Distribution of airborne particles from multi-emission source

The purpose of this work was to study the distribution of airborne particles in the surroundings of an iron and steel factory in southern Finland. Several sources of particulate emissions are lying side by side, causing heavy dust loading to the environment. This complicated multi-pollutant situation was studied mainly by SEM/EDX methodology.Particles accumulated on Scots pine bark were identified andquantitatively measured according to their element content,size and shape. As a result, distribution maps of particulateelements were drawn and the amount of different particle typesalong the study lines was plotted. Particulate emissions fromthe industrial or energy production processes were not themain dust source. Most emissions were produced from theclinker crusher. Numerous stockpiles of the industrial wastesand raw materials also gave rise to particulate emissions as aresult of wind erosion. It was concluded that SEM/EDXmethodology is a useful tool for studying the distribution ofparticulate pollutants.     

Partial characterization of the exopolysaccharide from Oscillatoria trichoides Szafer and the role of released polysaccharide in sequestration of Cr6+

The structural investigation and the chromium adsorptive potential of an exopolysaccharide (EPS) released during the growth of an indigenous cyanobacterium, Oscillatoria trichoides Szafer, were investigated in a laboratory‐scale study. The results showed that, of the total EPS produced, 410.53 milligrams/gram (mg g^?1) were released polysaccharides (RPS) and 11.36 mg g^?1 were capsular polysaccharides (CPS). The sorption of hexavalent chromium (Cr⁶⁺) by the RPS achieved a maximum amount of metal removal (q_max) value of 76.92 mg g^?1 of polysaccharide dry weight. The highest coefficient of determination (0.9742) for the Langmuir adsorption model indicates best fitness of the model in explaining the sorption as a unilayer process. Equilibrium studies indicated that 30 to 40 milligrams per liter initial chromium concentration and a pH of 2 were optimal for biosorption of chromium by the RPS. Scanning electron microscopy with energy‐dispersive X‐ray spectroscopy analysis of Cr⁶⁺‐treated RPS showed the presence of 3.76% bound chromium. Compositional analysis of the EPS showed the presence of carbohydrates, proteins, pyruvic acid, and hexosamines. High‐performance liquid chromatography analysis demonstrated the presence of hexoses, as neutral sugars and glucuronic acid as an acidic sugar. The presence of carboxylic groups was also detected by infrared spectroscopy. The presence of these chemical constituents may serve as binding sites for the metal ions; therefore, the RPS of this species appears to be a promising biosorbent for Cr⁶⁺.     

Rapid detection of toxic metals in non-crushed oyster shells by portable X-ray fluorescence spectrometry

The aim of this study was the multi-elemental detection of toxic metals such as lead (Pb) in non-crushed oyster shells by using a portable X-ray fluorescence (XRF) spectrometer. A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using a portable XRF which provides a quick, quantitative, non-destructive, and cost-effective mean for assessment of oyster shell contamination from Pb. Pb contamination in oyster shells was further confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results indicated that Pb is distributed in-homogeneously in contaminated shells. Oyster shells have a lamellar structure that could contribute to the high accumulation of Pb on oyster shells.     

Particle emissions of a railway line determined by detailed single particle analysis

The goal of this study was to identify and quantify particles emitted from railway traffic. For that purpose PM10 samples were collected near a busy railway line using a wind direction and speed controlled sampling equipment consisting of five devices. Measurements taken perpendicular to the railway lines at 10, 36 and 120 m distance enable an identification and separation of particles caused by the railway traffic from background particles. Morphology and chemistry of more than 11,000 particles were analysed by computer controlled scanning electron microscopy (CCSEM). Based on chemical composition five particle classes are defined and assigned to their sources. The mass of the individual particles is determined by multiplying their volumes, calculated based on their morphology with a density assigned specifically to each particle class. The density of the particle classes is derived from their chemical composition. To estimate the PM10 contributions of the railway lines, the mass of PM10 at 120 m (background, not influenced by the railway lines) is subtracted from the mass of PM10 at 10 m. The emissions of the railway lines are dominated by ‘iron’ particles, which contribute 2.9 μg m⁻³ or 67% to the railway related PM10. In addition, ‘aluminium’ and ‘calcium’ particles contribute also to the railway related PM10 (1.0 μg m⁻³ or 23% for the ‘aluminium’ and 0.4 μg m⁻³ or 10% for the ‘calcium’ particles). These particles are assigned to abrasion of the gravel bed and re-suspension of mineral dust.Long-term gravimetric results of the contribution of iron to the mass of railway related PM10 from a study performed earlier at the same site are in good agreement with the data presented in this study.     

Unique zinc mass in mandibles separates drywood termites from other groups of termites

Previously, the presence of metals in arthropod mandibles has been linked with harder cuticle, and in termites, a 20% increase in hardness has been found for mandibles containing major quantities of zinc. The current study utilises electron microscopy and energy-dispersive X-ray microanalysis to assess incidence and abundance of metals in all extant subfamilies of the Isoptera. The basal clades contain no zinc and little to no manganese in the cutting edge of the mandible cuticle, suggesting that these states are ancestral for termites. However, experimentation with mandibles in vitro indicates the presence of some elements of the cuticular biochemistry necessary to enable uptake of zinc. The Termopsidae, Serritermitidae, Rhinotermitidae and Termitidae all contain minor quantities of manganese, while trace to minor quantities of zinc occur in all except the Serritermitidae. In contrast, all Kalotermitidae or drywood termites contain major levels of zinc in the mandible edge. Diet and life type are explored as links to metal profiles across the termites. The presence of harder mandibles in the drywood termites may be related to lack of access to free water with which to moisten wood. Scratch tests were applied to a set of mandibles. The coefficient of friction for Cryptotermes primus (Kalotermitidae) mandibles, when compared with species from other subfamilies, indicates that zinc-containing mandibles are likely to be more scratch resistant.     

重庆城区大气颗粒物的元素、离子及物相组成研究

采用X－射线能谱（EDX），傅立叶红外光谱（FT－IR），X－射线衍射（XRI）对重庆市区大气颗粒污染物的元素组成，离子，物相组成进行顾研究，EDX检出了S，Cl,K,Ca,Ti,Cr,Mn,Fe,Cu,Se,Sr,Zr,Rb,Ga,Hg,Zn,Ni元素，FT－IR光谱发现主要存在SO4^2-,NH4^ 和NO3^-,XRD结果表明存在CaSO4.2H2O,α-SiO2,(NH4)2Ca(SO4)2.2H2O,(NH4)2SO4等4个主要物相以及Fe3O4,CaCO3等物相，初步讨论了重庆大气颗粒物的污染来源及其时间，空间分布。     

用扫描电镜分析表征大气气溶胶单颗粒

1　IntroductionAtmosphericaerosolsarecomplexmixture,originatedfromavarietyofsources.Mostoftheanalyticaltechniquesusedforitscharacterizationarebulkmethodsthatgenerateonesetofdatapersample,describingtheoverallcompositionofthesample .Toworkoutusefulinformationonpollu tionsources,itrequiresdataofagreatnumberofsamplesandmultivariatedataanalysismethodsusuallyareneeded .Ontheotherhand ,scanningelectronmicroscope energydispersiveX rayanaly sissystem (SEM EDX)isabletoprovideanalyticaldataforeachsing…     

木霉(Trichoderma sp.)HR-1活细胞吸附Pb(Ⅱ)的机理

从重金属废水中筛选得到一株能够吸附Pb(II)的丝状真菌,编号为HR-1,初步鉴定其为木霉属(Trichodermasp.).研究了pH值对活细胞吸附铅离子能力的影响及其对铅的耐受性,结果表明,该细胞对铅离子的最大吸附量为597mg/g;扫描电镜(SEM)显示细胞吸附Pb(II)后发生明显的萎缩现象,在细胞表面存在大量的沉积物;X射线光散射能谱(EDX)验证了铅的吸附,同时吸附过程中存在离子交换作用.对比细胞吸附Pb(II)前后的傅立叶红外光谱(FTIR)图谱表明,葡聚糖或几丁质中的羟基和C-O-C、蛋白质的羧基是铅的主要吸附位点,与含氮官能团无关.XPS证实细胞吸附铅离子后生成PbO,XRD图谱得出其处于无定形和晶体之间.     

Color removal efficiency of dyes using nanozerovalent iron treatment

In this study, zerovalent iron nanoparticles (Fe⁰) were synthesized by chemical reduction method using ferric chloride hexahydrate (FeCl₃?·?6H₂O) as a starting material. Sodium borohydride (NaBH₄) was used as a reducer. The synthesized nanozerovalent iron (NZVI) was separated using magnets. The X-ray diffraction pattern of iron (Fe) nanoparticles showed that the presence of intensive diffraction peak at 2θ value of 45.33° from the lattice plane of face-centered cubic Fe unequivocally indicates that the particles are made of pure Fe. The size of the synthesized NZVI was found to be 16.64?nm. The scanning electron micrograph revealed that the particles have a hexagonal and spherical shape in nature. EDX showed the surface atomic distribution and chemical composition of NZVI. The decolorization efficiency rose with increasing concentration of nanoparticles as well as with time. Maximal color removal efficiency was 90.72% when using 0.5?g/100?mL Fe nanoparticle for acridine orange. Data revealed that the function of NZVI on color removal efficiency was statistically significant. The correlation coefficient between NZVI concentration and time showed a strong negative correlation for dyes used in the experiment.     

基于EDX的飞灰元素组成及重金属分布研究

介绍了用于X射线能谱分析(EDX)的飞灰颗粒表面和断面样品的制作方法.对用EDX分析飞灰组成元素及重金属分布的实验方法(包括点(或面)分析、线扫描以及元素能谱图)和信息分析方法进行了探讨.168组的飞灰EDX分析结果表明:飞灰成分非常复杂,其中Si,Ca和Al是基本组成元素,Cl和S出现频率处于第2位,而作为盐基的Na,K和Mg出现频率处于第3位;在以Si,Ca和Al为主体的飞灰颗粒表面和断面重金属富集少,呈随机分布.推测重金属在飞灰上的吸附作用机理包括了物理吸附过程和自飞灰颗粒表面向内部的化学扩散过程.