应用化学提取法评价大气颗粒物中重金属的生物有效性

以广州市楼顶降尘为研究对象,在分析其粒度分布和重金属总量的基础上,采用单一化学提取法（DWLP、TCLP）和多级化学提取法（SEP）研究了大气颗粒物中4种重金属元素的生物有效性。结果表明：样品中96％以上颗粒小于100μm,其中10μm和2．5μm以下颗粒分别占33％和11％。大气颗粒物中重金属含量很高,Cu、Pb、Zn和Cd的平均含量分别为362．43、1033．81、830．32和5．80mg／kg,是广东省环境土壤背景值的17～64倍。单一提取法中,TCLP的提取效率明显高于DWLP,表明pH值是影响大气颗粒物中重金属释放的主要因素。SEP法结果显示,Zn和Cd的生物可利用态比例远高于Cu和Pb。经DWLP和TCLP法提取后,颗粒物中重金属的总含量有不同程度的降低,生物可利用态所占比例明显增加。通过综合分析,发现SEP此其他两种方法更适用于评价大气颗粒物中重金属的生物有效性。     

Microalgae binary culture for higher biomass production,nutrients recycling,and efficient harvesting: a review

Environmental Chemistry Letters - Microalgae are photosynthetic cell factories of global interest for fuels, food, feed, bioproducts, carbon sequestration, waste mitigation, and environmental...     

Equilibrium sorption of phenanthrene by soil humic acids

This study investigated the effect of chemical heterogeneity of humic acids (HAs) on the equilibrium sorption of phenanthrene by HA extracts. Six HA samples were extracted from three different soils with 0.5 M NaOH and 0.1 M Na₄P₂O₇ and were characterized with elemental analysis, infrared spectrometry, and solid-state ¹³C nuclear magnetic resonance (NMR) spectrometry. The equilibrium sorption measurements were carried out with a batch technique and using the six HA solids as the sorbents and phenanthrene as the sorbate. The measured sorption isotherm data were fitted to the Freundlich equation. The results showed that, for the same soil, (i) the total HA mass extracted with Na₄P₂O₇ was 13.7–22.6% less than that extracted with NaOH, (ii) the Na₄P₂O₇-extracted HA had higher O/C atomic ratio, greater content of polar organic carbons (POC), and lower aliphatic carbon content than the NaOH-extracted HA, and (iii) the Na₄P₂O₇-extracted HA exhibited greater sorption isotherm linearity and but not dramatic difference in sorption capacities than the NaOH extracted HA. The differences in the HA properties resulting from the two different extraction methods may be because NaOH can hydrolyze insoluble HA fractions such as fatty acid like macromolecules bound on soils whereas Na₄P₂O₇ could not. As a result, the HAs extracted with the two different methods had different polarity and functionality which affected their sorption property for phenanthrene.     

Mobility of heavy metals associated with the natural weathering of coal mine spoils

Knowledge of chemical mobility of heavy metals is fundamental to understanding their toxicity, bioavailability, and geochemical behavior. In this paper, two different methods, i.e. mineralogical means and sequential extractions, were employed to analyze the total contents, existing states, and chemical forms of heavy metals in coal mine spoils. The results demonstrate that the mobility of heavy metals in coal mine spoils depends not only on their existing states and the stability of their host minerals but also on the properties of the coal mine spoils. In the process of coal mine spoils-water interaction, sulfides that contain heavy metals first break down and release metals, which are then adsorbed and complexed by the iron oxyhydroxide colloid resulting from pyrite oxidization and organic matter. During the natural weathering of coal mine spoils, only a small fraction of these metals are released to the environment, and most of them still remains in the residual material.     

磁黄铁矿氧化机理及酸性矿山废水防治的研究进展

磁黄铁矿是矿山尾矿堆中最为常见且分布很广的一种硫化铁矿物.由于硫化物矿物氧化后不仅产生酸性废水,还会释放出大量可溶的、生物可利用形态的微量金属,并且酸性环境会进一步增强这些有毒金属的移动性,因此是造成矿山周围水体环境污染的罪魁祸首.为了阻止或降低磁黄铁矿的自然风化反应速度从而达到源头治理酸性矿山废水的目的,首先必须研究它在各种条件下的氧化机理、氧化产物和氧化速度.对近年来国外在磁黄铁矿晶体结构、反应活性以及酸性矿山废水的产生与防治等方面的研究进行了综述.     

小龙潭电厂脱硫工艺的探讨

介绍了国外几种成熟的脱硫工艺，通过分析与比较并结合小龙潭电厂的实际情况，最终选择烟气循环流化床半干法作为该电厂褐煤锅炉的脱硫工艺。     

New methods of life expectancy estimation

Environmental and Ecological Statistics - Two novel methods of life expectancy estimation, applied to various annual reported demographic datasets, are proposed. First, for datasets that fully...     

Stability properties of natural estrogen conjugates in different aqueous samples at room temperature and tips for sample storage

Environmental Science and Pollution Research - It is important to keep natural estrogen conjugates (C-NEs) intact in aqueous environmental sample before sample preparation; otherwise, this may...     

Mechanical properties of steel slag replaced mineral aggregate for road base/sub-base application based Vietnam and Japan standard

Steelmaking slag is one of the most massive industrial by-products generated during steelmaking processes. This paper presents the current steelmaking slag production status and its potential to use as mineral aggregates in base/sub-base layer of road pavement. The mechanical properties of steelmaking slag were confirmed by the test method specified in Vietnam specification. The volume stability test of the slag was conducted based on JIS A 5015-2018 (Japanese Industrial Standard: Iron and steel slag for road construction). From the results, it was confirmed that steelmaking slag can satisfy all the mechanical requirements specified in Vietnam specification and the requirements regarding stability specified in JIS A 5015-2018. In addition, it was found that the elastic modulus of steelmaking slag applied as a base or sub-base layer in pavement was higher than that of the conventional graded aggregate made from mineral aggregate. Therefore, the thickness of pavement can be reduced by using steelmaking slag, and the construction cost can be lower.