电弧炉炼钢过程中二□英类的排放浓度和同类物分布

对国内某电弧炉炼钢设施的烟气和飞灰样品中二(噁)英类物质进行了采样分析.结果表明:炉内直接排烟和屋顶罩排烟烟气中的二(噁)英类毒性当量(TEQ)浓度平均值分别为0.13和0.17 ng/m3(均指I-TEQ当量);2种烟气的布袋飞灰中二(噁)英类毒性当量质量分数分别为7.5和55.0 ng/kg;PCDDs同类物的质量浓度随着氯取代数的增加而呈升高趋势,PCDFs实测质量浓度和毒性当量浓度均远大于PCDDs;排放分布特征表明,电弧炉炼钢设施排放的二(噁)英类生成机理应为从头合成反应.     

滑动弧放电等离子体杀菌的研究进展

在介绍现有杀菌方法及其局限性的基础上提出滑动弧放电等离子体杀菌技术,阐述滑动弧放电等离子体产生的基本原理,介绍了基本的反应装置及其发展情况;探讨此技术在杀菌方面的研究进展,并从紫外线、臭氧、NO.和.OH自由基、H2O2等角度出发对杀菌机理进行了分析。最后对该项技术在杀菌领域的应用与发展提出了建议及展望。     

氧化铜催化五氯苯生成二英的研究

研究在加热条件下,五氯苯在CuO表面催化生成二英（PCDD/Fs）的过程.结果表明,在200～350℃,PCDD/Fs的生成量随温度的升高而增加;在350～450℃,PCDD/Fs的生成量随温度的升高而减少.温度较低时（200～250℃）,生成的PCDD/Fs以高氯取代同系物为主;温度较高时（400～450℃）,则以低氯取代的同系物为主.但温度的改变并没有引起同一氯取代度PCDD/Fs中的异构体分布模式发生规律性变化.通过比较400℃条件下CuO催化五氯苯生成PCDD/Fs与CuO催化OCDD/F的脱氯降解情况,推测了五氯苯生成PCDD/Fs的途径.低氯取代的PCDDs可能主要来源于五氯苯生成的高氯取代PCDDs的进一步脱氯降解.而PCDFs则主要由五氯苯脱氯降解生成的低氯取代产物直接缩合生成.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in different tissues of the cormorants (Phalacrocorax carbo) from Dongting Lake, China

Tissue distribution provides important information regarding the pharmacokinetic behavior of pollutants and is invaluable when analyzing the risk posed to avian species by the exposure to such kind of pollutants. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in muscle, liver, spleen, kidney, stomach, gall bladder, skin, heart, pancreas, intestine and lung tissue extracts of cormorants collected from Dongting Lake, China. Tissue distribution results showed preferential accumulation of PCDD/Fs in both liver and skin. The total concentration of PCDD/Fs ranged from 421 to 5696 pg/g lipid weight. Octachlorinated dibenzo-p-dioxin (OCDD) was the predominant congener in all tissues and contributed between 31% and 82% to all 17 PCDD/Fs in different tissues. The liver/muscle ratios progressively increased with the degree of chlorination of PCDDs, except for OCDD. The relative toxic potential of PCDDs and PCDFs in tissues were calculated using the World Health Organization (WHO) Toxic Equivalency Factors (TEFs) for birds. The concentrations of WHO-toxic equivalent in different tissues ranged between 14.8 and 2021 pg/g lipid weight. These results indicated PCDD/Fs may have been bio-accumulated in cormorant via food-web. Furthermore, when compared with studies reported in the literatures, the PCDD/Fs levels in the cormorant collected from Dongting Lake were still relatively high.     

等离子工艺与H_2O_2联合处理酸性橙Ⅱ溶液的研究

对气液两相滑动弧等离子与H2O2联合处理酸性橙Ⅱ溶液进行了研究。结果表明:两者具有明显的协同效应,可减少等离子放电时间,提高了降解效率。质量浓度为300 mg/L的酸性橙Ⅱ溶液,加入体积分数为0.48～0.96 mL/L的H2 O2(30%),循环降解2次的脱色率在92%以上。当加入过氧化氢的体积分数是1.92 mL/L时,循环降解1次脱色率为93.32%。而且降解后的溶液随着放置时间的延长,脱色率进一步降低;且放置8 h时,降解率下降最明显。     

Effects of inorganic chlorine source on dioxin formation using fly ash from a fluidized bed incinerator

Chlorine source is indispensable for polychlorinated dibenzo-p-dioxin and furan (PCDD/F) formation during municipal solid waste (MSW) incineration. Inorganic chlorine compounds were employed in this study to investigate their effects on PCDD/F formation through heterogeneous synthesis on fly ash surfaces. A fly ash sample obtained from a fluidized bed incinerator was sieved to different size fractions which served as the PCDD/F formation sources. The capability of different metal chlorides which facilitate the formation of PCDDs/Fs was found to follow the trends: Na ＜ Mg ＜ K ＜ Al ＜ Ca, when two particle fractions of ＞177 μm and 104-125 μm were used in the experiments. However, the capability of NaCl, MgCl2 and KCl did not seem much different from each other, whereas CaCl2 and AlCl3 were much more active in PCDD/F formation. NaCl and MgCl2 were relatively effective to produce more PCDDs, while KCl, AlCl3 and CaCl2 generated more PCDFs during heterogeneous reactions occurring on fly ash. 2,3,7,8-TCDF was the most significant contributor to the toxicity of the PCDDs/Fs formed from inorganic chlorine sources. Decreasing the sizes of fly ash particles led to more active formation of PCDDs/Fs when NaCl was used as inorganic chlorine in the experiment. The highest PCDDs/Fs produced from particles with size ＜37 μm, while the lowest PCDDs/Fs produced from particles with size ＞177 μm. The toxicity generally increased with decreasing size of the fly ash particles. The formation of PCDDs was mainly facilitated by the two size fractions, 104-125 μm and ＜37 μm, while formation of PCDFs was favored by the two other size fractions, ＞177 μm and 53-104 μm.     

Laboratory-scale study of the suppression of PCDD/F emission during coal and MSW co-incineration

The experimental test of co-incinerating Chinese raw municipal solid waste （MSW） and coal in a laboratory-scale tubular reactor was first reported in present study, and the emission of normal gas components and the effects of the S/Cl molar ratio or coal mixing percentages on polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDDs/Fs） emission were investigated and discussed. The results indicated that OCDD was the only PCDD homologues since others like TCDD-HpCDD was hardly detected, while as the categories of PCDF homologues were comparatively much more general. The amount of PCDD was much larger than that of PCDF in all operating conditions. Since ZPCDF/∑PCDD〈〈1, the dominant role of the precursor formation was proven in our experimental conductions. With increasing the coal addition to MSW （from 0 to 16%）, PCDD and PCDF were reduced considerably. Coal and MSW may suppress the PCDD/F emissions efficiently （over 95%） during the MSW incineration process. The PCDD/F suppression results of the present study could be helpful guidance to the industrial application of Chinese MSW and auxiliary coal co-incineration processes. The PCDD/F stack emission data of two industrial incinerators using co-incineration technology in China seem to have a great positive reduction of PCDDs/Fs.     

Detoxifying PCDD/Fs and heavy metals in fly ash from medical waste incinerators with a DC double arc plasma torch

Medical waste incinerator (MWI) fly ash is regarded as a highly toxic waste because it contains high concentrations of heavy metals anddioxins, including polychlorinateddibenzo-p-dioxins (PCDDs) and polychlorinateddibenzofurans (PCDFs). Therefore fly ash from MWI must be appropriately treated before beingdischarged into the environment. A melting process based on adirect current thermal plasma torch has beendeveloped to convert MWI fly ash into harmless slag. The leaching characteristics of heavy metals in fly ash and vitrified slag were investigated using the toxicity characteristic leaching procedure, while the content of PCDD/Fs in the fly ashes and slags was measured using method 1613 of the US EPA. The experimental results show that thedecomposition rate of PCDD/Fs is over 99% in toxic equivalent quantity value and the leaching of heavy metals in the slag significantlydecreases after the plasma melting process. The produced slag has a compact and homogeneous microstructure withdensity of up to2.8 g/cm3 .     

基于污泥掺烧的某生活垃圾焚烧厂烟道气、飞灰及炉渣中的二(口恶)英特征

以我国南方某生活垃圾焚烧厂掺烧10%市政污泥的生活垃圾为研究对象,对前/后口废气、飞灰、炉渣及用于掺烧的污泥中17种二(口恶)英的含量进行了测定,并分析了其指纹分布特征.结合焚烧工况及处理设施,从生成机理角度探讨了二(口恶)英的排放特征、毒性当量浓度主成分特征及主要单体的排放因子线性关系.结果表明：掺烧10%的市政污泥后,废气中二(口恶)英的去除率为99.4%,低于国家排放标准;固体废物中二(口恶)英含量为飞灰 > 炉渣 > 污泥.这说明采用高温焚烧和"活性炭喷射+布袋除尘"装置不会影响掺烧10%污泥的达标排放.指纹分布特征表明,前口废气以1,2,3,4,6,7,8-HpCDF和OCDD为主,后口废气以OCDD和OCDF为主;飞灰、炉渣及污泥中的主要单体为OCDD、1,2,3,4,6,7,8-HpCDD、OCDF、1,2,3,4,6,7,8-HpCDF.主成分分析显示,前口废气和飞灰中的二(口恶)英毒性分布特征相似;炉渣和污泥的毒性分布特征相似;后口废气有自身的特征.这说明在相同工况条件下,经同一设施处理的废物中二(口恶)英排放特征相似.排放因子分析表明,2,3,4,7,8-PeCDF和1,2,3,6,7,8-HxCDF、1,2,3,6,7,8-HxCDD和1,2,3,7,8,9-HxCDD与总毒性排放因子具有较强的线性关系,且呋喃类（PCDFs）强于二(口恶)英类（PCDDs）.     

滑动弧放电等离子体裂解正己烷实验研究

考察了一种新型低温等离子体发生方式滑动弧放电对正己烷的裂解效果,检测了主要裂解产物,并分析了供给电压、正己烷初始浓度、电极材料和反应器结构对裂解率的影响.结果表明,该法可以有效处理正己烷,最高裂解率达96%.在空气中的主要裂解产物为CO2、CO、NO2和H2O.增大供给电压可以提高正己烷裂解率;初始浓度增大后裂解率下降,但绝对处理量增大;相同能耗情况下,采用铁电极时能量利用率最低,正己烷裂解率低于铝电极和铜电极;电极最小间距和喷嘴直径之间的比例关系影响裂解效果,优化两者的匹配关系可以提高裂解率.     

13C同位素稀释法测定国产多氯联苯的2,3,7,8－TCDD毒性当量

应用质量控制方法测定了２种国产商品多氯联苯中１７个，２，３，７，８位有氯取代的二ｅｙｉｎｇ同族体，获得准确的定量结果，加入＾１３Ｃ标记物的ＰＣＢｓ样品用多级酸碱硅胶柱和氧化铝柱提取分离，用毛细管色谱／高分辨质谱定量，２种样品中都含有较多的２，３，７，８－ＴＣＤＦ和２，３，７，８Ｐ５ＣＤＦ，１＾＃ＰＣＢ的２，３，７，８－ＴＣＤＤ毒性当量值为２１７ｎｇ／ｇ，２＾＃ＰＣＢ为４１７ｎｇ／ｇ，毒性主要来自Ｐ     

干法水泥回转窑共处置滴滴涕废物的示范工程

利用新型干法悬浮预热预分解回转窑对滴滴涕废物进行共处置研究.滴滴涕废物以1t/h的投加速率,从窑尾烟室加入窑系统,比较了未处置废物工况和处置滴滴涕废物工况下烟气、生料、熟料、飞灰中滴滴涕和二 浓度.结果表明:在投加滴滴涕废物工况下,滴滴涕得到有效分解,其销毁率和销毁去除率分别为99.99953%和99.999982%;在处置滴滴涕废物前后烟气二 浓度没有发生明显变化,其浓度排放远低于水泥窑废物处置要求低于0.1ng-ITEQ/Nm3的水平;该水泥生产工艺系统在处置滴滴涕废物时,二 烟气排放因子为0.0396μg/t熟料,熟料排放因子为0.220μg/t;滴滴涕废物处置对炉窑生产,运行工况参数和常规污染排放没有显著影响.     

PCDD/Fs in sodium pentachlorophenate(Na-PCP)and human blood , milk and sediment samples from Chinese schistosomiasis areas

ＰＣＤＤ／Ｆｓｉｎｓｏｄｉｕｍｐｅｎｔａｃｈｌｏｒｏｐｈｅｎａｔｅ（Ｎａ－ＰＣＰ）ａｎｄｈｕｍａｎｂｌｏｏｄ，ｍｉｌｋａｎｄｓｅｄｉｍｅｎｔｓａｍｐｌｅｓｆｒｏｍＣｈｉｎｅｓｅｓｃｈｉｓｔｏｓｏｍｉａｓｉｓａｒｅａｓＪｉａｎｇＫｅ；ＣｈｅｎＹｕｄｏｎ...     

Burden levels of polychlorinated dibenzo-p-dioxins, dibenzofurans, and polychlorinated biphenyls in typical edible meat animals

The concentrations and distributions of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in the whole blood and meat of eight typical edible animals (chicken, donkey, horse, cattle, rabbit, sheep, duck, and pig) were illustrated. Total concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and PCBs (on a basis of liquid volume) in animal bloods were 142-484 pg/L and 46-62 ng/L, respectively. Total concentrations of PCDD/Fs and PCBs (on a basis of dry weight (dw) and lipid weight (lw)) in animal meat samples were 0.47-1090 pg/g dw (0.47-4513 pg/g lw) and 7.2-23 ng/g dw (10-776 ng/g lw), respectively. TEQs for both PCDD/Fs and PCBs in animal blood and meat samples were (67 ± 27) pg/L and (5.3 ± 14) pg/g dw (24 ± 56 pg/g lw), respectively. Besides, the dietary intakes of PCDD/Fs and PCBs were also estimated. Chicken and pig contributed more TEQs than other animals. Chicken contributed the most (95%) with high toxicity, followed by pig (3.4%) with high consumption. The dietary intake of chicken might pose risks to consumers who prefer to eat chicken products, who should comprehensively consider the essential nutrients and contaminants in food during dietary intake.     

Emission characteristics of dioxins, furans and polycyclic aromatic hydrocarbons during fluidized-bed combustion of sewage sludge

Pre-dried sewage sludge with high sulfur content was combusted in an electrically heated lab-scale fluidized-bed incinerator. The emission characteristics of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polycyclic aromatic hydrocarbons (PAHs) were studied. Coal and calcium oxide (CaO) were added during the sewage sludge combustion tests to optimize combustion conditions and control SO2 emission. The results indicated that the flue gases emitted during mono-combustion of sewage sludge were characterized by relatively high concentrations of SO2, NOx and organic pollutants, due to the high sulfur, nitrogen, and volatile matter content of sewage sludge. The total 16 USEPA priority PAHs and 2,3,7,8-substituted PCDD/Fs produced from sewage sludge combustion were found to be 106.14 g/m3 and 8955.93 pg/m3 in the flue gas, respectively. In the case of cocombustion with coal (msludge/mcoal = 1:1), the 16 PAHs and 2,3,7,8-substituted PCDD/Fs concentrations were markedly lower than those found during mono-combustion of sewage sludge. During co-combustion, a suppressant e ect of CaO on PCDD/Fs formation was observed.     

添加剂对垃圾焚烧飞灰熔融过程二不断噁英分解的影响

为了研究添加剂对垃圾飞灰熔融处理过程中二噁英分解特性的影响，选择碱性氧化物CaO和液体陶瓷(LC)2种添加剂，改变温度、气氛和熔融时间研究2种添加剂对二噁英分解率的影响．研究表明CaO对二噁英分解影响随气氛不同而改变，氧化气氛下，加入CaO使二噁英的分解率略微降低，而在还原气氛下则会使二噁英分解率升高．液体陶瓷添加剂对熔融过程二噁英分解有显著影响．1400℃时，随着LC添加比例由0增加到10％，二噁英分解率则从99．997％升高到100％．同时加入10％的LC可以使二噁英的完全分解温度由无添加剂时的1460℃降低至1100℃．     

我国PCDD/Fs网格化大气排放清单

PCDD/Fs排放清单是进行PCDD/Fs控制、环境归趋行为研究和健康风险评估的基础.本研究基于我国官方发布的2004年各行业PCDD/Fs排放清单的基础上,结合联合国环境规划署(UNEP) 2013年发布的最新《鉴别及量化PCDD/Fs类排放标准工具包》中PCDD/Fs排放因子,估算了我国2016年各省各行业PCDD/Fs大气排放量,并结合各行业网格化指代数据,建立了我国PCDD/Fs大气网格化排放清单(1/4°×1/4°经纬度),最后利用蒙特卡洛模型分析了清单的不确定性.结果表明,2016年我国PCDD/Fs大气排放量(以TEQ计,下同)为10 366 g,与2004年相比增加了约2倍.从排放行业来看,金属生产是我国大气中PCDD/Fs的主要来源,2016年排放量为5 333 g,其次为垃圾焚烧(2 469 g),供热和发电(1 290 g)和矿物产品生产(933 g),以上4个行业排放量占我国PCDD/Fs大气总排放的97%.从空间来看,我国大气PCDD/Fs排放主要集中在京津冀、长三角和珠三角地区,其中京津冀和长三角地区PCDD/Fs排放主要来自钢铁生产,珠三角地区主要来自垃圾焚烧.     

Removal of PCDD/Fs and PCBs from sediment by oxygen free pyrolysis

Few studies have dealt on the evaluation of volatilization and decomposition reactions of dioxins from sediment by oxygen free pyrolysis. In this study, the performance of pyrolysis on the removal of dioxins from sediment was investigated. Dioxin concentrations of the raw sediment and the solid residues after pyrolysis were analyzed at different conditions. Results showed a removal efficiency of 99.9999% for total dioxins at 800℃ and retention time of 30 min. All the polychlorinated dibenzo-furans （PCDFs） have been removed and were not formed in the solid residues at the retention time range of 30-90 min at 800℃. Close to 100% removal of polychlorinated dibenzo-p-dioxins （PCDDs） was also achieved. Only trace PCDDs were detected in the solid yields at a retention time of 60 min. The highest removal efficiency of polychlorinated biphenyls （PCBs） was more than 99.9994% at a retention time of 30 min. During cooling period following pyrolysis, however, the concentration of total dioxins in solid residues increased 130 times as compared to that of the raw sediment under air atmosphere. This confirmed that some complex reactions do occur to form PCDD/Fs and PCBs from 800 to 400℃ in the presence of oxygen. Oxygen-free atmosphere therefore can prevent formation of dioxin during thermal process thus generating clean solid residues.     

滑动弧等离子体降解印染废水的影响研究

在电压为10kV,载气为O2,气体流速为0.4m3/h,废水流量为20mL/min,电极为不锈钢材料,电极间最窄距离处为3.5mm的条件下,采用气液滑动弧等离子体降解印染废水。结果表明:印染废水pH值为偏碱性和碱性时,CO32-分别主要以HCO3-、CO32-的形式存在,使COD的去除率降低,20min后,其值分别为76.42%和64.36%;pH值呈强酸性时,CO32-主要以H2CO3和CO2的形式存在,对COD的去除率不产生影响,20min后,其值达到92%。印染废水pH值为偏碱性和碱性时,HCO3-和CO32-的存在消耗了等离子体放电产生的羟基自由基。pH=3时,研究了印染废水的COD和TOC的降解动力学,降解符合一级动力学规律,其速率方程分别为ln(COD0/COD)=0.13090t,ln(TOC0/TOC)=0.06395t。印染废水的紫外光谱和红外光谱表明,废水中的发色基团被破坏,溶液脱色,吸收峰降低或消失表明废水中芳香环降解。     

某垃圾焚烧厂投产前后周边土壤二英类化合物的分布

为研究垃圾焚烧厂运行对周边土壤二英类化合物（PCDD/Fs）含量的影响,采集了珠三角地区某垃圾焚烧厂投产前和投产后周边土壤样品,分析研究了该垃圾焚烧厂运行对周边土壤中PCDD/Fs含量和组分的变化.结果表明:①2012年（投产前）珠三角地区某垃圾焚烧厂周边土壤PCDD/Fs含量较低,范围为163~591 ng/kg（毒性当量范围为0.198~0.863 ng I-TEQ/kg,I-TEQ为国际毒性当量因子折算的毒性当量值）;2017—2019年（投产后）周边土壤PCDD/Fs含量范围为151~1.75×103 ng/kg（毒性当量范围为0.812~3.88 ng I-TEQ/kg）,与其他研究相比处于较低的水平.②投产后,距该垃圾焚烧厂较近（1.5 km）的采样点（S1）土壤PCDD/Fs含量逐年增长,在较远（5.2 km）但人口较密集的采样点（S3）土壤PCDD/Fs含量整体较高,但呈逐年下降趋势.③投产后,土壤中的17种PCDD/Fs单体组分中,毒性当量贡献率最高的单体为八氯二苯并二英（OCDD）和2,3,4,7,8-五氯二苯并呋喃（2,3,4,7,8-PeCDF）,二者毒性当量贡献率范围为15.7%~45.4%.④在同一采样点土壤PCDD/Fs单体组分年间差异不明显,但同一年份不同采样点差异明显.研究显示,目前该垃圾焚烧厂周边土壤PCDD/Fs含量较低,但仍需要长期监测其可能带来的风险.