松果去除水体中左氧氟沙星的研究

以松果为原料制备生物吸附剂,通过等温吸附模型和吸附动力学模型对吸附过程进行拟合,分析松果对左氧氟沙星的吸附特征,并考察了左氧氟沙星的最佳吸附条件.结果表明,最佳的吸附条件为pH为8,温度为40℃,吸附剂用量为0.8 g/L,最大吸附量为104.17 mg/g.吸附过程能较好被准二级动力学方程(R2＞0.99)和Langmuir等温吸附模型(R2 ＞0.99)拟合.以农业废弃物松果制备出价廉、高效的新型生物吸附剂,为水体中抗生素的处理提供了一种新的方法.     

裂隙对雾龙洞岩溶发育及地下径流的影响分析

尝试利用裂隙测量结果探究区域岩溶发育规律。采用统计窗口法对湖北鄂西地区雾龙洞岩溶流域的碳酸盐岩地层进行了大量的裂隙测量,分析了流域内裂隙发育的情况,研究了裂隙的几何参数——倾向、倾角、隙宽、线密度、面裂隙率等在不同层位、不同裂隙分组内的变化情况;结合构造、岩溶洼地发育方向、洞穴野外探测结果,综合分析了裂隙发育对本区岩溶发育的影响;运用渗透张量理论对岩溶流域裂隙的各向异性和非均质性进行了研究,并分析了雾龙洞岩溶流域地下水的主要渗流方向形成的原因,对查明雾龙洞岩溶流域岩溶发育规律以及地下水的运移、赋存规律具有一定的指导作用。     

基于Matlab分析的台阶式场地平整方案优化设计

在某市餐厨垃圾处理厂场地平整设计中,利用Matlab软件对台阶式场地平整方案进行优化设计,即在Auto CAD环境下用等高线法计算各级台阶的土方量,用Matlab软件拟合出台阶设计高程和土方量的函数关系式,在约束条件下求解,得到了最优设计高程和基于土方挖填平衡条件下场地平整的最小土方工程量,为工程总平面布置提供优化方案。其分析设计方法可为工业企业台阶式场地的总平面布置设计提供借鉴。     

毛细管离子色谱法测定空气中的氯化氢

以多孔玻板吸收管采样,用氢氧化钾-碳酸钠溶液吸收空气中的氯化氢(HCl),毛细管离子色谱法测定吸收液中的氯离子含量,根据采气量计算空气中的HCl含量。该方法灵敏度高,检出限低,结果准确,可避免其他阴离子及卤素和含卤酸盐离子的干扰,适用于环境空气中低含量HCl的测定。     

Genomic analyses of metal resistance genes in three plant growth promoting bacteria of legume plants in Northwest mine tailings,China

To better understand the diversity of metal resistance genetic determinant from microbes that survived at metal tailings in northwest of China, a highly elevated level of heavy metal containing region, genomic analyses was conducted using genome sequence of three native metal-resistant plant growth promoting bacteria(PGPB). It shows that: Mesorhizobium amorphae CCNWGS0123 contains metal transporters from P-type ATPase, CDF(Cation Diffusion Facilitator), Hup E/Ure J and CHR(chromate ion transporter) family involved in copper, zinc, nickel as well as chromate resistance and homeostasis. Meanwhile, the putative Cop A/Cue O system is expected to mediate copper resistance in Sinorhizobium meliloti CCNWSX0020 while Znt A transporter, assisted with putative Czc D, determines zinc tolerance in Agrobacterium tumefaciens CCNWGS0286. The greenhouse experiment provides the consistent evidence of the plant growth promoting effects of these microbes on their hosts by nitrogen fixation and/or indoleacetic acid(IAA) secretion,indicating a potential in-site phytoremediation usage in the mining tailing regions of China.     

Spatial character of polychlorinated biphenyls from soil and respirable particulate matter in Taiyuan, China

As one of China’s great metropolises, Taiyuan is affected by heavy chemical industry and manufacture of chemical products, and faces pollution from polychlorinated biphenyls (PCBs). Therefore, this study was conducted to determine the PCB concentrations in various environmental media in Taiyuan. We collected 15 soil samples, 34 respirable particulate matter (PM) samples (17 of PM_2.5 and 17 of PM₁₀) from urban areas of Taiyuan, and measured a total of 144 PCB congeners (including some coeluting PCB congeners). The total PCB concentrations were 51–4.7 × 10³ pg g⁻¹ in soil, 27–1.4 × 10² pg m⁻³ in PM_2.5 and 16–1.9 × 10² pg m⁻³ in PM₁₀. Of the PCB homologues, the dominant PCBs detected in the various media were all tri-CBs. Soil was relatively the most polluted media. Furthermore, principal-component analysis revealed that the major PCB source in Taiyuan may be associated with the main commercial PCB through long-range transmission. Toxic equivalency (TEQ) concentrations (based on ten dioxin-like PCBs) ranged from N.D. to 5.9 × 10⁻³ pg-WHO TEQ g⁻¹ in soil, 2.0 × 10⁻⁴–3.4 × 10⁻³ pg-WHO TEQ m⁻³ and 1.0 × 10⁻⁴–1.2 × 10⁻³ pg-WHO TEQ m⁻³ in PM_2.5 and PM₁₀, respectively. In previous studies, PCBs were not a severe component of contaminant in Taiyuan; however, this study suggested there is a potential threat of human exposure to PCBs for residents of Taiyuan.     

A new direct thermal desorption-GC/MS method: Organic speciation of ambient particulate matter collected in Golden, BC

Particulate matter having an aerodynamic diameter less than 2.5 μm (PM2.5) is thought to be implicated in a number of medical conditions, including cancer, rheumatoid arthritis, heart attack, and aging. However, very little chemical speciation data is available for the organic fraction of ambient aerosols. A new direct thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method was developed for the analysis of the organic fraction of PM2.5. Samples were collected in Golden, British Columbia, over a 15-month period. n-Alkanes constituted 33–98% by mass of the organic compounds identified. PAHs accounted for 1–65% and biomarkers (hopanes and steranes) 1–8% of the organic mass. Annual mean concentrations were: n-alkanes (0.07–1.55 ng m⁻³), 16 PAHs (0.02–1.83 ng m⁻³), and biomarkers (0.02–0.18 ng m⁻³). Daily levels of these organics were 4.89–74.38 ng m⁻³, 0.27–100.24 ng m⁻³, 0.14–4.39 ng m⁻³, respectively. Ratios of organic carbon to elemental carbon (OC/EC) and trends over time were similar to those observed for PM2.5. There was no clear seasonal variation in the distribution of petroleum biomarkers, but elevated levels of other organic species were observed during the winter. Strong correlations between PAHs and EC, and between petroleum biomarkers and EC, suggest a common emission source – most likely motor vehicles and space heating.     

Important role of reaction field in photodegradation of deca-bromodiphenyl ether: Theoretical and experimental investigations of solvent effects

Photolysis of deca-bromodiphenyl ether (BDE-209) was investigated in tetrahydrofuran, dichloromethane, isopropanol, acetone, ethanol, methanol, acetonitrile and dimethylsulfoxide. Noticeable differences of the photolytic rates and quantum yields were found in the diverse solvents. Different to the previous deductions, hydrogen donating efficiency and electron donating efficiency of solvents were not the decisive factors for the photolytic rate in this study, which was proved by the fast photolysis of BDE-209 in CCl₄, a solvent without hydrogen and difficult to donate electrons. Besides hydrogen addition process, intermolecular polymerization might occur during the photolysis. Density functional theory (DFT) calculation was performed to understand the molecular properties of BDE-209 in different solvents. The lowest singlet vertical excitation energy (E_ex) and the average formal charge on Br () of BDE-209, reflecting the difficulty for the excitation of BDE-209 and for the departing of Br atom, respectively, were changed by the reaction fields formed by the different solvents. E_ex and linearly correlated with the photolytic activity (log k). This study is helpful to better understand the photolytic behavior of BDE-209 in different media.     

Pollution characterization and diurnal variation of PBDEs in the atmosphere of an E-waste dismantling region

Diurnal air samples were collected from the E-waste dismantling region Guiyu and the underwear industry region Chendian. This was the first report to present the diurnal variation of PBDEs in the atmosphere. The average concentrations of 11 PBDE congeners were 11,742 pg m⁻³ in the daytime, and 4830 pg m⁻³ at night in Guiyu, while the concentrations were lower in Chendian with 376 pg m⁻³ in the daytime, and 237 pg m⁻³ at night. BDE-209 accounted for 22% and 31.3% of the total PBDEs in Guiyu and Chendian, respectively. The diurnal variation trends of BDE-47, -99, -153, -183, and -209 were also analyzed in detail in the two regions.     

Carbon isotope analysis for source identification of atmospheric formaldehyde and acetaldehyde in Dinghushan Biosphere Reserve in South China

Formaldehyde and acetaldehyde are two most abundant carbonyls in ambient air. Biogenic emission has been proposed as a significant source other than anthropogenic emissions and atmospheric secondary formation. Here at a forest site in South China, the carbon isotopic compositions of formaldehyde and acetaldehyde emitted from leaves of three tree species (Litsea rotundifolia, Canarium album and Castanea henryi) were measured in comparison with the bulk carbon isotopic compositions of tree leaves. δ¹³C data of the emitted aldehydes (from ?31‰ to ?46‰) were quite different for tree species, which were all more depleted in ¹³C than the tree-leaf bulk δ¹³C values (from ?27‰ to ?32‰). Formaldehyde in ambient air at the forest site had δ¹³C values different from those of leaf-emitted formaldehyde, indicating other sources for ambient formaldehyde apart from direct emission from leaves, most probably the photooxidation of biogenic hydrocarbon like isoprene and monoterpene. The δ¹³C differences of acetaldehyde between ambient data and those of tree leaves emission were less than 1‰, implying direct biogenic emission as the dominant source.