气体放电/高效混溶协同制取·OH的pH影响

羟基自由基(·OH)对海洋微小生物有很强的杀灭效果,因此可以用来预防由船舶压载水引发的外来生物入侵性传播对海洋环境造成的危害.为提高·OH的产量以及提高压载水处理的效果,采用·OH探针化合物法研究了去离子水、海水中pH变化对强电场电离放电/高效混溶协同制取·OH的影响.结果表明:OH-是臭氧分解链反应的引发剂和促进剂,适当提高pH值能够提高系统·OH的产量.以亚心形扁藻(Platymonas subcorodiformis),小新月菱形藻(Nitzschia closterum)为处理对象,进一步研究了水体pH值对压载水处理效果的影响.pH值越高,藻的杀灭率越高.     

羟自由基快速灭活压载水中藻类模拟研究

应用强电场电离放电方法产生羟自由基溶液,对基于国际海事组织<控制和管理船舶压载水及沉积物国际公约>第D-2条的羟自由基快速灭活海藻进行了模拟实验研究.结果表明.羟自由基对模拟压载水中初始浓度分别为1.1×1 04、5.0×104、4.0×104和2.4×104 cell/mL的球等鞭金藻、聚球藻、小新月菱形藻以及上述3种海藻混合藻都表现出良好的杀灭效果.在模拟处理压载水系统中.在羟自由基浓度为0.62 mg/L条件下.同时在输送管道中接触时间达到6 S时.藻类的致死率均达到99.96%以上,24 h后检测无活藻再生现象.满足<公约>第D-2条排放标准.同时监测的排放压载水水质情况表明.海水的pH值、盐度、电导率几乎不变;浊度明显下降,总固体悬浮物含量降低85%,化学需氧量降至未检出程度:磷酸盐和无机氮总含量等检测均符合海洋水质标准.     

羟基自由基杀灭压载水搭乘生物的中试实验

船舶压载水的给排过程是造成地理性隔离水体间海洋生物传播的最主要途径.为安全有效治理船舶压载水,采用强电离放电方法制取羟基自由基溶液,进行了杀灭压载水搭乘生物的中试实验研究.在20t/h外排压载水流量条件下,羟基自由基溶液比值浓度达到0.45 mg/L时,可以完全杀灭异氧细菌;羟基自由基溶液比值浓度达到0.65 mg/L时,可以在4 m(反应时间约1 s)长的排放管道中杀灭海洋微生物,同时改善了压载水水质.结果表明采用强电离放电方法制取羟基自由基可以有效的治理船舶压载水.     

氮浓度和光照强度对小新月菱形藻生长和总脂含量的影响

以NaNO3为氮源,研究了氮浓度的五个水平及光照强度对小新月菱形藻的生长率及总脂含量的影响.结果表明:小新月菱形藻(Nitzschia closterium f. minutissima)(MACC/B222)在氮浓度为32 mmol/L时平均生长率μ达到最大值0.710 0 d-1,脂肪含量在16 mmol/L时达到最大值34.8%;在光强260 μmol/(s·m2)处获得最大生长率0.650 5 d-1,140 μmol/(s·m2)处获得最大总脂含量33.9%.     

密封袋半连续培养新月菱形藻

利用密封袋装置代替水泥池半连续培养新月菱形藻,通过控光、控温、控气来满足新月菱形藻的生长条件要求,进行了密封袋培养新月菱形藻的生产试验,效果明显好于水泥池培养,对培养水体的监控情况也进行了分析.并根据新月菱形藻的相对生长常数K、平均日增量X和平均倍增时间G,选出其最佳生长条件:光照5000～8000lx,水温15～20℃,pH7.8～8.5,接种浓度40×104～60×104个/mL.     

秋茄凋落叶酚酸动态变化及其对新月菱形藻的化感效应

采用生物测试法,以九龙江口的优势藻种新月菱形藻(Nitzschia closterium)为受体研究了秋茄[Kandelia obovata(S.L.)Yong]凋落叶的抑藻作用,并利用高效液相色谱法对其分解过程中的酚酸化感物质进行了分析.通过酚酸对新月菱形藻密度以及生理生化的影响,探讨了秋茄凋落叶对底栖硅藻的化感效应,丰富了安全、有效防治藻类的爆发的理论依据与实践经验,为揭示红树植物与林内微藻间相互关系提供新的科学依据.对新月菱形藻密度测定的研究发现:未分解秋茄凋落叶水提液的抑藻作用存在浓度效应,随着水提液浓度的增加,抑制作用增强;半分解秋茄凋落叶(半分解期t50=42d)水提液对新月菱形藻的生长则无明显影响.高效液相色谱检测结果确定秋茄凋落叶中存在对羟基苯甲酸、香草酸、丁香酸、绿原酸和咖啡酸;随着凋落叶的分解,酚酸的含量下降.标准酚酸物质及混合酸均对新月菱形藻产生化感抑制作用,且随着浓度增大,抑制作用增强.这表明在红树林根际-沉积物-水环境界面上,红树植物凋落物对微藻的繁殖起到了一定的调控作用,而酚酸是其中起重要作用的一类物质.     

蒽与苯并[a]芘对海洋微藻致毒影响的比较研究

新月菱形藻,球等鞭金藻８７０１和亚心形扁藻,分别用不同浓度的蒽和苯并「ａ」芘肋迫７２ｈ,测定三种藻的生长速率,叶绿素ａ含量。实验表明,三种微藻对蒽的敏感性由高到低集资为新月菱形藻、球等鞭金藻８７０１和亚心形扁藻,它们７２ｈ的关抑制浓度ＥＣ５０分别是０．０６０ｍｇ／Ｌ、０．０６５ｍｇ／Ｌ和０．０９４ｍｇ／Ｌ。而对苯并「ａ」芘的敏感性由高到低依次为亚心形扁藻,新月菱形藻和球等鞭金藻８７０１,它们的７２     

高浓度CO_2对小新月菱形藻胞外碳酸酐酶活性和光合作用的影响

以赤潮硅藻小新月菱形藻(Nitzschia closterium var.minutissima)为实验材料,研究了短期内(12 h)高浓度CO2(5%CO2)对其胞外碳酸酐酶活性和光合作用的影响,结果显示,高浓度CO2培养导致小新月菱形藻胞外碳酸酐酶活性、叶绿素a和叶绿素c含量明显下降.与通空气培养(0.035%CO2)相比,在短期内(12 h)胞外碳酸酐酶活性下降了75.4%,叶绿素a、c含量分别降低了5.6%和7.3%;高浓度CO2培养下最大光化学效率(Fv/Fm)、实际光化学效率(Yield)和光化学淬灭系数(qP)下降,但非光化学淬灭系数(gN)升高.研究结果表明,高浓度CO2对胞外碳酸酐酶活性具有明显的抑制作用,小新月菱形藻通过调整光系统Ⅱ的能量流动和能量利用效率以适应高浓度CO2的环境.     

高分子改性絮凝剂在船舶压载水有害生物治理中的应用

以农业废弃物玉米芯粉为原材料,用自制的阳离子醚化剂N-(2、3-环氧丙基)三甲基氯化铵对其进行阳离子化改性,以制备高分子改性絮凝剂.红外光谱扫描图谱显示,产物是含有季胺基团的胺基化纤维素和淀粉.用其絮凝沉淀处理船舶压载水中微藻,总体絮凝沉淀效果良好,用量为50 mg/L时,作用48 h后对新月菱形藻的去除率达到95%;作用72 h对小球藻达到同样的处理效果.同时,对添加絮凝剂前后上述两种藻的叶绿素a测定结果进一步表明,该絮凝剂对其有杀灭抑制作用.     

铁对尖刺拟菱形藻生长及光合作用的影响

目的:研究铁对尖刺拟菱形藻生长及光合作用的影响,探讨其作用机制及生态意义.方法:以赤潮硅藻尖刺拟菱形藻为材料,采用细胞计数、测光合放氧和测DCMU增益叶绿素荧光的方法,研究了不同铁浓度对该藻生长和光合作用的影响.结果:尖刺拟菱形藻的最适生长铁浓度为10-7～10-6mol/L,缺铁(10-9～10-8mol/L)抑制其生长.在10-9～10-6mol/L,随着铁浓度的增加,光合放氧及叶绿素合成均受到促进,荧光增益比率FD/FN上升,荧光产额F/Chla下降.结论:缺铁使光合器官吸收的光能减少,光合电子传递链的活性降低,从而抑制光合作用,延缓生长.提出"临界铁浓度"概念,并有可能作为预报赤潮的指标.     

Hierarchical recognition on the taxonomy of <Emphasis Type="Italic">Nitzschia closterium</Emphasis> f. minutissima

Nitzschia closterium f. minutissima, a marine eukaryotic unicellular diatom, originally classified as Bacillariophyta/Bacillariophyceae/Bacillariales/Bacillariaceae/Nitzschia, is one of the most important feed sources in mariculture. In this study, its morphological features were examined under DIC Microscopy （differential interference contrast microscope）; its pigments and fatty acids composition were analyzed by using High Performance Liquid Chromatography （HPLC） and gas chromatography （GC）; the complete Actin cDNA, part 18S rDNA, complete ITS1 and ITS2 sequences, part 28S rDNA sequences, and a putatively encoding A5 fatty acid desaturase gene were cloned respectively and further functioned in transgenic yeast. The sequence alignments were separately conducted using the related sequences from Nitzschia closterium f. minutissima, Cylindrotheca closterium （Bacillariophyta/Baci- Ilariales/Bacillariaceae/Cylindrotheca） and Phaeodactylum tricornutum （Naviculales） with ClustalX 1.83. No distinct difference was discovered between N. closterium f. minutissima and P. tricornutum in both biochemical and molecular level. Their identity was more than 99.6% among 18S rDNA, 5.8S rDNA and actin-gene sequences, and is up to 98.6% even among ITS1 and ITS2 sequences. Their △5 desaturase similarity was 99.4%. However, the lower similarity was disclosured between N. closterium f. minutissima and Cylindrotheca closterium, which shared less than 40% identity in the ITS1 and ITS2 sequences. So, N. closterium f. minutissima should not be placed in Bacillariales, Bacillariaceae, Nitzschia, but in Naviculales, Phaeodactylaceae, Phaeodactylum, and it was actually a strain of P. tricornutum.     

Fenton反应产生的羟基自由基及其清除的分光光度法测定

Fenton反应产生的羟基自由基氧化二甲亚砜(DMSO)生成的甲醛与2,4-二硝基苯肼(DNPH)反应在碱性条件下生成稳定的酒红色腙类物质,其最大吸收波长为390nm,光度法测定其含量可间接测定·OH的生成量。拟定的方法测定了数种清除剂的IC50。该方法简便可靠,可用于羟基自由基清除剂的筛选.     

电化学方法测定羟自由基反应速度常数

在维生素C存在下，铁－EDTA与H2O2反应生成的羟自由基和脱氧核糖作用，在酸性条件下生成丙二醛（MDA）；MDA与甲醛、氨通过Hantzsch反应，生成产物3，5－二甲酰－1,4-氢吡啶，加入羟自由基“清除剂”，用电化学方法监测3，5－二甲酰－1，4－二氢吡啶的形成，以此求得羟自由基“清除剂”与羟自由基反应的反应速度常数。     

Hydroxyl radicals induced by quartz particles in lung alveolar macrophages： the role of surface iron

Previous studies have shown that hydroxyl radical generation is a key step in the mechanism of pathogenic process caused by airborne particles to the lung. However, there is no direct evidence for dose-response relationship between airborne particles and hydroxyl radical generation. In this study, hydroxyl radicals generated in lung alveolar macrophages exposed to quartz particles were measured using a highly sensitive capillary electrophoresis-fluorescence detection method. The results demonstrated that quartz particles induced the generation of hydroxyl radical in a dose-dependent manner, and the amount of the hydroxyl radicals was 10^-10 mol/10⁶ cells. The viability of alveolar macrophages exposed to quartz particles decreased with the increase of quartz concentration, showing a clear dose-response relationship. Hydroxyl radical scavenger mannitol could increase the viability of quartz-treated cells, suggesting that hydroxyl radical contributed directly to cell death. In this study this contribution accounted for about 5%?20% of cell death. The hydroxyl radical generating potential was found to be related to surface iron content of the quartz particles.     

无声放电场作用下产生OH自由基的实验研究

用一种无声放电方法，使反应器中Ｎ２－Ｈ２Ｏ介质在高频高压电场作用下产生ＯＨ，以促进燃烧反应，抑制碳烟生成，并开发一种追踪化学反应的分子物理测量手段，用共振吸收光谱法测定ＯＨ浓度。     

羟基对压载水中三态氮影响的实验研究

在强电离电场作用下,利用H2O和O2制成高浓度羟基溶液,处理压载水取得明显效果．针对处理后的水质问题,模拟低浓度羟基溶液处理船舶压载水过程,检测了其中三态氮的变化情况．实验结果显示,当羟基比值浓度达到0．68mg／L,亚硝酸盐含量降低了69％,氨氮含量也有所降低,硝酸盐的含量略微增加,并且在培养24h和48h后含量很稳定,表明了羟基溶液对压载水中的无机氮在三个价态上的分布更趋于无害,改善了水质,进而说明了羟基治理压载水的方法是可行的．     

Formation of hydroxyl radicals and oxidation of toluene under corona discharge with water vapor as radical source

With water vapor as the radical source, hydroxyl radicals （. OH） of strong oxidation property were formed by corona discharge, which was directly detected by electron spin resonance （ESR） technology. These · OH could efficiently degrade gaseous organic pollutants so as to reduce the toxicity of waste gas. The experimental result of toluene degradation under DC corona discharge showed that the degradation efficiency of toluene was nearly 100% in the medium of air containing saturated water vapor under the condition that interelectrode voltage was 20 kV, discharge current was 0.1 mA, reaction time was 120 s and initial concentration of toluene was 168 mg/m^3, respeUvely. Seven intermediate products of toluene oxidation dissolving in liquid phase were also determined. The empolyment of environmental friendly - OH provides a new approach for the removal of gas pollutants.