Dispersive liquid–liquid microextraction of silver nanoparticles in water using ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate

Using the ionic liquid(IL)1-octyl-3-methylimidazolium hexafluorophosphate as the extractant and methanol as the dispersion solvent,a dispersive liquid–liquid microextraction method was developed to extract silver nanoparticles(AgN Ps)from environmental water samples.Parameters that influenced the extraction efficiency such as IL concentration,pH and extraction time were optimized.Under the optimized conditions,the highest extraction efficiency for AgN Ps was above 90% with an enrichment factor of 90.The extracted AgN Ps in the IL phase were identified by transmission electron microscopy and ultraviolet–visible spectroscopy,and quantified by inductively coupled plasma mass spectrometry after microwave digestion,with a detection limit of 0.01 μg/L.The spiked recovery of AgN Ps was 84.4% with a relative standard deviation(RSD)of 3.8%(n = 6)at a spiked level of 5 μg/L,and 89.7% with a RSD of 2.2%(n = 6)at a spiked level of 300 μg/L,respectively.Commonly existed environmental ions had a very limited influence on the extraction efficiency.The developed method was successfully applied to the analysis of Ag NPs in river water,lake water,and the influent and effluent of a wastewater treatment plant,with recoveries in the range of 71.0%–90.9% at spiking levels of 0.11–4.7 μg/L.     

Diurnal and spatial variations of soil NOx fluxes in the northern steppe of China

NOx emissions from biogenic sources in soils play a significant role in the gaseous loss of soil nitrogen and consequent changes in tropospheric chemistry. In order to investigate the characteristics of NOx fluxes and factors influencing these fluxes in degraded sandy grasslands in northern China, diurnal and spatial variations of NOx fluxes were measured in situ. A dynamic flux chamber method was used at eight sites with various vegetation coverages and soil types in the northern steppe of China in the summer season of 2010. Fluxes of NOx from soils with plant covers were generally higher than those in the corresponding bare vegetation-free soils, indicating that the canopy plays an important role in the exchange of NOx between soil and air. The fluxes of NOx increased in the daytime, and decreased during the nighttime, with peak emissions occurring between 12:00 and 14:00. The results of multiple linear regression analysis indicated that the diurnal variation of NOx fluxes was positively correlated with soil temperature (P < 0.05) and negatively with soil moisture content (P < 0.05). Based on measurement over a season, the overall variation in NOx flux was lower than that of soil nitrogen contents, suggesting that the gaseous loss of N from the grasslands of northern China was not a significant contributor to the high C/N in the northern steppe of China. The concentration of NOx emitted from soils in the region did not exceed the 1-hr National Ambient Air Quality Standard (0.25 mg/m³).     

黑龙江省土壤保护重要性评价

根据黑龙江省土壤保持现状和国家规定的评价方法与指标,对黑龙江省土壤保护重要性进行评价,将黑龙江省土壤保护敏感地区分为3级,即轻度敏感、中度敏感、重度敏感,并确定了它们的分布区域.这一成果为黑龙江省生态功能区划奠定了基础,提供了科学依据.     

基于RDBMS的水环境GIS系统集成方法研究

提出了基于关系型数据为（RDBMS，Relational Database Management System)GIS集成方法，分析了此方法与GIS系统总体框架的融合关系，探讨了其集成方式在GIS空间数据、属性数据和模型库存储及管理中的应用，并以开发的一个水环境GIS系统为例作了介绍。展望了将关系理论和对象理论相结合进行GIS集成的方法。     

液化天然气装卸泄漏扩散模拟研究

针对目前国内LNG槽车装卸采用万向旋转接卸臂+法兰盘接头进行LNG装卸作业,可能出现泄漏的位置为法兰盘接头和万向旋转接头情况,利用有限元仿真软件对LNG装卸时万向旋转接头密封完全失效进行模拟,计算得到泄漏量为1.507 t/h;并针对某接收站采用PHAST软件模拟计算法兰接头全脱、局部破裂及万向旋转接头密封意外失效工况下,LNG泄漏扩散情况,分析得到泄漏孔径、泄漏时间、天气条件对于形成可燃气云尺寸及扩散范围的影响情况,法兰接头完全脱开时泄漏形成气云的最大距离和最大面积为万向旋转接头密封失效泄漏时的12倍和1 000倍。LNG槽车装卸采用法兰盘接头,LNG泄漏可燃气云覆盖面积大,存在巨大爆炸风险,应开展LNG低温干式接头研究,避免LNG装卸接头泄漏爆炸事故发生。     

原油生产过程中的清洁生产管理

文章叙述了清洁生产的定义与发展,原油生产过程中的清洁生产管理,清洁生产前期工作,采油作业过程中的清洁生产,集输作业过程中的清洁生产,对基层单位原油生产过程中污染物的产生治理进行分析,提出了一些节能减排思路,为基层推行清洁生产管理提供参考。     

连续流培养好氧颗粒污泥研究进展

好氧颗粒污泥(AGS)因其沉降性能好,生物量高,抗冲击能力强等优点而受到青睐.相比于传统的序批式反应器(SBR),连续流AGS技术具有易于操作控制以及匹配实际污水厂的大水量,连续流的优势,因而更具有研究价值和应用潜力.通过文献分析和整理,归纳了连续流AGS技术面临的挑战,总结了连续流培养AGS的研究现状和经验教训,并对...     

铁氧化物对模拟印染废水中锑的去除性能研究

含锑化合物常作为纺织工业的催化剂,易引发锑(Sb)污染问题.本文以针铁矿、四方纤铁矿与水铁矿等3种常见的铁氧化物作为吸附剂,比较了不同铁氧化物对Sb(Ⅴ)的去除性能,探究了印染废水中各类因素对锑吸附性能的影响.研究结果显示,3种铁氧化物均可使锑浓度为200μg·L-1的模拟印染废水的出水Sb(Ⅴ)浓度小于50 μg·L...