纳米二氧化钛的毒性研究进展

随着纳米技术的迅猛发展,纳米材料越来越广泛地应用于社会科技生活的各个领域,在给人们生活带来便利的同时,纳米毒性也日益受到越来越广泛的关注。然而目前纳米毒性关注的焦点多集中在碳纳米管等早先发现的纳米材料上,却对纳米TiO2这一取得方便、制备容易、应用广泛、产量最大的纳米材料关注不足。本文从细胞水平和在体水平综述了纳米TiO2毒性研究进展,阐述了纳米TiO2对人体及其它生物潜在的生物效应,并提出对纳米TiO2进行安全性评估的必要性。     

Pyrene partition behavior to the NOM: Effect of NOM characteristics and its modification by ozone preoxidation

Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study. The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated. According to the fluorescence quenching method, the partition coefficient K _oc of pyrene to NOM was calculated, which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM. The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene. Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K _oc of pyrene.     

Photocatalytic degradation of methyl orange using ZnO/TiO2 composites

ZnO/TiO₂ composites were synthesized by using the solvothermal method and ultrasonic precipitation followed by heat treatment in order to investigate their photocatalytic degradation of methyl orange (MO) in aqueous suspension under UV irradiation. The composition and surface structure of the catalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscopy (TEM). The degradation efficiencies of MO at various pH values were obtained. The highest degradation efficiencies were obtained before 30 min and after 60 min at pH 11.0 and pH 2.0, respectively. A sample analysis was conducted using liquid chromatography coupled with electrospray ionization ion-trap mass spectrometry. Six intermediates were found during the photocatalytic degradation process of quinonoid MO. The degradation pathway of quinonoid MO was also proposed.     

The influence of long term trends in pollutant emissions on deposition of sulphur and nitrogen and exceedance of critical loads in the United Kingdom

In the United Kingdom, as with other European countries, land-based emissions of NO_x and SO₂ have fallen significantly over the last few decades. SO₂ emissions fell from a peak of 3185 Gg S in 1970 to 344 Gg S in 2005 and are forecast by business-as-usual emissions scenarios to fall to 172 Gg by 2020. NO_x emissions were at a maximum of 951 Gg N in 1970 and fell to 378 by 2005 with a further decrease to 243 Gg N forecast by 2020. These large changes in emissions have not been matched by emissions changes for NH₃ which decreased from 315 Gg N in 1990 to 259 in 2005 and are forecast to fall to 222 by 2020. The Fine Resolution Atmospheric Multi-pollutant Exchange model (FRAME) has been applied to model the spatial distribution of sulphur and nitrogen deposition over the United Kingdom during a 15-year time period (1990–2005) and compared with measured deposition of sulphate, nitrate and ammonium from the national monitoring network. Wet deposition of nitrogen and sulphur was found to decrease more slowly than the emissions reductions rate. This is attributed to a number of factors including increases in emissions from international shipping and changing rates of atmospheric oxidation. The modelled time series was extended to a 50-year period from 1970 to 2020. The modelled deposition of SO_x, NO_y and NH_x to the UK was found to fall by 87%, 52% and 25% during this period. The percentage area of sensitive habitats in the United Kingdom for which critical loads are exceeded is estimated to fall from 85% in 1970 to 37% in 2020 for acidic deposition and from 73% to 49% for nutrient nitrogen deposition. The significant reduction in land emissions of SO₂ and NO_x focuses further attention in controlling emissions from international shipping. Future policies to control emissions of ammonia from agriculture will be required to effect further significant reductions in nitrogen deposition.     

沈阳市新城子铬渣堆存区土壤铬污染分布及形态分析

采用Tessier A连续提取法,研究分析了沈阳市新城子铬渣堆存区土壤中重金属铬的污染分布和迁移转化规律,土壤中重金属铬的5种形态分布,主要以残渣态和碳酸盐结合态为主,分别占总量的49.74%和21.4%,而有机结合态含量最低,占总铬含量的6.25%。不同的功能区域铬的形态分布有所不同。总体的分布特征是残渣态>碳酸盐结合态>交换态>铁猛氧化态>有机态。     

依靠科技进步节能减排,提高钢铁行业发展的内力

节能减排是我国经济发展中必须解决的问题,特别是高耗能产业更应首当其冲。我国钢铁行业节能减排任务很重,但依靠科学技术的进步,提高了企业发展的内力,取得了一定的成绩。但是,钢铁业总能耗依然占到全国总能耗的14%以上,今后面临的节能减排任务仍很艰巨。     

无铅焊料合金中重金属元素浸出行为的研究

选用Sn.3.5Ag-0.5Cu、Sn-3.5Ag、Sn-0.5Cu无铅焊料合金及它们与Cu的钎焊接头,研究了它们在典型的酸性、碱性和盐溶液中的重金属元素的浸出规律.结果表明,焊料合金中的主要浸出元素Sn在酸性或碱性溶液中的浸出量都不是太多,而在NaCl盐溶液中浸出量增大2个数量级.制备成钎焊接头后,在酸性环境中,Sn-3.5Ag和Sn.0.5Cu钎焊接头中Sn的浸出量增加1个数量级以上,而在NaOH碱性环境中.Sn-3.5Ag-0.5Cu钎焊接头中Sn的浸出量相对较高.该结果对电子垃圾填埋环境选择及相关决策提供了参考.     

苯乙烯装置环境风险评价与危害分析

通过对苯乙烯装置所涉及物质的风险识别、生产设施的风险识别,分析出这些风险进入外环境的途径以及对外环境造成的环境影响,并制定简单的环境风险防范措施。     

大型储油罐一次机械密封改造的安全效果

介绍了大型储油罐一次机械密封结构改造为一次机械镀锌钢板加内隔膜弹性耐腐蚀橡胶软密封后,一次机械密封与二次机械密封之间的可燃气体浓度由原来的80％LEL以上下降至10％LEL以下,大型储油罐防雷击火灾取得了较好的效果。     

炼油企业硫化氢危害识别与中毒防治措施

介绍了炼油行业硫化氢中毒的现状,识别了炼油企业硫化氢危害,分析了硫化氢中毒的事故原因,并介绍了三级预防的防治措施。