区域经济重心及 COD、SO_2、TSP排放重心演变路径分析——以江苏省为例

运用重心模型,采用1996~2006年江苏省经济和环境数据,计算出各年份GDP、工业产值、COD、SO ₂和TSP排放重心坐标,揭示江苏省经济重心和环境污染排放重心变化轨迹及演变规律,以期为江苏省环境宏观战略决策及生态省建设提供理论参考。研究表明,经济重心总体上向东南方向偏移,GDP重心偏移距离为14.81 km,工业产值重心偏移距离为12.84 km;经济重心在南北方向上的偏移程度大于东西方向的偏移程度。环境污染排放重心也向东南方向偏移,COD和TSP排放重心轨迹呈现较大变化,SO2排放重心轨迹变动较小;COD排放重心偏移距离为79.26 km,SO₂排放重心偏移距离为15.73 km,TSP排放重心偏移距离为42.24 km;各污染排放重心轨迹在不同时段表现出不同特点。COD、SO₂和TSP排放重心相对于经济重心偏向于西北方向,且COD排放重心近年来明显趋向于工业产值重心;COD排放重心和TSP排放重心与经济重心存在着强正相关.     

Chemical characterization of fine particles from on-road vehicles in the Wutong tunnel in Shenzhen, China

Vehicle populations in China have been increasing sharply since 1990s. Vehicle emissions including various gaseous pollutants and particulate matter cause deterioration of air quality. However, measurements of particulate mater from on-road vehicles in China are scarcely reported, and thus the chemical compositions of particles emitted from vehicles in China are unknown. In this research, tunnel experiments were performed to measure PM2.5 in the Wutong tunnel, Shenzhen, China. Detailed PM2.5 chemical compositions, with organic compounds determined by GC/MS, in the tunnel were presented. Elemental carbon and organic matter composed 63% and 34% of the total PM2.5 mass in the Wutong tunnel, respectively. Alkanes, PAHs, hopanes, fatty acids, and dicarboxylic acids were the major identified organic compounds, and their source profiles in the PM2.5 in the Wutong tunnel were characterized. The comparisons of our measurements with those in the literature were also made to demonstrate the characteristics of the vehicle source profiles in the Wutong tunnel. The experimental results in this paper can improve understanding of particulate matter emitted from vehicles in China.     

Methods for the preparation of a biodesulfurization biocatalyst using Rhodococcus sp

Several methods to prepare a biodesulfurization (BDS) biocatalyst were investigated in this study using a strain of Rhodococcus sp. 1awq. This bacterium could selectively remove sulfur from dibenzothiophene (DBT) via the "4S" pathway. DBT, dimethylsulfoxide (DMSO), sodium sulphate and mixed sulfur sources were used to study their influence on cell density, desulfurization activity, desulfurization ability, and the cost of biocatalyst production. In contrast to that observed from bacteria cultured in DBT, only partial desulfurization activity of strain 1awq was induced by DBT after cultivation in a medium containing inorganic sulfur as the sole sulfur source. The biocatalyst, prepared from culture with mixed sulfur sources, was found to possess desulfurization activity. With DMSO as the sole sulfur source, the desulfurization activity was shown to be similar to that of bacteria incubated in medium with DBT as the sole sulfur source. The biocatalyst prepared by this method with the least cost could remove sulfur from hydrodesulfurization (HDS)-treated diesel oil efficiently, providing a total desulfurization percent of 78% and suggesting its cost-effective advantage.     

操作条件对UF&RO工艺制取纯水效率的影响

采用UF＆RO膜组合工艺制取纯水,考察各项操作条件对系统效率的影响.结果表明,自来水经UF＆RO膜组合工艺装置的出水满足试验纯水水质要求.对于UF系统,冲洗频率、过滤方式和操作压力均影响系统的制水效率.冲洗频率越大,制水效率越高;各种过滤方式中,死端过滤效率最高;在一定范围内,操作压力升高,制水效率反而下降.对于RO系统,应根据出水水质要求,选择合适的回收率和操作压力.     

无锡市大气PM2.5中黑碳的粒径分布与混合态特征

针对长江三角洲地区PM2.5中的重要组分黑碳(BC)气溶胶,2010~2011年利用单颗粒黑碳光度计(SP2),对江苏省无锡市夏冬两季BC气溶胶的质量浓度、粒径分布及单颗粒混合态进行了连续在线观测.结果表明,无锡市冬季BC质量浓度(6.1μg/m3)是夏季(2.5μg/m3)的2.4倍,内混态BC比例(NIB)冬季(64.8%)也显著高于夏季(44.6%),说明冬季BC污染与来外来污染传输有关.反向轨迹分析表明,来自华北平原的污染气团输入是冬季高浓度BC污染的首要原因. NIB的日变化趋势与BC质量浓度的完全相反.午后BC质量浓度最低时NIB最高,反映了二次光化学产物包覆在BC颗粒外层的老化过程.此外,夏冬两季BC粒径分布保持稳定,其质量浓度峰值对应粒径在225nm左右,数浓度峰值对应粒径在120nm左右.     

Spatial variations of Pb in the vertical zone of the soil-plant system in the Changbai Mountain National Nature Reserve

The characteristics of vertical and horizontal variations of lead element (Pb) in soil-plant system of vertical zone in Changbai Mountain National Nature Reserve(CNNR)were studied.The results showed that Pb concentrations in soils of vertical zone are all above 25mg/kg,and the average Pb concentration of each soil zone negatively correlates its degree of variation,i.e.brown coniferous forest soil zone has the lowest average Pb concentration of four soil zones,and the highest horizontal variation;however,mountain soddy forest soil has the highest average Pb concentration,and the lowest horizontal variation;the average concentration of plant Pb of each plant zone is lower than the worldwide average level of Pb in plant(Clarke),respectively,and plant Pb content order is consistent with soil Pb content order,but their horizontal variations are different from those in soil zones,the variation of mountain tundra forest zone is highest,but Betula ermanii forest zoner the lowest.Vertical variation of plant Pb is obviously higher than that in soils with variation coefficient of 89.76%;the enrichment capability of plant for Pb is depended on the plant types and the different organs of plant;parent material and parent rock,pH values,soil organic matter and soil particle fraction etc.are the main factors influencing variations of Pb contant in soil-plant system of vertical zone in CNNR.     

滇池北岸典型农区韭菜田大气氮湿沉降与氮挥发研究

选择滇池北岸大清河下游典型农区韭菜田为对象,对雨水进行化学分析,研究了2007年大气氮湿沉降通量及其动态变化,并通过田间试验观测了地表(韭菜地土壤、韭菜废弃物原位腐解、沟渠污水)的氨氮挥发.结果表明,全年大气湿沉降氮(以N计)7.1kg/hm2,其中雨季(4～9月份)占89%.韭菜一次基施尿素(以N计)276kg/hm2,35d累计氨挥发占施氮量的32%,其中前9d氨挥发占总氨挥发96%.韭菜残体腐解21d累计氮挥发占植株氮23%.含氮7～51mg/L的污水(其中氨氮2.7～25.8mg/L)露天放置12d,水体总氮的27%～38%挥发进入大气.可见,韭菜田氮挥发是该地大气氮重要来源之一.     

露天堆场防风抑尘网后湍流结构及抑尘效率的数值模拟

建立了开放性露天堆场周围空气流动的三维数学物理模型,选择应用标准k-ε紊流模型进行了静态流场的数值模拟;分析了典型棱形堆迎风面、平顶面和背风面周围空气的湍流结构和表面受力特性;基于流场数据揭示了防风抑尘网不同孔隙率下空气动力学结构的分布规律.结果显示:物料堆平顶面剪切力随孔隙率增大而增大;料堆迎风面在孔隙率较小时出现局部涡流,表面剪切力方向向下,孔隙率较大时,网后空气垂直方向压差作用显著,表面剪切力方向向上;背风面始终处于回流区,表面剪切力和回流点数随孔隙率大小变化不显著.综合流场结构和受力分布可得最佳孔隙率为0.2~0.4.该研究中对物料堆逐个表面进行空气动力学模拟可以避免由于剪切力方向不同产生矢量抵消而带来的计算失真.     

沸石负载对叔丁基杯[4]芳烃乙酸对铀的吸附行为

以对叔丁基杯[4]芳烃与溴乙酸乙酯为主要反应底物合成了对叔丁基杯[4]芳烃乙酸,然后将其负载在沸石上,红外光谱显示合成物具有杯[4]芳烃乙酸的特征结构,扫描电镜分析表明对叔丁基杯[4]芳烃乙酸成功负载于沸石之上,且分布均匀,分散性良好.通过静态吸附实验,结果表明在pH值 4,对叔丁基杯[4]芳烃乙酸/沸石的负载比0.025/1,吸附剂用量0.5g,铀初始质量浓度10mg/L,吸附时间30min时,沸石在负载了对叔丁基杯[4]芳烃乙酸后,对溶液中铀的吸附率从30%左右提高到93%.沸石和负载沸石吸附动力学行为均符合准二级动力学模型,但负载沸石对铀的吸附速率明显高于沸石.沸石和负载沸石吸附等温式都符合Langmuir吸附等温线,说明都为单分子层吸附;由此推导出的最大吸附量Qm从16.8919提高到32.5733mg/g,这主要是因为沸石负载了对叔丁基杯[4]芳烃乙酸增加了吸附点位.吸附铀前后的红外光谱表明,负载沸石对铀的去除主要依靠对叔丁基杯[4]芳烃乙酸与铀的强络合作用和Si—O和Al—O的吸附作用,两种作用的协同加快了吸附速率,增加了吸附容量.