热分解齐化原子吸收光度法测定土壤中汞

固体测汞仪采用热分解齐化原子吸收光度法,此方法可以直接测定土壤中汞的含量。通过实验分析表明:此方法相关系数r≥0.999,检出限为0.01 ng,精密度为6.0%~9.1%,准确度为0%~6.7%,加标回收率为95%~107%。本方法具有简便、快速、准确、干扰少、成本低等优点,适合大批量土壤样品的测定。     

医疗废物无害化处置工艺设计

采取AB型热解两次焚烧(3T控制)和烟气净化处理新技术进行医疗废物无害化处置工艺设计,运行结果表明:该工艺技术能有效地处理医疗废物,具有无二次污染和社会、经济、环境效益好等优点,值得在实践中进一步推广应用。     

介质阻挡放电降解SF6的研究

采用GC-TCD考察介质阻挡放电技术(DBD)处理SF6的效果,并采用红外吸收光谱进行产物分析.结果表明,电源电压的增加、放电时间的延长、气体介质分压的降低,以及少量其它气体(Ar,N2,O2,H2O,空气)的加入能够提高转化效果.另外,SF6的降解率随着空气湿度的增加而增加,28.2 kPa相对湿度为51%的空气与2.0 kPa SF6的混合气体放电后SF6降解率达92%.放电产物包括SiF4,SF4,SOF2,SOF4,SO2F2.     

光照下高岭土悬浮液中产生羟基自由基的测定

对高岭土悬浮水溶液在光照过程中产生的羟基自由基(·OH)进行了测定.在pH2.0,苯浓度为7.0mmol·l-1的条件下,经过250W金属卤素灯(λ≥365nm)光照5h,高岭土浓度为20.0g·l-1的悬浮液中,·OH的产生量为21.6μmol·l-1.在pH 2.0-10.0范围内,·OH产生量随pH值的降低而增加.高岭土浓度在0-20.0g·l-1的范围内,·OH产生量随高岭土浓度的升高而增加,高岭土浓度增加到25.0g·l-1时,·OH产生量反而减少.高岭土中的铁是·OH产生的重要因素.     

碱熔-氟离子选择性电极法测定土壤氟含量

用碱熔法处理3个土壤样品,采取不同澄清时间的上清液及过滤后的沉淀物分析土壤氟含量。结果表明,上清液中氟含量测值随着澄清时间的延长而增加,24 h内增加迅速,而后增速趋缓,58 h后基本达到平衡。3个样品澄清平衡后的测值比澄清10 h的测值分别增加了39.4%、21.8%和27.8%。综合澄清平衡后的上清液及沉淀物得到的土壤氟含量测值比高温热水解法的测值仍然分别偏低0.48%、6.17%和11.88%,这是由于溶液中阳离子的存在使氟离子活度降低造成的。采用传统的碱熔法和高温热水解法分别研究了27个土壤样品的氟含量,碱熔法测值与高温热水解法测值相比普遍偏低,相对偏低在4.23%~34.82%之间,平均相对偏低19.12%。     

大气光化学烟雾反应机理比较(Ⅱ)HOx和光化学氧化产物的比较

在相同初和排放条件下,对四种应用较广的光化学烟雾反应机理（GB4－99RADM2,RACM,SAPPRC99）进行了6组方案的比较,比较物种包括：（1）OHHO2自由基,（2）H2O2,HNOE,PAN,甲醛和有机硝酸酯光学产物,（3）甲苯和SO2,（4）NOy,NOa,由于各机理对VOCs,自由基及含氮化合物处理的不同,导致了模拟结果存在较大差异,我们用模式模拟这些物种时,应特别注意要理不同而带来的模拟结果差异。     

Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Decomposition studies were carried out at sites throughout Sweden, including the four Integrated Monitoring sites. Scots pine needle litterbag weight loss measurements over 3 or 5 years were determined at 26 sites and repeated up to 27 times, depending on the site. Humus layer respiration rates were determined for 20 sites in 1987–1989 and repeated in 2007–2008. Partial Least Squares (PLS) regression was used to elucidate the relative importance of climatic and soil factors. Annual needle weight losses decreased only slowly (20–10%) over 3–5 years for all northern (>60°N) sites but decreased sharply from 30 to 10% in the third year in southern (<60°N) sites. Respiration rates of southern sites were less (40% on average) than those of northern sites. Humus layer N was positively correlated to needle weight loss during the first and the second years, but negatively correlated in the third year and to respiration rates. The results indicated that litter formed in southern Sweden became more recalcitrant in later stages of decomposition compared to litter produced in northern Sweden.     

Geotechnical properties of municipal solid waste at different phases of biodegradation

This paper presents the results of laboratory investigation conducted to determine the variation of geotechnical properties of synthetic municipal solid waste (MSW) at different phases of degradation. Synthetic MSW samples were prepared based on the composition of MSW generated in the United States and were degraded in bioreactors with leachate recirculation. Degradation of the synthetic MSW was quantified based on the gas composition and organic content, and the samples exhumed from the bioreactor cells at different phases of degradation were tested for the geotechnical properties. Hydraulic conductivity, compressibility and shear strength of initial and degraded synthetic MSW were all determined at constant initial moisture content of 50% on wet weight basis. Hydraulic conductivity of synthetic MSW was reduced by two orders of magnitude due to degradation. Compression ratio was reduced from 0.34 for initial fresh waste to 0.15 for the mostly degraded waste. Direct shear tests showed that the fresh and degraded synthetic MSW exhibited continuous strength gain with increase in horizontal deformation, with the cohesion increased from 1 kPa for fresh MSW to 16–40 kPa for degraded MSW and the friction angle decreased from 35° for fresh MSW to 28° for degraded MSW. During the triaxial tests under CU condition, the total strength parameters, cohesion and friction angle, were found to vary from 21 to 57 kPa and 1° to 9°, respectively, while the effective strength parameters, cohesion and friction angle varied from 18 to 56 kPa and from 1° to 11°, respectively. Similar to direct shear test results, as the waste degrades an increase in cohesion and slight decrease in friction angle was observed. Decreased friction angle and increased cohesion with increased degradation is believed to be due to the highly cohesive nature of the synthetic MSW. Variation of synthetic MSW properties from this study also suggests that significant changes in geotechnical properties of MSW can occur due to enhanced degradation induced by leachate recirculation.     

基于Divisia分解法的江苏沿海地区碳排放影响因素研究

能源消费是碳排放的主要来源。随着江苏沿海经济的快速发展,能源消费的增长以及以煤为主的能源结构在短期内难以改变,因此碳排放呈增长趋势。为了研究影响江苏沿海地区碳排放的因素,采用对数平均权重Divisia分解法,建立江苏省沿海地区人均碳排放量的影响因素分解模型,分析了2000～2008年经济发展、能源结构和能源效率对江苏省沿海地区人均碳排放的影响。研究结果表明：经济发展对江苏省沿海地区人均碳排放的贡献值和贡献率均呈指数增长趋势,能源效率的提高和能源结构的改善对人均碳排放的抑制作用比较有限,经济发展是造成江苏省沿海地区人均碳排放量快速增长的主要因素。通过研究,为江苏沿海地区控制和减少碳排放提供一些针对性的措施     

介质阻挡放电和水吸收联合降解挥发性有机化合物

依据介质阻挡放电(DBD)和溶液吸收处理气态污染物的原理,设计出一种DBD和水吸收联合降解挥发性有机化合物(VOCs)的实验装置.研究其对甲苯的降解效果.考察了放电电压、甲苯初始浓度、模拟废气流量对甲苯降解效果的影响.分析了DBD和水吸收的相互作用.结果表明.DBD和水吸收联合可以提高甲苯的降解率.在放电电压为15.9 kV时甲苯的降解率为81.5%.比单独放电时提高了13.3百分点;甲苯的降解率随着放电电压增大而升高,随着气体流量和甲苯初始浓度增大而降低.该技术可以作为放电等离子体前处理工艺,为高效处理上业废气提供参考.