Fate and transport of engineered nanomaterials in the environment

With the fast development of nanotechnology, engineered nanomaterials (ENMs) will inevitably be introduced into the various environment. Increasing studies showed the toxiccity of various ENMs, which raises concerns over their fate and transport in the environment. This review focuses on advances in the research on environmental transport and fate of ENMs. Aggregation and suspension behaviors of ENMs determining their fate and transport in aqueous environment are discussed, with emphasis on the influencing factors, including natural colloids, natural organic matter, pH, and ionic strength. Studies on the transport of ENMs in porous media and its influencing factors are reviewed, and transformation and organismcleansing, as two fate routes of ENMs in the environment, are addressed. Future research directions and outlook in the environmental transport and fate of ENMs are also presented.     

我国实施循环经济的制度初探

循环经济是在资源与环境约束下追求有效经济增长的一种新的经济发展模式。循环经济本质上是一种生态经济,以资源利用的生态性、技术基础的复杂性、经济运行的社会性等为根本特征。制度与循环经济相互依存、相互制约,发展循环经济离不开制度的规范和引导。论述了我国当前在市场经济条件下发展循环经济中遇到的制度障碍,如市场机制障碍、产权制度障碍和政策法规障碍等,并提出解决循环经济发展的制度障碍需要建立一个完整的、相互补充的制度体系。     

城市污泥干燥焚烧一体化处理工艺的研究

城市污泥的产量日益增加,若不进行处理,不仅浪费土地资源而且污染环境。对污泥中的水分形式和污泥的处理工艺进行了分析,认为污泥的干燥和焚烧是最完全、稳定的处理工艺。提出一种城市污泥干燥焚烧一体化处理工艺,利用污泥自身焚烧产生的热值,提供干燥系统所需的热量,达到整个污泥处理系统能量的基本自给。对该系统的流程和各工艺进行了分析,结果表明该系统的污泥减量大、干燥效率高、运行成本低、尾气排放有效控制。     

Levels,congener profile and inventory of polychlorinated biphenyls in sediment from the Songhua River in the vicinity of cement plant,China: a case study

This study investigated the contamination levels, homologue, and congener profiles and evaluated the residue inventory of polychlorinated biphenyls (PCBs) in sediment of the Songhua River in the vicinity of cement plant. The total concentration of detected 35 PCB congeners ranged from 1.12 to 2.19 ng/g dry weight (dw) in sediment, with a mean value of 1.56 ng/g dw, and the concentration of PCBs decreased in the following order: the downstream?>?cement plant?>?upstream. The results of total organic carbon (TOC)-normalized PCB concentrations indicate that the sediments have low potential ecological risk in this area. The study results on homologue and congener of PCBs show that the emissions from cement production could be the major sources of PCBs in sediment, and the low-chlorinated PCBs will be exchanged among air, water, and sediment with increasing temperature during summer and flow to downstream with water during the wet season. The spatial density and total burden of PCBs in the surface sediments were 17.2 ng/cm² and 1.2 kg, respectively. To our knowledge, this study is the first to explore the pollution characteristics of unintentionally produced PCB emissions from cement industry by means of monitoring sediment samples.     

利用多年期赤泥和煤矸石制备烧结砖

以多年期赤泥和煤矸石为主要原料,分析了其化学成分和物性特征,通过设计不同的原料配比和烧结温度,探讨其最佳工艺条件以及各种参数指标,试图为赤泥的大宗化利用提供一种新的途径。实验结果表明最佳工艺条件为:多年期赤泥与煤矸石质量比为20∶80,成型压力为6 MPa,烧结温度为1 100℃左右保温2 h。烧结砖体"泛霜"现象基本消失,抗压强度为12.18 MPa、吸水率为21.6%,满足国家粉煤灰普通烧结砖GB5101-2003中的要求。     

珠海市社会经济发展与资源环境的协调度分析

经济与资源环境协调发展成为研究热点,众多学者运用不同的数学方法对区域经济和环境的协调度进行了分析。目前这方面的研究仅包括经济和环境两大系统,未将社会发展作为独立的系统,且指标的选取未能体现区域经济发展的特点。根据珠海市的实际,对原有的协调度计算方法进行适当调整,得出珠海市社会经济发展与资源环境协调度发展的状况属于良好协调发展类中的经济滞后型。     

Influence of anionic, cationic and nonionic surfactants on adsorption and desorption of oxytetracycline by ultrasonically treated and non-treated multiwalled carbon nanotubes

High adsorption capacity of carbon nanotubes (CNTs) may greatly determine the bioavailability and mobility of organic contaminants. The fate of contaminants adsorbed by CNTs may be substantially influenced by surfactants used both in the synthesis and dispersion of CNTs. The aim of this research was to determine the influence of surfactants (nonionic - TX100, cationic - CTAB and anionic - SDBS) on adsorption and desorption of oxytetracycline (OTC) by multiwalled carbon nanotubes (MWCNTs). The surfactants used had a substantial influence on both adsorption and desorption of OTC. The direction of changes depended clearly on the type of surfactant. In case of anionic SDBS, increased adsorption of OTC by MWCNTs was observed. The presence of TX100 and CTAB decreased the adsorption of OTC by MWCNTs significantly. The increase of OTC adsorption after ultrasonic treatment was observed in case of MWCNTs alone and MWCNTs with SDBS and TX100. However, ultrasonic treatment caused OTC adsorption decrease in the presence of CTAB. The change of pH had also an important effect on OTC adsorption in the presence of surfactants. Depending on the surfactant and pH, an increase or decrease of OTC adsorption was observed. The presence of surfactants increased OTC desorption from MWCNTs significantly as follows: SDBS = CTAB < TX100. The results obtained suggest new potential threats and constitute a basis for further research considering the bioavailability and toxicity of antibiotics in the presence of MWCNTs and surfactants.     

东江干流富营养化评价及区域差异性研究

利用综合营养状态指数评价东江富营养化状况.结果表明,东江富营养化程度较轻,干流绝大部分区域(96％)为中营养及中营养以下水平,只有少数区域(4％)达到富营养水平.同时,东江干流富营养化程度区域差异性明显,从上游至下游河口富营养化程度逐渐加重.针对东江水质污染现状,建议东江水体管理应以保护为主,同时采取有效措施,改善下游...     

大宝山尾矿重金属形态及其潜在迁移能力分析

以大宝山槽对坑尾矿库、新鲜尾矿排放口和铁龙尾矿库3个不同区域尾矿为研究对象,采用Dold七步分级化学提取法研究了4种重金属Cu、Pb、Zn、Mn的化学形态特征,并分析了其潜在迁移能力.结果表明,Cu、Pb在所有尾矿中以原生硫化态和残渣态为主;Zn在槽对坑尾矿和新鲜尾矿中以原生硫化态和残渣态为主,在铁龙尾矿中水溶态、可交...     

活性焦烟气脱硫技术在有色行业的推广应用

介绍了活性焦烟气脱硫技术原理、流程和特点,该技术具有脱硫效率高、工况适应性强、流程简单、节水、无二次污染、可同时脱除多种污染物和可回收硫资源等优点,介绍了活性焦烟气脱硫技术在有色金属行业的发展和应用情况。针对我国硫资源和水资源短缺的国情,建议在有色金属行业加快推广应用活性焦烟气脱硫技术,在治理大气污染的同时回收硫资源。