历史上的灾难年2007

2007年是历史上的灾难年。由于受全球气候变暖影响,我国多个省市发生了各种自然灾害,如干旱、洪水、泥石流、滑坡、飓风等,尤其是洪涝灾害,经济损失惨重。另有朝鲜、缅甸以及南亚的印度、孟加拉国、尼泊尔也成了一片泽国;就连美国也未幸免于洪灾。现简述如下。     

三维有机LDH的制备及其对有机物的普适性吸附

以表面活性剂十二烷基硫酸钠(SDS)为软模板剂,制得有机三维花状层状双金属氢氧化物(3D-SLDH).采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱仪(EDS)和N2吸附-脱附等表征手段对3D-SLDH的结构进行表征,确定最佳合成尿素浓度,并通过静态吸附实验考察了3D-SLDH对金橙Ⅱ(AO7)、罗丹明...     

PH3液相催化氧化净化研究

以Mn2 和Pd2 为催化剂的吸收液对含低浓度PH3的混合气进行了液相催化氧化净化研究.考察了催化剂配比、混合气中O2浓度、PH3初始浓度、反应温度、气体流量和吸收液pH与PH3净化效率的关系.结果表明,催化剂中Pd2 与Mn2 的质量比为1:4时可获得较佳的净化效果;随着混合气中O2浓度的增加,吸收液对PH3的净化效率有所提高;在20～75℃内,低温对PH3净化有利,较适宜的反应温度为20℃;较低的PH3初始浓度和低气体流量均有利于PH3的净化;较高的pH有利于吸收液中催化剂催化效能的发挥.吸收液对PH3的净化效率可达100%,但因吸收液中的金属离子易与催化氧化PH3产生的PO3-4形成沉淀,使金属离子脱离液相催化氧化系统,吸收液失效较快.     

黄铁矿焙烧过程中铊析出影响因素及其烧渣中重金属的相态分布研究

通过模拟硫酸厂的沸腾焙烧炉,考察了黄铁矿焙烧过程中铊(T1)析出的影响因素.并通过分级提取法考察了黄铁矿烧渣中重金属的相态分布.结果表明,T1释放率随焙烧温度的升高而增加,随停留时间的增长而增加;当O2流量在20～300 mL/mi.范围变化时,T1释放率先增后减.环境中备受关注的重金属(如Pb、Cd、Cr等)在黄铁矿烧渣中以Pb为主,各相态Pb的总量达到1 429.20 μg/g,且黄铁矿烧渣中的重金属(除Cu和Sr外)主要是以分布于硅酸盐矿物相中的残余态形式存在,因此在环境中不易迁移释放.尽管黄铁矿烧渣中的重金属(除Cu和Sr外)不是以非残余态分布为主,但非残余态重金属的总量也不少,因此黄铁矿烧渣在环境中的潜在污染风险应当引起重视.     

类芦对铅的耐性及富集能力探讨

通过野外调查和盆栽试验,研究了类芦(Neyraudia reynaudiana)对Pb的耐性和富集能力.研究结果表明,类芦对Pb耐受的临界浓度为800 mg/kg,在此浓度以下Pb对类芦的生长基本无抑制作用.随着处理浓度的增加,类芦生长变缓慢、出现中毒症状,但仍能存活.从富集能力来看,土壤Pb为中低浓度时,类芦的富集能力较强,但Pb浓度超过1 000 mg/kg后地上部富集量增加缓慢,而根部的含量则降低.在各种Pb处理浓度下,类芦地上部Pb含量均大于根部,说明这种植物对Pb有较好的迁移能力.研究发现,类芦具有较高的生物量,因此其地上部Pb迁移总量较高,在土壤Pb浓度为800 mg/kg时类芦地上部的迁移总量可达到221.77 mg/m2.综合分析可知,类芦对中度Pb污染土壤的植物修复具有较大的潜力.     

Sorption of polar and nonpolar aromatic compounds to four surface soils of eastern China

Improved predictions on the fate of organic pollutants in surface environments require a better understanding of the underlying sorption mechanisms that control their uptake by soils. In this study, we monitored sorption of nine aromatic compounds with varying physicochemical properties (hydrophobicity, electron-donor/acceptor ability and polarity), including two polycyclic aromatic hydrocarbons, two chlorobenzenes, two nitroaromatic compounds, dichlobenil, carbaryl and 2,4-dichlorophenol in aqueous suspension of four surface soils of eastern China. The tested soils were characterized with respect to organic carbon (OC) content, black carbon content, mineralogy, morphology and size fraction to assess the role of the diverse soil characteristics in sorption. The results of this study show that not only the solute hydrophobicity and the OC content of soil are important to the retention of organic pollutants, but also the solute molecular structure and the soil nature.     

有毒气体危害区域划分之临界浓度标准研究

通过研究毒物伤害准则进而界定有毒气体危害浓度,对有毒气体泄漏扩散后的危害区域进行分级划分,以采取相应的防护措施,最大限度的即时有效的减轻有毒气体对人员的伤害.最后,以氯为例,对比其在不同伤害准则下危害区域划分临界浓度标准值,数值差别较大,因此在使用时应根据实际情况加以判断,选择最适当的标准来划分危害区域.     

用汶川8.0级地震及余震序列探讨陕西数字地震台网地震数据处理系统定位稳定性问题

选取了2008年5月12日四川汶川8.0级主震及5月份发生在陕西省M≥2.5级、四川省M≥4.0级余震共60个,利用"十五"地震数据处理系统处理的地震定位结果与四川台网定位结果比较,并参照陕西数字地震台网"九五"与"十五"地震数据处理系统对所选取30个地震定位结果的对比情况,对陕西数字地震台网"十五"地震数据处理系统定位稳定性问题进行探讨.     

A full-scale sequencing batch reactor system for swine wastewater treatment

A full-scale sequencing batch reactor (SBR) system was evaluated for its ability to remove carbon and nitrogen from swine wastewater. The SBR was operated on four, six-hour cycles each day, with each cycle consisting of 4.5 hours of "React," 0.75 hours of "Settling", 0.75 hours for "Draw" and "Fill." Within each cycle, an amount of wastewater equivalent to about 5% of the reactor volume (5,500 litres) was removed and added. The SBR system was able to remove 82% of biochemical oxygen demand (BOD) and more than 75% of nitrogen. Even though the SBR effluent, with an average effluent BOD5 of about 588 mg L(-1), did not meet the discharge criteria, it enabled a reduction of the land base required for land application of swine wastewater by about 75%. Results indicated that the SBR system was a viable method for the treatment of swine wastewater.     

Polycyclic aromatic hydrocarbons in Dalian soils: distribution and toxicity assessment

Concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils collected from Dalian, China, for examination of distributions and composition profiles and their potential toxicity. The sum of 15 PAHs (SigmaPAHs) ranged from 190 to 8595 ng g(-1) dry weight, and showed an apparent urban-suburban-rural gradient in both SigmaPAHs and composition profiles. Using hierarchical cluster analysis (HCA), the sampling sites were grouped into four clusters corresponding to traffic area, park/residential area, suburban and rural areas. The ratios of naphthalene (Nap) and fluorene (Fl) versus fluoranthene (Flu), pyrene (Pyr) and indeno(1,2,3-cd)pyrene (InP) in the four clusters provided evidence of local distillation. The diagnostic ratios indicated the prevalent PAH sources were petroleum combustion and coal combustion in Dalian, and a cross plot of diagnostic ratios distinguished the urban samples from suburban and rural ones. Toxic potency assessment of soil PAHs presented a good relationship with benzo(a)pyrene (BaP) levels, toxic equivalent concentrations based on BaP (TEQ(BaP)) and dioxin-like toxic equivalent concentrations (TEQ(TCDD)). The study highlights that BaP is a good indicator for assessing the potential toxicity of PAHs, and presents a promising toxicity assessment method for soil PAHs.