高效液相色谱法测定环境空气酰胺类化合物

高效液相色谱法测定环境空气中酰胺类化合物,采用多孔玻板吸收管采集环境空气中的酰胺类化合物,吸收液经0.22μm膜过滤后,经C18色谱柱分离,采用紫外检测器检测。丙烯酰胺、二甲基甲酰胺、二甲基乙酰胺的检出限分别为0.04μg/m3、0.000 2 mg/m3、0.000 2mg/m3（10 ml吸收液,采集15 L环境空气样品计）。高、中、低三种浓度三种酰胺类化合物的回收率区间为70.8%~90.2%,相对标准偏差范围小于9.6%。该方法操作简单,结果准确、可靠,适用于环境空气中酰胺类化合物的快速、准确监测。     

基于Guassian、Multiwfn及ECOSAR的氮磷系阻燃剂在UV/PDS体系中的降解路径及产物毒性预测研究

氮磷系阻燃剂作为一类新兴无卤阻燃剂被广泛应用,但其在环境中难降解,紫外活化过二硫酸钠（UV/PDS）高级氧化技术能有效降解结构复杂的有机污染物.为探究氮磷系阻燃剂在UV/PDS氧化体系的降解路径,本研究选取3种典型氮磷系阻燃剂9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物（DOPO）、三聚氰胺（Melamine）及磷酸三苯酯（TPP）为降解目标物.首先利用Guassian模型结合Fukui指数推测了UV/PDS体系中HO?和SO₄^?-自由基与阻燃剂发生反应的位点及其相应的降解路径,通过分析DOPO及其降解产物的质谱数据验证了所推测降解路径的合理性,并进一步利用ECOSAR模型进行降解产物的毒性预测.结果表明,各氮磷系阻燃剂键能较低的位点与Fukui指数较高的位点相吻合,UV/PDS反应体系中的自由基主要通过攻击苯环上的碳氢键（键能较低的位点）来降解氮磷系阻燃剂,DOPO降解的质谱分析数据表明,依据低键能位点推测的降解产物与质谱鉴定结果相一致.同时利用ECOSAR模型评估发现,降解产物毒性普遍低于阻燃剂母体.因此,本研究采用模型预测阻燃剂降解路径与产物毒性的方法便捷有效,可为光催化降解复杂结构有机物的研究提供理论依据.     

Pd/silicalite-1: An highly active catalyst for the oxidative removal of toluene

Catalytic combustion is thought as an efficient and economic pathway to remove volatile organic compounds, and its critical issue is the development of high-performance catalytic materials. In this work, we used the in situ synthesis method to prepare the silicalite-1 (S-1)-supported Pd nanoparticles (NPs). It is found that the as-prepared catalysts displayed a hexagonal prism morphology and a surface area of 390−440 m²/g. The sample (0.28Pd/S-1-H) derived after reduction at 500°C in 10 vol% H₂ showed the best catalytic activity for toluene combustion (T_50% = 180°C and T_90% = 189°C at a space velocity of 40,000 mL/(g·hr), turnover frequency (TOF_Pd) at 160°C = 3.46 × 10⁻³ sec⁻¹, and specific reaction rate at 160°C = 63.8 µmol/(g_Pd·sec)), with the apparent activation energy (41 kJ/mol) obtained over the best-performing 0.28Pd/S-1-H sample being much lower than those (51−70 kJ/mol) obtained over the other samples (0.28Pd/S-1-A derived from calcination at 500°C in air, 0.26Pd/S-1-im derived from the impregnation route, and 0.27Pd/ZSM-5-H prepared after reduction at 500°C in 10 vol% H₂). Furthermore, the 0.28Pd/S-1-H sample possessed good thermal stability and its partial deactivation due to CO₂ or H₂O introduction was reversible, but SO₂ addition resulted in an irreversible deactivation. The possible pathways of toluene oxidation over 0.28Pd/S-1-H was toluene → p-methylbenzoquinone → maleic anhydride, benzoic acid, benzaldehyde → carbon dioxide and water. We conclude that the good dispersion of Pd NPs, high adsorption oxygen species concentration, large toluene adsorption capacity, strong acidity, and more Pd⁰ species were responsible for the good catalytic performance of 0.28Pd/S-1-H.     

精对苯二甲酸生产企业挥发性有机物泄漏检测与排放估算

采用泄漏检测与修复(LDAR)技术分析了某精对苯二甲酸生产装置动静密封点的泄漏情况,共完成1 367个密封点的现场LDAR检测,测出28个泄漏点,总泄漏检出率为2.05%。其中储存单元的泄漏点数量较氧化单元和精制单元高,泄漏程度也较严重。泄漏点主要集中在法兰、开口管线和泵三类密封点;涉及轻液的泄漏密封点数量较多。依据LDAR检测结果,采用相关方程法估算设备动静密封点泄漏产生的挥发性有机物(VOCs)排放量约为4.999 t/a。法兰的VOCs泄漏排放量最大,约占63.89%,其次是泵和采样连接系统,占泄漏排放量的20.78%和7.89%。     

土壤-苦丁茶树系统中Cu的分布及迁移富集规律

采用火焰原子吸收光谱（FAAS）技术,测定出苦丁茶冬青（Ilex kudingcha C．J．Tseng）的根、茎、叶及其栖息土壤中Cu的含量,并对土壤．苦丁茶树系统中Cu的分布特征进行了研究,以探讨苦丁茶树对Cu的富集规律。结果表明：栖息土壤中Cu的含量不同时,苦丁茶树巾Cu的含量表现出吸收根〉嫩叶〉茎〉主根;茶树对Cu的吸收存在饱和特性,表现为随土壤Cu含量升高,茶树对Cu的富集系数和传输效率降低,使得根际土壤中Cu含量高于非根际土壤。同时对土壤剖面不同深度Cu含量研究表明：苦丁茶栖息土壤中Cu含量呈现出随土层深度增加而增加的垂直分布趋势。本研究旨在认清Cu迁移到苦丁茶树的内在规律,以利于进一步研究其迁移的调控,使苦丁茶产品中元素处在安全有效的利用范围内。     

有机磷系阻燃剂的全球污染现状

作为目前普遍使用的阻燃剂主要种类之一,有机磷系阻燃剂被大量应用于各领域,从而导致了其在环境中的持续释放和分布,由此引发的环境问题逐步引起了人们的广泛关注。本文对全球范围内有机磷系阻燃剂在水体、大气、土壤、沉积物以及生物体内等环境介质中的残留现状进行了分析,并对其生态危害和生态风险进行了总结,同时对目前该领域仍有待探讨的问题及研究趋势进行了讨论。     

典型电子废物处置场地表层土壤中的德克隆阻燃剂研究

以我国广东省汕头市贵屿镇典型电子废物处置场地为研究区域,对其表层土中的德克隆(DP)阻燃剂的污染水平及分布模式进行了研究.结果表明,DP在全部23个表层土样品中均被检出,浓度范围为0.308~209ng/g,东南部地区的污染水平显著高于西北部地区,各区域的污染水平也存在一定差异.DP浓度最高点(209ng/g)和次高点(46.2ng/g)均位于主要从事电子废物手工拆解及物理破碎的片区.表层土样品中anti-DP质量分数(fanti)的变化范围为0.444~0.754 (平均值:0.652±0.064),同DP工业品中的fanti值(0.65)不存在显著性差异,表明在表层土中不存在明显的异构体选择性降解.不同的电子废物处置方式对各片区表层土中DP的分布模式影响不明显.     

Hormonal responses of broiler chickens to simulated crude petroleum flame and fumes

Hormonal responses of broiler chickens exposed to crude petroleum flame and fumes at varying distances over a period of 16 h daily were evaluated for 56 days in a poultry house. The burning of crude petroleum was simulated in a designed burner. The measured distances were 4, 8, or 12 m from the flame point. The experimental design was a two-factor factorial in a completely randomized design (CRD) with factor A as distance from the crude petroleum flame and factor B was the age of birds in weeks. One hundred and eighty Anak day-old broiler chickens were divided into four groups of 45 birds each, replicated thrice at 15 birds per replicate. Control birds were located in a separate poultry building without the flame treatment. Gaseous emissions from the burning crude oil were monitored. Proprietary broiler starter and finisher diets were fed ad libitum. Blood samples were taken at the fourth and eighth week for hormone radioimmunoassay from each treatment. The hormones assayed were growth hormone (GH), thyroxine (T₄,), and adrenaline. Results indicated that treatments did not significantly alter hormonal levels. The age of birds significantly affected the levels of all three hormones measured.     

管道内甲烷/空气预混火焰加速传播特性研究

搭建了基于可视化燃烧管道的预混火焰精细结构实验台,通过理论分析和实验等手段对预混火焰的瞬态传播过程及加速传播特性进行了研究,分析得出了不同甲烷含量的预混火焰加速传播规律及预混火焰由层流向湍流的转变规律.     

可燃气体爆炸破坏效应的试验研究

借助高速摄像机及ProAnalyst软件,研究可燃气体体积分数和障碍物对可燃气体爆炸破坏力的影响。测定不同体积分数下的甲烷-空气预混气体爆炸冲击波超压,和爆炸火焰波在有无乒乓球方向传播的平均速度。试验结果表明:超压和平均速度均随着甲烷体积分数的增加呈现先增大后减小的变化趋势,其最大值均出现在甲烷体积分数为10%～11%之间;同一体积分数下的甲烷-空气预混气体爆炸火焰波在有乒乓球方向传播的平均速度比没有乒乓球方向传播的平均速度大。根据试验结果,推导出可燃气体爆炸冲击波超压和爆炸火焰波传播平均速度与可燃气体体积分数之间的函数关系,并得出障碍物对爆炸火焰波传播的加速作用随着体积分数的增加呈现先加强后减弱的变化趋势。