Influence of complexation on lead(II) and cadmium(II) percolation through a clay liner

Wastes are usually stocked in waste disposals without any pre-treatment. Runoff waters lead to the formation of leachates containing mineral and organic pollutants. In order to prevent groundwater contamination, a double barrier is placed on the landfill bottom. The first one is an active barrier made up of a draining system and a geomembrane, and the second one, consisting of a clay liner allowing pollutant retention, is considered as a passive system. The aim of this work is to evaluate the complexation impact on the organic and inorganic retention. Percolations on columns filled with clay are performed, which allow a better knowledge of the transfer of metallic pollutants, complexed or not, through a model porous media, considering charge and conditional stability of complexes.     

PERCOLATION OF LEAD(II) AND CADMIUM(II) THROUGH TWO BENTONITES USED AS LANDFILL LINER

In order to prevent contamination of subsoil and groundwater by leachates containing heavy metals, montmorillonite linings are used on landfill bottoms. It is therefore important to understand ion uptake by this clay. In this study we have performed percolation of lead(II) and cadmium(II) through columns filled firstly with a technical bentonite and then with a reference bentonite. Elution curves provide an evaluation of metals retention. After the percolation step, columns are cut and metal ions are extracted to evaluate influence of side effects and soil depth on metal uptake. Moreover retentions of lead(II) and cadmium(II) are compared.     

Percolation of Lead(II) and Cadmium(II) through two bentonites used as landfill liner

In order to prevent contamination of subsoil and groundwater by leachates containing heavy metals, montmorillonite linings are used on landfill bottoms. It is therefore important to understand ion uptake by this clay. In this study we have performed percolation of lead(II) and cadmium(II) through columns filled firstly with a technical bentonite and then with a reference bentonite. Elution curves provide an evaluation of metals retention. After the percolation step, columns are cut and metal ions are extracted to evaluate influence of side effects and soil depth on metal uptake. Moreover retentions of lead(II) and cadmium(II) are compared.     

Removal of cadmium(II), lead(II), and chromium(VI) ions from aqueous solution using clay

Removal of cadmium(II), lead(II), and chromium(VI) from aqueous solution using clay, a naturally occurring low-cost adsorbent, under various conditions, such as contact time, initial concentration, temperature, and pH has been investigated. The sorption of these metals follows both Langmuir and Freundlich adsorption isotherms. The magnitude of Langmuir and Freundlich constants at 30°C for cadmium, lead, and chromium indicate good adsorption capacity. The kinetic rate constants (K _ad) indicate that the adsorption follows first order. The thermodynamic parameters: free energy change (ΔG ^o), enthalpy change (ΔH ^o), and entropy change (ΔS ^o) show that adsorption is an endothermic process and that adsorption is favored at high temperature. The results reveal that clay is a good adsorbent for the removal of these metals from wastewater.     

室内环境中持久性卤代有机污染物的人体暴露及潜在生殖健康影响

卤代持久性有机污染物(Hal-POPs),如多溴联苯醚(PBDEs)、多氯联苯(PCBs)、滴滴涕(DDT)等是环境中广泛存在的全球性有机污染物,同时它们又是内分泌干扰物,是威胁人类生殖健康的重要因素之一。由于人们每天约有80%以上的时间在室内度过,且室内环境是Hal-POPs人体暴露的主要来源之一,因此室内环境中Hal-POPs对人体内分泌系统的干扰作用及其机理等问题亟待研究,但目前这方面的研究很有限。本文通过综述Hal-POPs在室内环境中的赋存水平和在人体体内的负荷水平及其半衰期,探讨了其对人体内分泌系统尤其是男性生殖健康的影响情况及其可能的机理,并分析了目前研究的不足之处及研究前景,为进一步开展这方面的研究提供借鉴。     

Synthesis,structural characterization and antimicrobial activity of nickel(II) tetrathiocyanato dicuperate(I) complexes with some acyl hydrazones

Heterobimetallic complexes of the type Ni[Cu(SCN)₂]₂ · L (where L = acetophenone benzoylhydrazone, acetophenone isonicotinoyl hydrazone, acetophenone salicyloylhydrazone (ash), acetophenone anthraniloylhydrazone, p-hydroxy acetophenone benzoylhydrazone, p-hydroxy acetophenone isonicotinoyl hydrazone p-hydroxy acetophenone salicyloylhydrazone (phash), p-hydroxy acetophenone anthraniloyl hydrazone), were synthesized and characterized. The complexes are polymeric, insoluble in common organic solvents and are nonelectrolytes. Magnetic moments and electronic spectral studies suggest a spin-free octahedral geometry for the complexes. IR spectra show the bidentate nature of all the ligands bonding through >C=O and >C=N–groups. The SCN group acts as a bridge between two metal centers. X-ray powder diffraction parameters for Ni[Cu(SCN)₂]₂ · ash and Ni[Cu(SCN)₂]₂ · phash correspond to orthorhombic and tetrahedral crystal lattices, respectively, for these complexes. The complexes show a significant antifungal activity against Rizoctonia, Stemphylium and Aspergillus sp. and antibacterial activity against Clostridium and Pseudomonas sp. The metal complexes are more active than the ligands.     

Neue Aspekte in der Behandlung von Siedlungsabflüssen

The surface runoff from urban areas is one of the most important sources of pollutants emitted into surface waters. Suspended solids which act as a transport vehicle for many anthropogenic pollutants (e.?g. heavy metals, PAH) are a key factor in this regard. The development of efficient measures of storm water runoff treatment thus requires a further differentiation of suspended solids in a fine (clay and silt) and coarse (sand and gravel) fraction. Both fractions show distinctly different characteristics in pollutant loading, transport and retention on urban surfaces and sewer systems. The primary aim of storm water runoff treatment is the reduction of the fine particles which are always highly loaded with anthropogenic pollutants. In contrast the coarse particles are almost unpolluted especially if they have a low organic share. The widespread sedimentation tanks with surface loadings between 10 and 2?m/h are very inefficient. A significant, save and lasting reduction of the emitted load of fine particles requires a considerable reduction of the surface loads. That can be achieved with the installation of lamellar settler or the utilization of the very large volumes of flood management tanks frequently present in urban areas. Filtration plants are highly efficient but there application in urban areas is limited due to their high space demands.     

2种水稻土中Cu(Ⅱ)和Pb(Ⅱ)的解吸动力学

用一次平衡法研究了2种水稻土表面吸附态Cu(Ⅱ)和Pb(Ⅱ)的解吸动力学行为及柠檬酸和酒石酸对2种重金属离子解吸的影响。结果表明,虽然2种土壤对Pb(Ⅱ)的吸附量比Cu(Ⅱ)高得多,但无论在单一重金属体系还是Cu(Ⅱ)和Pb(Ⅱ)共存体系中,Cu(Ⅱ)的解吸量均大于Pb(Ⅱ),湖州水稻土Cu(Ⅱ)的解吸量大于嘉兴水稻土,说明土壤对重金属离子的吸附亲和力越大,吸附的重金属离子越不易解吸。用E lovich方程拟合动力学数据可以获得比较满意的结果。解吸速率与时间的关系曲线表明,Cu(Ⅱ)和Pb(Ⅱ)的解吸速率随时间的增加迅速减小。Cu(Ⅱ)的解吸速率大于Pb(Ⅱ),柠檬酸和酒石酸不仅使重金属的解吸量增加,而且使Cu(Ⅱ)和Pb(Ⅱ)的解吸速率大大提高。2种有机酸对Cu(Ⅱ)解吸的促进作用大于Pb(Ⅱ),柠檬酸的促进作用大于酒石酸。     

Geometry of Zn(II) complexes with dissolved organic matter: X-ray studies at variable pH

The structure of Zn(II) complexes with dissolved organic matter (DOM) is an important consideration in developing molecular-level models of Zn(II) speciation, but recent reports favoring the tetrahedral geometry differ from earlier findings that geometry was largely octahedral. In general, the presence of thiolate ligands favors the tetrahedral geometry, while O and N ligands favor the octahedral geometry. This work presents extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopic results, indicating an octahedral geometry over the pH range of 5–9 for a freshwater DOM isolate. Changes in XANES derivatives as a function of pH can be explained in terms of ligand protonation and/or changing ligand groups. Tetrahedral Zn(II)–DOM geometry may be restricted to binding environments containing thiol groups.     

六溴环十二烷(HBCD)对H4细胞和SK-N-AS细胞脱碘酶2和3表达的影响

六溴环十二烷(hexabromocyclododecane,HBCD)与多溴联苯醚(polybrominated diethyl ethers,PBDEs)复合污染体系,对人类健康尤其神经系统所造成的潜在危害及其机制一直是笔者课题组的研究方向。HBCD是广泛使用的溴化阻燃剂,与PBDEs一样,会通过干扰内分泌系统、影响甲状腺激素分泌及损伤神经系统,对生物体产生发育神经毒性。作为系列研究之一,本研究以H4人脑神经胶质瘤细胞和SK-N-AS人神经母细胞瘤细胞为体外生物模型,通过观察HBCD对H4细胞Ⅱ型脱碘酶(Dio2)和SK-N-AS细胞Ⅲ型脱碘酶(Dio3)表达的调控,初步探讨了HBCD对神经系统局部甲状腺激素水平的潜在影响。H4细胞和SK-N-AS细胞分别暴露于0、1、3和9μmol·L-1HBCD 24 h后,采用MTT法检测细胞活力,Western Blot和RT-PCR法分别分析Dio2和Dio3蛋白和基因的表达,酶联免疫吸附测定(ELISA)法检测H4细胞脑源性神经细胞营养因子(BDNF)的分泌。结果表明,HBCD以剂量依赖方式降低H4细胞和SK-N-AS细胞生存率,引起H4细胞Dio2蛋白和基因表达下调,而致SK-N-AS细胞Dio3蛋白和基因表达上调。此外,HBCD还降低H4细胞BDNF的分泌。这表明,HBCD很可能通过影响神经和胶质细胞脱碘酶的表达,影响脑局部甲状腺激素水平,从而引起神经系统损伤及发育神经毒性。     

The abatement of major pollutants in air and water by environmental catalysis

This review reports the research progress in the abatement of major pollutants in air and water by environmental catalysis. For air pollution control, the selective catalytic reduction of NO _x (SCR) by ammonia and hydrocarbons on metal oxide and zeolite catalysts are reviewed and discussed, as is the removal of Hg from flue gas by catalysis. The oxidation of Volatile organic compounds (VOCs) by photo- and thermal-catalysis for indoor air quality improvement is reviewed. For wastewater treatment, the catalytic elimination of inorganic and organic pollutants in wastewater is presented. In addition, the mechanism for the procedure of abatement of air and water pollutants by catalysis is discussed in this review. Finally, a research orientation on environment catalysis for the treatment of air pollutants and wastewater is proposed.     

高分子量多环芳烃--苯并[a]芘的生物降解研究进展

多环芳烃(PAHs)是一类广泛分布于海洋环境中的含有两个以上苯环的有机化学污染物.苯并[a]芘(BaP)是一种由5个苯环组成的分布广泛、致癌性极强的多环芳烃化合物,人们将其作为多环芳烃的指示物,通过研究其在环境中的产生、迁移、转化、降解及毒理作用来判断多环芳烃的污染情况.BaP已成为国内外环境监测的重要指标之一.本文综述了不同环境中BaP的来源与分布,BaP在环境中的行为,微生物对BaP的代谢途径,以及微生物降解BaP的相关限制因子,并结合作者在这方面研究的部分工作与目前国际研究的热点,提出值得进一步探究的有关问题.图4表3参51     

Enrichment and transfer of polycyclic aromatic hydrocarbons (PAHs) through dust aerosol generation from soil to the air

● Compositional patterns of PAHs in dust aerosol vary from soil during dust generation. ● The EF of PAH in dust aerosol is affected by soil texture and soil PAH concentration. ● The sizes of dust aerosol play an important role in the enrichment of HMW-PAHs. Polycyclic aromatic hydrocarbons (PAHs) are major organic pollutants in soil. It is known that they are released to the atmosphere by wind via dust aerosol generation. However, it remains unclear how these pollutants are transferred through the air/soil interface. In this study, dust aerosols were generated in the laboratory using soils (sandy loam and loam) with various physicochemical properties. The PAH concentrations of these soils and their generated dust aerosol were measured, showing that the enrichment factors (EFs) of PAHs were affected by soil texture, PAH contamination level, molecular weight of PAH species and aerosol sizes. The PAHs with higher EFs (6.24–123.35 in dust PM_2.5; 7.02–47.65 in dust PM₁₀) usually had high molecular weights with more than four aromatic rings. In addition, the positive correlation between EFs of PAHs and the total OC_aerosol content of dust aerosol in different particle sizes was also statistically significant (r = 0.440, P < 0.05). This work provides insights into the relationship between atmospheric PAHs and the contaminated soils and the transfer process of PAHs through the soil-air interface.     

Electrochemical hydride generation of tin(II) and its determination by electrothermal atomic absorption spectrometry with in situ trapping in the graphite tube atomizer

An electrolytic hydride generation system for the determination of tin(II) by means of batch electrochemical hydride generation-electrothermal atomic absorption spectrometry (EcHG-ETAAS) with in situ trapping in a graphite tube atomizer is described. The effects of four permanent chemical modifiers – palladium, tungsten, iridium, and platinum – for graphite tube treatment on analyte absorbance and the effects of four cathode materials, i.e., Pb, Sn, Pb–Sn alloy, and glassy carbon, are checked. Three electrolytes, i.e., nitric acid, sulfuric acid, and hydrochloric acid, are examined as catholyte solutions. The influence of several parameters on EcHG is investigated using multivariate and univariate methods. Interferences of some concomitant ions are evaluated. The calibration curve is linear from 1 to 200?µg?L^?1, with a detection limit of 0.8?µg?L^?1 and a relative standard deviation of 6.2% (n?=?3) for 100?µg?L^?1 Sn(II). The proposed method was successfully applied in the analysis of real environmental water samples and reference materials, and good spiked recoveries over the range of 93.1–115% were obtained. The proposed technique provides a means for developing hydride generation of other elements.     

铜在日本青鳉体内的累积特征及其对肝脏组织结构的影响

为了解水体铜(Cu(Ⅱ))在日本青鳉(Oryzias latipes)脑、鳃、肝脏、性腺和肌肉组织中的累积特征,以及Cu(Ⅱ)对肝脏组织结构的影响,本文采用生态学单因子梯度实验,进行20 d的日本青鳉毒性暴露试验。结果显示,日本青鳉各个组织对Cu(Ⅱ)的累积量随着浓度的升高而增多,但不同组织对Cu(Ⅱ)的累积量有较大的差异,铜累积量由大到小依次为:肝脏脑鳃性腺肌肉。铜暴露后的日本青鳉肝细胞出现肿大、大小不一、排列混乱,静脉扩张淤血,部分肝细胞固缩和坏疽等现象。肝脏是日本青鳉蓄积铜的主要器官之一,实验发现高浓度的Cu(Ⅱ)对肝脏组织结构造成了明显的损伤,进而严重影响日本青鳉的存活率。     

Excitation-emission matrix (EEM) fluorescence spectroscopy for characterization of organic matter in membrane bioreactors: Principles,methods and applications

• Principles and methods for fluorescence EEM are systematically outlined. • Fluorophore peak/region/component and energy information can be extracted from EEM. • EEM can fingerprint the physical/chemical/biological properties of DOM in MBRs. • EEM is useful for tracking pollutant transformation and membrane retention/fouling. • Improvements are still needed to overcome limitations for further studies. The membrane bioreactor (MBR) technology is a rising star for wastewater treatment. The pollutant elimination and membrane fouling performances of MBRs are essentially related to the dissolved organic matter (DOM) in the system. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy, a powerful tool for the rapid and sensitive characterization of DOM, has been extensively applied in MBR studies; however, only a limited portion of the EEM fingerprinting information was utilized. This paper revisits the principles and methods of fluorescence EEM, and reviews the recent progress in applying EEM to characterize DOM in MBR studies. We systematically introduced the information extracted from EEM by considering the fluorescence peak location/intensity, wavelength regional distribution, and spectral deconvolution (giving fluorescent component loadings/scores), and discussed how to use the information to interpret the chemical compositions, physiochemical properties, biological activities, membrane retention/fouling behaviors, and migration/transformation fates of DOM in MBR systems. In addition to conventional EEM indicators, novel fluorescent parameters are summarized for potential use, including quantum yield, Stokes shift, excited energy state, and fluorescence lifetime. The current limitations of EEM-based DOM characterization are also discussed, with possible measures proposed to improve applications in MBR monitoring.     

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

• Simultaneous removal of organic contaminants and Pb(II) was achieved by Mn(VII). • Pb(II) enhanced Mn(VII) oxidation performance over a wide pH range. • Pb(II) did not alter the pH-rate profile for contaminants oxidation by Mn(VII). • Mn(VII) alone cannot oxidize Pb(II) effectively at pH below 5.0. • Pb(III) plays important roles on enhancing Mn(VII) decontamination process. The permanganate (Mn(VII)) oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds. Nonetheless, only a few studies have been conducted to explore the role of the heavy metals (especially the redox-active ones) during the Mn(VII) oxidation process. In this study, taking Pb(II) as an example, its influence on the Mn(VII) decontamination performance has been extensively investigated. It was found that, with the presence of Pb(II), Mn(VII) could degrade diclofenac (DCF), 2,4-dichlorophenol, and aniline more effectively than without. For instance, over a wide pH range of 4.5–8.0, the dosing of 10 μmol/L Pb(II) accelerated the DCF removal rate from 0.006–0.25 min⁻¹ to 0.05–0.46 min⁻¹ with a promotion factor of 1.9–9.4. Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII) could react with Pb(II) to produce Mn(IV) and Pb(IV) at pH 6.0–8.0, further experiments revealed that Pb(II) did not exert its enhancing effect through promoting the generation of MnO₂, as the reactivity of MnO₂ was poor under the employed pH range. At pH below 5.0, it was interesting to find that, a negligible amount of MnO₂ was formed in the Mn(VII)/Pb(II) system in the absence of contaminants, while once MnO₂ was generated in the presence of contaminants, it could catalyze the Pb(II) oxidation to Pb(IV) by Mn(VII). Collectively, by highlighting the conversion process of Pb(II) to Pb(IV) by either Mn(VII) or MnO₂, the reactive Pb(III) intermediates were proposed to account for the Pb(II) enhancement effect.     

土壤中反应性溶质保持模拟模型概述

水溶性污染物和有机污染物在非饱和带的运动规律是当前土壤物理学研究的前沿领域．模拟反应性溶质的运移模型，必须包含溶质和土壤基质之间的保持和释放反应．本文简要综述土壤对溶质保持反应的平衡模型、动力学模型和多反应模型的主要特点．     

分子电性距离矢量用于多氯代二苯并呋喃光解半衰期的QSPR研究（Molecular Electronegativity Distance Vector（MEDV）Applied to Quantitative Structure-Property Relationship Study on Photolysis Half-Lives of PCDFs）

多氯代二苯并呋喃(PCDFs)是一种典型的持久性有机污染物(POPs),光解是其在环境中转化的主要途径.以分子电性距离矢量(Molecular Electronegativity Distance Vector,MEDV)为参数,应用多元线性回归(Multiple Linear Regression,MLR)和偏最小二乘回归(PLSR)对48种PCDFs在云杉针叶和飞灰表面的光解半衰期(t1/2)进行模拟分析,均获得由2个变量所建的定量结构-性质相关(QSPR)模型.多元线性回归结果:建模相关系数(R)分别为0.860和0.836,标准偏差(SD)分别为0.052和0.053,交互检验复相关系数(Rcv)分别为0.839和0.807,外部检验相关系数(Qex)t分别为0.939和0.853;偏最小二乘回归结果:建模相关系数(R)分别为0.857和0.829,交互检验复相关系数(Rcv)分别为0.849和0.807.结果表明,MEDV能较好地表征该类分子的结构信息,所建QSPR模型具有良好的稳定性和预测能力.     

Fabrication of highly efficient Bi2WO6/CuS composite for visible-light photocatalytic removal of organic pollutants and Cr(VI) from wastewater

• A novel Bi₂WO₆/CuS composite was fabricated by a facile solvothermal method. • This composite efficiently removed organic pollutants and Cr(VI) by photocatalysis. • The DOM could promoted synchronous removal of organic pollutants and Cr(VI). • This composite could be applied at a wide pH range in photocatalytic reactions. • Possible photocatalytic mechanisms of organic pollutants and Cr(VI) were proposed. A visible-light-driven Bi₂WO₆/CuS p-n heterojunction was fabricated using an easy solvothermal method. The Bi₂WO₆/CuS exhibited high photocatalytic activity in a mixed system containing rhodamine B (RhB), tetracycline hydrochloride (TCH), and Cr (VI) under natural conditions. Approximately 98.8% of the RhB (10 mg/L), 87.6% of the TCH (10 mg/L) and 95.1% of the Cr(VI) (15 mg/L) were simultaneously removed from a mixed solution within 105 min. The removal efficiencies of TCH and Cr(VI) increased by 12.9% and 20.4%, respectively, in the mixed solution, compared with the single solutions. This is mainly ascribed to the simultaneous consumption electrons and holes, which increases the amount of excited electrons/holes and enhances the separation efficiency of photogenerated electrons and holes. Bi₂WO₆/CuS can be applied over a wide pH range (2–6) with strong photocatalytic activity for RhB, TCH and Cr(VI). Coexisiting dissolved organic matter in the solution significantly promoted the removal of TCH (from 74.7% to 87.2%) and Cr(VI) (from 75.7% to 99.9%) because it accelerated the separation of electrons and holes by consuming holes as an electron acceptor. Removal mechanisms of RhB, TCH, and Cr(VI) were proposed, Bi₂WO₆/CuS was formed into a p-n heterojunction to efficiently separate and transfer photoelectrons and holes so as to drive photocatalytic reactions. Specifically, when reducing pollutants (e.g., TCH) and oxidizing pollutants (e.g., Cr(VI)) coexist in wastewater, the p-n heterojunction in Bi₂WO₆/CuS acts as a “bridge” to shorten the electron transport and thus simultaneously increase the removal efficiencies of both types of pollutants.