La-Na-Co-Mn-O系钙钛矿型催化剂同时去除柴油机碳颗粒和NOx性能的研究

采用低温燃烧法制备了Na+部分取代La3+的La1-xNaxCo0.5Mn0.5O3系钙钛矿型复合氧化物催化剂。利用程序升温反应(TPR)技术,对催化剂应用于柴油机常规排放物中的碳微粒(soot)和氮氧化合物(NOx)的同时催化脱除性能进行了研究。     

循环式活性污泥法中厌氧生物选择区的运行条件研究

研究了循环式活性污泥法中厌氧生物选择区的停留时间、进水有机物浓度和系统中泥龄、曝气时间等运行参数对选择区内厌氧释磷以及有机物的吸收贮存的影响。结果表明，选择区停留时间lh，系统泥龄5d，曝气2h，进水有机物浓度COD／TP=60--70，选择器中释磷效果及微生物的吸附性能最优，可去除进水中78％的COD。而且污泥沉降性能良好，试验运行过程中，SVI一直保持在30--40ml／g左右。     

臭氧氧化法深度处理生活垃圾焚烧厂沥滤液

采用臭氧氧化法对生活垃圾焚烧厂沥滤液经生化处理后的废水(称沥滤液生化处理水)进行深度处理。实验结果表明,COD降解速率随废水pH的提高明显增加,其中pH=10.5时的COD降解速率常数约为pH=4时的5.8倍。在臭氧投量为52.92 mg/min、pH=10.5的条件下反应70 min后,UV254和COD去除率分别达到84.7%和59.3%。向反应体系投加叔丁醇后COD去除率下降了约15%,由羟自由基氧化去除的COD占总COD去除量的26.7%。毒性实验结果表明,沥滤液生化处理水的96 h-EC50为38%,经臭氧氧化进一步处理后出水的96 h-EC50为77%,表明经臭氧深度处理后沥滤液生化处理水的毒性明显降低。     

净化SO2的生物膜填料塔中微生物类群分析

对净化废气中SO2的生物膜填料塔内的微生物进行了分离纯化并做鉴定,得到一株嗜酸性氧化硫硫杆菌（Acidithiobacillus thiooxidans IEL001）和一株分类地位非常接近链二孢属（Bispora sp.）的极端嗜酸真菌IEL002,生物膜填料塔内的极端酸性环境和有机营养的缺乏导致生物膜上的微生物种类较为单一,多样性程度不高。本研究还发现IEL002自身并不能氧化单质硫,但它能促进Acidithiobacillus thiooxidans IEL001对单质硫的氧化。     

京、津、冀地区地闪特征的统计分析

京、津、冀地区地闪的区域特征十分明显,利用该地区2004年的地闪的定位资料,通过分析得到以下主要结论:(1)正地闪占总闪的比率为10.86%,而各地区正地闪占总地闪的百分率与相应地闪产生地区的中心纬度之间都存在着很好的线性关系.由于与中、低纬度地区相比,高纬度地区雷暴云整体高度发展得较低,雷暴云中主正电荷区域的位置也较低,因此高纬度地区较中、低纬度地区的正地闪发生得多.(2)雷暴以7月份为最多,且7月份地闪次数的逐日分布较均匀.(3)地闪在空间分布上有4个相对较为集中的区域,这些区域主要是山地的迎风坡、或下垫面水汽的充足处、或人口相对集中的城市中心区.     

西北地区沙尘暴引发的荒漠化问题

从西北地区继1993～1995年连续3a出现沙尘暴之后，1996年甘肃和内蒙古西部的阿盟等地再次遭到沙尘暴的袭击入手，分析了沙尘暴发生的原因，指出它归根结底是荒漠化的直接后果。概述了荒漠化的状况及危害，并分析了其成因。     

海河干流、大沽排污河沉积物中有机氯农药的残留状况

调查了海河干流和大沽排污河沉积物中持久性有机氯杀虫剂(OCPs)的残留状况.在所选取的16个断面沉积物样品中均有大量HCHs、DDTs检出,表明海河和大沽排污河的DDT和HCH污染相当严重.海河沉积物中HCHs和DDTs总质量浓度分别为3.30～75.96、1.57～221.57 ng/g.大沽排污河沉积物中HCHs和DDTs的残留量分别为2.30～124.61、11.28～237.30ng/g.与国内外部分河流表层沉积物中HCHs、DDTs的含量相比,海河和大沽排污河沉积物中有机氯农药含量较高.最后根据两条河流沉积物中的OCPs的残留量,分析了其可能的污染源.     

Enhanced sludge solubilization by microbubble ozonation

A microbubble ozonation process for enhancing sludge solubilization was proposed and its performance was evaluated in comparison to a conventional ozone bubble contactor. Microbubbles are defined as bubbles with diameters less than several tens of micrometers. Previous studies have demonstrated that microbubbles could accelerate the formation of hydroxyl radicals and hence improve the ozonation of dyestuff wastewater. The results of this study showed that microbubble ozonation was effective in increasing ozone utilization and improving sludge solubilization. For a contact time of 80 min, an ozone utilization efficiency of more than 99% was obtained using the microbubble system, while it gradually decreased from 94% to 72% for the bubble contactor. The rate of microbial inactivation was obviously faster in the microbubble system. At an ozone dose of 0.02 g O₃ g⁻¹ TSS, about 80% of microorganisms were inactivated in the microbubble system, compared with about 50% inactivation for the bubble contactor. Compared to the bubble contactor, more than two times of COD and total nitrogen, and eight times of total phosphorus content were released from the sludge into the supernatant by using the microbubble system at the same ozone dosage. The application of microbubble technology in ozonation processes may provide an effective and low cost approach for sludge reduction.     

Factors influencing arsenic accumulation by Pteris vittata: a comparative field study at two sites

This study compared the factors influencing arsenic (As) accumulation by Pteris vittata at two sites, one containing As along with Au mineralization and the other containing Hg/Tl mineralization. The soils above these two sites contained high As concentrations (26.8-2955 mg kg(-1)). Although the As concentration, pH, soil cation exchange capacity and plant biomass differed significantly between the two sites, no differences were observed in the As concentrations in the fronds and roots, or the translocation factors, of P. vittata, suggesting that this species has consistent As hyperaccumulation properties in the field. The As concentration in the fronds was positively related to phosphorus (P) and potassium (K), but negatively related to calcium (Ca), at one site. This suggested that P, K and Ca influenced As accumulation by P. vittata in the field.     

制备方法对MgAl水滑石衍生氧化物负载钯催化剂丙烷完全氧化活性的影响

以沉积沉淀法(DP)、浸渍法(IM)和共沉淀法(CP)制备MgAl水滑石衍生氧化物负载钯催化剂,用ICP、XRD、SEM、TEM、EDS、TPR以及比表面测定等手段对催化剂进行了表征.ICP和XRD数据表明用上述3种方法均可成功制备水滑石为前体载钯催化剂.SEM、TEM、EDS数据表明不同方法制备的样品具有不同的形貌以及钯在其中的分散度.综合各类表征数据可知Pd在催化剂中暴露的活性位是影响其活性的主要因素.