蘑菇培养废料的土壤培肥增产效果研究

蘑菇培养后的废料做水稻基肥 1～4t/亩 ,可增加土壤有机质 ,有效磷和有效钾 ;提高水稻产量 .     

Role and importance of oxidized nitrogen oxide adspecies on the mechanism and dynamics of reaction over copper-based catalysts

The formation of nitrate and NO₂ adspecies over Cu/MFI and copper-on-alumina catalysts and their role in the mechanism of reaction is discussed on the basis of FT-IR results and catalytic tests in unsteady-state conditions. Three specific cases are discussed: (i) reduction of NO by propane/O₂ over Cu/MFI, (ii) conversion of NO by NH₃/O₂ over copper-on-alumina catalysts and (iii) oxygen-promoted reduction of NO in the absence of reductants over Cu/MFI. The formation of nitrate species leads to self-deactivation, but Cu²⁺-NO₂ like adspecies are suggested to be a key intermediate in the reduction of NO to N₂ in all three cases examined.     

施肥对蔬菜累积硝酸盐影响的研究进展

施肥是提高蔬菜产量的重要措施,然而不合理施肥会引起蔬菜硝酸盐的积累。本文主要对近年来国内外有关氮、磷、钾和有机肥料等的施用对蔬菜硝酸盐积累的影响进行了讨论并对今后的研究提出了一些建议。     

环境因素对蔬菜累积硝酸盐影响的研究进展

蔬菜中的硝酸盐是一种对人体有害的化学物质,其含量比其它植物都高,人体摄入它会引起多种疾病。对近年来国内外有关光照、温度、气体、土壤中的水分和养分等对蔬菜硝酸盐积累的影响进行了综述。     

Counter-current Electrophoresis

Abstract

Historical development, principal operation, different ways of experimental realization, and typical examples of application of countercurrent electrophoresis are reviewed. The separation process is principally capable of being applied to all types of ions, as far as any difference is shown in their ionic behavior. Different types of columns can be adapted to varying amounts of substance from approximately 10^?6 mole up to several moles (in the laboratory scale). The production of high purity components and the use of the column as an absolute ion filter are further possible applications.     

Arsenic,Nitrate, Chloride And Bromide Contamination In The Gulf Coast Aquifer,South-Central Texas,USA

Arsenic, nitrate, chloride, and bromide concentrations in the Gulf Coast Aquifer of south-central Texas, USA, were compiled, mapped, and evaluated in the context of local land use and geology. Agriculture and oil production are predominant land uses and potential sources of groundwater contamination in the study area. Data were compiled from 69 wells with a median depth of 160.5 v m. Eight observations surpassed the 44.3 v mg/L standard for nitrate (10 v mg/L NO 3 -N), and 24 observations exceeded the 10 v µg/L standard for arsenic. There was a statistically significant, inverse correlation between nitrate and well depth, and a direct correlation between nitrate and arsenic. Arsenic concentrations were significantly higher in a uranium-bearing sand formation compared to other formations in the study area. Chloride concentrations were also high relative to the (secondary) drinking water standard (250 v mg/L), with a median of 342 v mg/L and maximum of 6840 v mg/L. Most chloride/bromide ratios were near 300, but there were four significantly lower values, consistent with oilfield brine or evaporite dissolution. Results of this study suggest that (1) geology exerts a major control on arsenic concentrations in groundwater, (2) agricultural activity contributes substantially to nitrate and chloride and, to a lesser extent, arsenic concentrations in groundwater, and (3) oilfield brine has locally impacted groundwater in the study area.     

离子色谱法检测硝酸盐亚硝酸盐前处理方法的研究

目的 利用离子色谱法检测乳及乳制品中亚硝酸盐、硝酸盐,在实际检测中用该国标方法在前处理样品时,存在沉淀样品不完全进而影响检测准确性、重复性不理想的弊端,为提高检测的准确性,缩小检测偏差,需对国标方法中样品的前处理改进。方法 样品经乙腈沉淀脂肪蛋白质后,采用相应的方法提取和净化,以氢氧化钾溶液为淋洗液,阴离子交换柱分离,电导检测器检测。以保留时间定性,外标法定量。结果 该方法克服了乳及乳制品GB5009.33-2010第三法检测检出限高及检测用时长,精密度低的的弊端。结论本方法适合于乳及乳制品定量测定。     

吸水膨胀弹性体PVA-g-PBA的研究

在水介质中.在氮气保护下以硝酸铈铵(CAN)为引发剂,将丙烯酸丁酯(BA)接枝到聚乙烯醇(PVA)上,制得水膨胀弹性体PVA—g—PBA。通过红外光谱证实了接枝物的形成。讨论了PVA浓度、单体浓度、引发剂浓度和反应温度对接枝物接枝率(G％)的影响。结果表明随PVC浓度增大,接技率降低.[PVA2.5×10-4mol/L.[BA]0.702mol/l、[CAN]0.01mol/L45℃接枝率较高.接枝率越高其吸水膨胀率越低,8h达吸水平衡,最大吸水率为165.1％。     

筼筜湖藻类与氮磷营养盐相关性研究

筼筜湖是厦门市区内唯一人工湖泊,近年来其水质污染日益严重,引起市民的极大关注,清淤截污工程不断深化。2009年1月至2011年11月逢单月采集样品,对筼筜湖水体浮游藻类叶绿素a和总磷、总氮项目进行监测分析,根椐实测数据,探讨叶绿素a与总磷、总氮各营养盐要素含量之间的相关性。为筼筜湖水质的保护,水体富营养化的预测及研究富营养化的发生机制提供依据。     

Nitrate reduction in a simulated free-water surface wetland system

The feasibility of using a constructed wetland for treatment of nitrate-contaminated groundwater resulting from the land application of biosolids was investigated for a site in the southeastern United States. Biosolids degradation led to the release of ammonia, which upon oxidation resulted in nitrate concentrations in the upper aquifer in the range of 65-400 mg N/L. A laboratory-scale system was constructed in support of a pilot-scale project to investigate the effect of temperature, hydraulic retention time (HRT) and nitrate and carbon loading on denitrification using soil and groundwater from the biosolids application site. The maximum specific reduction rates (MSRR), measured in batch assays conducted with an open to the atmosphere reactor at four initial nitrate concentrations from 70 to 400 mg N/L, showed that the nitrate reduction rate was not affected by the initial nitrate concentration. The MSRR values at 22 °C for nitrate and nitrite were 1.2 ± 0.2 and 0.7 ± 0.1 mg N/mg VSS_COD-day, respectively. MSRR values were also measured at 5, 10, 15 and 22 °C and the temperature coefficient for nitrate reduction was estimated at 1.13. Based on the performance of laboratory-scale continuous-flow reactors and model simulations, wetland performance can be maintained at high nitrogen removal efficiency (>90%) with an HRT of 3 days or higher and at temperature values as low as 5 °C, as long as there is sufficient biodegradable carbon available to achieve complete denitrification. The results of this study show that based on the climate in the southeastern United States, a constructed wetland can be used for the treatment of nitrate-contaminated groundwater to low, acceptable nitrate levels.