Mg-Fe layered double hydroxide with chloride intercalated: synthesis,characterization and application for efficient nitrate removal

Environmental Science and Pollution Research - Mg-Fe layered double hydroxide intercalated with chloride (Mg-Fe-Cl LDH) was synthetized, characterized, and evaluated as adsorbent to remove nitrate...     

基于核心企业视角的虚拟生态工业园构建分析

虚拟生态工业园(VEIP)是一种基于循环经济的新型的大循环生态工业组织形式,是对实体生态工业园的补充和扩展.而核心企业作为VEIP的组建者,是整个园区日常运营的信息指挥中枢,对VEIP的成功运营至关重要.分析了核心企业的内涵和应具备的特质,然后从核心企业的视角出发,给出了核心企业构建VEIP的一般流程,并阐述了核心企业在VEIP构建过程中的主要职能.     

碳基材料负载纳米零价铁去除六价铬的研究进展

近年来,纳米零价铁(nZVI)因具有比表面积大、还原能力强、成本低的特点被用于去除环境中的六价铬〔Cr(Ⅵ)〕,然而由于高表面能、固有磁力等因素的影响,nZVI具有易团聚、易氧化和不稳定的缺点,限制了其广泛应用. 鉴于此,本文以碳材料作为支持材料改性nZVI,比较了制备碳基nZVI复合材料的方法,分析了不同碳基nZVI复合材料去除Cr(Ⅵ)的反应效能,阐述了影响复合材料去除Cr(Ⅵ)的因素. 结果表明:①湿化学法合成的复合材料有利于提高nZVI的分散性,减少团聚. 热转化法合成的复合材料有利于节约成本,提高碳材料和nZVI的结合性. ②不同碳材料负载nZVI能有效提高nZVI的分散性、稳定性和抗氧化性. ③碳基材料负载nZVI能有效降低环境因素对nZVI的负面影响. ④碳基nZVI复合材料能提高对Cr(Ⅵ)的去除能力,其对Cr(Ⅵ)的最大吸附容量比nZVI高1.2～20倍. 本文旨在深入了解碳基nZVI复合材料的合成方法,提高碳基nZVI复合材料的性能,以期为开发高效稳定的碳基nZVI复合材料修复环境中的Cr(Ⅵ)提供一些启示.      

Exploring soil erosion trajectories and their divergent responses to driving factors: a model-based contrasting study in highly eroded mountain areas

Environmental Science and Pollution Research - Soil erosion threatens environmental sustainability worldwide. Exploring the trajectories of soil erosion and associated drivers is of great...     

Fish mercury increase in Lago Manso, a new hydroelectric reservoir in tropical Brazil

It has been frequently demonstrated that mercury (Hg) concentrations in fish rise in newly constructed hydroelectric reservoirs in the Northern Hemisphere. In the present work, we studied whether similar effects take place also in a tropical upland reservoir during impoundment and discuss possible causes and implications. Total Hg concentrations in fish and several soil and water parameters were determined before and after flooding at Rio Manso hydroelectric power plant in western Brazil. The Hg concentrations in soil and sediment were within the background levels in the region (22-35 ng g(-1) dry weight). There was a strong positive correlation between Hg and carbon and sulphur in sediment. Predatory fish had total Hg concentrations ranging between 70 and 210 ng g(-1) f.w. 7 years before flooding and between 72 and 755 ng g(-1) f.w. during flooding, but increased to between 216 and 938 ng g(-1) f.w. in the piscivorous and carnivorous species Pseudoplatystoma fasciatum, cachara, and Salminus brasiliensis, dourado, 3 years after flooding. At the same time, concentrations of organic carbon in the water increased and oxygen concentrations decreased, indicating increased decomposition and anoxia as contributing to the increased Hg concentrations in fish. The present fish Hg concentrations in commonly consumed piscivorous species are a threat to the health of the population dependent on fishing in the dam and downstream river for sustenance. Mercury exposure can be reduced by following fish consumption recommendations until fish Hg concentrations decrease to a safe level.     

苯并(a)芘神经毒性研究进展

苯并(a)芘(BaP)是一种广泛存在于环境中的多环芳烃,具有致癌、致畸、致突变性。目前BaP的神经毒性研究零散而不深入,本文主要总结分析了BaP的神经毒性表现,简要介绍了BaP诱发神经毒性呈现的剂量-效应关系,进一步系统阐述了目前研究中发现的可能分子机制,包括BaP诱导神经递质及其代谢物含量的改变,相关DNA及蛋白质的损伤,抗氧化系统及线粒体的改变等,以期为进一步研究提供参考。     

铁碳微电解处理染料污水的影响因素筛选与优化

为提高铁碳微电解处理染料废水中COD_Cr去除率,将Plackett-Burman和Box-Behnken试验设计方法相结合应用于废水处理条件的筛选与优化. Plackett-Burman设计试验结果表明:铁碳比(体积比)、反应时间和曝气量是影响铁碳微电解处理染料废水COD_Cr去除率的3个关键性因素. Box-Behnken试验设计方法和三维响应面分析表明,铁碳微电解处理染料废水对COD_Cr去除率的最优化操作条件是铁碳比为3∶2、反应时间为120 min、曝气量为40 L/min. 在该优化条件下,当ρ(COD_Cr)在1 000~10 000 mg/L之间变化时,COD_Cr去除率的试验结果均落在模型预测结果的95%置信区间(75.5%~83.3%)内,说明模型能对铁碳微电解处理结果进行良好的预测,因此具有一定的可信度.      

Half a century of changing mercury levels in Swedish freshwater fish

The variability of mercury (Hg) levels in Swedish freshwater fish during almost 50 years was assessed based on a compilation of 44 927 observations from 2881 waters. To obtain comparable values, individual Hg concentrations of fish from any species and of any size were normalized to correspond to a standard 1-kg pike [median: 0.69 mg kg^?1 wet weight (ww), mean ± SD: 0.84 ± 0.67 mg kg^?1 ww]. The EU Environmental Quality Standard of 0.02 mg kg^?1 was exceeded in all waters, while the guideline set by FAO/WHO for Hg levels in fish used for human consumption (0.5–1.0 mg kg^?1) was exceeded in 52.5 % of Swedish waters after 2000. Different trend analysis approaches indicated an overall long-term decline of at least 20 % during 1965–2012 but trends did not follow any consistent regional pattern. During the latest decade (2003–2012), however, a spatial gradient has emerged with decreasing trends predominating in southwestern Sweden.     

抗坏血酸改性纳米硫化亚铁对水体Cr（Ⅵ）的还原特性及机制

为提高纳米硫化亚铁的稳定性及其对水体Cr(Ⅵ)的还原特征,本文通过化学共沉淀法制备抗坏血酸改性纳米硫化亚铁(VC-nFeS)并阐明其对水体Cr(Ⅵ)的还原特性与机制.实验结果表明,VC-nFeS对水中的Cr(Ⅵ)具有优良的还原效果,当pH为7.0,温度为25℃,材料中还原成分FeS与废水中Cr(Ⅵ)的物质的量比为1.5∶1时,还原率可达到99%以上.VC-nFeS投加量、反应温度、初始pH值等因素都会影响Cr(Ⅵ)还原,增加投加量和提高反应温度都能够提高还原速率,酸性和中性环境更有利于Cr(Ⅵ)的还原.VC-nFeS还原Cr(Ⅵ)的过程符合伪二级动力学反应模型,主要以化学吸附为主.等温吸附实验结果表明,两者之间的反应过程用Langmuir模型拟合程度较好,该材料在25℃条件下的最大吸附容量为595.24 mg·g^-1.扫描电镜(SEM)和Zeta电位测定结果表明,加入抗坏血酸改性能够有效分散纳米硫化亚铁.X射线衍射图谱(XRD)和红外光谱图(FTIR)结果显示,抗坏血酸改性处理能够提高纳米硫化亚铁的稳定性,并减少材料表面氧化.另外,产物表征结合水体实验结果表明反应...     

A2/O-MBR工艺处理印染废水中试研究

将平板微滤膜与A2/O工艺结合构建了A2/O-MBR中试系统,探讨了中试系统处理印染废水的效果及稳定性.结果表明,水解酸化可提高印染废水的可生化性,对COD平均去除率达到了43%.系统处理效果稳定,在最佳工况下COD、NH3-H和TN的去除率分别为88%、98%和80%.