Interactions between viruses and goethite during saturated flow: effects of solution pH, carbonate, and phosphate

Metal oxides have great potential for controlling the fate and transport of viruses in the subsurface and water-treatment systems. The processes, however, are subject to solution chemistry. In this study, a number of column experiments were conducted to examine the effects of solution pH and anions (carbonate and phosphate) on attachment, transport, and inactivation of two bacteriophages (phiX174 and MS-2) in goethite-coated sand medium. Removal of both viruses on goethite-coated sand increased as solution pH decreased from 9.3 to 7.5, due mostly to virus inactivation. MS-2, a relatively hydrophobic virus with a lower isoelectric point (3.9), was more sensitive to the change of solution pH than phiX174, a relatively hydrophilic virus with a higher isoelectric point (6.6), in terms of their attachment and inactivation on goethite. About 90% of the MS-2 particles removed by goethite (accounting for 81% of the total input) were inactivated at pH 7.5, whereas all of the removed MS-2 particles (accounting for 10% of the total input) still remained infectious at pH 9.3. In comparison, approximately 74% of the goethite-bound phiX174 particles (accounting for 95% of the total input) lost their infectivity at pH 7.5, in contrast to a complete recovery at pH 9.3 (accounting for 65% of the total input) when the columns were eluted using a beef extract solution (pH 9.5). Presence of phosphate (20 mM H(2)PO(4)(-)) in input solution reduced virus attachment and appeared to protect the viruses from being inactivated during transport; this effect was more significant on MS-2 than on phiX174. Specifically, approximately 29% of the phiX174 particles and approximately 49% of MS-2 particles injected into the column were removed during transport. Mass recovery data showed that no phiX174 was inactivated in the presence of phosphate, whereas about 38% of the MS-2 particles attached on goethite lost their infectivity. Conversely, presence of carbonate on goethite increased virus attachment and inactivation due to contribution of additional attachment sites from protonated surface groups of the carbonate ions that were adsorbed on goethite. About 70% of the total input viruses (both phiX174 and MS-2) were removed during transport, of which 35% phiX174 and 85% MS-2 were eventually inactivated.     

有机絮凝剂对水中染料的絮凝作用探讨

本文在ＰＡＮ－ＤＣＤ对水中活性染料的絮凝脱色研究基础上,用ＩＲ分析以及平衡渗析实验探讨了ＰＡＮ－ＤＣＤ与多种染料的相互作用。     

Progress in decontamination by halophilic microorganisms in saline wastewater and soil

Environments with high-salt concentrations are often populated by dense microbial communities. Halophilic microorganisms can be isolated from different saline environments and different strains even belonging to the same genus have various applications. Wastewater and soil rich in both organic matter and salt are difficult to treat using conventional microorganisms typically found in wastewater treatment and soil bioremediation facilities. Studies on decontaminative capabilities and decontamination pathways of organic contaminants (i.e., aromatic compounds benzoate, cinnamate, 3-phenylpropionate, 4-hydroxybenzoic acid), heavy metals (i.e., tellurium, vanadium), and nutrients in the biological treatment of saline wastewater and soil by halophilic microorganisms are discussed in this review.     

聚硅酸铝铁絮凝剂的制备及其在印染废水处理中的应用

以粉煤灰为主要原料制备了聚硅酸铝铁絮凝剂。通过L16(45)正交实验得出粉煤灰中Al3+和Fe3+的最佳浸取实验条件为焙烧温度900℃,m(Na2CO3)∶m(粉煤灰)=0.10,浸取温度为70℃,盐酸质量分数20%,浸取时间为2.0h。通过L9(34)正交实验得出聚硅酸铝铁的最佳制备条件为n(聚硅酸)∶n(Al3+)=1∶0.5,n(聚硅酸)∶n(Fe3+)=1∶0.5,浸出液pH为5.0,熟化温度为60℃。利用制得的聚硅酸铝铁絮凝剂对200mL模拟印染废水进行处理,在絮凝剂加入量为4mL时絮凝效果最好,透光率超过70%。     

考虑空间效应的出租车超速行为道路因素分析

为充分利用道路特征干预出租车超速行为,搜集成都市区内出租车全球定位系统(GPS)轨迹数据,识别其超速行为,并采集道路特征数据,以各道路的出租车超速频数及平均超速严重度为超速特征,应用全局莫兰指数和4类空间回归模型,分别确定超速特征及道路因素的空间自相关性和显著影响出租车超速特征的道路因素.研究结果表明:出租车超速行为和...     

模拟污染指标水体统计分析

介绍了模拟污染水体中各类指标的单回归，逐步聚类分析，主成份分析及逐步判别分析，在聚类图和判虽函数中，溶解氧与色度具有最紧密关系，水中总和氮氮对水质也有显影响。对模拟试验样品，主成份分类与判别分析分类的结果相类似，而对城市河流体品用判别函数别的结果与观察到的天然状态相一致。     

Simultaneous catalytic removal of NOx and diesel soot particulate over perovskite-type oxides and supported Ag catalysts

A series of perovskite-type oxides and supported Ag catalysts were prepared,and characterized by X-ray diffraction (CRD)and x-ray photoelectron spectroscopy(XPS).The catalytic activities of the catalysts as well as influencing factors on catalytic activity have been investigated for the simultaneous removal of NOx and diesel soot particulate.An increase in catalytic activity for the selective reduction of NOx was observed with Ag addition in these perovskite oxides,especially with 5% Ag loading.This catalyst could be a promising candidate of catalytic material for the simultaneous elimination of NOx and diesel soot.     

Haze insights and mitigation in China: An overview

The present article provides an overview of the chemical and physical features of haze in China, focusing on the relationship between haze and atmospheric fine particles, and the formation mechanism of haze. It also summarizes several of control technologies and strategies to mitigate the occurrence of haze. The development of instruments and the analysis of measurements of ambient particles and precursor concentrations have provided important information about haze formation. Indeed, the use of new instruments has greatly facilitated current haze research in China. Examples of insightful results include the relationship between fine particles and haze, the chemical compositions and sources of particles, the impacts of the aging process on haze formation, and the application of technologies that control the formation of haze. Based on these results, two relevant issues need to be addressed： understanding the relationship between haze and fine particles and understanding how to control PM2.5.     

造纸污泥的流变特性实验研究

造纸污泥是制浆造纸产生的废弃物,含有一定量的热值,将造纸污泥通过管道远距离输送到流化床锅炉焚烧是目前解决造纸污泥的最佳途径。造纸污泥作为高浓度黏稠物料进行管道远距离输送存在很多困难,其流变特性研究是管道输送的重要理论基础。从上述角度出发,介绍了造纸污泥的物理特性和实验仪器,通过对质量分数为28.84%~37.30%的造纸污泥进行系统地测试,绘制了黏度曲线和流变曲线,确定了造纸污泥的流变类型,得出了造纸污泥的流变方程。通过对造纸污泥的流变特性研究,为造纸污泥管道输送设备优化设计以及泵的吸入特性研究提供基本参数。     

Road transport and urban air quality in China

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