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981.
温度、pH值及盐度对龙须眼子菜吸附镉、铅的影响 总被引:2,自引:0,他引:2
以龙须眼子菜(Potamogeton pectinatus)干样为材料,研究了不同温度、pH值和盐度对龙须眼子菜吸附镉、铅离子的影响.结果表明,不同温度及不同pH值下龙须眼子菜对镉吸附符合Langmuir模型,对铅的吸附符合Freundlich模型.与5 ℃、10 ℃、30 ℃处理相比,20 ℃时龙须眼子菜对镉、铅的吸附能力较强.当其它条件不变时,在pH值为3~7的范围内,龙须眼子菜对镉的吸附随pH值升高而增加,对铅的吸附随pH值升高而减少.在0.5~10 g·L-1的盐度范围内,随着溶液盐度的增加龙须眼子菜对镉吸附减少,但对铅的吸附却增加.龙须眼子菜是一种对镉、铅有很强的吸附能力的沉水植物,对温度、酸碱度、盐度适应范围也很广,因而可作为生物吸附剂用于含镉、含铅废水的处理. 相似文献
982.
广州市PM10的时空变化特征分析 总被引:4,自引:0,他引:4
广州市的空气颗粒物污染呈逐年加重趋势,因此利用2001-2004年广州市空气自动监测点(国控点)监测的PM10日平均质量浓度资料,分析了广州市PM10的时空变化特征.统计结果表明,广州市PM10年平均质量浓度逐年递增,月平均质量浓度和季节变化趋势也较明显,秋冬季节污染较重,春夏季节污染较轻;污染较重的是海珠区和黄埔区,污染较轻的为越秀区、天河区和花都区;主成分分析显示各监测点对广州市PM10污染的贡献相当,不同监测点之间PM10质量浓度的变化主要受大尺度上的天气现象影响. 相似文献
983.
Ecotone shift and major droughts during the mid-late Holocene in the central Tibetan Plateau 总被引:1,自引:0,他引:1
A well-dated pollen record from a large lake located on the meadow-steppe ecotone provides a history of ecotone shift in response to monsoonal climate changes over the last 6000 years in the central Tibetan Plateau. The pollen record indicates that the ecotone shifted eastward during 6000-4900, 4400-3900, and 2800-1600 cal. yr BP when steppes occupied this region, whereas it shifted westward during the other intervals when the steppes were replaced by meadows. The quantitative reconstruction of paleoclimate derived from the pollen record shows that monsoon precipitation fluctuated around the present level over the last 6000 years in the central Tibetan Plateau. Three major drought episodes of 5600-4900, 4400-3900, and 2800-2400 cal. yr BP are detected by pollen signals and lake sediments. Comparison of our record with other climatic proxy data from the Tibetan Plateau and other monsoonal regions shows that these episodes are three major centennial-scale monsoon weakening events. 相似文献
984.
985.
高、中频混响声场噪声治理技术的研究及应用 总被引:1,自引:0,他引:1
我国目前纺织厂织造车间的噪声级均较高。应用吸声降噪原理 ,通过模拟、中试和二项试点三步的实践证明 ,采用在厂房建筑上架设大面积“强吸声吊顶”技术的方法 ,能使织造车间的噪声降低 4~ 6dB(A) ,收到较好的降噪效果。 相似文献
986.
采用上流式厌氧污泥床 (UASB)处理城市垃圾渗沥液 ,结果表明 :在水力停留时间为 1~ 6d和容积负荷为 1 5~ 7 8kgCOD/m3 ·d的条件下 ,COD的去除率为 6 0 %~ 85 5 % ,且去除率随水力停留时间的延长和负荷的增加而增加 ;甲烷产量随容积负荷的增加而呈线性增加 ;沼气中甲烷的含量基本在 90 %之上 ;污泥的VSS/SS先由 0 6 2逐渐减小到 0 5 6 ,随后稳定在 0 5 4~ 0 5 8之间 ;污泥的比产甲烷速率一直维持在 0 0 0 35~ 0 0 0 5 3gCODCH4 /gVSS·gCOD·d之间 ;厌氧处理渗沥液的基本动力学常数Ks、μm、Y和kd 分别为 380 7mgCOD/L、0 0 337d-1、0 0 6 6 1gVSS/gCOD和 0 0 0 14d-1。 相似文献
987.
de Toledo Renata Alves Hin Chao U. Shen Tingting Lu Qihong Li Xueqing Shim Hojae 《Environmental science and pollution research international》2019,26(12):11591-11604
Environmental Science and Pollution Research - This study evaluated the reutilization of waste materials (scrap tires, sewage sludge, and wood chips) to remove volatile organic compounds (VOCs)... 相似文献
988.
Shuixia Zhao Hung Tao Shen Xiaohong Shi Changyou Li Chao Li Shengnan Zhao 《Journal of the American Water Resources Association》2020,56(2):348-356
This study analyzed the wintertime surface heat exchange for the Inner Mongolia reach of the Yellow River, China, based on the data from the nearby weather station at Wulateqianqi. In this analysis, the solar radiation is based on the observed data. Other components of the surface heat flux, that is, long‐wave radiation, and evaporative and conductive heat fluxes, are calculated. The relative importance of the contributions of long‐wave radiation, conductive, and evaporative heat fluxes are in descending order. The air temperature is the most important meteorological factor to the total heat flux. Although the wind speed influences evaporative and conductive heat fluxes, it has the least correlation with the total heat budget. The heat exchange coefficient for the linearized surface heat exchange equation is 21.87 W/(m2 °C), which is comparable with published values in the regions of United States and Canada with similar latitudes. 相似文献
989.
Chemical fingerprint and source apportionment of PM 2.5 in highly polluted events of southern Taiwan
Huazhen Shen Tsung-mou Yang Chun-chung Lu Chung-shin Yuan Chung-Hsuang Hung Chi-tsan Lin Chia-wei Lee Guohua Jing Gongren Hu Kuo-cheng Lo 《Environmental science and pollution research international》2020,27(7):6918-6935
To investigate the spatial distribution and diurnal variation of the chemical composition of PM2.5 pollution in an industrial city of southern Taiwan, 12-h PM2.5 was diurnally continuously collected simultaneously at the Kaoping Air Quality Zone (KAQZ) during one highly PM2.5-polluted episode. Water-soluble ions, metallic elements, carbonaceous contents, dicarboxylic acids, and anhydrosugars were analyzed to characterize the chemical fingerprint of PM2.5. Backward trajectory simulation and chemical mass balance (CMB) receptor modeling were applied to identify the potential sources of PM2.5 and their contributions. It showed that Chaozhou (rural area) accompanying the highest SORs and NORs suffered from the most severe PM2.5 pollution during the episode. Sulfate (SO42−) was probably formed by the atmospheric chemical reaction in the daytime, while NO3− processed at nighttime at the KAQZ. A homogeneous formation of NO3− occurred at Chaozhou. The concentrations of Zn, Pb, Fe, Cu, V, and Al, mainly emitted from anthropogenic sources, increased significantly at the KAQZ. The highest OC, SOC/OC, and DA/OCs at Daliao (industrial area) were attributed to the transformation of primary VOCs to secondary OC via photo-oxidation during the episode. Oxalic acid was mainly produced through photochemical reactions since a high correlation between oxalic acid and Ca2+ was observed at Nanzi (urban area) and Daliao during the episode. During the episode, PM2.5 mostly originated from local primary or secondary aerosol than long-range overseas transport. The dominant source was anthropogenic emissions, accounting for 67.1% and 70.4% of PM2.5 at Nanzi and Daliao, respectively. At Chaozhou, the contribution of anthropogenic emissions was the lowest (42.4%), but secondary aerosols had the highest contribution of 38.3% of PM2.5 among the three areas during the episode. 相似文献
990.