大气悬浮颗粒物和植物树叶中二噁英分布特征的研究

采用同位素稀释、高分辨气相色谱/高分辨质谱(HRGC/HRMS)联用技术,分析了广州市某一地区两采样点大气悬浮颗粒物和大叶榕、龙眼树树叶中二噁英的含量。结果表明,两地点大气悬浮颗粒物中二噁英质量浓度(10.87 pg/Nm3和10.34 pg/Nm3)和毒性当量(0.119 pg/Nm3和0.121 pg/Nm3)接近,而大叶榕、龙眼树树叶中二噁英质量浓度分别为268.4 ng/kg.dry和972.5 ng/kg.dry,毒性当量为3.99 ng/kg.dry和15.11 ng/kg.dry。通过分析大气和树叶样品中17种有毒同系物的分布特征,可推断这两种植物树叶中的二噁英主要来源于大气干沉降。此外,龙眼、大叶榕树叶中六氯代以上的有毒PCDD/Fs质量分数较高,说明高氯代二噁英在树叶中较稳定,易累积到较高的水平。     

烧结炼铁过程中二噁英排放浓度及同类物分布研究

二噁英是一种高毒性持久性有机物,可对人体及周围环境造成深远影响。文章通过对国内某钢铁生产企业烧结工段废气及周边土壤二噁英物质的监测研究,得出二噁英排放浓度及厂区周边土壤中的污染程度。并依据废气及土壤中17种二噁英同类物的分布特征的相似性进一步推断出土壤中的二噁英主要来源于该厂的烧结工段。     

环境中剧毒物二噁英的成因、危害及治理技术

综述二口恶英的来源、成因和危害 ,讨论前人在治理二口恶英方面所采用的热技术和非热技术及其存在的局限性。二口恶英治理的热技术包括高温过燃烧技术、红外脱毒技术、等离子体高温分解技术、熔盐脱毒技术、超临界水氧化技术、原位玻璃化技术等 ;非热技术包括化学脱氯技术、紫外光解技术、溶剂萃取技术、吸附技术、生物降解技术、化学降解技术、γ射线分解技术、光催化氧化技术等。文中还简要分析当前研究工作所面临的问题     

含环戊二烯络铁基团二苯并二噁英的合成

采用含环戊二烯络铁(FeCp)基团邻二氯苯和含羟基、巯基的二元酚类化合物合成含FeCp基团的二苯并二噁英.实验中,以N,N-二甲基甲酰胺(DMF)为溶剂,室温下,在K2CO3弱碱性介质中,产品收率高,副反应少,反应时间短.通过1H NMR和13C NMR对该类产品结构的研究表明产品纯度高;酚类的选择不同,H、C化学位移有一定差异.     

多氯代苯基三氯硅烷的合成研究

采用复合催化剂,维持反应温度80℃合成了多氯代苯基三氯硅烷,多氯代苯基三氯硅烷含量可达90%以上.采用无水络合剂使复合催化剂失活,之后减压蒸馏,得到了接近无色的多氯代苯基三氯硅烷,减压蒸馏没有发生明显的Si-C键断裂.     

广谱杀菌剂三氯新中二恶英类化合物的形成及其危害

阐述了三氯新中二恶英的形成途径及在三氯新应用中可能给消费群体带来的危害,并提出了一定的建议和对策。     

二()英的毒害、来源及治理

介绍了二恶英的种类、来源、毒性、对人类健康的影响以及二恶英的处理方法,认为对工业污染的治理和生态环境的保护是堵住二恶英进行入人体和生物体的有效措施。     

棉热转印用苯并二呋喃红色分散染料的研究

本文合成了苯并二呋喃类染料的基本结构(简称X);将X与两种同类商品染料C.I.分散红356(简称红356)和C. I.分散红367(简称红367)热转移印花(简称热转印)到棉织物上;测定了上色后棉织物的色度参数及皂洗变色牢度;绘制了三种染料的立体结构.通过对三种染料印花后性能的比较,从立体结构等方面进行了比较深入的分析,初步得出:现有商品染料红356和红367难以符合实际应用要求;对基本结构进行改性有望获得牢度优良的红色染料.     

氟取代基对基于苯并三氮唑聚合物光伏性能的影响

设计并合成了基于苯并二噻吩(BDT)与氟代苯并三氮唑(FBTz)的聚合物太阳能电池给体材料PBDBz-H,同时通过引入氟原子合成了聚合物PBDBz-F。通过对比研究发现,在聚合物中引入氟原子可以有效地提升聚合物之间的π-π堆积作用,并降低其HOMO能级,有利于提升器件的短路电流密度与开路电压;PBDBz-F的器件的能量转换效率比PBDBz-H提升了50%,达到1.81%。     

Chemical Conversion Pathways and Kinetic Modeling for the OH-Initiated Reaction of Triclosan in Gas-Phase

As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs) and polychlorinated biphenyls (PCBs) are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD). Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of k_add/k_total and k_abs/k_total at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.     

三氯生的应用及主要合成方法

介绍了三氯生的特点及其在几个方面的应用 ,并简单介绍了一种合成方法。     

Mammalian Cytochrome P450-Dependent Metabolism of Polychlorinated Dibenzo-p-dioxins and Coplanar Polychlorinated Biphenyls

Polychlorinated dibenzo-p-dioxins (PCDDs) and coplanar polychlorinated biphenyls (PCBs) contribute to dioxin toxicity in humans and wildlife after bioaccumulation through the food chain from the environment. The authors examined human and rat cytochrome P450 (CYP)-dependent metabolism of PCDDs and PCBs. A number of human CYP isoforms belonging to the CYP1 and CYP2 families showed remarkable activities toward low-chlorinated PCDDs. In particular, human CYP1A1, CYP1A2, and CYP1B1 showed high activities toward monoCDDs, diCDDs, and triCDDs but no detectable activity toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD). Large amino acids located at putative substrate-recognition sites and the F-G loop in rat CYP1A1 contributed to the successful metabolism of 2,3,7,8-tetraCDD. Rat, but not human, CYP1A1 metabolized 3,3'',4,4'',5-pentachlorobiphenyl (CB126) to two hydroxylated metabolites. These metabolites are probably less toxic than is CB126, due to their higher solubility. Homology models of human and rat CYP1A1s and CB126 docking studies indicated that two amino acid differences in the CB126-binding cavity were important for CB126 metabolism. In this review, the importance of CYPs in the metabolism of dioxins and PCBs in mammals and the species-based differences between humans and rats are described. In addition, the authors reveal the molecular mechanism behind the binding modes of dioxins and PCBs in the heme pocket of CYPs.     

水对前驱物催化合成二噁英的影响

The effect of water on the formation of polychlorinated dibenzo-p-dioxins（PCDDs）and dibenzofurans（PCDFs）from precursor was investigated by the experiments with a fixed-bed reactor：the reactant mixture with different moisture of 123-TrCB and CuCl₂ for metal-catalyzed formation,that of 123-TrCB and fly ash for surface-catalyzed formation. The experimental results show that the water has the following effects：first,suppressing the formation of PCDD/Fs as less its yield;second,inhibiting chlorination reaction as lower chlorination degree;third,having different effect on PCDDs and PCDFs as lower ratio of PCDFs/PCDDs.The explanations might be the competitive adsorption of water vapor with TrCB on active sites of the fly ash and the catalysis of copper was weakened chloride because of its oxidative conversion to copper oxide.     

洗手液中三氯生含量的测定方法

建立盐辅助超声提取、高效液相色谱法测定洗手液中三氯生含量的方法。在硫酸铵条件下,以乙腈为提取剂,超声提取洗手液中的三氯生,并用高效液相色谱仪进行测定。在0.1~20μg/mL浓度范围内,三氯生峰面积与其浓度呈良好的线性关系。三氯生的检出限(S/N=3)为0.02μg/mL,加标回收率在94.6%~97.3%之间,相对标准偏差为3.69%。该方法经济简便、重复性好,可用于测定洗手液中三氯生的含量。     

三氯新在抗菌洗洁精中的应用研究

将三氯新与普通洗洁精复配 ,制得了w(三氯新 ) =0 3%的抗菌洗洁精。采用抑菌环法做抑菌实验 ,该抗菌洗洁精在稀释至质量分数为 0 2 %时 ,对金黄色葡萄球菌和大肠杆菌的抑菌环直径分别为 2 8 8mm和 11 5mm。在 5 4℃存放 14d和 37℃存放 90d ,该抗菌洗洁精的抑菌环直径没有变小 ,抑菌效果和稳定性均很满意。急性经口毒性实验表明 ,该抗菌洗洁精半致死量LD50 >5 0 0 0mg/kg ,属实际无毒级。用该抗菌洗洁精洗涤厨房抹布 ,证明抑菌除臭功能显著。该抗菌洗洁精具有较高的实用价值和良好的市场前景。     

液相色谱法测定化妆品中三氯生含量的不确定度评定

分析了液相色谱法测定化妆品中三氯生含量的检测过程,建立了该方法的定量数学模型并推导出不确定度计算公式,找出了该检测过程中的不确定度来源,并计算了公式中各个变量的不确定度,最后计算出了检测结果的合成不确定度和扩展不确定度。     

高效液相色谱法测定洗涤用品中的三氯生

建立了洗涤用品中三氯生的高效液相色谱(HPLC)测定方法。以二氯甲烷为提取溶剂,采用超声提取法提取洗涤用品中的三氯生,用配有紫外检测器的高效液相色谱仪进行测定,流动相为V(甲醇)∶V(水)=90∶10,紫外检测波长为282 nm。当三氯生浓度在0.5~100 mg/L时,其HPLC峰面积与其浓度呈良好的线性关系。三氯生的检出限(3S/N)为0.1 mg/L,加标回收率在96.2%~104.3%之间,相对标准偏差为1.2%~4.4%。该方法准确、灵敏、快速、重复性好,能满足洗涤用品中三氯生定量分析的要求。     

Simultaneous Removal of Heavy Metals and PCDD/Fs from Hospital Waste Incinerator Fly Ash by Flotation Assisted with Hydrochloric Acid

Hospital solid waste (HSW) incinerator fly ash was designated as a special controlled waste because of its high concentrations of toxic heavy metals, polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs). Most of the PCDD/Fs along with carbon constituents including powder activated carbon and unburned carbon in fly ash could be removed by column flotation on the basis of their hydrophobicity. The feasibility of extracting heavy metals from fly ash by adding a little of hydrochloric acid to the slurry during the flotation process was examined in this paper. The results showed that the acidic pulp could contribute to the high extraction ratio of the heavy metals, but the performance of decarburization and removal of PCDD/Fs was inhibited at very low pH value. Given consideration to the removal of two toxic matter including PCDD/Fs and heavy metals in HSW incinerator fly ash, the appropriate pulp pH value should be controlled at about 5. After flotation, both PCDD/Fs and heavy metals in the tailings could simultaneously meet the permitted limits of a landfill site of municipal solid waste in China. It was suggested that flotation with the assistance of an appropriate amount of acid might be a potential technology for the treatment of HSW incinerator fly ash.