高效液相色谱-原子荧光光谱联用测定水中形态砷

采用高效液相色谱-氢化物发生-原子荧光光谱联用技术测定水中亚砷酸盐[As(Ⅲ)]、二甲基砷(DMA)、一甲基砷(MMA)和砷酸盐[As(V)]等4种形态砷,以磷酸盐缓冲溶液为流动相,硼氢化钾为还原剂,优化了仪器主要技术参数.As(Ⅲ)、DMA、MMA和As(V)在7 min内实现了良好的基线分离,在5.00 μg/L～...     

Global Warming Impact of Electricity Generation from Beef Cattle Manure: A Life Cycle Assessment Study

We compare calculated greenhouse gas emissions for a North American beef feedlot operation, which includes biogas production by anaerobic digestion with subsequent electricity generation (the AD case), to the emissions for a “business as usual” case, which includes both a feedlot and an equivalent amount of grid-generated electricity. Anaerobic digestion, biogas production and electricity production are the major sources of differences in emissions. Fertilizer production, crop production, manure collection and spreading, as well as the associated transport stages are also considered within the LCA system boundaries; impacts on life cycle emissions from these sources are lower. Running a feedlot and producing electricity using typical grid power plants produces 3,845 kg CO_2?eq/MWh while running a feedlot, which generates biogas to produce electricity, produces 2,965 kg CO_2?eq/MWh. This savings of 880 kg CO_2?eq/MWh arises because the net power generation in the AD case emits about 90% less life cycle GHG emissions compared to grid-average electricity. The high overall emission levels arise due to emissions associated with enteric fermentation in beef cattle as the main source of GHG emissions in both the “business as usual” and the AD cases. It contributed 57% of total emissions for the feedlot /biogas /electricity system and 44% of total emissions for the feedlot /grid electricity system.     

EVALUATION OF THE SUSTAINABILITY OF WATER WITHDRAWALS IN THE UNITED STATES, 1995 TO 20251

To evaluate the long term sustainability of water withdrawals in the United States, a county level analysis of the availability of renewable water resources was conducted, and the magnitudes of human withdrawals from surface water and ground water sources and the stored water requirements during the warmest months of the year were evaluated. Estimates of growth in population and electricity generation were then used to estimate the change in withdrawals assuming that the rates of water use either remain at their current levels (the business as usual scenario) or that they exhibit improvements in efficiency at the same rate as observed over 1975 to 1995 (the improved efficiency scenario). The estimates show several areas, notably the Southwest and major metropolitan areas throughout the United States, as being likely to have significant new storage requirements with the business‐as‐usual scenario, under the condition of average water availability. These new requirements could be substantially eliminated under the improved efficiency scenario, thus indicating the importance of water use efficiency in meeting future requirements. The national assessment identified regions of potential water sustainability concern; these regions can be the subject of more targeted data collection and analyses in the future.     

氢化物原子荧光法同时测定水中的硒和汞

采用氢化物一原子荧光法，应用AFS-2202a型双道原子荧光仪联合测定水中的硒和汞，方法的检出限为：Se0．31μg／L、Hg0．01μg／L，线性范围为：Se0-20．0μg／L、Hg0～2．00μg／L。     

四川省秸秆综合利用困局及对策建议

以四川省为例,分析了秸秆综合利用中5个方面的问题,提出了相应的3点对策和建议。     

氢化物发生原子荧光法测定地表水和饮用水中的痕量砷、汞、硒

文章研究了用SK-2002 AFS analyser氢化物发生原子荧光法测定地表水和饮用水中的砷、汞、硒的测定。在5％的酸度条件下加入5％硫脲＋5％抗坏血酸,20g／L的硼氢化钾为还原剂,调整仪器的空气和辅气流量及分析条件为文中条件,取水样中分别添加砷,汞,硒,使它们的浓度分别为2μg/L,0．4μg／L,4μg／L,连续测定12次,以砷,汞,硒的相对标准偏差分别为0．4％,1．1％,1．2％。取水样加入As,Hg,Se标准分别为2．0ng,0．6ng,4．0ng,测定的添加标准回收率分别为99．5％,97．5％,95．8％。研究结果表明,该方法操作简便,快速,灵敏,干扰少,检出限低等特点,适合于测定地表水和饮用水中砷,汞,硒的测定。     

原子荧光法测定医疗废弃物焚烧废气中的汞

采用王水消解-氢化物-原子荧光光谱法,对医疗垃圾焚烧炉所产生的废气进行采集所得到的滤筒进行消解分析,讨论并确定了实验的最佳条件,结果表明,汞的检出限为0．009μg/L,回收率为90．8％和94．3％,结果表明,该方法操作简便,灵敏度高,准确性好。     

Fenton试剂处理稻壳热解发电含酚废水的实验研究

稻壳热解发电含酚废水是稻壳热解发电过程中产生的各种废水的集合,它是一种有毒、有害废水,会对环境产生污染。本文在微波条件下进行了正交实验研究和单因素实验研究,发现pH值、反应时间、H2O2浓度、FeSO4浓度等因素对反应有影响,而且其影响程度从大到小为：pH值、FeSO4浓度、H2O2浓度、反应时间。实验得出了最佳条件：pH值为3,反应时间为7min,H2O2浓度为1500mg／L,FeSO4浓度为120mg／L,微波功率为400W。处理后水样的COD去除率超过81％,挥发酚去除率超过99％。     

以吡啶和葡萄糖为燃料的MFC产电特性研究

不同类型的有机物对MFC的产电性能有不同的影响,通过构建填料型MFC,以吡啶和葡萄糖为混合燃料,以铁氰化钾为电子受体,对有机物在MFC中的降解以及产电性进行研究.结果表明,外阻为1 000Ω的条件下,MFC的最大输出电压随着葡萄糖浓度的降低而降低,当吡啶初始浓度为500 mg/L,葡萄糖浓度分别为500、250、100 mg/L时,运行周期逐渐缩短,分别为49.5、25.7、25.2 h;最大体积功率密度为48.5、36.2、15.2 W/m3,最高电压为623 mV.MFC可实现对吡啶的高效降解,24h内吡啶去除率高达95%,但葡萄糖的浓度对吡啶的降解速率影响不大;高浓度吡啶存在的条件下对MFC利用葡萄糖产电的性能影响不大.利用500 mg/L单一吡啶作为MFC的燃料时,无明显产电现象.MFC利用吡啶和葡萄糖作为混合燃料时,可以在实现吡啶降解的同时稳定地向外输出电能.     

秸秆发电环保性能研究

文章阐述了国内外秸秆发电现状,并单独突出了江苏省秸秆发电情况。分析了秸秆发电过程中产生污染物的控制技术;通过秸秆与煤炭对比研究,同时结合国内秸秆电厂运行情况,对技术改造前后污染物排放情况作了对比分析,阐明了秸秆发电的环保性能,结果显示,CO2、SO2、烟尘、灰渣减排量可观。最后结合国内秸秆发电厂运行现状不乐观的情况,总结了秸秆发电实际运行中存在成本偏高、核心技术不成熟、灰渣利用等问题。