黄铁矿还原固定水中的高铼酸根

以铼作为放射性锝的替代元素,用黄铁矿粉末对高铼酸根的还原固定进行了研究。采用球磨法制备出黄铁矿粉末。分别研究了不同固液比、不同的初始p H值和不同粒径条件下,黄铁矿粉末对高铼酸根的还原固定效果。结果显示,固液比为1∶10(g/m L)为宜,在体系初始p H为12时,形成铁氧体,吸附高铼酸根,提升还原固定效果。对产物进行XPS表征,证明还原产物为Re O2。在乙醇介质中机械活化后利用超声分散可得到具有大的比表面积和晶格畸变的粒径较小的黄铁矿粉末,使其反应的活性位点增多,处理效果明显好于大粒径的黄铁矿粉末,在相对较短的时间内,铼的去除率可以达42%。在缺氧环境下黄铁矿能够长期保持有效性,在地质处置库应用中有实际意义。     

China’s air pollution reduction efforts may result in an increase in surface ozone levels in highly polluted areas

China, as a fast growing fossil-fuel-based economy, experiences increasing levels of air pollution. To tackle air pollution, China has taken the first steps by setting emission–reduction targets for nitrogen oxides (NO_x) and sulphur dioxide (SO₂) in the 11th and 12th Five Year Plans. This paper uses two models—the Energy–Environment–Economy Model at the Global level (E3MG) and the global Chemistry Transport Model pTOMCAT—to test the effects of these policies. If the policy targets are met, then the maximum values of 32 % and 45 % reductions below ‘business as usual’ in the monthly mean NO_x and SO₂ concentrations, respectively, will be achieved in 2015. However, a decrease in NO_x concentrations in some highly polluted areas of East, North-East and South-East China can lead to up to a 10% increase in the monthly mean concentrations in surface ozone in 2015. Our study demonstrates an urgent need for the more detailed analysis of the impacts and designs of air pollution reduction guidelines for China.     

钯/聚合物复合催化膜制备及催化还原对硝基苯酚

钯金属具有较高的催化加氢性能,钯催化还原降解水体中污染物的研究一直是国内外研究的热点。为了制备催化性能稳定、催化活性高且易于回收利用的Pd催化剂,实验以聚丙烯腈(PAN)聚合物分离膜作为基材,采用层层自组装方法将聚乙烯亚胺/钯配合物(PEI-Pd(II))和聚苯乙烯磺酸钠(PSS)交替组装在基膜表面,制备了(PEI-Pd(0)/PSS)n复合催化膜,并采用膜分离装置通过对硝基苯酚催化加氢反应来评价催化膜的催化性能。实验结果表明,荷电化处理时间、NaOH溶液浓度、PEI和Pd(II)摩尔比、自组装层数影响着膜的催化性能。当荷电化处理时间为1.5 h,NaOH溶液浓度为1.5 mol/L,PEI和Pd(II)摩尔比为60∶4,自组装层数为5层时,复合催化膜有最佳的催化性能,其对对硝基苯酚的去除率能达到90%以上。     

Decabromodiphenyl ethane and decabromodiphenyl ether in Swedish background air

Decabromodiphenyl ethane (DPDPE) is a flame retardant that has been on the market for more than 20 years and is used as a replacement for decabromodiphenyl ether (BDE-209). Environmental data on DPDPE are scarce but for BDE-209, studies have shown that long-range transport in the atmosphere leads to contamination of remote regions. Given their similar physical-chemical properties, we hypothesized that this is also true for DPDPE. In this study we explored the European continent as a source for DBDPE by collecting air samples at a back-ground location in southern Sweden. Twelve samples with stable air mass back trajectories over the 24 h sampling period were analysed. BDE-209 and 5 polycyclic aromatic hydrocarbons (PAHs) were also included in the study. The concentration ranges of DBDPE and BDE-209 were similar, 0.077-7.9 and 0.093-1.8 pg m⁻³ air, respectively. The highest concentrations were detected when the air originated from the European continent and the lowest during periods with rather stagnant air over southern Scandinavia. The concentrations of DBDPE and BDE-209 did not co-vary, indicating that there are different major sources of the two compounds. In air, the compounds measured in this study are predominantly associated with particles. PAHs in the atmosphere are known to originate primarily from combustion processes and their concentrations were highly correlated with several measures of atmospheric particle concentration, i.e. PM 10, PM 2.5, soot, and N 450 (number of particles in the size range approximately 420-450 nm). No clear correlations were found between the concentrations of DBDPE or BDE-209 and any of the measures of particle concentrations, indicating that the emissions of these are not related to the major sources of emissions of soot or small particles.     

Atmospheric mercury pollution at an urban site in central Taiwan: mercury emission sources at ground level

Total gaseous mercury (Hg) (TGM), gaseous oxidized Hg (GOM), and particulate-bound Hg (PBM) concentrations and dry depositions were measured at an urban site in central Taiwan. The concentrations were 6.14 ± 3.91 ng m⁻³, 332 ± 153, and 71.1 ± 46.1 pg m⁻³, respectively. These results demonstrate high Hg pollution at the ground level in Taiwan. A back trajectory plot shows the sources of the high TGM concentration were in the low atmosphere (<500 m) and approximately 50% of the air masses coming from upper troposphere (>500 m) were associated with low TGM concentrations. This finding implies that Hg is trapped in the low atmosphere and comes from local Hg emission sources. The conditional probability function (CPF) reveals that the plumes of high TGM concentrations come from the south and northwest of the site. The plume from the south comes from two municipal solid waste incinerators (MSWIs). However, no significant Hg point source is located to the northwest of the site; therefore, the plumes from the northwest are hypothesized to be related to the combustion of agricultural waste. Dry deposition fluxes of Hg measured at this site considerably exceeded those measured in North America. Overall, this area is regarded as a highly Hg contaminated area because of local Hg emission sources.     

亚微米颗粒物和微米颗粒物中的铅在水稻叶片中的富集比较

叶片对大气颗粒物中铅的吸收富集会对水稻本身产生毒性效应,然而目前关于叶片对不同粒径颗粒物中铅富集能力的研究较少.因此,本研究采用叶片喷施等铅浓度飞灰颗粒物的方法,探讨水稻生长后期剑叶对亚微米颗粒物和微米颗粒物中铅的吸收作用,讨论不同粒径颗粒物中铅向叶片迁移的可能机制.结果表明,向水稻剑叶分别喷施等铅浓度的亚微米飞灰颗粒物和微米颗粒物后,亚微米颗粒物处理组的剑叶和稻米的铅含量均显著高于微米颗粒物处理组.亚微米颗粒物中的铅从叶片反面表皮向内扩散,富集在维管束中,并引起叶肉中铅含量的显著升高.相比之下,微米颗粒物处理组的铅向植物叶片内迁移扩散趋势较弱.基于铅同位素分析,亚微米颗粒物组飞灰源对叶肉中铅含量的贡献为80%,而微米颗粒物组飞灰源的贡献仅为31%～42%.亚微米颗粒物组铅在细胞质中的含量比例升高,由此产生的毒性作用会更大.因此,关注大气亚微米颗粒物中铅在水稻叶片的迁移富集具有一定的必要性.     

北京地区大气可吸入颗粒物中多环芳烃分布特征

采集北京城乡结合区和郊区冬季12个大气可吸入颗粒物不同粒径样品,用色谱-质谱技术分析鉴定了75种多环芳烃化合物,并对各粒径中美国EPA优控的16种多环芳烃做了定量分析,研究其在不同粒径的分布规律。结果表明:城乡结合区大气颗粒物中优控多环芳烃总量明显高于郊区;郊区和城乡结合区大气分别有68%和85%的优控多环芳烃吸附在粒径小于2 0μm颗粒物上;可吸入颗粒物中都相对富集高环数的多环芳烃;2个地区主要污染源可能为化石燃料的燃烧排放,燃煤的影响相对较大。      

莱芜大气污染源排放颗粒物中多环芳烃研究

为了解莱芜市大气污染源排放颗粒物中多环芳烃的浓度及影响因素,采集机动车尾气尘、扬尘、工业燃煤颗粒物、民用燃煤颗粒物等4种样品,分别测定多环芳烃的含量。结果表明,莱芜市大气环境颗粒物中多环芳烃主要来源于机动车尾气和民用燃煤,12种多环芳烃类值分别为(1 536. 48±0. 78)和(299. 83±0. 30)μg/g,机动车尾气尘与扬尘、民用燃煤、工业燃煤多环芳烃均存在显著性差异。不同组分中,苯并(ghi)苝的值最高,为(559. 96±7. 59)μg/g,其次为晕苯,为(445. 36±5. 94)μg/g,城市空气污染呈现煤烟和机动车尾气复合污染的特点。     

地表水悬浮物分析中的几个问题

对地表水悬浮物分析中的样品烘干时间、次数和取样问题进行了实验,提出了减少悬的体操的烘干恒重次数、缩短分析过程呼时间的意见。同时提出悬浮物应单独采集样品,以提高悬浮物的分析质量。