污水厂二级出水溶解性有机物臭氧化特性研究

采用液相色谱荧光检测器将三维荧光图谱与凝胶色谱分子量分布相结合,对污水处理厂二级出水溶解性有机物(EfOM)的臭氧化反应特性进行了研究.结果表明臭氧会使得二级出水溶解性有机物三维荧光强度明显降低.HPLC-SEC的结果表明臭氧不会改变腐殖质类物质的分子量分布,但臭氧会与小分子蛋白类物质发生反应.根据制备液相的分析结果,小分子蛋白类物质中含有大量苯环及其他共轭结果物质,因此臭氧会优先与小分子蛋白类物质发生反应.同时,XPS分析结果表明臭氧在低投加量下就会与苯环结构反应,提高脂肪类饱和有机物含量,随着投加量进一步升高,含氧官能团(羰基,羧基)数量有所升高.     

表面活性剂与Pb、Zn协同作用对蚕豆叶细胞的损伤

采用透射电子显微镜及能量发散X-射线微量分析技术,研究了非离子型表面活性剂烷基酚聚氧乙烯醚(AE)与矿山尾砂中高浓度Pb、Zn协同作用对蚕豆叶细胞的损伤.结果表明,高浓度Pb、Zn使蚕豆叶绿体中类囊体解体,嗜锇颗粒的数量和体积显著增加.细胞外间隙和液泡中出现大量的不溶性毛发状晶体.AE与Pb、Zn复合污染时,细胞内膜结构的透性增加,细胞内毛发状晶体扩散到叶绿体、细胞核中.因此,AE可加重Pb、Zn对蚕豆叶细胞的损伤作用,毛发状晶体的形成可能与细胞脱毒有关.     

气体爆轰波在管道中绕射和反射的实验研究

本文实验研究了氢/氧/氩气体爆轰波在矩形管中900尖角绕射时的传播特性,利用烟迹技术记录了实验现象,运用爆轰波波阵面结构理论和激波绕射及反射理论对实验结果作了分析。结果表明平面气体爆轰波在900尖角绕射时由于横波失去碰撞以及稀疏波作用,稳定三波结构在绕射区发生变化,在反射激波作用下形成热点产生子爆炸,重新在垂直分支管中形成稳定爆轰波。     

燃煤烟气脱硫氧化镁活性研究

为更好地提高镁法湿法烟气脱硫的脱硫效率,从脱硫剂氧化镁的活性出发,通过X射线衍射分析研究550～800℃高温煅烧制备的氧化镁,得出氧化镁活性与氧化镁制备温度及晶体结构之间的关系,并通过鼓泡床脱硫实验得出活性大的氧化镁脱硫效率较高,对实际生产和运行具有一定的指导意义。     

大气颗粒物的形态、成分分布的透射电镜、X-射线衍射研究

本文利用透射电镜和X-射线衍射技术,对酸雨危害较为严重的重庆市市区大气颗粒物样品进行了较力细致的研究工作。通过对大气飘尘的表面状态、元素组成以及其结合形态的研究,发现粒度较小的球状颗粒物及粗柱状矿物飘尘对酸雨形成影响较大。同时,本文还对酸雨的形成机理进行了一些探讨。      

Concentration effect of trace metals in Jordanian patients of urinary calculi

Due to the increase in the number of urinary calculi disease cases in Jordan, stone samples were collected from patients from various Jordanian hospitals (Princes Basma (PBH), King Abdullah University (KAUH), Al-Basheer (ABH) and Al-Mafraq (AMH)). This study concentrates on the effect of trace metals in patients of urinary calculi. Trace metals were detected in 110 urinary calculi samples using X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS) techniques. Of the calculi examined, 21 were pure calcium oxalate (CaOax), 29 were mixed calcium oxalate/uric acid, 23 were mixed calcium oxalate/phosphate (apatite), 25 were phosphate calculi (apatite/struvite), five were mixed calcium oxalate monohydrate/struvite, four were urate calculi (mixed ammonium acid urate/sodium acid urate) and three were pure cystine calculi. The concentration measurement of Ca and other trace metals levels has been found useful in understanding the mechanism of stone formation and in evaluating pathological factors. It has been found that Ca is the main constituent of the urinary calculi, especially those stones composed of calcium oxalate and calcium phosphate. The concentration of most of the trace metals that were analyzed was (Ca = 48.18, Na = 1.56, K = 0.9, Mg = 3.08, Fe = 1.17, Al = 0.49, Zn = 0.7, Cu = 0.19, Mn = 0.029, P = 10.35, S = 1.88, Sr = 0.306, Mo = 0.2, Cr = 0.146, Co = 0.05, Ni = 0.014)%. In conclusion, metals concentration in Jordanian patient’s urinary calculi samples was higher than its equivalents of other patients’. It has been noted that there is no concentration of toxic trace elements (like Li, V, Pb, Cd, and As). Some heavy metals, however, were detected Mo, Cr, Co and Ni as traces. P and S ions are present in few calculi stones as traces.     

The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the ‘tightest barrier’ in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings.     

Preparation and X-ray structural characterization of further stereoisomers of 1,2,5,6,9,10-hexabromocyclododecane

Technical 1,2,5,6,9,10-hexabromocyclododecane (HBCD) consists largely of three diastereomers (α-, β-, and γ-HBCD) produced by the trans addition of bromine to cis,trans,trans-cyclododeca-1,5,9-triene (CDT). However, another seven diastereomers are theoretically possible and may be produced by trans addition of bromine across the double bonds of the other three isomers of 1,5,9-CDT. There are indications that small amounts of the minor HBCD isomers may be present in commercial HBCD mixtures or in products containing this brominated flame retardant (BFR). Such minor components may indeed derive from traces of other 1,5,9-CDTs in the cis, trans, trans starting material, however their formation may also be possible through isomerizations during the processing of this BFR or by bioisomerization subsequent to its release into the environment. Two of the seven additional diastereomers (δ- and ε-HBCD) were synthesized previously from trans,trans,trans-CDT. We now report the preparation of the remaining five diastereomers, ζ-, η-, and θ-HBCD from cis,cis,trans-CDT and ι- and κ-HBCD from cis,cis,cis-CDT, and their characterization by ¹H NMR spectroscopy and X-ray crystallography. The availability of these further diastereomers of HBCD should aid in determining if the minor isomers are present in commercial samples of this BFR, in products containing HBCDs, or in environmental samples. We have also carried out an X-ray crystal structure determination on ε-HBCD, so that crystal structures are now available for all 10 HBCD diastereomers.     

The impact of EDTA on lead distribution and speciation in the accumulator Sedum alfredii by synchrotron X-ray investigation

The in vivo localization and speciation of lead (Pb) in tissues of the accumulator Sedum alfredii grown in EDTA-Pb and Pb(NO₃)₂ was studied by synchrotron X-ray investigation. The presence of EDTA-Pb in solution resulted in a significant reduction of Pb accumulation in S. alfredii. Lead was preferentially localized in the vascular bundles regardless of treatments but the intensities of Pb were lower in the plants treated with EDTA. Lead was predominantly presented as a Pb-cell wall complex in the plants regardless of its supply form. However, a relatively high proportion of Pb was observed as Pb-EDTA complex when the plant was treated with EDTA-Pb, but as a mixture of Pb₃(PO₄)₂, Pb-malic, and Pb-GSH when cultured with ionic Pb. These results suggest that EDTA does not increase the internal mobility of Pb, although the soluble Pb-EDTA complex could be transported and accumulated within the plants of S. alfredii.     

Impacts of natural weathering on the transformation/neoformation processes in landfilled MSWI bottom ash: a geoenvironmental perspective

Natural weathering processes are significant mechanisms that noticeably affect the fundamental nature of incineration ash residues. To provide a greater understanding of these processes, a MSWI (mono)landfill site in the north east of the US was selected as the target for systematic investigation of the natural weathering of bottom ash residues. Samples of various ages were collected from locations A (1 yr), B (10 yrs), C (13-14 yrs) and D (20 yrs) of the landfill in 2009. We investigated the phase transformation of the collected bottom ash particles, neoformation processes as well as the behavior and distribution of certain heavy metals (Cu, Pb, Zn, Ni, and Cr) in the neoformed phases using optical microscopy, SEM-EDX, and bulk examinations. Key findings: at the preliminary stage, the waste metallic particles (Al, Fe, and Cu) and unstable minerals such as lime, portlandite, ettringite and hydrocalumite convert to oxide and hydroxide (hydrate) phases, calcite, alumina gel and gypsum. At the intermediate stage, the decomposition of melt products including magnetite spinels and metallic inclusions is triggered due to the partial dissolution of the melt glass. At the longer time horizon it is possible to track the breakdown of the glass phase, the extensive formation of calcite and anhydrite, Al-hydrates and more stable Fe-hydrates all through the older ash deposits. Among the dominant secondary phases, we propose the following order based on their direct metal uptake capacity: Fe-hydrates>Al-hydrates>calcite. Calcite was found to be the least effective phase for the direct sorption of heavy metals. Based on overall findings, a model is proposed that demonstrates the general trend of ash weathering in the landfill.