原子荧光法测定水中汞的原子化条件研究

分别采用热原子化原子荧光法(热汞法)和冷原子化原子荧光法(冷汞法)测定水中汞,比较了两种方法的检出限、线性相关系数、准确度和精密度的差异。冷汞法和热汞法的检出限分别为0.003和0.01μg/L,标准曲线相关系数分别为0.999 9和0.999 7,加标回收率范围分别为102%~106%和106%~113%。结果表明,冷汞法比热汞法具有更低的检出限,灵敏度和准确度也略优于热汞法。对于冷汞法,提高负高压有利于提高方法的灵敏度、准确度,并具有更低的方法检出限。     

用荷电水雾控制敞开空间粉尘污染

1 前言 荷电水雾除尘技术是一门正在兴起的除尘技术,它的基本原理是工业过程中产生的绝大多数粉尘或多或少地带有电荷,如果使水雾带上与粉尘极性相反的电荷就能借助静电引力来提高水雾的捕尘效率。 为了保证武钢“双七百万吨”扩建工程的顺利完成,武汉交通科技大学为武钢工业港设计研制了大宗散货链斗式连续卸船机。但该机在工作中会产生大量的粉尘,严重污染作业环境。为了抑制粉尘污染,同时考虑到该机的工作特点,我们尝试用荷电水雾除尘技术控制该机在工作过程中产生的大量粉尘。     

亲水性多孔载体在流化床中的生物膜形成过程分析

采用实验制备的一种新型亲水性多孔聚合物作为流化床反应器中生物膜附着生长的载体,实现流态化水力条件下的生物挂膜过程.在3个结构尺寸相同的流化床反应器中考察了接种污泥浓度、进水有机负荷及载体粒径对亲水性多孔载体生物挂膜量的影响,试验结果表明,接种污泥浓度为30 g VSS/L、进水TOC值为350 mg/L、载体粒径为5～8 mm时载体表面的附着生物量最大,反应器运行12 d的载体附着生物量达到4.45 g VSS/L,膜结构稳定,表现出较活性污泥法更高的活性.在进水TOC、氨氮浓度分别为350 ms/L、50 mg/L,HRT为6 h的情况下,两者的去除率分别达到了97.1%和64.3%,表明载体上的生物膜对污水中TOC及氨氮的去除表现出高效率.挂膜后载体表面上的微生物以丝状菌为主,孔壁上的微生物以球菌和杆菌为主要生物相,证明载体内外表面皆适宜微生物的生长,并且形成合理的生物相分布.     

Analysis and residue levels of forchlorfenuron (CPPU) in watermelons

This paper describes the application of liquid chromatography-tandem mass spectrometry (LC/MS-MS) for analysis of residues of forchlorfenuron (CPPU), a new plant growth regulator, in watermelons, after a sample preparation step based on the buffered Quick, Easy, Cheap, Effective, Rugged and Safe extraction method. Analytical determinations were carried out in a triple quadrupole system fitted with an electrospray interphase operating in the positive ionisation mode (ESI+). Three simultaneous MS-MS transitions of the quasi-molecular ion m/z 248 (precursor ion) were monitored for data acquisition (248 > 129, 248 > 155, and 248 > 248), using the transition 248 > 129 for quantitation. Recovery studies on watermelons at levels of 1-200 microg/kg, performing five replicates at each level and using bracketing single-level calibration with matrix-matched standards for quantitation, gave forchlorfenuron mean recoveries ranging from 82 to 106% with relative standard deviations (RSD) lower than 18%. The limit of determination was established at 1 microg/kg. The method was applied to evaluate the persistence of forchlorfenuron residues in watermelons grown in plastic greenhouses, after applying an individual spray treatment to the flower ovary at the anthesis stage (45 mu g/flower and 60 mu g/flower for cv "Extazy" and cv "reina de corazones" watermelons, respectively). One month after treatment, 20 "Extazy" watermelon units (1.5-2 kg/unit) and 20 "Reina de corazones" watermelon units (4-5 kg/unit) were collected and analyzed individually. None of the samples contained forchlorfenuron residues higher than 1 microg/kg.     

Preliminary assessment of polybrominated diphenyl ethers (PBDEs) in the Scottish aquatic environment, including the Firth of Clyde

This paper presents preliminary data on polybrominated diphenyl ethers (PBDEs) in the Scottish aquatic environment. Sediment and biota (fish liver, fish muscle and mussels) from a number of locations around Scotland were analysed for PBDEs with samples being from both remote and from potentially contaminated areas such as the former sewage sludge dump site at Garroch Head in the Clyde. PBDEs were measured in both cultivated, rope grown mussels and wild mussels collected from 5 sites around Scotland in 2006. Total PBDE concentrations (sum of tri- to hepta-BDEs) ranged from 相似文献   

Particle size distributions and elemental composition of atmospheric particulate matter in southern Italy

Three 2-wk seasonal field campaigns were performed in 2003 and 2004 at a sampling site on the southern Tyrrhenian coast of Italy with the aim to investigate the dynamics and characteristics of particle-bound pollutants in the Mediterranean area. Fine (PM(2.5)) and coarse particulate matter (PM(10-2.5)) size fractions were collected by a manual dichotomous sampler on 37-mm Teflon filters over a 24-hr sampling period. On average, 70% of the total PM(10) (PM(2.5) + PM(10-2.5)) mass was associated with the coarse fraction and 30% with the fine fraction during the three campaigns. The ambient concentrations of Pb, Ni, Cr, Zn, Mn, V, Cd, Fe, Cu, Ca, and Mg associated with both size fractions were determined by atomic absorption spectrometry. Ambient concentrations showed differences in their absolute value, ranging from few ng x m(-3) to microg x m(-3), as well as in their variability within the PM(2.5) and PM(10-2.5) size fractions. PM(10) levels were well below the European Union (EU) limit value during the study period with the exception of three events during the first campaign (fall) and five events during the third campaign (spring). Two main sources were identified as the major contributors including mineral dust, transported from North Africa, and sea spray from the Tyrrhenian Sea. Comparing the results with backward trajectories, calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) and Total Ozone Mapping Spectrometer-National Aeronautics and Space Administration (TOMS-NASA) maps, it was observed that in central and eastern Europe, the Tyrrhenian Sea and North Africa were the major emission source regions that affected the temporal variations and daily averages of PM(2.5) and PM(10-2.5) concentrations.     

工业区群环境影响评价初探

阐述了开展工业区群环境影响评价的意义,比较了单个工业园区和工业区群环评的异同,以广州番禺区工业区群环评项目为例,简述了该环评的主要内容和特点,并提出了建议。     

冲天炉类气除尘净化技术及其发展

针对冲天炉熔炼过程中产生污染物的特性，提出了一种净化效率高且经济可行的冲天炉烟气多级复合除尘净化技术。