电位滴定法测定铁矿石中全铁的微波溶样法

详细地探讨、优化了在密闭容器内微波消解制备铁矿石样品溶液的条件,对来自各国的大部分矿石进行消解试验。结果表明,在0.20 g样品量、15 mL盐酸、2 mL氯化亚锡、100psi(1 psi=6.894 76 kPa)的消解压力、25 min消解时间、10 min压力保持时间的条件下,大多数矿种均能完全溶解,只有少数难溶铁矿,例如秘鲁铁精矿,需将溶样酸改成10 mL硫酸-磷酸(2+8),消解压力变成10 psi,其他条件不变的情况下才能完全溶解。分析结果与常规方法相比具有一致性。     

微波消解技术应用于难分解贵金属化合物的分析

提出了微波密闭快速消解难分解的KAu(CN)2,KAu(CN)4,Pt(NH3)2(NO2)2,K2[Pt(NO2)4],Pt(NH3)2Cl2,Pt(NH3)4Cl2,(NH4)2PtCl6,K2PtCl4,Pt(C5H7O2)2等化合物的方法。比较了微波密闭消解法与传统分解法的条件;采用精密电化学滴定法分析了Au和Pt的含量,并与传统分析方法BS5658法(H2SO4发烟重量法)、火试金法和湿法重量法进行了结果对照。结果表明:以HCl-H2O2,HCl-HNO3分别为Au和Pt类化合物的消解试剂,于优     

城市生活垃圾厌氧消化处理技术的应用研究进展

总结了国内外可生物降解有机城市生活垃圾(BOFMSW)厌氧消化处理技术的应用和发展概况。详细分析了垃圾成分、碳氮比、接种物、温度、pH 值、总固体含率、有机负荷率以及搅拌对BOFMSW厌氧消化的影响。介绍了国内外厌氧消化法处理可降解有机垃圾的几种工艺,比较各种工艺类型的特点,并辅以实例分析。最后指出我国利用厌氧消化技术处理BOFMSW,以及城市生活垃圾综合利用两个层面存在的问题,并给出了我国城市生活垃圾的厌氧消化技术研究和应用的发展方向。     

微波消解-原子吸收法测定酥油粉中微量元素

本研究以消化温度、消化时间和消化压力为三个考察因素设计正交试验,对实验室自制微胶囊酥油粉进行微波消化。用火焰原子吸收光谱法对样品中的Ca、Mg、Fe、Cu、Zn五种元素进行测定。结果表明,最佳消化条件为:消化温度200℃,消化时间5min,消化压力15atm。在最佳实验条件下,对酥油粉各元素的含量做了回收实验,回收率范围在94.1%～105.1%,相对标准偏差0.41%～3.78%(n=6)。     

煤中氮的测定及相关问题

以开氏法测定氮的方法为例,着重介绍了煤中氮测定的实际意义及测定原理。介绍了实际工作中的相关注意事项,立志于煤中氮的更准确的测定。     

Biohydrogen production by dark fermentation: Experiences of continuous operation in large lab scale

Hydrogen is a clean energy carrier which can be used as fuel in fuel cells. Today, hydrogen is produced mainly by steam reforming of fossil fuels like natural gas or oil. But only hydrogen produced by renewable sources can be called clean energy production. One possibility for hydrogen production is the biological fermentation of biogenous wastes by hydrogen producing bacteria. For the experimental setup four 30-L-working-volume reactors were constructed for continuous biohydrogen production. As inoculum, heat-treated sludge of a wastewater treatment plant was used. Different hydraulic retention times (HRT) were tested and an organic loading rate (OLR) of 2–14 kg VS/m³*d. As starting substrate, waste sugar medium was used. The pH and other parameters were observed to find boundary conditions for a stable continuous process with a minimum of online-control measurements. The high concentration of organic acids in the reactor led to a very low pH, which was controlled manually and online > 4 up to 5.5, otherwise the biohydrogen production decreased rapidly. The gas amount varied with the different OLRs, but could be stabilised on a high level as well as the hydrogen concentration in the gas with 44–52%. No methane was detected in the gas. It turned out, that continuous biohydrogen production with stable gas amounts and qualities could be achieved at different operation conditions. The results showed, that the operation of a continuous biohydrogen reactor has to be observed very carefully to ensure a constant gas production, and that pH-control is necessary to ensure stable operation conditions.     

Use of waste for heat,electricity and transport—Challenges when performing energy system analysis

This paper presents a comparative energy system analysis of different technologies utilising organic waste for heat and power production as well as fuel for transport. Technologies included in the analysis are second-generation biofuel production, gasification, fermentation (biogas production) and improved incineration. It is argued that energy technologies should be assessed together with the energy systems of which they form part and influence. The energy system analysis is performed by use of the EnergyPLAN model, which simulates the Danish energy system hour by hour. The analysis shows that most fossil fuel is saved by gasifying the organic waste and using the syngas for combined heat and power production. On the other hand, least greenhouse gases are emitted if biogas is produced from organic waste and used for combined heat and power production; assuming that the use of organic waste for biogas production facilitates the use of manure for biogas production. The technology which provides the cheapest CO₂ reduction is gasification of waste with the subsequent conversion of gas into transport fuel.     

Fermentative biohydrogen production by mixed anaerobic consortia: Impact of glucose to xylose ratio

Glucose and xylose are the dominant monomeric carbohydrates present in agricultural materials which can be used as potential building blocks for various biotechnological products including biofuels production. Hence, the imperative role of glucose to xylose ratio on fermentative biohydrogen production by mixed anaerobic consortia was investigated. Microbial catabolic H₂ and VFA production studies revealed that xylose is a preferred carbon source compared to glucose when used individually. A maximum of 1550 and 1650 ml of cumulative H₂ production was observed with supplementation of glucose and xylose at a concentration of 5.5 and 5.0 g L⁻¹, respectively. A triphasic pattern of H₂ production was observed only with studied xylose concentration range. pH impact data revealed effective H₂ production at pH 6.0 and 6.5 with xylose and glucose as carbon sources, respectively. Co-substrate related biohydrogen fermentation studies indicated that glucose to xylose ratio influence H₂ and as well as VFA production. An optimum cumulative H₂ production of 1900 ml for 5 g L⁻¹ substrate was noticed with fermentation medium supplemented with glucose to xylose ratio of 2:3 at pH 6. Overall, biohydrogen producing microbial consortia developed from buffalo dung could be more effective for H₂ production from lignocellulosic hydrolysates however; maintenance of glucose to xylose ratio, inoculum concentration and medium pH would be essential requirements.     

不同年生西洋参中铅、镉含量分析

采用微波消解- 石墨炉原子吸收法对不同年生、不同地块西洋参中的毒害元素铅(Pb)、镉(Cd)进行检测分析。结果表明,同一地块西洋参随着生长年份的增加,Cd、Pb 元素的含量有所提高,呈现随年份增加在根内积累的规律;不同地块,相同生长年份西洋参Cd、Pb 元素含量存在差异。方法检出限分别为Pb 3.545ng/ml,Cd0.225ng/ml;测定精密度的RSD 分别为Pb 1.5%,Cd 1.0%;回收率分别为Pb 113.57%,Cd 94.28%。     

汽车催化剂试样消解方法的研究进展

试样的消解方法是样品分析预处理的研究热点之一。针对汽车催化剂中铂族金属（主要是铂、钯、铑）的预处理和检测问题,归纳总结了催化剂试样的消解方法（主要是酸溶法、碱熔融法、火试金法）,阐述其利弊,为分析和测试铂族金属选择适宜的试样预处理方法,并对其今后的发展进行了展望。