Ca2+对酸性硫酸盐环境中次生铁矿物合成的影响

通过摇瓶培养试验,在富铁酸性硫酸盐环境中,探析0、50、100、200或400mg/L Ca2+加入对嗜酸性氧化亚铁硫杆菌(A. ferrooxidans)生物合成次生铁矿物过程的影响.分析了体系pH值、氧化还原电位(ORP)、Fe2+氧化率、总Fe沉淀率以及次生铁矿物矿相等相关指标的变化情况.结果表明,0~24h培养过程中,各体系pH值、ORP、Fe2+氧化率及总Fe沉淀率变化幅度基本一致.24~108h培养过程中,体系中Ca2+加入量越大,Fe2+氧化越迅速,相应总Fe沉淀率相对较高.400mg/L Ca2+的加入使得体系Fe2+在72h氧化完全,总Fe沉淀率在108h达到39.1%.0、50、100或200mg/L Ca2+ 加入的体系在24~84h培养过程中,体系Fe2+氧化速率随着Ca2+加入量逐渐增加而依次升高,并在84h Fe2+氧化完全,且在108h,相应体系总Fe沉淀率分别为27.0%、29.7%、33.9%或36.9%.不同体系所得次生铁矿物均为施氏矿物与黄铁矾的混合物.本研究结果对明晰富铁酸性硫酸盐环境钙离子调控生物成因次生铁矿物合成的影响机理有一定指导意义.     

Preconcentration of some trace metal ions on coated alumina modified by 1-((6-(-(2-hydroxynaphthalen-1-yl)methyleneamino) hexylimino) methyl) naphthalen-2-ol

A sensitive and efficient method for preconcentration of trace amounts of some metal ions such as Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Pb²⁺, Cd²⁺, Cr³⁺, and Fe³⁺ ions based on modification of sodium-dodecyl-sulphate (SDS) coated alumina with 1-(6-(-(2-hydroxynaphthalen-1-yl) methyleneamino) hexylimino) methyl) naphthalen-2-ol (HNMAHN) is reported. The method is based on the uptake of these ions following their chelation with HNMAHN and their recovery using a suitable eluent. The influence of parameters such as pH, concentration of ligand and amount of coated alumina, SDS concentration, eluent (type and concentrations), and elution volume on metal ion recoveries are investigated. The preconcentration factor is 150 (10?mL elution volume) for a 1500?mL sample volume. The method has been successfully applied for extraction and determination of these ions content in some real samples. Extraction efficiency is generally >95% with low relative standard deviations between 1.8% and 2.4 %.     

Passive sampling of PAHs in indoor air in Nepal

PAHs were sampled in ten homes in the Makwanpur region, Nepal. SPMDs and moss bags (Sphagnum girgensohnii) were used as passive samplers. Soot particles on the SPMD surfaces were also analyzed for PAHs. The overall PAH concentrations in SPMDs were significantly higher than those in moss bags. Total PAH mean concentrations of ten houses were 535μg/g lipid for SPMDs and 7.2 μg/g moss (dw) for moss bags. Ratios of phenanthrene/anthracene in indoor SPMDs and particulate matter varied from 2.9 to 3.5 and ratios of fluoranthene/pyrene varied from 1.1 to 1.4. The values for moss bags were respectively 1.7–3.6 and 0.8–2.4. These ratios indicate that the PAHs are from combustion origin. The PAH concentrations in ambient air were estimated as B(a)P TEQs and they were 17–64 times higher than acceptable limit for Finnish community air. Based on PAH levels in the gas phase (SPMD) we may expect PAHs to have an impact on respiratory disease prevalence in Nepalese villages. Both of the sampling methods were feasible in the difficult conditions under which the study was performed.     

土荆芥不同发育期根际土壤养分、酶活及微生物数量的变化

采用盆栽试验,通过比较土荆芥营养期和果期根际土壤中养分、土壤酶活和微生物数量的变化规律,明确土荆芥入侵对土壤生态系统的影响效应,为进一步了解土荆芥入侵机理和制定防控措施提供理论依据.结果表明：（1）土荆芥入侵对土壤养分具有一定的影响.与对照相比,除了土荆芥营养期根际土壤总钾的含量增加了12.26%外,所测其它土壤养分指标均不同程度下降.其中,果期总钾含量降低3.27%,营养期和果期的有机质含量分别降低20.41%和1.22%、总氮含量分别降低27.87%和16.39%、总磷含量分别降低29.41%和14.71%、速效磷含量分别降低49.24%和34.69%、速效钾含量分别降低76.65%和57.22%;（2）土荆芥的生长对土壤胞外酶具有-定的影响.与对照相比,营养期和果期土壤硝酸还原酶活性显著升高（P〈0.05）,分别升高了87.23%和137.23%;营养期的脲酶活性降低了45.92%,与对照差异显著（P〈0.05）;营养期和果期根际土壤的蔗糖酶、酸性磷酸酶、过氧化氢酶活性的变化均未达到显著程度（P〉0.05）;（3）土壤微生物数量随着土荆芥生长而增加,但只有真菌数量与对照的差异达到显著水平（P〈0.05）,营养期和果期真菌数量分别增加32.11%和86.18%;（4）与果期相比,营养期土壤养分含量、土壤酶活性和微生物数量普遍较低,推测土荆芥生长初期通过降低土壤营养水平,抑制其周围对营养水平要求较高的植物生长,以获得竞争优势,而果期则通过释放根系分泌物增加了土壤微生物数量和土壤酶活,使土壤养分回升,从而为其繁殖提供有利条件.     

固相萃取-超高效液相色谱-串联质谱法测定地表水中5种磺胺类抗生素

建立了固相萃取-超高效液相色谱-串联质谱对水中5种磺胺类抗生素的测定分析方法。将水样经固相萃取后进样,经ACQUITY UPLC BEH C18(2.1 mm×100 mm,1.7μm)分离后,采用串联质谱电喷雾电离(ESI+),多反应监测(MRM)模式检测,内标法定量。方法的线性范围为5.0~100.0μg/L,线性相关系数均大于0.995,样品100倍浓缩后,检出限低至0.009μg/L;在5.0~100.0μg/L范围内,高中低3个水平的加标回收率为80.2%~90.7%,相对标准偏差(RSD)为4.3%~12.0%。该方法能够满足《国务院关于印发水污染防治行动计划的通知》限制使用抗生素等化学药品开展专项整治的需要,是一种高效、准确、灵敏度高的方法。     

应急管理阶段理论新模型研究

本文回顾了应急管理阶段理论的发展过程,分析了传统应急管理阶段理论存在的一些不足。根据突发事件中危害因素、受灾体、应急管理的不同行为特征,提出了应急管理阶段的新模型。在该新模型中,应急管理的生命周期包括"预防-监测-响应-恢复-重建"五个前后相续的阶段,而"减灾"与"准备"则被提升为贯穿应急管理整个生命周期的两类基础性活动。     

Multispectral image analysis method to determine dynamic fluid saturation distribution in two-dimensional three-fluid phase flow laboratory experiments

The need for measuring dynamic fluid saturation distribution in multi-dimensional three-fluid phase flow experiments is hampered by lack of appropriate techniques to monitor full field transient flow phenomena. There is no conventional technique able to measure dynamic three-fluid phase saturation at several array points of the flow field at the same time. A multispectral image analysis technique was developed to determine dynamic NAPL, water and air saturation distribution in two-dimensional three-fluid phase laboratory experiments. Using a digital near-infrared camera, images of sand samples with various degrees of NAPL, water and air saturation were taken, under constant lighting conditions and within three narrow spectral bands of the visible and near-infrared spectrum. It was shown that the optical density defined for the reflected luminous intensity was a linear function of the NAPL and the water saturation for each spectral band and for any two and three-fluid phase systems. This allowed the definition of dimensionless lump reflection coefficients for the NAPL and the water phase within each spectral band. Consequently, at any given time, two images taken within two different spectral bands provided two linear equations which could be solved for the water and the NAPL saturation. The method was applied to two-dimensional three-phase flow experiments, which were conducted to investigate the migration and the distribution of LNAPL in the vadose zone. The method was used to obtain continuous, quantitative and dynamic full field mapping of the NAPL saturation as well as the variation of the water and the air saturation during NAPL flow. The method provides a non-destructive and non-intrusive tool for studying multiphase flow for which rapid changes in fluid saturation in the entire flow domain is difficult to measure using conventional techniques.     

Porous silica synthesis out of coal fly ash with no residue generation and complete silicon separation

● Both amorphous and crystalline silicon are completely separated from coal fly ash. ● Porous silica is synthesized out of coal fly ash. ● No residues is produced during the whole synthesis process. ● The one-step method to synthesize silica don’t need long-time reaction and aging. Ordered mesoporous silica materials exhibit enormous potential in industrial production. Since coal fly ash (CFA) is abundant in Si, it has become a green and promising way to utilize CFA by synthesizing porous silica materials. However, the stable crystalline structure of CFA limits the extraction of Si, and the residue is generated during the process of extracting Si. In this work, we proposed a no-residue method to synthesize ordered mesoporous silica out of CFA. Sodium carbonate (Na₂CO₃) was used to reconstruct the crystals of the CFA, and the calcined mixture then directly reacted with the precipitators. This method combined the process of Si extraction and porous material synthesis. In this method, no residue was generated and the silicon in both amorphous and crystalline phases of CFA was fully utilized. By this method, the extraction efficiency of Si was increased from 31.75% to nearly 100%. The as-synthesized mesoporous silica had a highly-ordered pore structure with a space group of la-3d, a surface area of 663.87 m²/g, a pore volume of 0.41 cm³/g, and an average pore diameter of 2.73 nm. The mechanism of crystalline transformation and material structure formation were systematically studied. This method provides a new idea to dispose of CFA and synthesize porous silica materials.     

快速固相萃取法测定食品中多种有机磷农药残留

报道了一种简便、快速的石墨碳固相萃取(SPE)食品中多种有机磷农药残留及测定的方法.采用丙酮浸泡、超声提取食品中的有机磷农药,经石墨碳固相小柱净化萃取后,用气相色谱-火焰光度检测法直接测定,加标回收率在72.0%～107%之间,RSD为6.2%～12.7%,最低检出限可达0.001 mg/kg.     

金属矿山中后期矿井通风安全问题探讨

金属矿山中后期在生产中是一个特殊时期.矿井通风面临的问题比前期更多,更复杂.分析了金属矿山矿井通风安全现状及原因,提出了解决问题的措施及改进方向.