磁场对酪氨酸酶活性及其催化降解酚类有机物影响的研究

研究了恒磁场对酪氨酸酶(TYR)活性及其催化降解酚类有机物的影响.结果显示,不同磁场强度(10～350 mT)处理下TYR酶活性均有提高,最佳磁场强度150mT下酶活力提高了27.1%.不同磁化时间下TYR酶活都有上升,但磁化60min后酶活上升幅度有所下降.酶经磁场处理后对温度、pH值稳定性增强,在温度为20～35 ℃、pH为5.0～10.0时均能保持较高活性,最佳温度为25℃,最佳pH为7.0;磁化后TYR酶的Michaelis常数Km为3.83 mmol·L-1,未磁化的Michaelis常数Km为2.65 mmol·L-1.磁场作用可促进TYR对酚类有机物邻苯二酚、苯酚、2,4-二氯酚的转化,反应速度依次递减,磁化处理对邻苯二酚反应的促进作用尤其明显;磁化处理后的酶对不同浓度苯酚和2,4-二氯酚的去除率均明显高于未磁化处理的酶,且随着酶用量增加,酚去除率提高.荧光发射光谱分析表明,磁化酪氨酸酶的荧光强度增强,构像发生了变化.     

硝基苯灌胃致小鼠蛋白质氧化损伤作用的研究

为了探讨硝基苯对小鼠多器官的蛋白质氧化损伤程度,采用不同剂量的硝基苯对小鼠进行灌胃染毒(每天1次,共30 d),用2,4-二硝基苯肼比色法测定小鼠组织蛋白质羰基含量,用以判断蛋白质的损伤程度.结果显示,各组织空白对照和油对照组间差异均不显著(p＞0.05),随着染毒剂量的增加,肝脏、肾脏、脾脏和心脏的蛋白质羰基含量呈上升趋势,脑组织只在高剂量组表现明显升高趋势;低剂量组与油对照组相比,只有肝脏蛋白质羰基含量显著性升高(p＜0.05);中、高剂量组与油对照组相比,各组织蛋白质羰基含量显著性升高(p＜0.05).以上结果表明,低剂量硝基苯可以对细胞蛋白质产生氧化损伤作用,并且随着染毒剂量的增加,小鼠各组织蛋白质羰基含量呈上升趋势,蛋白质氧化损伤程度加重.     

生物滴滤器去除挥发性有机物的影响因素

生物滴滤器用于处理挥发性有机物,有机物的去除效率受到许多因素的影响。总结和讨论了填料、营养液、进气等诸多因素对生物滴滤器性能的影响。这些讨论结果有助于在生物滴滤器实际应用中选择合适的设计和操作条件,从而达到更佳的处理效果。     

广州大气中羰基化合物特征

在广州选择不同的区研究了广州大气中羰基化合物的浓度水平,分布特征及来源。广州大气中羰基化合物的浓度在城区不同的采样地点,不同的采样时间变化不大;浓度水平与世界上其他污染比较严重的几个城市相当。利用文献中羰基化合物与.OH的反应常数,计算出在广州大气中羰基化合物对.OH消除贡献。     

PTR-MS在线监测大气挥发性有机物研究进展

PTR-MS是近年来兴起的一种痕量挥发性有机物在线检测技术,它测量响应时间短,灵敏度高。已经广泛应用在环境监测领域。文章介绍了它的工作原理和装置结构,给出了一些大气挥发性有机物监测的例子,并对该在线监测技术的发展方向进行了一些展望。     

热解析-固相微萃取-气相色谱法测定空气样品中挥发性有机化合物

建立了热解析-固相微萃取-气相色谱法测定空气样品中挥发性有机化合物的分析方法,并对色谱分离条件、玻璃针筒保存样品的稳定性、固相微萃取萃取纤维、萃取时间、色谱进样时间等条件进行了优化,9种挥发性有机化合物的峰面积与其质量浓度在所测范围内有较好的线性关系,相对标准偏差＜8.8%,检出限为0.05～0.75 μg/100 mL,满足实际空气样品测定需要。     

不同小叶章湿地H2S和COS的排放通量研究

利用静态箱/气相色谱法,观测了小叶章沼泽化草甸和小叶章典型草甸两种湿地类型中H2S和COS在生长季(5-9月)的释放动态,结果表明:在两种小叶章湿地中,H2S和COS的排放通量均具有明显的季节和日变化规律.在小叶章沼泽化草甸中H2S和COS的平均释放通量分别为0.34μg·m-2·h-1和-0.29μg·m-2·h-1;小叶章典型草甸H2S和COS的平均释放通量分别为0.14μg·m-2·h-1和-0.20μg·m-2·h-1;小叶章沼泽化草甸H2S和COS的平均释放通量均高于小叶章典型草甸.在生长季两种小叶章湿地均能向大气释放H2S,对COS则表现为从大气中吸收.小叶章的生长过程对H2S和COS的排放影响显著,在小叶章生长旺盛期,H2S出现排放峰值,COS出现吸收高峰.     

大气中痕量挥发性有机物的结构表征和保留时间的估计与预测

采用分子电性距离矢量（MEDV）表征大气中痕量挥发性有机物的分子结构,同时采用逐步回归结合统计检测对模型进行变量筛选,建立了大气中痕量挥发性有机物定量结构-色谱保留（QSRR）关系的8个变量和5个变量模型,两种QSRR模型的建模计算值复相关系数（R）分别为0.937和0.931;留一法（leave-one-out）交互校验复相关系数（RCV）分别为0.901和0.906,表明模型具有良好的估计能力与稳定性.     

Leaching of styrene and other aromatic compounds in drinking water from PS bottles

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene （PS） bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as ＂purge and trap＂ and analysed by gas chromatograph-mass spectrometer （GC/MS）. Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.     

Adsorption thermodynamics and kinetic investigation of aromatic amphoteric compounds onto different polymeric adsorbents

The adsorption behavior of p-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature.Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm.The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest,which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid.The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid.Thermodynamic studies suggested the exothermic,spontaneous physical adsorption process.Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.