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181.
Xian Q Chen H Liu H Zou H Yin D 《Environmental science and pollution research international》2006,13(4):233-237
Background, Aims and Scope
Vallisneria spiralis Linn., a common, submerged macrophyte, is widely available in quiet waters of lakes, ponds, marshes and streams in Southeast Asia. V. spiralis plays a significant role not only in decreasing eutrophication of water body for its productivity, but also in inhibiting the growth of blue-green algae? The aim of the paper involves the isolation and identification of allelochemicals from extracts of V. spiralis by activity-guided fractionation and column chromatography.Methods
Leaves of V. spiralis was washed free of debris, air-dried and refluxed in 95% EtOH. The extract was isolated using column chromatography and fractionation with antialgal activity. Potential allelochemicals were analyzed by high-resolution gas chromatography-mass spectrometry (HRGC-MS).Results
Two fractions with strong antialgal activity were isolated using column chromatography and activity-guided fractionation from the extract of V. spiralis. 2-Ethyl-3-methylmaleimide, dihydroactinidiolide and 4-oxo-β-Ionone were identified in the first fraction, and 3-hydroxy-5,6-epoxy-β-ionone, loliolide, 6-hydroxy-3-oxo-α-ionone and an unknown compound in the second fraction. They had strong inhibitory effects on Microcystis aeruginosa Kütz.Discussion
2-Ethyl-3-methylmaleimide is a byproduct of photooxidation of chlorophyll, and five other compounds identified were derivatives of β-carotene. HRGC-MS and derivatization technology were used to identify and confirm their molecular structures. The formula of the unknown compound was C16H19NO4. Metabolites of plant pigments had strong inhibitory activities on growth of algae.Conclusions
Six compounds had been identified in V. spiralis, among them, 2-ethyl-3-methylmaleimide was the main allelochemical, and derivatives of ionone were also potential allelochemicals.Recommendations and Perspective
. The results of our research could help us to study further mechanisms of inhibitory effect on algae and develop new potential antialgal substances. 相似文献182.
Economic Analysis of CO2 Emission Trends in China 总被引:1,自引:0,他引:1
Climate change is one of hot spots all around the world. China, the second biggest CO2 emitter, is facing increasingly severe pressure to reduce CO2 emission. The article first describes Kaya Identity and its policy implications. Second, it uses the modified Kaya Identity and makes decomposition without residues on CO2 emission during the period 1971-2005. Taking into account the changes of macroeconomic background, it conducts a detailed analysis in terms of CO2 emission trend from 4th Five Year Plan through 10th Five Year Plan. The decomposition results indicate that economic development and increase in population are major driving forces, and that improvement in energy efficiency contributes to the reduction of CO2 emission, and that decarbonization in primary energy structure is also an important strategic choice. Finally, the article stresses that in CO2 order to realize the binding target of 20% reduction in GDP energy intensity during the 11th Five Year Plan, China should speed up the readjustment of the industrial structure and energetically develop the energy-efficient technologies and clean fuel technology, which will effectively promote the country to reduce CO2 emission and contribute to the mitigation of climate change. 相似文献
183.
三氧化硫磺化工艺用于DSD酸生产 总被引:2,自引:0,他引:2
用三氧化硫磺化工艺替代发烟硫酸磺化工艺是可行的。在DSD生产中,采用干燥空气稀释三充气相磺对化硝基甲苯具有反应易控制,副反应少,产品质量好,对设备防腐要求低,投资省等优点,彻底解决了老工艺的废酸问题。 相似文献
184.
185.
东南沿海陆相多旋回双模式火山岩 总被引:2,自引:0,他引:2
以闽东永泰地区为实例,具体阐述东南沿海陆相多旋回双模式火山岩及其区域性分布特点。早白垩世为主要形成期,与世界其它地区以太古代为主体有所不同。区内双模式火山岩为主元结构,Ⅰ旋回(下组合)为沉积岩——玄武岩——流纹质凝灰岩;Ⅱ旋回(上组合)为沉积岩——碱性玄武岩——流纹质凝灰岩;Ⅲ旋回为沉积岩——玄武岩——火山集块岩及钾长流纹岩,其形成的构造环境为活动大陆边缘板内拉张环境,岩浆结晶温度大约在970—1156℃,估算过渡岩浆房形成深度约3.5—5km。 相似文献
186.
袋式除尘器在锅炉干法脱硫系统上的应用 总被引:3,自引:0,他引:3
在干法脱硫系统上,用长袋低压脉冲袋式除尘器取代电除尘器,即可提高除尘效率,也可提高脱硫效率。 相似文献
187.
188.
采用序批式反应器(SBR)处理模拟精对苯二甲酸(PTA)废水,考察了曝气量、沉降时间、进水方式等对对苯二甲酸(TA)生物降解效果的影响。实验结果表明,对于TA质量浓度小于1500mg/L的废水,采用完全曝气SBR运行4h,TA和COD的去除率均能达到95%以上,TA平均去除速率随TA浓度的增加而增大。TA质量浓度为1500mg/L时,曝气量、沉降时间和进水方式是影响其降解效果的主要因素。采用SBR处理高浓度PTA废水可克服污泥膨胀和抗冲击负荷能力弱的问题,且系统的稳定性和PTA废水的处理效果较好。 相似文献
189.
190.
不同状态下的同一污泥胞外聚合物提取方法研究 总被引:8,自引:2,他引:6
以由厌氧污泥向好氧污泥转变前后2种不同状态下的污泥为研究对象,采用5种不同方法对污泥胞外聚合物(EPS)进行了提取实验。实验结果表明,NaOH法提取的EPS含量最高,但会导致胞内物质泄漏。CER和离心提取法较温和,但EPS产量不高。甲醛-NaOH和H2SO4法提取的EPS含量较高,且无大量细胞自溶发生,是有效的EPS提取方法。厌氧污泥转变为好氧污泥后蛋白质/多糖(PN/PS)比例有所增加,表明EPS各组分含量发生改变。红外分析表明厌氧污泥转变为好氧污泥前后EPS中主要组成成分没有发生改变,但各成分含量有所增加,特征明显的峰表明EPS中存在蛋白质、多聚糖。 相似文献