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本文研究了大豆油中砷的氢化物-原子吸收法测定方法。样品中砷用HNO3和H2SO4湿法硝化提取,采用氢化物发生器和原子吸收分光光度计进行测定。本实验采用添加法测定回收率,添加水平为0.01-0.2mg·ks-1时,其平均回收率为94.85%-101.24%。本方法的最低检出限为测定0.01mg·kg-1。 相似文献
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采用微波消解样品,流动注射-氢化物发生原子吸收光谱法测定原油中的砷。在酸性介质中,用硼氢化钠作还原剂,通过载气导入仪器,在波长193.7 nm处进行测定。线性方程为y=3.011x-0.0002,R=0.9992。 相似文献
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提出了微波消解原子吸收法测定煤中砷的分析方法。采用在密闭容器中,用浓王水和少量氢氟酸做溶剂来消解煤,样品溶解完毕泄压后定容,用内置氢化物和耐氢氟酸装置的原子吸收仪测定砷的含量。同时考察了微波消解称样量、浓王水和少量氢氟酸用量及压力对消解效果的影响,测量结果的检出限、回收率、相对标准偏差(n=6)和样品的测定结果与国家标准方法测定的结果相一致。本法适应于煤中砷的测定。 相似文献
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基于对贵州兴仁某村煤中砷的含量及赋存状态的研究,得出研究区砷含量分布范围在17.83mg/kg~140.64mg/kg,平均值为93.31mg/kg,远高于中国(4.09mg/kg)和世界(5mg/kg)煤砷含量.其赋存状态复杂多样,煤砷各形态含量比例分布为:残渣态(56.74%)铁锰氧化物结合态(20.74%)硫化物结合态(15.20%)有机结合态(5.07%)碳酸盐结合态(1.73%)水溶态和可交换态(0.52%).煤中砷主要以残渣态形式存在,铁锰氧化物结合态砷含量也较高.其中一个煤样砷含量相对于其他样品较小,有机砷结合态所占比例相对较大,结合前人研究推断:此次研究的煤样多以大分子有机砷结合态存在,但不易提取,导致残渣态砷含量较高. 相似文献
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对煤制烯烃的工业技术进行了分析,从砷平衡的角度分析了砷在煤制烯烃工业中的危害。综述了目前在化学工业中可以采用的有效脱砷技术和方法,包括控制气化原料煤中的砷含量、采用湿法技术脱除合成气中的砷、采用脱砷催化剂脱砷。重点介绍了铜系、铅系、锰系和镍系等4类脱砷催化剂的研究进展。对煤制烯烃脱砷方案提出了建议。 相似文献
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选取3个国内煤样,利用自制恒温热重装置研究了燃烧过程中砷的赋存特性及其挥发规律。通过测定不同停留时间下燃烧样品中砷的含量,拟合得到砷的挥发曲线和挥发速率曲线,并采用逐级化学提取的方法对原煤和不同停留时间下的燃烧样品进行形态分析。实验结果表明:温度是影响砷挥发的重要因素,700~1000℃是砷挥发的主要温度区间。煤粉燃烧过程中,砷的挥发速率与煤粉的失重速率具有同步性;伴随着煤中水分和挥发分的快速析出,砷也具有较高的挥发速率;随着燃烧过程的深入进行,砷的挥发速率变得缓慢。煤粉燃烧结束,3种煤(五里庄、红岩和梅花井)砷的挥发比例分别为49.5%、80.7%、65.0%,且在燃烧过程中煤中残渣态、硫化物结合态和可交换态砷相互作用迁移。 相似文献
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Cheng-Fang Lin Chung-Hsin Wu Hsien-Tin Lai 《Separation and Purification Technology》2008,60(3):292-298
Long time uptake arsenic will cause cancers and blackfoot disease. There are still several million people suffering from drinking arsenic contaminated water. This work studied the performance of coupled chitosan/UF for arsenic removal and the influence of dissolved organic matter on arsenic removal with UF operation. Humic acid representing dissolved organic matter was fractionated into five groups of molecular sizes by gel filtration chromatography. Arsenic rejection by UF under the experimental condition is only 10%. In the presence of humic compounds, the arsenic removal of 22% is obtained. DOM with apparent molecular weight > 35,000 Da is the principle component responsible for chelating arsenic and thereafter being rejected by UF membrane. The combined interactions of humic compounds, chitosan, and arsenic enable a 65% arsenic rejection by UF. The results presented here enable our understanding of the complicated mechanisms involved in chitosan/UF/DOM/arsenic system. 相似文献
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Groundwater in the area of eastern Croatia contains high concentrations of iron, manganese, ammonia, organic substances and arsenic. The appearance of inorganic arsenic in groundwater is mainly caused by arsenic from natural geological sources. Since the groundwater is the main source of drinking water for the population in this area, almost 200,000 people are daily drinking water with arsenic concentration ranging from 10 to 610 μg/L. The Croatian legislation recently revised the maximum concentration limit (MCL) for arsenic in drinking water to 10 μg/L. The population in the two towns (Osijek and Vinkovci) of this region is supplied with groundwater processed by coagulation-filtration method, but in the other towns and villages water treatment implies only rapid sand filtration. Both methods for water treatment have resulted with higher arsenic concentration than MCL, so the main goal of this study was determination of population exposure to arsenic via drinking water and possible improvement of drinking water quality. Population exposure to arsenic via drinking water is determined with hair analysis, since the hair arsenic concentration is one of three most commonly employed biomarkers used to identify or quantify overall arsenic exposure. During this study the preliminary analyses of hair arsenic concentrations in several towns and villages in eastern Croatia were provided. The positive correlation between heightened arsenic concentration in drinking water and hair arsenic concentration was determined. In order to improve drinking water quality e.g. arsenic removal from contaminated drinking water, different modified adsorbents were used and compared (zeolite–clinoptilolite, manganese greensand and cationic exchange resin). Adsorbents were chemically modified and saturated with Fe(III) ions, while the arsenic solutions were prepared by processed groundwater. 相似文献