微波消解-ICP-OES法测定黑芝麻中的18种矿质元素

采用HNO3/H2O2湿法微波消解制样,利用全谱直读电感耦合等离子原子发射光谱法(ICP-OES),全面详细地分析测定了黑芝麻中的矿质元素,共检出Ca、P、S、Mg、K、Al、Si、Fe、Na、Zn、Se、Sr、Cu、Mn、Ba、B、Ti、Cr等18种矿质元素,RSD值在1.21%～10.1%,其中13种元素在5%以内。黑芝麻中所含人体常量元素Ca、P、S、Mg、K、Na等的质量分数分别为1.79%,1.08%,0.59%,0.43%,0.41%和0.009 1%;微量元素Fe、Zn、Se、Cu、Mn、B、Cr、Sr、Si、Al等的含量分别为18.6,4.55,3.87,1.74,1.62,0.91,3.21,78.8,125.8 mg/100 g,未检出Pb、Hg、Cd、As以及Ni、Co、Mo等元素。     

微波消解-ICP-OES法测定岷县当归中的矿质元素

采用浓HNO3/H2O2混合酸体系,以微波消解法对岷县当归样品进行前处理,利用全谱直读电感耦合等离子体发射光谱法(ICP-OES法),对样品中矿质元素的组成及含量进行了测定和分析。结果表明,从岷县当归中检测出15种矿质元素,分别为K、Na、Al、B、Ba、Ca、Fe、Mg、Mn、P、S、Si、Sr、Zn、Cr,其中常量元素有K、Ca、Mg、P、S,微量元素有Al、B、Ba、Fe、Mn、Si、Sr、Zn等,未检测出Tl、Ti、Sn、Cu等元素,以及Pb、Cd等重金属元素,15种元素的RSD值在1.01%~19.01%。研究结果可为岷县当归食用药用价值的进一步开发利用提供一定的理论和科学依据。     

微波消解-ICP-OES法测定干荷叶中的矿质元素

采用浓HNO3/H2O2混合体系,以微波消解法对干荷叶样品进行前处理,利用全谱直读电感耦合等离子体发射光谱法(ICP-OES)测定了样品中矿质元素的组成及含量。结果表明,从干荷叶样品中定量分析了13种矿质元素,其含量由高到低依次为S、Ca、Si、P、Mg、Al、Mn、K、Na、Fe、Sr、Ba、B,其中含量1 000μg·g-1的元素有6种,分别为S、Ca、Si、P、Mg和Al,未检测出Tl、Ti、Sn、Cu、Zn等微量元素以及Pb、Cd、Cr等重金属元素,7种元素的RSD值在10%以下。可为荷叶药食两用价值的进一步开发利用提供一定的理论和科学依据。     

微波消解-ICP-OES法测定花草茶勿忘我中的矿质元素

采用浓HNO3-H2O2混合酸体系,以微波消解法对勿忘我干花进行前处理,利用电感耦合等离子体发射光谱法(ICP-OES法),分析测定了样品中矿质元素的组成及含量。研究结果表明,从勿忘我样品中定量分析了15种矿质元素,分别为K、Na、Ti、Al、B、Ba、Ca、Fe、Mg、Mn、P、S、Si、Sr、Zn,其中K、Na、Ca、Mg、P、S等常量元素含量均大于1000μg·g-1,未检测出Tl、Sn、Cu等微量元素以及Pb、Cd、Cr等重金属元素。10种元素的RSD值在1.76%~10.77%之间。研究结果为勿忘我的进一步开发利用提供了一定的理论依据。     

ICP-AES测定5种澳洲进口保健品中的元素

采用微波消解法对5种样品进行消解处理,应用ICP-AES法测定保健药品中Na、Ni、Mg、Sn、Zn、Mo、Si、Se、Sr、Ge、Ca、Au、Al、Hg、Pb、Ag、Fe等17种微量和中量元素的含量。方法回收率在91.3%~102.9%之间,相对标准偏差小于4.89%。此实验方法测定速度快、容易操作、灵敏度极好、准确性高,还能够实现同时测定多种元素。结果表明,所测药品中均含有丰富的人体所需的微量和中量元素,但个别保健品中含有的不益于人体健康的元素的含量也较高。     

微波消解-ICP—AES法测定华山松针叶的矿质元素

利用微波消解对华山松针叶进行前处理,采用电感耦合等离子体发射光谱（ICP-AES）法测定铮叶中的Al、As、Ca、Cr、Cu、Fe、K、Mg、Mn、Na、P、Pb、Si和Zn14种矿质元素的含量,结果表明,华山松针叶中元素含量丰富,K、Ca、Mg、P元素的含量较高,该测定方法快速、准确、分析精度高;为华山松针叶的合理利用提供科学依据。     

ICP-AES测定5种澳洲进口保健品中的元素

采用微波消解法对5种样品进行消解处理,应用ICP-AES法测定保健药品中Na、Ni、Mg、Sn、Zn、Mo、Si、Se、Sr、Ge、Ca、Au、Al、Hg、Pb、Ag、Fe等17种微量和中量元素的含量。方法回收率在91.3%¹02.9%之间,相对标准偏差小于4.89%。此实验方法测定速度快、容易操作、灵敏度极好、准确性高,还能够实现同时测定多种元素。结果表明,所测药品中均含有丰富的人体所需的微量和中量元素,但个别保健品中含有的不益于人体健康的元素的含量也较高。     

微波消解-ICP-OES法测定岷县当归中的矿质元素

采用浓HNO3/H2O2混合酸体系,以微波消解法对岷县当归样品进行前处理,利用全谱直读电感耦合等离子体发射光谱法(ICP-OES法),对样品中矿质元素的组成及含量进行了测定和分析。结果表明,从岷县当归中检测出15种矿质元素,分别为K、Na、Al、B、Ba、Ca、Fe、Mg、Mn、P、S、Si、Sr、Zn、Cr,其中常量元素有K、Ca、Mg、P、S,微量元素有Al、B、Ba、Fe、Mn、Si、Sr、Zn等,未检测出Tl、Ti、Sn、Cu等元素,以及Pb、Cd等重金属元素,15种元素的RSD值在1.01%¹9.01%。研究结果可为岷县当归食用药用价值的进一步开发利用提供一定的理论和科学依据。     

ICP-AES法同时测定中草药叶上花中的微量元素

采用HNO3-HF-HClO4系统湿法消解后,用ICP-AES法对中草药叶上花中16种微量元素进行了测定,含量从大到小的顺序为：Ca〉K〉Mg〉P〉Si〉Fe〉Na〉Al〉Mn〉Zn〉B〉Cr〉Pb〉Se〉Cu（其中Co未检测出）。该中草药接骨活性很可能与其中Ca、P、Fe、Mn、Zn、Se、Cu等元素有关。测定所用方法16种元素的线性相关系数在0.999 089～1.000 000之间,具有较高的准确度,并可多元素同时测定。     

同产地的黑米与白精米中微量元素含量的测定

采用电感耦合等离子体质谱(ICP-MS)法分别测定了4组同产地的黑米与白精米中Na、Mg、K、Ca、Al、V、Mn、Fe、Co、Cu、Zn、Se和Mo 13种微量元素的含量,方法的回收率为87%~108%。实验证明,同产地的黑米中Na、Mg、K、Ca、Al、V、Mn和Fe元素含量多于白精米,从有益微量元素含量角度来说黑米的营养价值更高。     

焦化轻蜡油掺炼加氢柴油试验研究

通过实沸点蒸馏仪对加氢柴油进行精密分离,得到不同馏程温度段的窄馏分油,分析了不同窄馏分油的收率分布与烃类组成分布,分析结果表明：随着馏程温度升高,窄馏分油收率逐渐降低,加氢柴油中的链烷烃主要富集在馏程温度点高的窄馏分中,环烷烃与芳烃主要富集在馏程温度低的窄馏分中。焦化轻蜡油回炼加氢柴油窄馏分油后,加氢裂化产物65~175 ℃馏分收率增加,>175 ℃馏分收率均降低。由于窄馏分油中的烃类组成不同,所得加氢裂化产物性质有所差异。掺炼富含环烷烃与芳烃的窄馏分油所得65~175 ℃馏分芳潜值最高,掺炼链烷烃窄馏分油所得>175 ℃馏分的十六烷值指数最高。     

提高蒸馏温度改善洗油品质的实验研究

通过实验研究了一次蒸馏与二次蒸馏温度对洗油质量的影响,并对洗油馏程及其馏出物进行分析,结果发现提高一次蒸馏温度与二次蒸馏温度可以明显地改善洗油质量,当一次蒸馏温度为308℃、二次蒸馏温度为315℃时,所得洗油样品230℃前馏出量为0,270℃前馏出物质量分数大于96.0%,甲基萘的质量分数达到51.09%,萘质量分数小于3.0%,酚类化合物和水分含量为0。     

硅铝调控与晶种诱导对水热稳定飞灰中重金属的协同影响

研究了选取的粉煤灰、膨润土、高岭土、硅藻土作为外源硅铝调理剂添加与雪硅钙石人工晶种诱导对150℃水热法稳定垃圾焚烧飞灰中重金属Pb、Zn、Cu、Cd、Cr的协同影响。飞灰由于富钙而低硅铝的元素特征,导致其在水热条件下无法直接合成沸石类,Pb的浸出浓度仍然超标;当单一或混合添加硅铝调理剂添加量为10%时,其水热产物中有水钙铝榴石或加藤石生成;提高添加量至30%时,均有目标雪硅钙石的生成,这与30%添加量下飞灰中Ca/（Al+Si）元素比接近雪硅钙石的理想元素比值0.67~1.20直接相关。混合添加30%的粉煤灰与硅藻土为最佳选择,水热产物Pb的浸出浓度降低至0.30 mg·L^-1,且在此基础上再添加3%的诱导晶种可加速从第6 h开始即合成雪硅钙石,并使Pb的浸出浓度下降到最低值0.28 mg·L^-1。硅铝调控（30%的复合硅铝调理剂,其中粉煤灰：硅藻土为1：1）与晶种诱导的协同影响下高效生成雪硅钙石,并显著抑制Pb、Zn等在水热过程中向液相的转移、降低其在水热液相中的浓度,使飞灰中的重金属在水热后确实稳定于水热固相产物中而非迁移至水热液相造成污染转移,真正实现了飞灰中重金属的固定化。     

Determination of Heavy Metal Distribution in PM10 During Asian Dust and Local Pollution Events Using Laser Induced Breakdown Spectroscopy (LIBS)

Hourly concentrations of heavy metals in PM₁₀ samples were continuously measured using Laser Induced Breakdown Spectroscopy (LIBS) to determine the metal distribution among Asian Dust (AD) events, local pollution events, and nonevents. Quantification of metals was performed by establishing a calibration line between 24 h average data determined by the ICP-MS after filter sampling and LIBS intensity data. It was found that in AD and local pollution events, significant anthropogenic heavy metals, such as Pb, Cr, Ni, and Zn, were detected compared to a nonevent, and that crustal elements (e.g., Al, Ca, Mg) were more abundant in the AD events than those in a local pollution event or nonevent. The AD events were further classified into “nonpolluted AD” and “polluted AD” events, depending on the air mass transport pathways. During “polluted AD” events where the air mass passed over industrialized zones, both crustal (Al, Ca, Mg) and anthropogenic (Cr, Ni, Zn) metal elements simultaneously increased with time, suggesting that the AD particles could not only include crustal elements but also have a significant quantity of anthropogenic heavy metals. The concentration of anthropogenic heavy metals (Cr + Pb + Zn) was the highest in the AD3 event in order of AD3 (polluted) > AD1 (polluted) > local pollution > AD2 (nonpolluted). However, the PM₁₀-weighted value (Cr + Pb + Zn/PM₁₀) was the highest in the local pollution event where concentrations of only anthropogenic heavy metals increased. Also, the hourly LIBS data was successfully used to discriminate metal contributions between AD events and local pollution events or among AD events by employing a chemometric method.

Copyright 2012 American Association for Aerosol Research     

固体吸附剂对油页岩半焦燃烧过程中重金属元素的影响

通过对桦甸油页岩半焦进行燃烧实验,研究了不同终温下部分重金属元素的挥发特性及吸附剂的吸附效果,研究表明：随着温度的增加,各元素的挥发率均呈现出增大的趋势,且当温度为650℃时,元素Cd、Te、Co、Sn、Pb、Sb的挥发率呈现出明显的增大趋势;相对而言,各温度段下元素Cd、Te的挥发率较大,元素Mn、Y、W的挥发率较低。添加吸附剂CaO和高岭土后,大部分元素在页岩灰中的含量均明显增加,表明吸附剂对大部分重金属元素具有良好的吸附效果;通过吸附率可以看出,吸附剂CaO除元素W、Te未发现吸附效果外,对其他所研究的重金属元素均有较强的吸附效果,尤其是元素Co、Mn、Cu、Y、Sn、Cd;而高岭土除对元素Pb、Te未发现吸附效果外,对其他元素均具有一定的吸附效果,尤其是元素Co、Mn。相比而言,CaO对重金属元素的吸附效果要比高岭土强。     

Catalytic graphitization of carbons by various metals

A study was made of the catalytic graphitization of carbons by 22 kinds of metals. Heat treatments were carried out at 2600°C for 1 hr and 3000°C for 10 min under argon atmosphere. In graphitizing 3,5-dimethylphenol-formaldehyde resin carbon powder with which 20w/o metal powder (Al, Cr, Mn, Fe, Co, Ni, Ca, Ti, V, Mo and W) was mixed, graphitic carbon was catalytically formed. The first six metals, which belong to the carbon dissolution-precipitation mechanism, gave large graphitic crystal flakes at an early stage of the reaction; the other metals resulted in fine crystals through the carbide formation-decomposition mechanism. For the non-graphitizing phenol formaldehyde resin carbon in which 10w/o metal powder was dispersed, Mg, Si, Ca, Cu and Ge catalyzed formation of only graphitic carbon; and Al, Ti, V, Cr, Mn, Fe, Co, Ni, Mo and W formed both graphitic and turbostratic carbons. Except for Al and Cu, the former effect was exerted by non-transition metals and the latter effect by transition metals. Boron alone markedly accelerated homogeneous graphitization of both kinds of carbon; and Zn, Sn, Sb, Pb and Bi had no catalytic effect. On the basis of these results, the relationships between some properties of the metals, their catalytic abilities and the kind of catalytic effects are discussed.     

The fate of trace elements and bulk minerals in pulverized coal combustion in a power station

The behaviour of 15 trace elements (As, Ba, Cr, Cu, Mn, Mo, Nb, Ni, Pb, Rb, Sr, V, Y, Zn and Zr) and 10 major and minor elements (Al, Ca, Fe, K, Mg, Na, P, S, Si and Ti) in coal during combustion in a power station has been studied. Synchronized sampling of pulverized coal, bottom ash and fly ash was undertaken over a limited time period. Fly ash morphology was studied by SEM and the mineral composition was studied by EDX and XRD. Major, minor and trace elements were determined by XRF and AAS. Differences between the composition of the ashes of pulverized coal, bottom ashes and fly ashes have been observed. As, Cu, Mo, Pb and Zn were concentrated in the fly ash. The relationship between the composition of the fly ashes and their particle size was studied. Enrichment factors were calculated for each element in different size fractions. As the particle sizes of fly ash decrease, the concentrations of As, Cu, Mo, Pb and Zn increase. From the different composition of bottom ashes and fly ashes (and relying on the results of the characterization of the feed coal carried out in previous work), it can be assumed that pyrite and carbonates make a greater contribution to the furnace bottom ashes. Quartz carries through into the fly ash. This mineral is almost absent in the finest fractions, reflecting the absence of small quartz particles in the feed coal.     

Catalytic influence of metal melts on the graphitization of monolithic glasslike carbon

A study was made of the graphitization of monolithic glasslike carbon as catalyzed by molten metals. The heat treatment temperatures were 100 to 200°C higher than the melting points of the metals used and the hold time was 5 min in all cases. The results are compared with those of previous investigations on compacts prepared from metal and carbon powders. It is concluded that elements such as Ni, Co, Fe, Pt, Mo, Cr, and B are highly effective in catalyzing the graphitization. In the case of Mo, Cr, and B, the reaction may take place via an intermediate formation of the carbide. The mechanism of isothermal solution and spontaneous reprecipitation as proposed by Fitzer and Kegel applies to these metal catalysts. Metals such as Ag, Mg, Zn, Cd, Ge, Sn, Pb, Sb, Bi, Se, Te, and Pd show no such reaction. The previous literature revealed that Cu and Al were effective in contact with powderized carbon. But in the present work the insolubility of carbon in these metals and their failure to wet carbon, prevent penetration and subsequent graphitization of monolithic glasslike carbon. Interaction of Si, Zr, and Nb with carbon leads to high melting carbides or solid solutions which are solids at the temperature of the experiment. The resulting thin intermediate layers prevent penetration of the metal melt into monolithic glasslike carbon.