粉煤灰-H2O2催化氧化水中对氨基苯酚的试验研究

研究了利用电厂粉煤灰作为非均相催化剂，催化H2O2氧化对氨基苯酚（PAP），讨论了各种因素对PAP去除率的影响。结果表明，在30℃，pH=1．5，H2O2和PAP的起始浓度分别为0．50mol／L和0．10mol／L，反应时间为100min，粉煤灰用量为6.0％，搅拌速度为1000r／min的条件下，粉煤灰具有良好的催化活性，能有效地催化H2O2氧化PAP，PAP的去除率可达81％左右。该法可用于预处理含PAP的工业废水。     

地坑压缩式城市生活垃圾转运站的设计与应用

介绍了一种具有压缩功能,并与吊装设备配套使用的城市生活垃圾转运站,具有操作方便,减少工人劳动强度等特点,通过压缩机的压缩增大了箱内垃圾比重,提高了垃圾的清理及运输效率,同以往相比运输次数减少半数以上,大大提高了工作效率,有效的节省了人力和物力资源.     

Nitrous oxide emissions from a maize field during two consecutive growing seasons in the North China Plain

Nitrous oxide (N₂O) emissions from a maize field in the North China Plain (Wangdu County, Hebei Province, China) were investigated using static chambers during two consecutive maize growing seasons in the 2008 and 2009. The N₂O pulse emissions occurred with duration of about 10 days after basal and additional fertilizer applications in the both years. The average N₂O fluxes from the CK (control plot, without crop, fertilization and irrigation), NP (chemical N fertilizer), SN (wheat straw returning plus chemical N fertilizer), OM- 1/2N (chicken manure plus half chemical N fertilizer) and OMN (chicken manure plus chemical N fertilizer) plots in 2008 were 8.51, 72.1, 76.6, 101, 107 ng N/(m²·sec), respectively, and in 2009 were 33.7, 30.0 and 35.0 ng N/(m²·sec) from CK, NP and SN plots, respectively. The emission factors of the applied fertilizer as N₂O-N (EFs) were 3.8% (2008) and 1.1% (2009) for the NP plot, 3.2% (2008) and 1.2% (2009) for the SN plot, and 2.8% and 2.2% in 2008 for the OM-1/2N and OMN plots, respectively. Hydromorphic properties of the investigated soil (with gley) are in favor of denitrification. The large differences of the soil temperature and water-filled pore space (WFPS) between the two maize seasons were suspected to be responsible for the significant yearly variations. Compared with the treatments of NP and SN, chicken manure coupled with compound fertilizer application significantly reduced fertilizer loss rate as N₂O-N.     

Allelopathic Potential of Switchgrass (Panicum virgatum L.) on Perennial Ryegrass (Lolium perenne L.) and Alfalfa (Medicago sativa L.)

This study investigated allelopathy and its chemical basis in nine switchgrass (Panicum virgatum L.) accessions. Perennial ryegrass (Lolium perenne L.) and alfalfa (Medicago sativa L.) were used as test species. Undiluted aqueous extracts (5 g plant tissue in 50 ml water) from the shoots and roots of most of the switchgrass accessions inhibited the germination and growth of the test species. However, the allelopathic effect of switchgrass declined when extracts were diluted 5- or 50-fold. Seedling growth was more sensitive than seed germination as an indicator of allelopathic effect. Allelopathic effect was related to switchgrass ecotype but not related to ploidy level. Upland accessions displayed stronger allelopathic potential than lowland accessions. The aqueous extract from one switchgrass accession was separated into phenols, organic acids, neutral chemicals, and alkaloids, and then these fractions were bioassayed to test for allelopathic potential. Alkaloids had the strongest allelopathic effect among the four chemical fractions. In summary, the results indicated that switchgrass has allelopathic potential; however, there is not enough evidence to conclude that allelopathic advantage is the main factor that has contributed to the successful establishment of switchgrass on China’s Loess Plateau.     

Isotopic evidences for provenance of East Asian Dust

We have systematically collected samples in the possible source regions (the deserts and sandy lands of North China, northeastern past of the Tibetan Plateau, Chinese Loess Plateau and southern part of Mongolia) of the East Asian dust. Based on Nd–Sr isotopic ranges, the source regions can be divided into four isotopic regions: Region A1: the Gurbantunggut Desert in Junggar basin and Hunlun Buir sandy land in northeastern China; Region A2: the Hunshandake sandy land, Horqin sandy land and southern part of Mongolia; Region B: the Taklimakan Desert in Tarim basin, northeastern past of the Tibetan Plateau, Chinese Loess Plateau, Badain Jaran Desert and Tengger Desert in Alashan Plateau; Region C: the Hobq Desert and Mu Us Desert in the Ordos Plateau. Through comparison of Nd–Sr isotopes, it can be inferred that the sediments of the north-central Pacific and dust particles in the Greenland ice cores are mainly derived from Region B. Dusts of East Asian dust storm are derived mostly from Region B also, and less from Region A2. The materials of dust storm at Beijing area in April 2006, originated largely from the Hobq Desert and Mu Us Desert in the Ordos Plateau. The floating dust at Beijing area in April 2006, is the mixing of dust of distant deserts and local dust at Beijing area. Loess of the Chinese Loess Plateau may largely originate from Region B.     

CuCoO_x/TiO_2催化氧化NO性能研究

采用浸渍法制备了CuCoOx/TiO2催化剂,考察了焙烧温度、反应温度、氧含量、NO浓度和空间速度对催化剂催化氧化NO性能的影响,并考察了催化剂的抗硫抗水性能.XRD、TPR和BET分析表明,350℃焙烧的催化剂具有Cu-Co2O4尖晶石结构,比表面积大,对N0的氧化效果好.在空速为5 000 h-1,NO进口浓度500 mg/m3,含氧量10%的条件下,反应温度300cc时N0转化率可达79.5%,250℃时N0转化率接近50%.该催化剂具有良好的单独抗SO2、抗H2O毒化性能,H2O和SO2同时存在时很快失活.该催化剂可用于不同时含H2O和SO2的含NO气体催化氧化后再吸收处理.     

贫营养生物膜系统脱氮效果及影响因素实验研究

为了有效解决饮用水源氮源污染问题,采用贫营养生物菌剂对新型悬浮填料进行人工强化挂膜,在无需外加碳源及模拟原位条件下考察贫营养生物膜系统对微污染原水的脱氮效果及其影响因素。研究表明:在水温为25℃左右,溶解氧浓度为4 mg/L左右,水源水质为NH4+-N0.140 mg/L,NO2--N0.005 mg/L,NO3--N1.096 mg/L,TN1.450 mg/L,CODMn4.810 mg/L的条件下,该系统运行22 d后对原水硝氮及总氮具有较明显的去除效果,去除率范围分别为43%～75%和49%～76%,运行期间氨氮浓度基本保持在0.1 mg/L以下,系统稳定运行时的脱氮效果可满足地表水环境Ⅲ类水体的质量标准要求。另外,通过考察水温、填料填充率、C/N比等因素对贫营养生物膜系统脱氮效果的影响作用,说明在不同时期和不同环境条件下该系统对微污染水体的脱氮效果具有一定差异。     

Evaluation and comparison of continuous fine particulate matter monitors for measurement of ambient aerosols

To provide a scientific basis for the selection and use of continuous monitors for exposure and/or health effects studies, and for compliance and episode measurements at strategic locations in the State of New Jersey, we evaluated the performance of seven continuous fine particulate matter (PM2.5) monitors in the present study. Gravimetric samplers, as reference methods, were collocated with realtime instruments in both laboratory and field tests. The results of intercomparison of real-time monitors showed that the two nephelometers used in this study correlated extremely well (r2 approximately 0.97), and two tapered element oscillating monitors (TEOM 1400 and TEOM filter dynamics measurement system [FDMS]) correlated well (r2 > 0.85), whereas two beta gauges displayed a weaker correlation (r2 < 0.6). During a summertime controlled (laboratory) evaluation, the measurements made with the gravimetric method correlated well with the 24-hr integrated measurements made with the real-time monitors. The SidePak nephelometer overestimated the particle concentration by a factor of approximately 3.4 compared with the gravimetric method. During a summertime field evaluation, the TEOM FDMS monitor reported approximately 30% higher mass concentration than the Federal Reference Method (FRM); and the difference could be explained by the loss of semi-volatile materials from the FRM sampler. Results also demonstrated that 24-hr average PM2.5 mass concentrations measured by beta gauges and TEOM (50 degrees C) in winter correlated well with the integrated gravimetric method. Seasonal differences were observed in the performance of the TEOM (50 degrees C) monitor in measuring the particle mass attributed to the higher semi-volatile material loss in the winter weather. In applying the realtime particulate matter monitoring data into Air Quality Index (AQI) reporting, the Conroy method and the 8-hr end-hour average method were both found to be suitable.     

等离子体-催化协同处理挥发性有机物的催化剂研究进展

等离子体与催化技术的结合解决了单一用等离子体时的能量利用率、产率低及应用条件高的缺陷.总结了不同等离子体-催化协同作用的催化剂催化活性;在此基础上探讨了催化剂的组成、表面性质和结构对其催化活性的影响以及催化剂使用过程中的稳定性,分析了等离子体催化协同处理挥发性有机物(VOCs)过程中的反应机制;最后,对催化剂存在的问题和今后的研究方向进行了探讨.