The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are u...The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.展开更多
In order to greatly improve adsorption capacity,the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis.The scan...In order to greatly improve adsorption capacity,the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis.The scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities(qe)of Pb2+ and Cd2+was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1–0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 °C for 120 min; aging at a temperature of 105 °C for 16 h.The adsorption capacities of Pb2+ and Cd2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite,respectively.The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite.The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.展开更多
Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BI...Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BIT) and characterized by 1 H NMR,IR and elemental analysis,respectively.The single crystals of compounds 1 and 2 were obtained and determined by X-ray diffraction analysis.The preliminary results of biological activity experiment show that some of the title compounds exhibited a favorable antimicrobial activity.展开更多
Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e...Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e.,in-plasma catalysis (IPC) and post-plasma catalysis (PPC).It was found that the catalytic performance of the catalysts for MPOM was strongly dependent on the hybrid configuration.A better synergistic performance of plasma and catalysis was achieved in the IPC configuration,but the catalysts packed in the discharge zone showed lower stability than those connected to the discharge zone in sequence.Active species,such as ozone,atomic oxygen and methyl radicals,were produced from the plasma-catalysis process,and made a major contribution to methanol synthesis.These active species were identified by the means of in situ optical emission spectra,ozone measurement and FT-IR spectra.It was confirmed that the amount of active species in the IPC system was greater than that in the PPC system.The results of TG,XRD,and N2 adsorption-desorption revealed that carbon deposition on the spent catalyst surface was responsible for the catalyst deactivation in the IPC configuration.展开更多
The title compound N-(2-ethoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxa-mide(C16H14N2O3S,Mr = 314.35) has been synthesized and structurally characterized by IR,1H NMR and single-crystal X-ray diffraction.The crys...The title compound N-(2-ethoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxa-mide(C16H14N2O3S,Mr = 314.35) has been synthesized and structurally characterized by IR,1H NMR and single-crystal X-ray diffraction.The crystal belongs to triclinic,space group P with a = 4.6395(15),b = 8.689(3),c = 17.917(7),α = 87.763(9),β = 84.625(9),γ = 82.344(9)°,V = 712.4(4)3,Z = 2,Dc = 1.465 Mg·m-3,λ(MoKa) = 0.71073,F(000) = 328,μ(MoKa) = 0.242 mm-1,the final R = 0.038 and wR = 0.089.A total of 3702 unique reflections were collected,of which 2762 with I > 2σ(I) were observed.X-ray analysis revealed that the benzisothiazolone ring and benzene moieties were essentially planar,and three intramolecular hydrogen bonds N(2)-H(2N)…O(1),N(2)-H(2N)…O(3) and C(10)-H(10)…O(2) were observed.The preliminary biologi-cal test showed that the title compound had antifungal and antibacteria activities against Bacillus subtilis(CMCC63003),Aeromonas hydrophila(ATCC7966),Staphylococcus aureus(ATCC6538),Escherichia coli(JM103),Blastomyces albicans,Gloeosporium papaya P.Henn,Colletotrichum gloeosporioides Penz and Botryodiplodia theobromae.展开更多
A beneficiation-metallurgy combination process is developed to recover Zn, Fe and to enrich In, Ag from high iron-bearing zinc calcine based on our former researches. In gaseous reductive roasting process, the roastin...A beneficiation-metallurgy combination process is developed to recover Zn, Fe and to enrich In, Ag from high iron-bearing zinc calcine based on our former researches. In gaseous reductive roasting process, the roasting conditions were tested by magnetic separation of roasted product. It is found that the V_(CO)(P_(CO)/(P_(CO+CO_2)) in roasting atmosphere should be maintained below 30% to avoid the generation of zinc iron solid solution(Fe_(0.85-x)Zn_xO), which can bring a decrease of iron recovery in magnetic separation. After roasting, acid leaching and multistage magnetic separation are carried out for the recovery of Zn, Fe and enrichment of Ag and In. About 90% of zinc is extracted and 83% of iron is recovered in the whole process. The Ag mainly enters the tailings with a recovery of 76%, the Ag grade increases from 0.12 g/t in raw materials to 1.18 g/t in the tailings. However, the In mainly enters the iron concentrations and the recovery reaches 86%. This process was proved to be technically feasible and may be a favorable option in the treatment of high iron-bearing zinc material with high Ag or In content.展开更多
The removal of four heavy metals i.e. Pb, Cr, Cu, and Zn from their aqueous solutions, using ordinary sand as an adsorbent, was studied at 20℃. The amount of metal adsorbed to form monolayer on sand(a_m), obtained fr...The removal of four heavy metals i.e. Pb, Cr, Cu, and Zn from their aqueous solutions, using ordinary sand as an adsorbent, was studied at 20℃. The amount of metal adsorbed to form monolayer on sand(a_m), obtained from Langmuir isotherm, exhibited the preference of metals for sand in the order Pb>Cr>Cu>Zn. The heavy metal-sand adsorption phenomena can be illustrated on the basis of the interaction between surface functional group of silicates (sand) and the metal ions. It is deduced that sand can be used as a low cost adsorbent for the removal of heavy metal from wastewater (containing low conc. of metals), especially in the developing countries.展开更多
Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as...Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as collection of wood for fuel purpose and livestock grazing. Removal of vegetation of rangelands has a significant negative impact on soil organic matter(SOM). This research evaluates litter decomposition in three sites of Hazarganji Chiltan mountain with varying history of human disturbances(unprotected site, young protected site and old protected site). Twigs of Pistacia khinjuk with approximately equal weight and length were placed in litter bags of mesh size 2 mm and were buried in 0-5 cm depth in three sites in January. Half of the twigs of each site received rain simulation in April, August, October, November and January while the other half of the twigs were subjected under natural conditions for 15 months. Twigs from each plot of each treatment of each site were collected from soil after every rain simulation in the previous month of experiment and were processed for weight loss assessment. Results showed that weight loss of twigs by decomposition was significantly higher in the soil of unprotected site as compared to other two sites and there was no difference between rain simulation and control treatments except that loss of weight of twigs of unprotected site was higher under control than rain simulation condition. To confirm that SOM was the major controlling factor for the decomposition of litter decay, soils of each site were collected and burned to remove SOM;thereafter, burned soil samples were mixed with homogenous powder of oven-dried native plants, incubated for 6 months and were provided with dissolved organic matter of the soils of each site. Results showed that there was no difference in the decomposition of litter between soils under controlled laboratory condition, which confirmed that SOM was a major controlling factor for the litter decay in soil under field conditions. The pyrosequencing analysis of the DNA of soils collected from three sites revealed the presence of bacterial species Thermovum composti.展开更多
The adsorption potential of titanium dioxide(TiO2) nanoparticles for removing arsenic from drinking water was evaluated.Pure and iron-doped TiO2 particles are synthesized via sol-gel method.The synthesized TiO2 nanopa...The adsorption potential of titanium dioxide(TiO2) nanoparticles for removing arsenic from drinking water was evaluated.Pure and iron-doped TiO2 particles are synthesized via sol-gel method.The synthesized TiO2 nanoparticles were then immobilized on ordinary sand for adsorption studies.Adsorption isotherms were conducted on the synthesized nanoparticles as well as the sand coated with TiO2 nanoparticles under varying conditions of air and light,namely,the air-sunlight(A-SL),air-light(AL),air-dark(AD) and nitrogen-dark(ND).X-ray diffraction(XRD) analysis showed that the pure and iron-doped TiO2 nanoparticles were in 100% anatase crystalline phase with crystal sizes of 108 and 65 nm,respectively.Adsorption of arsenic on the three adsorbents was non-linear that could be described by the Freundlich and Langmuir adsorption models.Iron doping enhanced the adsorption capacity of TiO2 nanoparticles by arresting the grain growth and making it visible light responsive resulting in a higher affnity for arsenic.Similarly,the arsenic removal by adsorption on the sand coated with TiO2 nanoparticles was the highest among the three types of sand used.In all cases,As(V) was adsorbed more compared with As(Ⅲ).The solution pH appeared to be the most important factor in controlling the amount of arsenic adsorbed.展开更多
A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical me...A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP)of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (tf/tr), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38％～50％ in the stable operation period with the organic loading rate of 0.37～0.54 kg COD/(m3.d) at the optimum conditions of tf/tr, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge.展开更多
There were six high diesel oil degrading bacteria strains isolated fro m the oil contaminated soil that collected from Linzi City. The strain Y1 was ab le to produce biosurfactant rhamnolipid when cultivated on diesel...There were six high diesel oil degrading bacteria strains isolated fro m the oil contaminated soil that collected from Linzi City. The strain Y1 was ab le to produce biosurfactant rhamnolipid when cultivated on diesel oil as carbon source. The critical micelle concentrations (CMC) of rhamnolipid in water and in the soil were measured respectively according to the correlation between the su rface tension of the medium and the added rhamnolipid concentration. The results showed that the CMC of rhamnolipid in water was 65 mg/L, and was 185 mg/L in so il. The tests on diesel oil biodegradation were conducted with the addition of d ifferent concentrations of rhamnolipid in water and in soil respectively. When 0 .01% rhamnolipid was added to water, the diesel oil degradation was enhanced. On the contrary, when the same concentration of rhamnolipid was added to the soil, the degradation of diesel oil was inhibited. The results suggested that the rha mnolipid could enhance the diesel oil biodegradation, indicating that the concen tration of rhamnolipid was higher than the corresponding CMC in the medium. Kine tics parameters for the diesel oil biodegradation parameters such as biodegradat ion constant (λ), coefficient of correlation(r) and half life (t1/2) in both t ests were numerically analyzed in this paper, indicating that the moderate conc entration of rhamnolipid in the medium could not only enhance the extent of dies el oil biodegradation but also shorten the time for oil remediation.展开更多
Vertical distribution processes of sediment contaminants in water were studied by flume experiments.Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major h...Vertical distribution processes of sediment contaminants in water were studied by flume experiments.Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants,especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.展开更多
Popular descriptive multivariate statistical method currently employed is the principal component analyses (PCA) method. PCA is used to develop linear combinations that successively maximize the total variance of a sa...Popular descriptive multivariate statistical method currently employed is the principal component analyses (PCA) method. PCA is used to develop linear combinations that successively maximize the total variance of a sample where th ere is no known group structure. This study aimed at demonstrating the performan ce evaluation of pilot activated sludge treatment system by inoculating a strain of Pseudomonas capable of degrading malathion which was isolated by enrichment technique. An intensive analytical program was followed for evaluating the effic iency of biosimulator by maintaining the dissolved oxygen (DO) concentration at 4.0 mg/L. Analyses by high performance liquid chromatographic technique revealed that 90% of malathion removal was achieved within 29 h of treatment whereas COD got reduced considerably during the treatment process and mean removal efficien cy was found to be 78%. The mean pH values increased gradually during the treatm ent process ranging from 7.36—8.54. Similarly the mean ammonia-nitrogen (NH3-N) values were found to be fluctuating between 19.425—28.488 mg/L, mean nitrite-n itrogen (NO3-N) ranging between 1.301—2.940 mg/L and mean nitrate-nitrogen (NO3 -N) ranging between 0.0071—0.0711 mg/L. The study revealed that inoculation of bacterial culture under laboratory conditions could be used in bioremediation of environmental pollution caused by xenobiotics. The PCA analyses showed that pH, COD, organic load and total malathion concentration were highly correlated and emerged as the variables controlling the first component, whereas dissolved oxyg en, NO3-N and NH3-N governed the second component. The third component repeated the trend exhibited by the first two components.展开更多
Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water c...Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water can be made safe for drinking simply by heating at 65℃ for 6 minutes. A colour indicating strip was developed which changes colour from red to purple at 67℃. Use of this strip can help in pasteurizing water without the above problems and with considerable energy saving.展开更多
To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during pr...To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption (SAWD) unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte (SPE) unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% (1000 L). About 950 L of CO2 was recovered with a recovery rate of 92%～97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 min when the start-up temperature was 187.3, 179.5 and 168 °C, respectively. The product water was colorless, transparent, and had a pH of 6.9～7.5, and an electrical conductivity of 80 μs/cm. The sum of the concentration of metal ions (Ru3+, Al3+, Pb2+) was 0.028% and that of nonmetal ions (Cl-, SO42-) was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m3/d and the quantity was 2400 L, sufficient to meet the submariners' basic oxygen demands. These results may be useful as a basis for establishing CO2-level limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.展开更多
This study presents the Multi Axis Differential Optical Absorption Spectroscopy(MAXDOAS) measurements for Glyoxal(CHOCHO) in Beijing, China(39.95°N, 116.32°E). CHOCHO is the smallest compound of di-carbonyl ...This study presents the Multi Axis Differential Optical Absorption Spectroscopy(MAXDOAS) measurements for Glyoxal(CHOCHO) in Beijing, China(39.95°N, 116.32°E). CHOCHO is the smallest compound of di-carbonyl group. As a primary sink of CHOCHO, its photolysis with NOx(oxides of nitrogen) results in the production of tropospheric ozone. Therefore,the focus of CHOCHO DOAS measurements is increasing in trend. We did the measurements from 09 May 2017 to 09 September 2017. The study was conducted to compare different retrieval settings in order to reveal best DOAS fit settings for CHOCHO;furthermore, effect of haze and non-haze days on CHOCHO concentration was examined.The root mean square of residual and Differential Slant Column density(dSCD) error was reduced when measurements were done with lower wavelength limit around 432–438 nm and upper intervals around 455–460 nm. Thus, lower wavelength intervals around432–438 nm and upper intervals around 457–460 nm were best for the retrieval of dSCDs for CHOCHO. Meteorological conditions like haze or non-haze days did not have significant effect on DOAS fit parameters. The CHOCHO vertical column densities range from 1.33 E +14 to 9.77 E + 14 molecules/cm2 during the study period with average of 6.16 E +14 molecules/cm2. The results indicated that during haze days CHOCHO concentration was higher because of lower rate of photolysis and atmospheric oxidation potential. Our results did not show any significant weekend effect on CHOCHO atmospheric concentration.展开更多
This paper discusses the findings of the first car MAX-DOAS(multi-axis differential optical absorption spectroscopy) field campaign(300 km long) along the National Highway-05(N5-Highway) of Pakistan conducted on 13 an...This paper discusses the findings of the first car MAX-DOAS(multi-axis differential optical absorption spectroscopy) field campaign(300 km long) along the National Highway-05(N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide(NO_2)columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore.Source identification of NO_2 revealed that the concentrations were higher within major cities along the highway. The highest NO_2 vertical column densities(NO_2VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO_2 VCDs measured by the ozone monitoring instrument(OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO_2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO_2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.展开更多
Based on the concept of ecosystem carrying capacity,the indicator system of quantitative assessment was set up,which consisted of support indicator system and pressure indicator system.And the factor analysis method w...Based on the concept of ecosystem carrying capacity,the indicator system of quantitative assessment was set up,which consisted of support indicator system and pressure indicator system.And the factor analysis method was used to screen the indicator system.Different from the traditional indicator weight determination based on the absolute values of the coefficients of regression equation,the squares of factor loadings in the rotated component matrix were attempted to determine the weights of 40 assessment indicators.The result shows that ecological support system and pressure system in Binhai New Area are relatively balanced among six years,and the developing level of urban ecosystem is basically healthy on the whole.However,due to continuously increasing pressure of the resources consumption caused by the rapid growth of the second industry,which is the Leading Industry of Binhai New Area,the ecosystem carrying capacity reached the minimum in 2005.展开更多
基金Y.C.and J.C.are contributed equally to the paper.Project supported by the National Natural Science Foundation of China (U19A2017)the Fundamental Research Funds for the Central South University and the Australian Research Council (DP180100731 and DP180100568)。
文摘The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.
基金Project(12JJ8016)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(CX2012B317)supported by Hunan Provincial Innovation Foundation For Postgraduate,ChinaProject(2006180)supported by the Hunan Key Discipline Construction Found of Environmental Science,China
文摘In order to greatly improve adsorption capacity,the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis.The scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities(qe)of Pb2+ and Cd2+was synthesized with the following conditions: Addition of pillaring solution containing Al3+-oligomers with a concentration range of 0.1–0.2 mol/L to a suspension containing Na+-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 °C for 120 min; aging at a temperature of 105 °C for 16 h.The adsorption capacities of Pb2+ and Cd2+ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite,respectively.The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite.The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.
基金Supported by the National Natural Science Foundation of China (No. 20962007)the Creative Talents Plan of Hainan University 211 Project
文摘Two compounds,3-oxo-N-o-tolylbenzo[d]isothiazole-2(3H)-carboxamide (1) and N-(2-methoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxamide (2),were synthesized from the initial compound benzo[d]isothiazol-3(2H)-one (BIT) and characterized by 1 H NMR,IR and elemental analysis,respectively.The single crystals of compounds 1 and 2 were obtained and determined by X-ray diffraction analysis.The preliminary results of biological activity experiment show that some of the title compounds exhibited a favorable antimicrobial activity.
基金supported by the National Natural Science Foundation of China(No. 20836008 and U0633003)the Zhejiang Provincial Natural Science Foundation of China(No. Y5080192)+3 种基金the Project of Science and Technology Department of Zhejiang Province of China(2007C13061)MOST Project of China(No. 2007AA06Z339,No. 2008BAC32B06 and No. 2007AA06A409)the Open Project Program of Key Laboratory of Non-point Sources Pollution Controlthe Ministry of Agriculture of the People’s Republic of China and Science Foundation of Chinese University
文摘Methane partial oxidation to methanol (MPOM) using dielectric barrier discharge over a Fe2O3-CuO/γ-Al2O3 catalyst was performed.The multicomponent catalyst was combined with plasma in two different configurations,i.e.,in-plasma catalysis (IPC) and post-plasma catalysis (PPC).It was found that the catalytic performance of the catalysts for MPOM was strongly dependent on the hybrid configuration.A better synergistic performance of plasma and catalysis was achieved in the IPC configuration,but the catalysts packed in the discharge zone showed lower stability than those connected to the discharge zone in sequence.Active species,such as ozone,atomic oxygen and methyl radicals,were produced from the plasma-catalysis process,and made a major contribution to methanol synthesis.These active species were identified by the means of in situ optical emission spectra,ozone measurement and FT-IR spectra.It was confirmed that the amount of active species in the IPC system was greater than that in the PPC system.The results of TG,XRD,and N2 adsorption-desorption revealed that carbon deposition on the spent catalyst surface was responsible for the catalyst deactivation in the IPC configuration.
基金Supported by the National Natural Science Foundation of China (No. 20962007)
文摘The title compound N-(2-ethoxyphenyl)-3-oxobenzo[d]isothiazole-2(3H)-carboxa-mide(C16H14N2O3S,Mr = 314.35) has been synthesized and structurally characterized by IR,1H NMR and single-crystal X-ray diffraction.The crystal belongs to triclinic,space group P with a = 4.6395(15),b = 8.689(3),c = 17.917(7),α = 87.763(9),β = 84.625(9),γ = 82.344(9)°,V = 712.4(4)3,Z = 2,Dc = 1.465 Mg·m-3,λ(MoKa) = 0.71073,F(000) = 328,μ(MoKa) = 0.242 mm-1,the final R = 0.038 and wR = 0.089.A total of 3702 unique reflections were collected,of which 2762 with I > 2σ(I) were observed.X-ray analysis revealed that the benzisothiazolone ring and benzene moieties were essentially planar,and three intramolecular hydrogen bonds N(2)-H(2N)…O(1),N(2)-H(2N)…O(3) and C(10)-H(10)…O(2) were observed.The preliminary biologi-cal test showed that the title compound had antifungal and antibacteria activities against Bacillus subtilis(CMCC63003),Aeromonas hydrophila(ATCC7966),Staphylococcus aureus(ATCC6538),Escherichia coli(JM103),Blastomyces albicans,Gloeosporium papaya P.Henn,Colletotrichum gloeosporioides Penz and Botryodiplodia theobromae.
基金Project(2014FJ1011)supported by the Major Science and Technology Project of Hunan Province,ChinaProject(51574295)supported by the National Natural Science Foundation of China
文摘A beneficiation-metallurgy combination process is developed to recover Zn, Fe and to enrich In, Ag from high iron-bearing zinc calcine based on our former researches. In gaseous reductive roasting process, the roasting conditions were tested by magnetic separation of roasted product. It is found that the V_(CO)(P_(CO)/(P_(CO+CO_2)) in roasting atmosphere should be maintained below 30% to avoid the generation of zinc iron solid solution(Fe_(0.85-x)Zn_xO), which can bring a decrease of iron recovery in magnetic separation. After roasting, acid leaching and multistage magnetic separation are carried out for the recovery of Zn, Fe and enrichment of Ag and In. About 90% of zinc is extracted and 83% of iron is recovered in the whole process. The Ag mainly enters the tailings with a recovery of 76%, the Ag grade increases from 0.12 g/t in raw materials to 1.18 g/t in the tailings. However, the In mainly enters the iron concentrations and the recovery reaches 86%. This process was proved to be technically feasible and may be a favorable option in the treatment of high iron-bearing zinc material with high Ag or In content.
文摘The removal of four heavy metals i.e. Pb, Cr, Cu, and Zn from their aqueous solutions, using ordinary sand as an adsorbent, was studied at 20℃. The amount of metal adsorbed to form monolayer on sand(a_m), obtained from Langmuir isotherm, exhibited the preference of metals for sand in the order Pb>Cr>Cu>Zn. The heavy metal-sand adsorption phenomena can be illustrated on the basis of the interaction between surface functional group of silicates (sand) and the metal ions. It is deduced that sand can be used as a low cost adsorbent for the removal of heavy metal from wastewater (containing low conc. of metals), especially in the developing countries.
基金supported by University of Balochistan Research Fund(UBRF)grant#UBRF-17/026。
文摘Hazarganji Chiltan National Park in Balochistan, Pakistan was established in 1980 and the protected area was further extended in 1998. Large area of this mountain is still open for unmanaged human disturbances such as collection of wood for fuel purpose and livestock grazing. Removal of vegetation of rangelands has a significant negative impact on soil organic matter(SOM). This research evaluates litter decomposition in three sites of Hazarganji Chiltan mountain with varying history of human disturbances(unprotected site, young protected site and old protected site). Twigs of Pistacia khinjuk with approximately equal weight and length were placed in litter bags of mesh size 2 mm and were buried in 0-5 cm depth in three sites in January. Half of the twigs of each site received rain simulation in April, August, October, November and January while the other half of the twigs were subjected under natural conditions for 15 months. Twigs from each plot of each treatment of each site were collected from soil after every rain simulation in the previous month of experiment and were processed for weight loss assessment. Results showed that weight loss of twigs by decomposition was significantly higher in the soil of unprotected site as compared to other two sites and there was no difference between rain simulation and control treatments except that loss of weight of twigs of unprotected site was higher under control than rain simulation condition. To confirm that SOM was the major controlling factor for the decomposition of litter decay, soils of each site were collected and burned to remove SOM;thereafter, burned soil samples were mixed with homogenous powder of oven-dried native plants, incubated for 6 months and were provided with dissolved organic matter of the soils of each site. Results showed that there was no difference in the decomposition of litter between soils under controlled laboratory condition, which confirmed that SOM was a major controlling factor for the litter decay in soil under field conditions. The pyrosequencing analysis of the DNA of soils collected from three sites revealed the presence of bacterial species Thermovum composti.
文摘The adsorption potential of titanium dioxide(TiO2) nanoparticles for removing arsenic from drinking water was evaluated.Pure and iron-doped TiO2 particles are synthesized via sol-gel method.The synthesized TiO2 nanoparticles were then immobilized on ordinary sand for adsorption studies.Adsorption isotherms were conducted on the synthesized nanoparticles as well as the sand coated with TiO2 nanoparticles under varying conditions of air and light,namely,the air-sunlight(A-SL),air-light(AL),air-dark(AD) and nitrogen-dark(ND).X-ray diffraction(XRD) analysis showed that the pure and iron-doped TiO2 nanoparticles were in 100% anatase crystalline phase with crystal sizes of 108 and 65 nm,respectively.Adsorption of arsenic on the three adsorbents was non-linear that could be described by the Freundlich and Langmuir adsorption models.Iron doping enhanced the adsorption capacity of TiO2 nanoparticles by arresting the grain growth and making it visible light responsive resulting in a higher affnity for arsenic.Similarly,the arsenic removal by adsorption on the sand coated with TiO2 nanoparticles was the highest among the three types of sand used.In all cases,As(V) was adsorbed more compared with As(Ⅲ).The solution pH appeared to be the most important factor in controlling the amount of arsenic adsorbed.
基金Project (No. 40272108) supported by the National Natural Science Foundation of China
文摘A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP)of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (tf/tr), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38％～50％ in the stable operation period with the organic loading rate of 0.37～0.54 kg COD/(m3.d) at the optimum conditions of tf/tr, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge.
基金The National Natural Science Foundation of China (No. 40272108) and the Doctor Subject Foundation of the Ministry of Educationof China (No. 20040423016)
文摘There were six high diesel oil degrading bacteria strains isolated fro m the oil contaminated soil that collected from Linzi City. The strain Y1 was ab le to produce biosurfactant rhamnolipid when cultivated on diesel oil as carbon source. The critical micelle concentrations (CMC) of rhamnolipid in water and in the soil were measured respectively according to the correlation between the su rface tension of the medium and the added rhamnolipid concentration. The results showed that the CMC of rhamnolipid in water was 65 mg/L, and was 185 mg/L in so il. The tests on diesel oil biodegradation were conducted with the addition of d ifferent concentrations of rhamnolipid in water and in soil respectively. When 0 .01% rhamnolipid was added to water, the diesel oil degradation was enhanced. On the contrary, when the same concentration of rhamnolipid was added to the soil, the degradation of diesel oil was inhibited. The results suggested that the rha mnolipid could enhance the diesel oil biodegradation, indicating that the concen tration of rhamnolipid was higher than the corresponding CMC in the medium. Kine tics parameters for the diesel oil biodegradation parameters such as biodegradat ion constant (λ), coefficient of correlation(r) and half life (t1/2) in both t ests were numerically analyzed in this paper, indicating that the moderate conc entration of rhamnolipid in the medium could not only enhance the extent of dies el oil biodegradation but also shorten the time for oil remediation.
基金supported by the National Natural Science Foundation of China (Grant 11502138)the National Key Research and Development Program (Grant 2016YFC0401500)the National Water Pollution Control and Treatment Science and Technology Major Project (Grant 2012ZX07506-002b)
文摘Vertical distribution processes of sediment contaminants in water were studied by flume experiments.Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants,especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.
基金Foundation item： Project（50925417） supported by the National Science Fund for Distinguished Young Scholars of China Project（50830301） supported by the National Natural Science Foundation of China Project（2011467062） supported by National Research Fund for Public Benefit （Environmental Protection） Industries, China
文摘Popular descriptive multivariate statistical method currently employed is the principal component analyses (PCA) method. PCA is used to develop linear combinations that successively maximize the total variance of a sample where th ere is no known group structure. This study aimed at demonstrating the performan ce evaluation of pilot activated sludge treatment system by inoculating a strain of Pseudomonas capable of degrading malathion which was isolated by enrichment technique. An intensive analytical program was followed for evaluating the effic iency of biosimulator by maintaining the dissolved oxygen (DO) concentration at 4.0 mg/L. Analyses by high performance liquid chromatographic technique revealed that 90% of malathion removal was achieved within 29 h of treatment whereas COD got reduced considerably during the treatment process and mean removal efficien cy was found to be 78%. The mean pH values increased gradually during the treatm ent process ranging from 7.36—8.54. Similarly the mean ammonia-nitrogen (NH3-N) values were found to be fluctuating between 19.425—28.488 mg/L, mean nitrite-n itrogen (NO3-N) ranging between 1.301—2.940 mg/L and mean nitrate-nitrogen (NO3 -N) ranging between 0.0071—0.0711 mg/L. The study revealed that inoculation of bacterial culture under laboratory conditions could be used in bioremediation of environmental pollution caused by xenobiotics. The PCA analyses showed that pH, COD, organic load and total malathion concentration were highly correlated and emerged as the variables controlling the first component, whereas dissolved oxyg en, NO3-N and NH3-N governed the second component. The third component repeated the trend exhibited by the first two components.
文摘Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water can be made safe for drinking simply by heating at 65℃ for 6 minutes. A colour indicating strip was developed which changes colour from red to purple at 67℃. Use of this strip can help in pasteurizing water without the above problems and with considerable energy saving.
基金supported by the National Natural Science Foundation of China (No. 50908062)the State Key Lab of Urban Water Resource and Environment (No. HIT-QAK200808)the Heilongjiang Natural Science Foundation (No. E2007-04), China
文摘To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption (SAWD) unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte (SPE) unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% (1000 L). About 950 L of CO2 was recovered with a recovery rate of 92%～97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 min when the start-up temperature was 187.3, 179.5 and 168 °C, respectively. The product water was colorless, transparent, and had a pH of 6.9～7.5, and an electrical conductivity of 80 μs/cm. The sum of the concentration of metal ions (Ru3+, Al3+, Pb2+) was 0.028% and that of nonmetal ions (Cl-, SO42-) was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m3/d and the quantity was 2400 L, sufficient to meet the submariners' basic oxygen demands. These results may be useful as a basis for establishing CO2-level limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.
基金supported by grants from the National Key Research and Development Program of China (Nos. 2018YFC0213104)National Natural Science Foundation of China (Nos. 41722501, 91544212, 51778596, 41575021)National Key Research and Development Program of China (Nos. 2016YFC0203302)
文摘This study presents the Multi Axis Differential Optical Absorption Spectroscopy(MAXDOAS) measurements for Glyoxal(CHOCHO) in Beijing, China(39.95°N, 116.32°E). CHOCHO is the smallest compound of di-carbonyl group. As a primary sink of CHOCHO, its photolysis with NOx(oxides of nitrogen) results in the production of tropospheric ozone. Therefore,the focus of CHOCHO DOAS measurements is increasing in trend. We did the measurements from 09 May 2017 to 09 September 2017. The study was conducted to compare different retrieval settings in order to reveal best DOAS fit settings for CHOCHO;furthermore, effect of haze and non-haze days on CHOCHO concentration was examined.The root mean square of residual and Differential Slant Column density(dSCD) error was reduced when measurements were done with lower wavelength limit around 432–438 nm and upper intervals around 455–460 nm. Thus, lower wavelength intervals around432–438 nm and upper intervals around 457–460 nm were best for the retrieval of dSCDs for CHOCHO. Meteorological conditions like haze or non-haze days did not have significant effect on DOAS fit parameters. The CHOCHO vertical column densities range from 1.33 E +14 to 9.77 E + 14 molecules/cm2 during the study period with average of 6.16 E +14 molecules/cm2. The results indicated that during haze days CHOCHO concentration was higher because of lower rate of photolysis and atmospheric oxidation potential. Our results did not show any significant weekend effect on CHOCHO atmospheric concentration.
基金financial support as Master thesis research fund to conduct this study
文摘This paper discusses the findings of the first car MAX-DOAS(multi-axis differential optical absorption spectroscopy) field campaign(300 km long) along the National Highway-05(N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide(NO_2)columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore.Source identification of NO_2 revealed that the concentrations were higher within major cities along the highway. The highest NO_2 vertical column densities(NO_2VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO_2 VCDs measured by the ozone monitoring instrument(OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO_2 columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO_2 VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.
文摘Based on the concept of ecosystem carrying capacity,the indicator system of quantitative assessment was set up,which consisted of support indicator system and pressure indicator system.And the factor analysis method was used to screen the indicator system.Different from the traditional indicator weight determination based on the absolute values of the coefficients of regression equation,the squares of factor loadings in the rotated component matrix were attempted to determine the weights of 40 assessment indicators.The result shows that ecological support system and pressure system in Binhai New Area are relatively balanced among six years,and the developing level of urban ecosystem is basically healthy on the whole.However,due to continuously increasing pressure of the resources consumption caused by the rapid growth of the second industry,which is the Leading Industry of Binhai New Area,the ecosystem carrying capacity reached the minimum in 2005.
