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Zhaojun Wen Xinping Duan Menglin Hu Yanning Cao Linmin Ye Lilong Jiang Youzhu Yuan 《环境科学学报(英文版)》2018,30(2):122-129
In this study, the effects of copper(Cu) additive on the catalytic performance of Ag/SBA-15 in complete soot combustion were investigated. The soot combustion performance of bimetallic Ag–Cu/SBA-15 catalysts was higher than that of monometallic Ag and Cu catalysts. The optimum catalytic performance was acquired with the 5 Ag_1-Cu_(0.1)/SBA-15 catalyst, on which the soot combustion starts at T_(ig)= 225°C with a T_(50)= 285°C. The temperature for 50% of soot combustion was lower than that of conventional Ag-based catalysts to more than 50°C(Aneggi et al., 2009). Physicochemical characterizations of the catalysts indicated that addition of Cu into Ag could form smaller bimetallic Ag–Cu nanolloy particles, downsizing the mean particle size from 3.7 nm in monometallic catalyst to 2.6 nm in bimetallic Ag–Cu catalyst. Further experiments revealed that Ag and Cu species elicited synergistic effects, subsequently increasing the content of surface active oxygen species. As a result, the structure modifications of Ag by the addition of Cu strongly intensified the catalytic performance. 相似文献
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Effects of lead and cadmium nitrate on biomass and substrate utilization pattern of soil microbial communities 总被引:10,自引:0,他引:10
A study was conducted to evaluate the effects of different concentrations of lead (Pb) and cadmium (Cd) applied as their nitrates on soil microbial biomass carbon (C(mic)) and nitrogen (N(mic)), and substrate utilization pattern of soil microbial communities. The C(mic) and N(mic) contents were determined at 0, 14, 28, 42 and 56 days after heavy metal application (DAA). The results showed a significant decline in the C(mic) for all Pb and Cd amended soils from the start to 28 DAA. From 28 to 56 DAA, C(mic) contents changed non-significantly for all other treatments except for 600 mgkg(-1) Pb and 100 mgkg(-1) Cd in which it declined significantly from 42 to 56 DAA. The N(mic) contents also decreased significantly from start to 28 DAA for all other Pb and Cd treatments except for 200 mgkg(-1) Pb which did not show significant difference from the control. Control and 200 mgkg(-1) Pb had significantly lower soil microbial biomass C:N ratio as compared with other Pb treatments from 14 to 42 DAA, however at 56 DAA, only 1000 mgkg(-1) Pb showed significantly higher C:N ratio compared with other treatments. No significant difference in C:N ratio for all Cd treated soils was seen from start to 28 DAA, however from 42 to 56 DAA, 100 mgkg(-1) Pb showed significantly higher C:N ratio compared with other treatments. On 56 DAA, substrate utilization pattern of soil microbial communities was determined by inoculating Biolog ECO plates. The results indicated that Pb and Cd addition inhibited the functional activity of soil microbial communities as indicated by the intensity of average well color development (AWCD) during 168 h of incubation. Multivariate analysis of sole carbon source utilization pattern demonstrated that higher levels of heavy metal application had significantly affected soil microbial community structure. 相似文献
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以济南市城区泉水SO42-、NO3-、Cl-为研究对象,从降水、补源、人类活动3个维度选取影响因子,研究影响因子与3种离子浓度的相关性;以通径分析判定影响因子的直接作用和间接作用,通过计算决策系数判定影响因子对离子浓度变化的作用大小和方向;通过建立的回归方程预测泉水NO3-浓度和环境可承载的废水排放总量.结果表明:20... 相似文献
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脱硫石膏改良碱化土壤种植水稻施用量研究 总被引:18,自引:1,他引:17
选择具有典型代表性的宁夏西大滩碱化土壤,采用拉丁方田间试验设计进行脱硫石膏改良碱化土壤种植水稻(Oryza sativa)的施用量研究.试验研究表明施用脱硫石膏能够降低土壤碱化度、总碱度和pH值,提高水稻的出苗率和产量.但是,脱硫石膏施用量不同,土壤碱化度、总碱度和pH值降低的值不同.根据脱硫石膏施用量与土壤碱化度、总碱度、pH值降低的模拟曲线关系,当脱硫石膏施用量为2.8~3.1kg·m~(-2)时,土壤碱化度、总碱度、pH值降低的值达到最大.同时,根据脱硫石膏施用量与水稻出苗率和产量的模拟曲线关系,当脱硫石膏施用量为2.86kg·m~(-2),水稻出苗率达到最大,为84.7%;当脱硫石膏施用量为2.79kg·m~(-2)时,水稻产量达到最大,为0.75kg·m~(-2).因此,建议脱硫石膏改良碱化土壤种植水稻的施用量为2.8~3.1kg·m~(-2). 相似文献
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硅对锰胁迫下水稻吸收矿质元素的影响 总被引:1,自引:0,他引:1
揭示Mn胁迫下硅对水稻中营养元素的影响特点,可为减轻水稻锰毒害提供理论依据.因此,本文通过水培试验,利用两个对Mn耐性不同的水稻品种,研究施Si(1.5 mmol·L-1)对Mn(2 mmol·L-1)胁迫下水稻营养元素的影响.同时,采用同步辐射X射线荧光(SRXRF)分析了营养元素的分布特点,以及各元素分布之间的相互关系.结果显示,高锰胁迫下,耐性品种叶片和根系的Mn含量都显著高于敏感品种.高锰胁迫抑制了敏感品种K元素从根部向叶片的转移,而降低了耐性品种的根部吸收K元素的能力.高锰胁迫下,施硅处理增加了敏感品种叶片中K、Fe和Zn的相对含量;可显著增加耐性品种叶片中K和Zn的相对含量,显著降低其Ca和Fe的相对含量.高锰胁迫下施硅可以促进敏感品种K元素的转运,促进耐性品种Zn元素转运.Si对耐性品种各元素含量保持相对平衡具有重要作用.水稻体内的锰大部分是硫酸锰,高锰胁迫下施硅不改变水稻植株体内的锰形态. 相似文献
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Seven soils were sampled from farmland at different distances (0.01-5 km) from a copper and zinc smelter. The total contents of heavy metals in these soils ranged from 46 to 4895 mg Cu kg-1, 96 to 1133 mg Zn kg-1, and 6.9 to 28.8 mg Cd kg-1, respectively. The available fractions were highly correlated with total contents of the metals. In order to assess the impact of combined contamination of heavy metals on soil bacterial communities, denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) amplicons of 16S rDNA sequence of bacteria in soil was used. Bacterial community structure was affected to some extent by heavy metals. The number of DGGE bands in soils increased with increasing distance from the copper and zinc smelter. Clustering analysis of the DGGE profiles showed that bacteria in the seven soils belonged to three clusters. Bacterial communities in three soils sampled at 0.01-0.60 km from the smelter belonged to one cluster, and those in three soils sampled at 0.8-1.2 km from the smelter belong to another cluster. Bacterial community in soil farthest from the smelter belonged to a single cluster. This study demonstrated that heavy metal contamination decreased both biomass and diversity of bacterial community in the soil. 相似文献
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医疗废物典型组分在回转窑内的热解-气化研究 总被引:4,自引:0,他引:4
在小型回转窑上对模拟医疗废物的4种典型组分进行了批量热解-气化试验.实验结果表明,热解-气化反应物料的转化率较高(80%~100%),基本上随热解-气化终温(FPT)的升高而升高.热解-气化反应中物料的热裂解反应在30min以内基本结束.FPT的升高,有利于挥发分的析出、减少残渣量和处置时间.从试验结果来看,第一段初级处理中采用约700℃的回转窑反应温度比较适合实现医疗垃圾的完全热解和气化. 相似文献