Hierarchical microspheres of a graphene oxide(GO) coupled to N‐doped(BiO)2CO3 composite(N‐BOC‐GO) was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic...Hierarchical microspheres of a graphene oxide(GO) coupled to N‐doped(BiO)2CO3 composite(N‐BOC‐GO) was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic activity compared to the pure BOC and N‐BOC samples. With 1.0wt% GO, 62% NO removal was obtained with N‐BOC‐GO. The factors enhancing the photocatalytic performance were the high electron‐withdrawing ability and high conductivity of GO and improved visible light‐harvesting ability of N‐BOC‐GO with a 3D hierarchical architecture due to the surface scattering and reflecting(SSR) effect. An effective charge transfer from N‐BOC to GO was demonstrated by the much weakened photoluminescene intensity of the N‐BOC‐GO composite. This work highlights the potential application of GO‐based photocatalysts in air purification.展开更多
The biotransformation of artemisinin by hairy root cultures ofRheum palmatum L. was investigated for the first time. The main product, deoxyartemisinin, was isolated and characterized on the basis of its spectral data.
A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of...A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.展开更多
The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. S...The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.展开更多
Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures (950, 1100, 1200, 1300 and 1400℃) using a muffle furnace. Demineralization of the char samples was performed by treating them wi...Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures (950, 1100, 1200, 1300 and 1400℃) using a muffle furnace. Demineralization of the char samples was performed by treating them with 10% nitric acid for 10 min in a CEM Discover microwave reactor. The gasification of the chars, and corresponding demineralized chars, in a carbon dioxide (CO2) atmosphere was conducted in a Netzsch STA 409Cl31F tempera- ture-programmed thermogravimetry apparatus. The effects of charring temperature and demineralization on the gasification reactivity of chars were systematically investigated. The results show that a char formed at a lower temperature is more reactive except for demineralized char formed at 1100℃, which is less reactive than char formed at 1200℃. Demineralization decreases the char reactivities toward gasification with CO2 to a small extent.展开更多
Heterogeneous Fenton-like process using fly ash as a catalyst was studied to degrade n-butyl xanthate form aqueous solution. The different reaction parameters on the degradation efficiency of the process were investig...Heterogeneous Fenton-like process using fly ash as a catalyst was studied to degrade n-butyl xanthate form aqueous solution. The different reaction parameters on the degradation efficiency of the process were investigated. The fly ash/H2O2 catalyst possesses a high oxidation activity for n-butyl xanthate degradation in aqueous solution. It is found that both the dosage of catalyst and initial solution pH significantly affect the n-butyl xanthate conversion efficient. The results indicate that by using 1.176 mmol/L H2O2 and 1.0 g/L fly ash catalyst with mass fraction of 4.14% Fe(III) oxide at pH 3.0, almost 96.90% n-butyl xanthate conversion and over 96.66% COD removal can be achieved within 120 min with heterogeneous catalysis by fly ash. CS2 as an intermediate of n-butyl xanthate oxidation. Finally, it is demonstrated that the fly ash/H2O2 catalytic oxidation process can be an efficient method for the treatment of n-butyl xanthate containing wastewater.展开更多
The mechanical dewatering of activated sludge is difficult due to its high compressibility, which can be improved by electroosmosis. In electroosmosis, direct electric field is applied to sludge cake. Based on the con...The mechanical dewatering of activated sludge is difficult due to its high compressibility, which can be improved by electroosmosis. In electroosmosis, direct electric field is applied to sludge cake. Based on the conductivity modes of different sludge beds, a model is presented in which sludge cake consists of two series parts in the circuit: a dewatered bed and an undewatered one. The dewatered bed called solid conductor is mainly made up of immovable water and sludge particles. The undewatered bed includes movable water and solid conductor, which are connected in parallel in the circuit. The model describes the variation of water content with time and electric power consumption as a function of water content in sludge cake, and interprets the reason for the variation of electroosmotic dewatering rate. Comparison with the experimental data for electroosmotic dewatering under constant voltage supports the validity of the model.展开更多
Laboratory scale model of DMMBF (dual mixed media biofilter) were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR colum...Laboratory scale model of DMMBF (dual mixed media biofilter) were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR column--2.2 m height and 300 mm diameter. The first mixed media filter of depth 640mm mixed of sand, rice husk and granular activated carbon. The percentage volume mix is 1:1:1. While the other mixed media of depth 740 mm, consisting of coal, crash porcelinaite, rock and granite with equally percentage volume. Fifty samples were collected during the experiments, which was spread over a period of forty two weeks. The obtained results indicate that when the flow loading raised from 0.15 L/min to 2.7 L/rain, the removal efficiency of BOD decreased 8%-11%, and the removal efficiency of COD deceased 3%-4%, while the removal efficiency of turbidity increased with the decreasing of hydraulic loading. The results showed that the removal efficiency of turbidity is more than 95% at the lower discharge (0.15 L/min). Therefore, infiltration should be conservatively designed using low loading rates.展开更多
The feasibility of adsorptive removal of single component organic compound(para-chlorophenol) by Calgon Filtrasorb 400(F400) carbon was investigated.The Redlich-Peterson equation was found to be the best fit model for...The feasibility of adsorptive removal of single component organic compound(para-chlorophenol) by Calgon Filtrasorb 400(F400) carbon was investigated.The Redlich-Peterson equation was found to be the best fit model for describing the equilibrium relationship between the para-chlorophenol adsorption onto F400 carbon.Four adsorption columns with different column geometry and adsorbent particle stratification were used to examine the adsorption kinetics onto F400 carbons.The Bed Depth Service Time(BDST) model was applied and modified to analyse the performance of the columns and the effect of different operating variables.When combining the effects of adsorption efficiency and the associated pressure drop of each type of adsorption columns tested,the carbon stratified tapered column has been determined to be the most efficient engineering option for removing organics,in which the enhancement of the adsorbent bed in terms of longer breakthrough time and higher saturation percentage is the greatest amongst the four types of columns with reasonably small pressure drop across the fixed-bed column.展开更多
Wastewater reclamation in the petroleum industries in Northern China is important because of the shortage of water resource. Conventional treatment technology used:in treating petroleum-based wastewater, namely the 3...Wastewater reclamation in the petroleum industries in Northern China is important because of the shortage of water resource. Conventional treatment technology used:in treating petroleum-based wastewater, namely the 3-phase biological process, typically removes COD, BODI grease, volatile hydrobenzenes, cyanides, sulfides and suspended solids. However, the process is often ineffective in ammonia-nitrogen removal, and thus the treated effluent quantity can' t meet the required standards for reuse. This paper investigated a novel ozone immobilized biological activated carbon(O3-IBAC) process for ammonia nitrogen removal from petroleum-based wastewater. Operated at a HRT ( Hydraulic Retention Time) of 15 minutes in IBACI and 27 minutes in IBAC2, the O3-IBAC process achieved ammonia nitrogen removal efficiency of 91%. In addition, the removal efficiencies 6f COD, volatile hydrobenzenes, suspended solids, turbidity and petroleum-based micropollutants were all above 90%. Competition between the autotrophs and heterotrophs was observed, which was indicated by an increase of ammonia nitrogen removal with a decrease of COD removal, and vise versa. Nitrite accumulation in IBACI followed by erobic shortcut denitrification in IBAC2 led to 28% of the Total Nitrogen removal efficiency. Pollutant reduction in' the IBAC process was achieved by a rapid physical adsorption and biodegradation on the activated carbon, which effectively retained the pollutants in the system despite the short hydraulic retention time.展开更多
The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate (grinding wheels with conic chamfer and grinding wheels with microdiscontinui...The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate (grinding wheels with conic chamfer and grinding wheels with microdiscontinuities on the active surface). Using these background details, a suggested thesis was put forward regarding the need to develop a device which will allow for the shaping of the macrogeometry of the grinding wheel (cylindrical and conical surfaces) and the microdiscontinuities within the dressing operation simultaneously. The device was presented and prepared in two functional variants (horizontal and vertical mounting of the motor), then a prototype was described. An example of the grinding wheel active surface, shaped by using this device, was also presented. The theoretical analysis and experimental verification performed determine that the error of shaping the conic chamfer angle within the range of 0-1.5°, using the developed device, is approximately ±3%.展开更多
The growth of reeds was impeded remarkably under a salinity of 15.0±3.4 g CI·L-1 in the first year of this experiment, recovered in the second year and then increased year-by-year afterward. The growth of re...The growth of reeds was impeded remarkably under a salinity of 15.0±3.4 g CI·L-1 in the first year of this experiment, recovered in the second year and then increased year-by-year afterward. The growth of reeds under a salinity of 9.3±1.9 g CI·Ll was much better than those under 15.0 ± 3.4 g CI·L1. The stress effect was significant for shoot extension but not for the quantity of shoots increase. The dense vegetation bed during the vegetation period (June-October) provided a high rate of evapotranspiration and water loss from HFs (horizontal subsurface flow constructed wetlands), which made large contributions to reducing pollutant load. The HFs with die-back reeds in the non-vegetation periods (November-March) provided slight evapotranspiration and water loss and made less of a contribution to reducing pollutants removal compared to HFs with the dense vegetation bed in the vegetation periods. However, the HFs with die-back reeds in the non-vegetation periods had higher removal performance than the HF without reeds. This indicated that the rhizosphere of HFs with reeds might play important roles, such as that the microbes around rhizomes might have a higher amount of pollutant-removing microbe activity than those in the HF without reeds during the non-vegetation period.展开更多
Grading procedure in routine sea cucumber hatchery production is thought to affect juvenile sea cucumber immunologi- cal response. The present study investigated the impact of a 3-min mechanical perturbation mimicking...Grading procedure in routine sea cucumber hatchery production is thought to affect juvenile sea cucumber immunologi- cal response. The present study investigated the impact of a 3-min mechanical perturbation mimicking the grading procedure on neuroendocrine and immune parameters of the sea cucumber Apostichopusjaponicus. During the application of stress, concentrations of noradrenaline and dopamine in coelomic fluid increased significantly, indicating that the mechanical perturbation resulted in a transient state of stress in sea cucumbers. Coelomocytes concentration in coelomic fluid increased transiently after the beginning of stressing, and reached the maximum in 1 h. Whereas, coelomocytes phagocytosis at 3 min, superoxide anion production from 3 min to 0.5 h, acid phosphatase activity at 0.5 h, and phenoloxidase activity from 3 min to 0.5 h were all significantly down-regulated. All of the immune parameters recovered to baseline levels after the experiment was conducted for 8 h, and an immunostimulation occurred after the stress considering the phagocytosis and acid phosphatase activity. The results suggested that, as in other marine invertebrates, neuroendocrine/immnne connections exist in sea cucumber A. japonicus. Mechanical stress can elicit a profound influence on sea cucumber neuroendocrine system. Neuroendocrine messengers act in turn to modulate the immunity fimctions. Therefore, these ef- fects should be considered for developing better husbandry procedures.展开更多
Cephalexin's traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, ...Cephalexin's traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to re- move cephalexin from aqueous solutions. Oxidization with H202 showed negative effect on the cephalexin sorption, whereas HNO3 oxidization improved the adsorption. The cephalexin adsorption isotherms on the native and HNO3 oxidized carbons correlated well with the Freundlich equation while their kinetics followed the pseudo-second order model. The removal of cephalexin by the native and HNO3 oxidized carbons was found to be most favored at low ionic strength and strong acidic conditions. Based on the thermal and FTIR analyses, the interaction mechanisms of the interaction between cephalexin and the carbons were proposed. Electrostatic attraction, hydrophobic interaction and chemical bonding with surface functional groups were demonstrated as primary mechanisms for cephalexin removal. The nitrogen functionalities on the carbon surface were considered to be an important factor affecting the adsorption process.展开更多
基金supported by the National Natural Science Foundation of China(21277097)the Key Projects in the National Science&Technology Pillar Program during the 12th Five-Year Plan Period(2012BAJ21B01)~~
文摘Hierarchical microspheres of a graphene oxide(GO) coupled to N‐doped(BiO)2CO3 composite(N‐BOC‐GO) was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic activity compared to the pure BOC and N‐BOC samples. With 1.0wt% GO, 62% NO removal was obtained with N‐BOC‐GO. The factors enhancing the photocatalytic performance were the high electron‐withdrawing ability and high conductivity of GO and improved visible light‐harvesting ability of N‐BOC‐GO with a 3D hierarchical architecture due to the surface scattering and reflecting(SSR) effect. An effective charge transfer from N‐BOC to GO was demonstrated by the much weakened photoluminescene intensity of the N‐BOC‐GO composite. This work highlights the potential application of GO‐based photocatalysts in air purification.
文摘The biotransformation of artemisinin by hairy root cultures ofRheum palmatum L. was investigated for the first time. The main product, deoxyartemisinin, was isolated and characterized on the basis of its spectral data.
基金Supported by the Major Science and Technology Program for Water Pollution Contro and Treatment-Crucial Technology Research and Engineering Sample Subject on Municipa Wastewater Treatment Process Updated to Higher Drainage Standard(2008ZX07317-02)Wuhan Water Pollution Control and the Water Environment Administer Technology and Synthetic Sample Project in Cities and Towns(2008ZX07317)
文摘A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.
基金Project(2012AA06A202)supported by Hi-tech Research and Development Project of China
文摘The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.
基金Projects 2004CB217704 supported by the Special Fund for Major State Basic Research Project, 104031 by the Key Project of Chinese Ministry of Education JHB05-33 by the Program of the Universities in Jiangsu Province for Development of High-Tech Industries
文摘Five Shenfu char samples were prepared from Shenfu raw coal at different temperatures (950, 1100, 1200, 1300 and 1400℃) using a muffle furnace. Demineralization of the char samples was performed by treating them with 10% nitric acid for 10 min in a CEM Discover microwave reactor. The gasification of the chars, and corresponding demineralized chars, in a carbon dioxide (CO2) atmosphere was conducted in a Netzsch STA 409Cl31F tempera- ture-programmed thermogravimetry apparatus. The effects of charring temperature and demineralization on the gasification reactivity of chars were systematically investigated. The results show that a char formed at a lower temperature is more reactive except for demineralized char formed at 1100℃, which is less reactive than char formed at 1200℃. Demineralization decreases the char reactivities toward gasification with CO2 to a small extent.
基金Project(CZQ13002)supported by the Special Fund for Basic Scientific Research of Central Universities,China
文摘Heterogeneous Fenton-like process using fly ash as a catalyst was studied to degrade n-butyl xanthate form aqueous solution. The different reaction parameters on the degradation efficiency of the process were investigated. The fly ash/H2O2 catalyst possesses a high oxidation activity for n-butyl xanthate degradation in aqueous solution. It is found that both the dosage of catalyst and initial solution pH significantly affect the n-butyl xanthate conversion efficient. The results indicate that by using 1.176 mmol/L H2O2 and 1.0 g/L fly ash catalyst with mass fraction of 4.14% Fe(III) oxide at pH 3.0, almost 96.90% n-butyl xanthate conversion and over 96.66% COD removal can be achieved within 120 min with heterogeneous catalysis by fly ash. CS2 as an intermediate of n-butyl xanthate oxidation. Finally, it is demonstrated that the fly ash/H2O2 catalytic oxidation process can be an efficient method for the treatment of n-butyl xanthate containing wastewater.
基金Supported by Tianjin Research Program of Application Foundation and Advanced Technology(No. 09JCYBJC08200)
文摘The mechanical dewatering of activated sludge is difficult due to its high compressibility, which can be improved by electroosmosis. In electroosmosis, direct electric field is applied to sludge cake. Based on the conductivity modes of different sludge beds, a model is presented in which sludge cake consists of two series parts in the circuit: a dewatered bed and an undewatered one. The dewatered bed called solid conductor is mainly made up of immovable water and sludge particles. The undewatered bed includes movable water and solid conductor, which are connected in parallel in the circuit. The model describes the variation of water content with time and electric power consumption as a function of water content in sludge cake, and interprets the reason for the variation of electroosmotic dewatering rate. Comparison with the experimental data for electroosmotic dewatering under constant voltage supports the validity of the model.
文摘Laboratory scale model of DMMBF (dual mixed media biofilter) were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR column--2.2 m height and 300 mm diameter. The first mixed media filter of depth 640mm mixed of sand, rice husk and granular activated carbon. The percentage volume mix is 1:1:1. While the other mixed media of depth 740 mm, consisting of coal, crash porcelinaite, rock and granite with equally percentage volume. Fifty samples were collected during the experiments, which was spread over a period of forty two weeks. The obtained results indicate that when the flow loading raised from 0.15 L/min to 2.7 L/rain, the removal efficiency of BOD decreased 8%-11%, and the removal efficiency of COD deceased 3%-4%, while the removal efficiency of turbidity increased with the decreasing of hydraulic loading. The results showed that the removal efficiency of turbidity is more than 95% at the lower discharge (0.15 L/min). Therefore, infiltration should be conservatively designed using low loading rates.
文摘The feasibility of adsorptive removal of single component organic compound(para-chlorophenol) by Calgon Filtrasorb 400(F400) carbon was investigated.The Redlich-Peterson equation was found to be the best fit model for describing the equilibrium relationship between the para-chlorophenol adsorption onto F400 carbon.Four adsorption columns with different column geometry and adsorbent particle stratification were used to examine the adsorption kinetics onto F400 carbons.The Bed Depth Service Time(BDST) model was applied and modified to analyse the performance of the columns and the effect of different operating variables.When combining the effects of adsorption efficiency and the associated pressure drop of each type of adsorption columns tested,the carbon stratified tapered column has been determined to be the most efficient engineering option for removing organics,in which the enhancement of the adsorbent bed in terms of longer breakthrough time and higher saturation percentage is the greatest amongst the four types of columns with reasonably small pressure drop across the fixed-bed column.
文摘Wastewater reclamation in the petroleum industries in Northern China is important because of the shortage of water resource. Conventional treatment technology used:in treating petroleum-based wastewater, namely the 3-phase biological process, typically removes COD, BODI grease, volatile hydrobenzenes, cyanides, sulfides and suspended solids. However, the process is often ineffective in ammonia-nitrogen removal, and thus the treated effluent quantity can' t meet the required standards for reuse. This paper investigated a novel ozone immobilized biological activated carbon(O3-IBAC) process for ammonia nitrogen removal from petroleum-based wastewater. Operated at a HRT ( Hydraulic Retention Time) of 15 minutes in IBACI and 27 minutes in IBAC2, the O3-IBAC process achieved ammonia nitrogen removal efficiency of 91%. In addition, the removal efficiencies 6f COD, volatile hydrobenzenes, suspended solids, turbidity and petroleum-based micropollutants were all above 90%. Competition between the autotrophs and heterotrophs was observed, which was indicated by an increase of ammonia nitrogen removal with a decrease of COD removal, and vise versa. Nitrite accumulation in IBACI followed by erobic shortcut denitrification in IBAC2 led to 28% of the Total Nitrogen removal efficiency. Pollutant reduction in' the IBAC process was achieved by a rapid physical adsorption and biodegradation on the activated carbon, which effectively retained the pollutants in the system despite the short hydraulic retention time.
文摘The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate (grinding wheels with conic chamfer and grinding wheels with microdiscontinuities on the active surface). Using these background details, a suggested thesis was put forward regarding the need to develop a device which will allow for the shaping of the macrogeometry of the grinding wheel (cylindrical and conical surfaces) and the microdiscontinuities within the dressing operation simultaneously. The device was presented and prepared in two functional variants (horizontal and vertical mounting of the motor), then a prototype was described. An example of the grinding wheel active surface, shaped by using this device, was also presented. The theoretical analysis and experimental verification performed determine that the error of shaping the conic chamfer angle within the range of 0-1.5°, using the developed device, is approximately ±3%.
文摘The growth of reeds was impeded remarkably under a salinity of 15.0±3.4 g CI·L-1 in the first year of this experiment, recovered in the second year and then increased year-by-year afterward. The growth of reeds under a salinity of 9.3±1.9 g CI·Ll was much better than those under 15.0 ± 3.4 g CI·L1. The stress effect was significant for shoot extension but not for the quantity of shoots increase. The dense vegetation bed during the vegetation period (June-October) provided a high rate of evapotranspiration and water loss from HFs (horizontal subsurface flow constructed wetlands), which made large contributions to reducing pollutant load. The HFs with die-back reeds in the non-vegetation periods (November-March) provided slight evapotranspiration and water loss and made less of a contribution to reducing pollutants removal compared to HFs with the dense vegetation bed in the vegetation periods. However, the HFs with die-back reeds in the non-vegetation periods had higher removal performance than the HF without reeds. This indicated that the rhizosphere of HFs with reeds might play important roles, such as that the microbes around rhizomes might have a higher amount of pollutant-removing microbe activity than those in the HF without reeds during the non-vegetation period.
基金financially supported by the 863 High Technology Project of the Ministry of Science and Technology (No. 2012AA10A412-4)the Special Funds for the Basic B & D Program in the Central Non-profit Research Institutes (No. 2010-cb-03)+1 种基金Science and Technology Development Planning Project of Shandong Province (No. 2012GGA06021)Science and Technology Development Fund of Shinan district of Qingdao (No. 2011-5-023-QT)
文摘Grading procedure in routine sea cucumber hatchery production is thought to affect juvenile sea cucumber immunologi- cal response. The present study investigated the impact of a 3-min mechanical perturbation mimicking the grading procedure on neuroendocrine and immune parameters of the sea cucumber Apostichopusjaponicus. During the application of stress, concentrations of noradrenaline and dopamine in coelomic fluid increased significantly, indicating that the mechanical perturbation resulted in a transient state of stress in sea cucumbers. Coelomocytes concentration in coelomic fluid increased transiently after the beginning of stressing, and reached the maximum in 1 h. Whereas, coelomocytes phagocytosis at 3 min, superoxide anion production from 3 min to 0.5 h, acid phosphatase activity at 0.5 h, and phenoloxidase activity from 3 min to 0.5 h were all significantly down-regulated. All of the immune parameters recovered to baseline levels after the experiment was conducted for 8 h, and an immunostimulation occurred after the stress considering the phagocytosis and acid phosphatase activity. The results suggested that, as in other marine invertebrates, neuroendocrine/immnne connections exist in sea cucumber A. japonicus. Mechanical stress can elicit a profound influence on sea cucumber neuroendocrine system. Neuroendocrine messengers act in turn to modulate the immunity fimctions. Therefore, these ef- fects should be considered for developing better husbandry procedures.
基金supported by the National Key Technology R&D Program for the 11th Five-year Plan (2006BAC10B03)the National Water Special Project (2009ZX07210-009-04)+1 种基金the Scientific Technology Research and Development Program of Shandong,China (2010GZX20605)Graduate Independent Innovation Foundation of Shandong University(2009JQ009)
文摘Cephalexin's traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to re- move cephalexin from aqueous solutions. Oxidization with H202 showed negative effect on the cephalexin sorption, whereas HNO3 oxidization improved the adsorption. The cephalexin adsorption isotherms on the native and HNO3 oxidized carbons correlated well with the Freundlich equation while their kinetics followed the pseudo-second order model. The removal of cephalexin by the native and HNO3 oxidized carbons was found to be most favored at low ionic strength and strong acidic conditions. Based on the thermal and FTIR analyses, the interaction mechanisms of the interaction between cephalexin and the carbons were proposed. Electrostatic attraction, hydrophobic interaction and chemical bonding with surface functional groups were demonstrated as primary mechanisms for cephalexin removal. The nitrogen functionalities on the carbon surface were considered to be an important factor affecting the adsorption process.