI） reduction were studied. The results showed that the pH, EBCT, and initial Cr（VI） concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57mg Cr（VI）-g1 Fe0 at pH 3, 5, and 7 （initial Cr（VI） concentration 4 mg.L 1, EBCT 2 min, and temperature 25℃）, 0.51, 1.51, and 2.85 mg Cr（VI）.g-I Fe0 at EBCTs of 0.5, 2.0, and 6.0rain （initial Cr（VI） concentration 4mg.L-1, pH 5, and temperature 25℃）, and 2.99, 1.51, and 1.01 mg Cr（VI）. gl Fe0 at influent concentrations of 1, 4, and 8 mg.L ^-1（EBCT 2 min, pH 5, and temperature 25℃）, respectively. Fe（total） concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr（VI） ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr6 ＋- g-~ Fe. Scanning electron micro- scope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron.展开更多
Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based ...Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftn A（encoding ferritin） was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftn A. After Fe3＋-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftn A was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftn A production and municipal wastewater（MW, including Scenedesmus obliquus and Bacillus） treatment, Synechocystis sp. PCC6803-ftn A accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%.These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftn A cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process.展开更多
基金funded by Science and Technology Projects in Guangzhou(No.202102010083)National Natural Science Foundation of China(No.32201062)Guangzhou Basic and Applied Basic Research Foundation(No.202201010339).
文摘Tumor angiogenesis is closely related to tumor development,immune escape,and drug resistance.Therefore,the development of effective anti-tumor angiogenesis drugs is of great research significance.Although the current clinical angiogenesis inhibitors have achieved certain efficacy,they also pose the problems of limited and short duration of efficacy,drug resistance,and intrinsic toxicity.Anti-tumor angiogenesis strategies targeting endothelial cells(ECs)have attracted widespread attention in the development of highly effective and low toxicity anti-angiogenesis inhibitors.Studies have verified that the trace element selenium(Se)can inhibit tumor growth by inhibiting tumor angiogenesis through different mechanisms.Nevertheless,it is unclear whether Se speciation has different effects on anti-tumor angiogenesis.Herein,we found that Se exhibited effective anti-angiogenic activity,and its mechanisms of activity were determined by its chemical speciation.Organic Se can significantly inhibit tumor angiogenesis by targeting thioredoxin reductase(TrxR)to trigger cell apoptosis and cell cycle arrest and by increasing reactive oxygen species(ROS)production in ECs.Inorganic Se can induce cell cycle arrest and increase ROS production in ECs,showing promising anti-angiogenic effects.Se nanoparticles(SeNPs)slightly inhibit tumor angiogenesis by inducing apoptosis and cell cycle arrest and by increasing the production of ROS.In summary,this study elucidates the anti-angiogenic activity of Se speciation control with a view to providing a scientific reference for the design and development of novel Se-based highly effective and low toxicity angiogenesis inhibitors.
基金supported by the National High Technology Research and Development Program (863) of China (No. 2012AA063608)the Major National S&T Program of China (No. 2011ZX07303-001)
文摘Bamboo charcoal （BC） was used as starting material to prepare Co-Fe binary oxideloaded adsorbent （Co-Fe-MBC） through its impregnation in Co（NO3）2 , FeCl3 and HNO3 solutions simultaneously, followed by microwave heating. The low-cost composite was characterized and used as an adsorbent for Cr（VI） removal from water. The results showed that a cobalt and iron binary oxide （CoFe2O4 ） was uniformly formed on the BC through redox reactions. The composite exhibited higher surface area （331 m2/g） than that of BC or BC loaded with Fe alone （Fe-MBC）. The adsorption of Cr（VI） strongly depended on solution pH, temperature and ionic strength. The adsorption isotherms followed the Langmuir isotherm model well, and the maximum adsorption capacities for Cr（VI） at 288 K and pH 5.0 were 35.7 and 51.7 mg/g for Fe-MBC and Co-Fe-MBC, respectively. The adsorption processes were well fitted by the pseudo second-order kinetic model. Thermodynamic parameters showed that the adsorption of Cr（VI） onto both adsorbents was feasible, spontaneous, and exothermic under the studied conditions. The spent Co-Fe-MBC could be readily regenerated for reuse.
基金supported by the National Natural Science Foundation of China (No. 41072173)the National High Technology Research and Development Program(863) of China (No. 2009AA062905)
文摘The mesoporous Cu/Mg/Fe layered double hydroxide（Cu/Mg/Fe-LDH） with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous solutions.The Cu/Mg/Fe-LDH was characterized by Fourier transform infrared spectrometry,X-ray diffraction crystallography,scanning electron microscopy,X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller.Effects of various physico-chemical parameters such as pH,adsorbent dosage,contact time and initial arsenate concentration on the adsorption of arsenate onto Cu/Mg/Fe-LDH were investigated.Results showed that it was efficient for the removal of arsenate,and the removal efficiency of arsenate increased with the increment of the adsorbent dosage,while the arsenate adsorption capacity decreased with increase of initial pH from 3 to 11.The adsorption isotherms can be well described by the Langmuir model with R 2 〉 0.99.Its adsorption kinetics followed the pseudo second-order kinetic model.Coexisting ions such as HPO42-,CO32-,SO42and NO3could compete with arsenate for adsorption sites on the Cu/Mg/Fe-LDH.The adsorption of arsenate on the adsorbent can be mainly attributed to the ion exchange process.It was found that the synthesized Cu/Mg/Fe-LDH can reduce the arsenate concentration down to a final level of 〈 10 μg/L under the experimental conditions,and makes it a potential material for the decontamination of arsenate polluted water.
基金supported by the National Mega-Project of Science and Technology of China (No.2008ZX07421-002)the National Eleventh Five-Year Pillar Program of Sciencethe Technology of China (No.2006BAJ04A07)
文摘The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts （DBPs） during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon （TOC） and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions, four trihalomethanes （THMs）, nine haloacetic acids （HAAs）, total organic halogen （TOX） and its halogen species fractions, including total organic chlorine （TOC1） and total organic bromide （TOBr）, were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species, which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.
基金financially supported by National Mega-Project of Science and Technology of China (No.2008ZX07421-002)the National Eleventh Five-Year Pillar Program of Science and Technology of China (No.2006BAJ04A07)
文摘For the system of water samples collected from Yangtze River,the effects of seasonal variation and Fe（III） concentrations on the formation and distribution of trihalomethanes （THMs） during chlorination have been investigated.The corresponding lifetime cancer risk of the formed THMs to human beings was estimated using the parameters and procedure issued by the US EPA.The results indicated that the average concentration of THMs （100.81 μg/L） in spring was significantly higher than that in other seasons,which was related to the higher bromide ion concentration resulted from the intrusion of tidal saltwater.The total cancer risk in spring reached 8.23 × 10 ？5 and 8.86 × 10 ？5 for males and females,respectively,which were about two times of those in summer under the experimental conditions.Furthermore,it was found that the presence of Fe（III） resulted in the increased level of THMs and greater cancer risk from exposure to humans.Under weak basic conditions,about 10% of the increment of THMs from the water samples in spring was found in the presence of 0.5 mg/L Fe（III） compared with the situation without Fe（III）.More attention should be given to the effect of the coexistence of Fe（III） and bromide ions on the risk assessment of human intake of THMs from drinking water should be paid more attention,especially in the coastland and estuaries.
基金supported by the National Key Technology R&D Program of China (No. 2012BAJ21B01)
文摘Bamboo charcoal（BC） was used as starting material to prepare iron-modified bamboo charcoal（Fe-MBC） by its impregnation in FeCl 3 and HNO 3 solutions simultaneously,followed by microwave heating.The material can be used as an adsorbent for Pb（Ⅱ） contaminants removal in water.The composites were prepared with Fe molar concentration of 0.5,1.0 and 2.0 mol/L and characterized by means of N 2 adsorption-desorption isotherms,X-ray diffraction spectroscopy（XRD）,scanning electron microscopy coupled with energy dispersive X-ray spectrometry（SEM-EDS）,Fourier transform infrared（FT-IR） and point of zero charge（pH pzc） measurements.Nitrogen adsorption analyses showed that the BET specific surface area and total pore volume increased with iron impregnation.The adsorbent with Fe molar concentration of 2 mol/L（2Fe-MBC） exhibited the highest surface area and produced the best pore structure.The Pb（Ⅱ） adsorption process of 2Fe-MBC and BC were evaluated in batch experiments and 2Fe-MBC showed an excellent adsorption capability for removal Pb（Ⅱ）.The adsorption of Pb（Ⅱ） strongly depended on solution pH,with maximum values at pH 5.0.The ionic strength had a significant effect on the adsorption at pH 〈 6.0.The adsorption isotherms followed the Langmuir isotherm model well,and the maximum adsorption capacity for Pb（Ⅱ） was 200.38 mg/g for 2Fe-MBC.The adsorption processes were well fitted by a pseudo second-order kinetic model.Thermodynamic parameters showed that the adsorption of Pb（Ⅱ） onto Fe-MBC was feasible,spontaneous,and exothermic under the studied conditions,and the ion exchange mechanism played an significant role.These results have important implications for the design of low-cost and effective adsorbents in the removal of Pb（Ⅱ） from wastewater.
基金supported by the National Major Project of Science & Technology Ministry of China (No.2008ZX07421-002)the National Natural Science Foundation of China (No. 50908142)
文摘Natural zeolite was modified by loading cetylpyridinium bromide （CPB） to create more efficient sites for humic acid （HA） adsorption. The natural and CPB modified zeolites were characterized with X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of various experimental parameters such as contact time, initial HA concentration, solution pH and coexistent Ca^2＋, upon HA adsorption onto CPB modified zeolites were evaluated. The results showed that natural zeolite had negligible affinity for HA in aqueous solutions, but CPB modified zeolites exhibited high adsorption efficiency for HA. A higher CPB loading on natural zeolites exhibited a larger HA adsorption capacity. Acidic pH and coexistent Ca^2＋ were proved to be favorable for HA adsorption onto CPB modified zeolite. The kinetic process was well described by pseudo second-order model. The experimental isotherm data fitted well to Langmuir and Sips models. The maximum monolayer adsorption capacity of CPB modified zeolite with surfactant bilayer coverage was found to be 92.0 mg/g.
基金This research was supported by the National Natural Science Foundation of China(Grant No.50908164)the 7th European Community Framework Program(PIIF-GA-2008-220665)。
文摘Nitrogen removal performance and nitrifyingpopulation dynamics were investigated in a redox stratifiedmembrane biofilm reactor(RSMBR)under oxygen limitedcondition to treat ammonium-rich wastewater.When theNH_(4)^(+)-N loading rate increased from 11.1±1.0 to 37:2±3:2 gNH_(4)^(+)-N·m^(-2)·d^(-1),the nitrogen removal inthe RSMBR system increased from 18.0±9.6 mgN·d^(-1)to 128.9±61.7 mgN·d^(-1).Shortcut nitrogen removal wasachieved with nitrite accumulation of about22:3±5:3 mgNO_(2)^(-)-N·L-1.Confocal micrographsshowed the stratified distributions of nitrifiers anddenitrifiers in the membrane aerated biofilms(MABs)atday 120,i.e.,ammonia and nitrite oxidizing bacteria(AOBand NOB)were dominant in the region adjacent to themembrane,while heterotrophic bacteria propagated at thetop of the biofilm.Real-time qPCR results showed that theabundance of amoA gene was two orders of magnitudehigher than the abundance of nxrA gene in the MABs.However,the nxrA gene was always detected during theoperation time,which indicates the difficulty of completewashout of NOB in MABs.The growth of heterotrophicbacteria compromised the dominance of nitrifiers inbiofilm communities,but it enhanced the denitrificationperformance of the RSMBR system.Applying a highammonia loading together with oxygen limitation wasfound to be an effective way to start nitrite accumulation inMABs,but other approaches were needed to sustain orimprove the extent of nitritation in nitrogen conversion inMABs.
基金supported financially by the Na tional Natural Science Foundation of China under the grant of 10432060 the Chinese Academy of Sci ences under the grant of KJCX2-SW-L05.
文摘A space experiment on bubble behavior and heat transfer in subcooled pool boiling phenomenon has been performedutilizing the temperature-controlled pool boiling (TCPB) device both in normal gravity in the laboratoryand in microgravity aboard the 22^(nd) Chinese recoverable satellite. The fluid is degassed R113 at 0.1 MPa andsubcooled by 26℃ nominally. A thin platinum wire of 60 μm in diameter and 30 mm in length is simultaneouslyused as heater and thermometer. Only the dynamics of the vapor bubbles, particularly the lateral motion and thedeparture of discrete vapor bubbles in nucleate pool boiling are reported and analyzed in the present paper. It'sfound that these distinct behaviors can be explained by the Marangoni convection in the liquid surrounding vaporbubbles. The origin of the Marangoni effect is also discussed.
文摘This paper presents a new set of experimental data of air-water flow patterns in a channel with a cross-section of 1×1 mm2. The ranges of the gas and liquid superficial velocities are 0.1-10 m/s and 0.2~7 m/s, respectively. Bubble, bubble-slug, slug, and frothy flows are observed. The present data are compared with other data in mini-channels reported in literature, and also compared with those in normal channel at microgravity, in which the Bond number has the same order of magnitude. The slug-frothy boundary is in consistent with each other, but for the bubble-slug transition, a much smaller value for the transition quality in the drift-flux model is obtained in the present study than those predicted by the empirical relations for the case of microgravity. It’s shown that the mini-scale modeling may not be an effective way to anticipate the bubble-slug transition of two-phase flow at microgravity.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 41372241）.
文摘A novel composite adsorbent, hydroxyapatite/ manganese dioxide （HAp/MnO2）, has been developed for the purpose of removing lead ions from aqueous solutions. The combination of HAp with MnO2 is meant to increase its adsorption capacity. Various factors that may affect the adsorption efficiency, including solution pH, coexistent substances such as humic acid and competing cations （Ca2＋, Mg2＋）, initial solute concentration, and the duration of the reaction, have been investigated. Using this composite adsorbent, solution pH and coexistent calcium or magnesium cations were found to have no significant influence on the removal of lead ions under the experi- mental conditions. The adsorption equilibrium was described well by the Langmuir isotherm model, and the calculated maximum adsorption capacity was 769 mg. gl. The sorption processes obeyed the pseudo-second-order kinetics model. The experimental results indicate that HAp/MnO2 composite may be an effective adsorbent for the removal of lead ions from aqueous solutions.
基金This work was supported by the Key Technologies Research and Development Program of the Eleventh-Five Year Plan of China(Grant No.2006BAJ08B02)the Innovation Project of Talented Scientific Youth of Fujian Province in 2008 Year(No.2008F3096).
文摘The dissociation constants of polyepoxysuccinic acid(PESA)were investigated in this study.Based on the potentiometric titration and the BEST program,the dissociation constants of PESA were determined.Considering the complexity of the dissociation of PESA in aqueous solution,several models were constructed to simulate the dissociation process of PESA.By comparison,the dissociation constants of PESA were obtained with model 4.The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results.It showed that the H_(2)L model with five basic structure units to describe the dissociation of PESA was reasonable,and the relevant constants had less error and better matching between the experimental and calculation data.The corresponding values of pK_(ai) were 4.68 and 4.92,respectively,for H2L at 35℃ with ionic strength of 0.1 mol/L.
基金supported by the National Key R&D Programs of China (No.2017YFC1103603)National Natural Science Foundation of China (No.21877049)+4 种基金Major Program for Tackling Key Problems of Industrial Technology in Guangzhou (No.201902020013)Dedicated Fund for Promoting High-Quality Marine Economic Development in Guangdong Province (Nos.GDOE2019-A31,2020-035)Guangzhou Key Laboratory of Molecular and Functional Imaging for Clinical Translation (No.201905010003)Innovation Team Project in Guangdong Colleges and Universities (No.2019KCXTD008)the Cultivation of Guangdong College Students’ Scientific and Technological Innovation – ‘‘Climbing Program’’ Special Funds (No.pdjh2019b0065)。
文摘Exploiting a tissue diagnosis method to abstain the involuted operating and consume valuable reagents while realizing high-speed and inexpensive pathological grading technology to supply a better scheme for cancer therapy is a significant method of cancers detection. A promising immuno-fluorescence strategy was rationally designed and synthesized by loading ruthenium complex into cervical cancer-targeted DNA-cage, which was well used to realize high-speed and inexpensive diagnosis of clinical cervical cancer tumor tissues avoiding the traditional multi-stage process, thus demonstrating high application potential in clinical pathological grading and surgical judgment. Moreover, it has been finding that Apts-DNA@Ru can enrichment in the tumor region, interestingly, no enrichment in normal cervical cancer tissue. It has the potential to realize the integration of in vivo diagnose and further synchronous treatment in the near future. Thence, this study demonstrates a strategy for integration of cancer-targeted DNA-cage and fluorescent Ru POP as alternative IHC reagents for next-generation more rapid convenient cancer detection.
基金This study was financially supported by the Specialized Research Fund for the Doctoral Program of Higher Education of Ministry of Education,China(Grant No.20050247016)China Everbright Environment Innovation Fund(Grant No.200709).
文摘The biosorption of Direct Black 38 by dried anaerobic granular sludge in a batch system under specific temperatures and initial pH was investigated.The adsorption reaction is pH dependent with higher removal at low pH.The adsorption equilibrium data fit very well with both Langmuir and Freundlich models in the concentration range of Direct Black 38 at all chosen temperatures.The adsorption parameters show that the adsorption of Direct Black 38 is an endothermic and more effective process at high temperatures.The kinetics of adsorption was found to be second order and adsorption rate constants increased with increasing temperature.Activation energy was determined as 26.8 kJ/mol for the process.This suggests that the adsorption of Direct Black 38 by dried anaerobic granular sludge is chemically controlled.
文摘The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time （EBCT）, and initial Cr（VI） concentration on Cr（VI） reduction were studied. The results showed that the pH, EBCT, and initial Cr（VI） concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57mg Cr（VI）-g1 Fe0 at pH 3, 5, and 7 （initial Cr（VI） concentration 4 mg.L 1, EBCT 2 min, and temperature 25℃）, 0.51, 1.51, and 2.85 mg Cr（VI）.g-I Fe0 at EBCTs of 0.5, 2.0, and 6.0rain （initial Cr（VI） concentration 4mg.L-1, pH 5, and temperature 25℃）, and 2.99, 1.51, and 1.01 mg Cr（VI）. gl Fe0 at influent concentrations of 1, 4, and 8 mg.L ^-1（EBCT 2 min, pH 5, and temperature 25℃）, respectively. Fe（total） concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr（VI） ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr6 ＋- g-~ Fe. Scanning electron micro- scope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron.
基金supported by the National Key Technologies R&D Program of China(No.2012BAJ25B02)
文摘Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftn A（encoding ferritin） was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftn A. After Fe3＋-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftn A was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftn A production and municipal wastewater（MW, including Scenedesmus obliquus and Bacillus） treatment, Synechocystis sp. PCC6803-ftn A accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%.These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftn A cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process.
