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881.
Feng Qin Shujuan Wang Inna Kim Hallvard F. Svendsen Changhe Chen 《International Journal of Greenhouse Gas Control》2011,5(3):405-412
A reaction calorimeter was used to determine the enthalpies of absorption of CO2 in aqueous ammonia and in aqueous solutions of ammonium carbonate at temperatures of 35–80 °C. The heat of absorption of CO2 with 2.5 wt% aqueous ammonia solution was found to be about 70 kJ/mol CO2, which is lower than that with MEA (around 85 kJ/mol) at 35 and 40 °C. The value decreases with increased loading, but not to as low a value as expected by the carbonate–bicarbonate reaction (26.88 kJ/mol). The enthalpy of absorption of CO2 in aqueous ammonia at 60 and 80 °C decreases with loadings at first, then increases between 0.2 mol CO2/mol NH3 and 0.6 mol CO2/mol NH3, and then decreases again. The behavior of the heat of absorption of CO2 in 10 wt% ammonium carbonate solution was found to be the same as that of aqueous ammonia at loadings above 0.6 mol CO2/mol NH3. The heat of absorption increases with increasing temperature. The heats of absorption are directly related to the extent of the various reactions with CO2 and can be assessed from the species variation in the liquid phase. 相似文献
882.
Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau 总被引:2,自引:0,他引:2
Qianggong Zhang Shichang Kang Chaoliu Li Feng Chen Zuzana Boukalova Ivo ?erny 《Environmental monitoring and assessment》2011,173(1-4):301-313
In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements(Ca and Mg), and nutrient(NO $_{3}^{-})$ were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007?C2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1?C22) and anthropogenic action (sites 23?C76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO $_{3}^{-}$ and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively. 相似文献
883.
Xu H Bi XH Feng YC Lin FM Jiao L Hong SM Liu WG Zhang XY 《Environmental monitoring and assessment》2011,183(1-4):581-592
To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH??, Ca2?, Mg2?, Na?, K?, SO?2?, NO??, F?, and Cl?). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO?2?/NO?? ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO?2?, Ca2?, and Mg2? and 33.7% of K? were of non-sea origins, while all Na? and Cl? and 66.3% of K? originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources. 相似文献
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通过野外调查研究了云南楚雄雨露砷矿区采矿、冶炼废弃地生长的16种优势植物的生长状态及其对应根区土壤的基本理化性质.结果表明,该矿区植物长势良好,未出现受害症状.土壤磷氮含量充足,As含量远远超过《土壤环境质量标准》3级标准中的旱地As含量标准值,高达133倍.16种植物的地上部重金属含量As最高,并且在总As平均质量比高达5 318 mg/kg的土壤环境条件下,蜈蚣草(Pteris vittata L.)体内As质量比可达2 327 mg/kg,小酸模(Rumex acetosella L.)、辣子草(Galinsoga parviflora Cav.)、鬼针草(Bidens pilosa L.)等7种植物对Cd,以及牛口刺(Cirsium shansiense Petrak.)对Zn的富集系数和转移系数均大于1.0,其中地石榴对Cd的富集系数高达7.99.上述植物对重金属污染均表现出了较强的耐性,具有进一步的研究潜力. 相似文献
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运用概率论和数理统计方法,基于湖南气象观测资料、NCEP资料及地理信息资料,分析了气象因子、地理因子对雨凇天气形成的影响,揭示了各影响因子的临界影响点。进而分析了主要影响因子位于不同影响点时其它因子对雨淞天气形成的作用,在此基础上,研制了基于气象要素因子、地理因子的雨凇日数学模型。选取平均连续雨凇日数、年平均雨凇日数、雨凇最长持续时间等3项与雨凇日数有关的气候指标对模型模拟结果进行了检验,结果表明模型模拟结果与实际观测结果相关性高,均值差异小。雨凇日模型已被用于精细化的雨凇气候区划。 相似文献
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890.
中国水泥行业面临巨大的碳达峰与碳中和压力.CO2捕集利用与封存(CCUS)技术是能够实现化石资源低碳利用的碳减排技术.在中国水泥企业数据基础上,采用全流程CCUS系统模型(ITEAM-CCUS)评估CCUS的碳减排潜力对水泥企业碳中和非常重要.模型从源汇匹配距离、捕集率、CCUS技术和技术水平这4个方面设置了10种情景,完成了水泥行业的企业筛选、场地筛选、CCUS技术经济评估和源汇匹配,初步回答了水泥企业结合CCUS的封存场地、减排规模、成本范围和优先项目分布等关键问题.在250 km匹配距离、85%净捕集率、CO2-EWR技术和当前技术水平情景,44%的水泥企业可以利用CO2强化地下水开采(CO2-EWR)技术开展碳减排,累计年碳减排量为6.25亿t,平准化成本为290~1838元·t-1;具有全流程CO2-EWR早期示范优势的地区为新疆、内蒙古、宁夏、河南和河北等.水泥企业开展全流程CCUS项目技术可行,可以实现大规模CO2减排,低成本项目具有早期示范机会.研究结果可为水泥行业低碳发展和CCUS商业化部署提供定量参考. 相似文献