Present and potential future contributions of sulfate,black and organic carbon aerosols from China to global air quality,premature mortality and radiative forcing

Aerosols are harmful to human health and have both direct and indirect effects on climate. China is a major contributor to global emissions of sulfur dioxide (SO₂), a sulfate (SO₄^2?) precursor, organic carbon (OC), and black carbon (BC) aerosols. Although increasingly examined, the effect of present and potential future levels of these emissions on global premature mortality and climate change has not been well quantified. Through both direct radiative effects and indirect effects on clouds, SO₄^2? and OC exert negative radiative forcing (cooling) while BC exerts positive forcing (warming). We analyze the effect of China's emissions of SO₂, SO₄^2?, OC and BC in 2000 and for three emission scenarios in 2030 on global surface aerosol concentrations, premature mortality, and radiative forcing (RF). Using global models of chemical transport (MOZART-2) and radiative transfer (GFDL RTM), and combining simulation results with gridded population data, mortality rates, and concentration–response relationships from the epidemiological literature, we estimate the contribution of Chinese aerosols to global annual premature mortality and to RF in 2000 and 2030. In 2000, we estimate these aerosols cause approximately 470 000 premature deaths in China and an additional 30 000 deaths globally. In 2030, aggressive emission controls lead to a 50% reduction in premature deaths from the 2000 level to 240 000 in China and 10 000 elsewhere, while under a high emissions scenario premature deaths increase 50% from the 2000 level to 720 000 in China and to 40 000 elsewhere. Because the negative RF from SO₄^2? and OC is larger than the positive forcing from BC, Chinese aerosols lead to global net direct RF of ?74 mW m^?2 in 2000 and between ?15 and ?97 mW m^?2 in 2030 depending on the emissions scenario. Our analysis indicates that increased effort to reduce greenhouse gases is essential to address climate change as China's anticipated reduction of aerosols will result in the loss of net negative radiative forcing.     

Mn/Co-Ba-Al-O催化氧化NO性能研究

采用共沉淀-浸溃法制备了Mn/Co-Ba-Al-O催化剂.考察了用共沉淀法制作载体Co-Ba-Al-O过程中加料顺序分别为正加法、反加法和并流法时催化剂的活性.BET测试和XBD分析表明,并流时制得的载体比表面积最大,且其中的γ-A12O3结晶度最好,不含BaCO3,对NO的催化氧化性能最好.考察了各操作条件对并流法制备的催化剂催化氧化NO效率的影响,结果显示,在NO体积分数为500 X 10-6,O2体积分数为10%,空速为4000h-1时,225°C左右,出1:3 NOX的氧化度(N02/NO2)达到50%-60%.将取得最大的吸收效率;300°C时,氧化度可达到83%左右,接近热力学平衡值.     

长期单施NK肥条件下几种典型土壤磷的演化

为探讨我国典型土壤长期单施氮钾肥对土壤全磷和Olsen-P磷的影响,研究了不同气候条件、不同耕作制度下,7种典型土壤类型长期定位试验单施氮钾肥下土壤全磷和Olsen-P变化及其影响因素.结果表明,在长期单施氮钾肥条件下,除杭州水稻土全磷含量稳定在1.0g·kg-1左右外,其余6种耕作土壤全磷含量和土壤Olsen-P均呈显著下降趋势,全磷含量下降幅度在13.6%～44.9%之间;土壤Olsen-P下降速率比全磷高几倍,Olsen-P下降有一定阈值,这一阈值大约为5 mg·kg-1.土壤全磷含量与土壤Olsen-P含量呈极显著直线相关关系.因此,长期单施氮钾肥在很大程度上减少了土壤磷素养分库.     

磷钼酸铵-聚乙烯醇复合材料的制备及其对水中Cs+的吸附性能研究

利用磷钼酸铵、聚乙烯醇和正硅酸四乙酯合成一种新型复合材料（AMP-PVA）,运用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射（XRD）、X射线光电子能谱（XPS）和热重分析仪（TG-DSC）等对AMP-PVA进行结构和形貌表征.同时,探究了不同初始浓度、pH、时间等因素对AMP-PVA特异性吸附Cs⁺性能的影响,并结合等温吸附曲线、吸附动力学等对AMP-PVA的吸附机制进行探讨.结果表明,AMP-PVA可在pH=2~11范围内使用,耐酸性能良好,且在35 ℃、pH=7.7、初始Cs⁺浓度为200 mg·L^-1的条件下达到最大吸附量109.56 mg·g^-1;吸附过程以自发的、吸热的、可持续的化学吸附为主,符合Freundlich等温吸附模型和准二级动力学模型,并伴随着内扩散和Boyd模型的特征;AMP-PVA主要作用机制为Cs⁺与AMP中的NH₄⁺发生离子交换.     

Electro-oxidation of Ni (II)-citrate complexes at BDD electrode and simultaneous recovery of metallic nickel by electrodeposition

The simultaneous electro-oxidation of Ni (II)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond (BDD) anode and a polished titanium cathode. Effects of initial nickel citrate concentration, current density, initial pH, electrode spacing, electrolyte type, and initial electrolyte dosage on electrochemical performance were examined. The efficiencies of Ni (II)-citrate removal and nickel metal recovery were determined to be 100% and over 72%, respectively, under the optimized conditions (10 mA/cm², pH 4.09, 80 mmol/L Na₂SO₄, initial Ni (II)-citrate concentration of 75 mg/L, electrode spacing of 1 cm, and 180 min of electrolysis). Energy consumption increased with increased current density, and the energy consumption was 0.032 kWh/L at a current density of 10 mA/cm² (pH 6.58). The deposits at the cathode were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%. The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.     

Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons

The concentration variation of C3-C11 non-methane hydrocarbons(NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically investigated using a gas chromatography-flame ionization detector(GC-FID) system. The percentage loss of each NMHC in the polyvinyl fluoride(PVF) bags was less than 5% during a 7-hr storage period; significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags. The thermal desorption effic...     

Concentration and distribution characteristic of main toxic metals in suspended particle material in Nanjing reach, Changjiang River

Six stations in the lower reach region of Changjiang River within Baguazhou Island, Nanjing reach were chosen to investigate the toxic metals pollution characteristic in suspended particle material (SPM). SPM concentration, as well as reflectance spectroscopy characteristic, toxic metal concentrations, and lead isotopes of suspended particle material were studied. SPM concentrations were obtained from fluvial cross-sectional sampling near the surface (20 cm) and the study presents the cross-sectional averages. SPM concentrations varied around 170?C300 mg L^???1. Reflectance spectroscopy measurements differed from each other over each cross-section but no common pattern characterizing the cross-sectional behavior of the measurements was observed. The metal concentrations in the SPM decreased in the sequence: Mn > Zn > Cu > Cr > Pb > Cd. The result of lead isotopes analysis proved that lead isotopes composition in SPM are mainly produced by natural contributions and influenced by anthropogenic activity at the same time.     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

新型CuMn/TiO2苯类催化燃烧催化剂的研制及活性实验

采用浸溃法制备了CuMn/TiO2新型甲苯燃烧催化剂,其活性明显优于传统CuMn/γ-Al2O3和Cu-Mn复合氧化物催化剂.研究发现,载体TiO2自身有一定催化活性,而γ-Al2O3则几乎没有活性;TiO2与Cu-Mn之间的协同作用更提高了新型催化剂的活性.XRD、LRS结果显示,CuMn/TiO2催化剂的主要活性相为铜锰尖晶石(CuMn2O4),它的存在是CuMn/TiO2催化活性优良的另一个主要原因.考察了Cu-Mn负载量、铜锰比和焙烧温度对催化剂活性的影响,CuMn/TiO2下对甲苯的去除率达95%以上时催化床层温度为215℃,比CuMn/γ-Al2O3和Cu-Mn复合氧化物对甲苯去除率达95%时分别下降了30℃、50℃左右.     

Anaerobic BTEX degradation in soil bioaugmented with mixed consortia under nitrate reducing conditions

Different concentrations of BTEX, including benzene, toluene, ethylbenzene, and three xylene isomers, were added into soil samples to investigate the anaerobic degradation potential by the augmented BTEX-adapted consortia under niwate reducing conditiom. All the BTEX substrates could be anaerobically biodegraded to non-detectable levels within 70 d when the initial concentrations were below 100 mg/kg in soil. Toluene was degraded faster than any other BTEX compounds, and the high-to-low order ofdegradation rates were toluene>ethylbenzene>m. xylene>o-xylene>benzene>P. xylene. Nitrite was accumulated with nitrate reduction. but the accumulation of nitrite had no inhibitory effect on the degradation of BTEX throughout the whole incubation. Indigenous bacteria in tIle soil could enhance the BTEX biodegradation ability of the enriched mixed bacteria. When the six BTEX compounds were simultaneously present in soil, there was no apparent inhibitory effect on their degradation with lower initial concentrations. Alternatively, benzene, o-xylene, and P-xylene degradation were inhibited with higher initial concentrations of 300 mg/kg. Higher BTEX biodegradation rates were observed in soil samples with the addition of sodium acetate compared to the presence of a single BTEX substrate. and the hypothesis of primary-substrate stimulation or cometabolic enhancement of BTEX biodegradation seems likely.