DMA-80自动测汞仪快速测定生物质燃料中汞含量

建立DMA-80直接测汞仪测定生物质燃料中汞含量的方法,考察了分解温度和分解时间对测定汞含量的影响,还研究了该方法的准确度和精密度。结果表明,分解温度为550℃和分解时间为80 s时,样品完全分解,检测结果稳定。汞含量在2~20 ng范围内,峰高和汞含量线性关系良好,用标准加入法进行回收率实验对方法的准确度进行考察,相对标准偏差为0.74%~1.51%,加标回收率为100.62%~101.43%。与其他检测方法比较,该方法无需前处理、操作简单、检测时间短、系统误差小,不仅减少样品处理过程中的误差,同时还减少化学试剂对环境的影响,是值得推广的一种方法。     

直接测汞仪测定化妆品中汞含量

目前化妆品中汞含量的测定主要以原子荧光光度法为主,较少采用直接测汞仪法对其进行测定分析。本文通过直接测汞仪法测定化妆品中的汞含量,得出该方法回收率为95. 40%～99. 50%,RSD为1. 08%～1. 41%,对化妆品中汞标准物质进行测定,测定结果与标准值无显著差异。通过与原子荧光光度法测定化妆品中汞含量比较,并对该法准确度和精密度进行探讨,结果表明,该法具有方便、快速、准确等特点,适用于化妆品中汞含量测定。     

中药中汞含量的测定

采用直接测汞仪,建立了简便、快捷、准确的中药中汞含量测定方法,方法检出限为1.2μg/kg,在高(30~1000 ng)低(0~25 ng)范围内线性良好,线性相关系数为0.9999,方法准确性高,加标回收率为95%~108%。对实际样品(黄连,菊花、桑叶、决明子、丹参等)进行检测,汞含量在0.8137~56.8719 ppb。     

直接测汞仪测定粗甘油中微量汞

利用热解析冷原子吸收光谱汞直接测量法对粗甘油中微量汞含量进行检测,结果表明:检出限0.004 7μg/kg;相对标准偏差1.7%;加标回收率为99.9%~103.5%,该方法具有良好的精密度与准确度,适用于粗甘油中微量汞的测定。     

直接测汞仪法测定橡胶中的汞含量

采用直接测汞仪法检测橡胶及其制品中的汞含量,并与原子荧光光谱法对比。结果表明:在最优试样分解条件(称样量为0. 05 g,分解温度为750℃,分解时间为4 min)下,直接测汞仪法检测汞含量的线性相关性好、检出限低、相对标准偏差小、精密度高;试样无需前处理,可避免汞挥发损失;操作简单、检测速度快,与原子荧光光谱法检测结果无明显差异。     

直接测汞仪测定粉状化妆品中的总汞

采用直接测汞仪对粉状化妆品总汞含量的快速分析方法。通过实验对干燥温度、干燥时间、分解温度、分解时间等条件进行优化,并进行了线性关系、回收率、精密度、方法比对等实验。结果表明,本方法线性范围(0~400)ng,相关系数r2≥0.9990,检出限0.01 ng,相对标准偏差小于3%,回收率在98.4%~104.4%之间。本方法灵敏度高,简便、快速、准确,适用于粉状化妆品总汞的测定。     

直接测汞仪测定涂料中的可溶性汞

文章采用直接测汞仪对涂料样品进行了可溶性汞含量的分析测定.通过正交试验法对干燥温度、干燥时间、分解温度、分解时间等条件进行了优化,并进行了线性关系、精密度、回收率等实验.结果表明,本方法线性范围0～500 ng,相关系数大于0.9994,检测低限为 0.015ng,回收率在97.1%～101.0%之间,相对标准偏差小于...     

固液相自动测汞法快速测定土壤中总汞含量

建立了固液相自动测汞仪对土壤样品中总汞含量的测定方法。无需将土壤样品进行消解,直接采用将热处理装置和原子吸收光谱集于一身的DMA80固液相自动测定仪测试。总汞在0~200 ng范围内,线性相关系数为0.999 9,在土壤样品中进行4个水平(0.5、1、10、20μg/kg)的加标回收实验,回收率在95.8%~100.7%,相对标准偏差RSD值为3.2%~18.5%,方法的检出限为0.05μg/kg。使用固液相自动测汞法与原子荧光法测试结果进行比对,结果表明固液相自动测汞法测定土壤样品汞含量,结果准确、简便、快速、安全,可用于土壤中总汞含量的快速检测。     

测定固体生物质燃料中碳氢含量的方法应用研究

结合我国固体生物质燃料中碳氢测定的检验标准和仪器使用现状,利用固体生物质燃料与煤炭的特性有较多相似之处,研究制定了运用电量-重量法测定固体生物质燃料中碳氢含量的标准方法。研究了固体生物质燃料中碳、氢的组成及其特点,按照GB/T 28734—2012《固体生物质燃料碳氢测定方法》的要求,结合GB/T 476—2008《煤中碳和氢的测定方法》,对8种固体生物质燃料中碳和氢的测定进行了正交试验,考察了氧气流量、进样时间方案、试样质量、催化剂等因素对测定结果的影响,得到电量-重量法的最佳测定条件为:试样质量0.065~0.070 g、覆盖足量的三氧化钨催化剂、氧气流量80 m L/min、进样时间方案2-4 min。试验结果为进一步制定固体生物质燃料中碳氢含量测定的标准方法奠定了基础。     

DMA-80汞分析仪测定粗制氧化锌中的汞

建立了DMA-80型汞分析仪直接固体进样测定粗制氧化锌中汞的方法。试样经干燥和高温分解处理,采用催化分解和吸附净化使分解产物转变为氧化汞蒸气,通过金质汞齐化器还原并以金汞齐形式被捕集,最后在波长253.65 nm处进行原子吸收测量,依据朗伯-比尔定律定量。优化了干燥时间和温度、分解时间和温度等实验条件,同时做了方法检出限、精密度、回收率等实验。结果表明：方法检出限为0.015 ng,线性范围为0.02~100 ng,相关性系数≥0.999,回收率为93.2%~102.7%,精密度（RSD,n=7）≤5.0%,可用于进口粗制氧化锌的快速检验。     

Chemical forms of ash-forming elements in woody biomass fuels

Advanced fuel characterization helps to predict ash fouling and slagging. Chemical fractionation analysis, i.e. sequential leaching in H₂O, NH₄Ac(aq), and HCl(aq), was applied to the biomass of spruce, pine, birch, and aspen. All of the Cl in the samples and most of the K, Na, and P were water-soluble; most of the Mg and Mn, and some of the Ca were leached in NH₄Ac; most of the Ca was leached in HCl; and most of the Si and S remained insoluble in the biomass. Ion Chromatography found the water-soluble Cl, P, and S present as Cl⁻, , and , respectively, and equimolar concentrations of as leached Ca in the acid fraction. The biomass solids were determined for anionic groups by methylene blue sorption. The contents were lowest in the wood samples (22-118 mmol/kg_D.S.) and highest in the bark samples (130-453 mmol/kg_D.S.). The closing of the ion charge balance led to a quantitative model for the ash-forming matter: water-soluble salts (KCl, K₂HPO₄, and K₂SO₄), acid-soluble minerals (CaC₂O₄), non-soluble minerals (SiO₂), and organically associated ash-forming elements (ionically bonded Ca²⁺, Mg²⁺, Mn²⁺, and K⁺, and covalently bonded P and S).     

全自动原子荧光法测定煤中汞含量的影响因素研究

试验研究了全自动原子荧光法测定煤中Hg含量的影响因素;煤样量的多少对测定结果没有影响,受Hg污染的王水以及受到污染的煤样对测定结果有影响;建议在干净清洁的环境中进行实验,以防止含Hg物质的污染,从而提高测定结果的准确度。     

Bioprocessing aspects of fuels and chemicals from biomass

This review deals with a recent development of biofuels and chemicals from biomass. Some of the grainbased biofuels and chemicals have already been in commercial operation, including fuel ethanol, biodiesel, 1.3-propanediol, polylactic acid (PLA) and polyhydroxy butyric acid/alkanoates (PHB/PHA). The next generation bioproducts will be based on lignocellulosics due to their abundance and to stabilize rising food prices. However, the technologies of handling biomass are yet in their infancy and suffer from low yield, low product titer, and low productivity. This review focuses on bioprocessing technologies for biofuels production: organic raw biomaterials available in Korea; volatile fatty acids platform, multi-stage continuous high cell density culture (MSC-HCDC), enrichment of fermentation broth by forward osmosis; various purification methods of pervaporation of ethanol, solvent extraction on succinic, lactic acids and reactive separation methods.     

Combustion properties of some power station biomass fuels

In this study, the combustion properties of three of the UK’s commonly imported biomass fuels for co-firing, which are palm kernel expellers, shea residue, and waste from olive oil production are examined. The fuels were characterised and their thermal decomposition properties were studied by thermogravimetric analysis (TGA). Additionally the products from their devolatilisation were identified by gas chromatography-mass spectrometry (py-GC-MS) analysis of the evolved vapours and tars from high heating rate pyrolysis tests. Finally, chars from the fuels were prepared, analysed, and combustion studies were conducted by TGA-MS to determine the conversion of char-nitrogen to different nitrogen-containing species. In general, the main constituents of their ash fractions were K, Si, Ca and Mg, resulting in high alkali indices, which predict a large tendency to fouling. The pyrolysis and combustion kinetic parameters, estimated from TGA studies of these fuels and their chars, are much lower than those reported in the literature for lignocellulosic biomass. It is suspected that there is oil/fat evaporation processes overlapping with the decomposition of their lignocellulosic fractions, which significantly affects the apparent kinetics. The pyrolysis conditions used promoted depletion of nitrogen in the char, resulting in approximately 79-91% of the fuel-N being released with the volatiles. In combustion of the char, NO_x and N₂ are the major nitrogen compounds detected. Another primary product, HCN, was detected from the combustion of some of the fuel chars, as well as C₂N₂.     

直接燃烧法快速测定煤及煤灰中总汞含量的方法研究

探讨直接燃烧法快速测定煤及煤灰中总汞含量方法的主要性能指标,方法的精密度和正确度。结果表明,采用直接燃烧法快速测定煤及煤灰中总汞含量的方法可获得较好的准确度,其方法精密度与ASTM D6722—11中规定的精密度无显著性差异,可直接采用ASTM D6722—11中规定的精密度作为本方法的精密度。方法最佳称样量为(80±10) mg,煤灰样品最佳粒度为0.1 mm,方法检出限为0.016μg/g。     

Biodegradability of biomass pyrolysis oils: Comparison to conventional petroleum fuels and alternatives fuels in current use

Concern with environmental issues such as global climate change has stimulated research into the development of more environmentally friendly technologies and energy sources. One critical area of our economy is liquid fuels. Fast pyrolysis of lignocellulosic biomass for liquids production is of particular concern, as it is one of the most interesting ways to produce renewable liquid fuel for transport and heat and power production.The aerobic biodegradability of various pyrolysis oils from different origins and of a EN 590 diesel sample was examined using the Modified Sturm (OECD 301B). The results demonstrate that all fast pyrolysis oils assessed are biodegradable with similar shaped curves with 41–50% biodegradation after 28 days, whereas the diesel sample reached only 24% biodegradation. Since pyrolysis oils achieved biodegradability over 20% these are classified as inherently biodegradable. Modelling of biodegradation processes was successfully performed with a first-order chemical reaction.The biodegradability results obtained for biomass pyrolysis oils are compared to those of conventional and alternative fuels.     

Multiple determination of volatile matter in solid fuels

The design of a furnace, crucible stand, and ancillary equipment is described to enable eight simultaneous determinations to be made of volatile matter in coal or coke. Equipment operation to achieve the recovery time and uniform heat zone specifications in standard methods is discussed. Rapid processing of large sample batches is possible, with accuracy and precision statistics acceptable to international standards. Design changes to existing equipment are described to accommodate eight samples.     

Open focused microwave-assisted sample preparation for rapid total and mercury species determination in environmental solid samples

This paper describes rapid, simple microwave-assisted leaching/ digestion procedures for total and mercury species determination in sediment samples and biomaterials. An open focused microwave system allowed the sample preparation time to be dramatically reduced to only 24 min when a power of 40-80 W was applied. Quantitative leaching of methylmercury from sediments by HNO₃ solution and complete dissolution of biomaterials by an alkaline solution, such as 25% TMAH solution, were obtained. Methylmercury compounds were kept intact without decomposition or losses by evaporation. Quantitative recoveries of total mercury were achieved with a two-step microwave attack using a combination of HNO₃ and H₂0₂ solutions as extractant. The whole pretreatment procedure only takes 15 min, which can be further shortened by an automated robust operation with an open focused system. These analytical procedures were validated by the analysis of environmental certified reference materials. The results confirm that the open focused microwave technique is a promising tool for solid sample preparation in analytical and environmental chemistry.