荷电对粉尘过滤过程影响的研究

针对电袋复合除尘器工程技术开发的需求,进行了粉尘荷电对过滤过程影响的测试实验。测试结果显示,荷电对粉尘的过滤压降等都会产生一定影响,并且在荷电条件下,粉尘颗粒在输送过程中会产生一定程度的聚并现象。     

纳米颗粒暴露评价研究综述

对国外最新的人造纳米颗粒的暴露评价方法和研究结果进行综述,旨在为我国今后工作现场的职业卫生暴露评价提供指导。检索和查阅2000—2010年发表的涉及纳米颗粒暴露评价的同行评审期刊的英文文献和报告,并对暴露评价设备和方法进行比较和分析,归纳描述部分研究结果,总结纳米颗粒暴露评价的特殊性和挑战,探讨解决这些问题的关键步骤。最后,提出今后在职业现场开展纳米暴露评价的2个可行的方法。     

人体呼出气溶胶在通风房间中运动的受力分析

分析了通风房间中人体呼出气溶胶颗粒运动的计算参数,得出了气溶胶颗粒所受的曳力、布朗力、Saffman升力以及热泳力随颗粒粒径变化的近似函数关系.结果表明,气溶胶粒径是颗粒受力的主要影响因素,而粒径不同对力的影响不同.除重力外,气溶胶粒径对其他4种力的影响从大到小依次为布朗力、曳力、热泳力和Saffman升力.通过计算得到了人体呼出的不同粒径气溶胶颗粒受到的上述4种主要作用力相对于重力的大小.计算人体呼出的μm级以下气溶胶在通风房间内的分布时,需要考虑曳力、布朗力以及Saffman升力,其量级均大于小颗粒所受的重力.气溶胶受到的热泳力小于重力,但室内局部的高温热源或者低温冷源附近的温度梯度远高于室内平均温度梯度,因此忽略热泳力会对计算结果造成较大误差.     

水环境中六溴环十二烷的光降解研究

研究了模拟太阳光和500W紫外灯两种光源下,水中六溴环十二烷(HBCDs)的光降解动力学,同时还研究了紫外光下pH、腐植酸(HA)、Fe(Ⅲ)、过氧化氢(H2O2)和二氧化钛(TiO2)纳米颗粒对HBCDs降解效率的影响.研究表明,在模拟太阳光和紫外光照下,HBCDs的降解速率常数和半衰期分别是7.5×10-3h-1、...     

水介质中C60纳米晶体颗粒的光化学反应活性木

C60作为一种新型纳米材料,其环境负效应日益受到关注.C60的光化学反应特性是其具有生物毒性的重要原因之一,但C60在水中形成纳米晶体颗粒后失去了C60分子本身的光化学反应活性,不能产生氧自由基.C60在水介质中光化学反应活性的转变使其生物毒性机制研究复杂化.本文综述了水介质中C60纳米晶体颗粒的光化学反应活性相关研究...     

锆铁复合氧化物颗粒对As（Ⅴ）的去除研究

系统研究了锆铁氧化物颗粒吸附剂（GZI）对As（Ⅴ）的去除性能,考察了反应时间、溶液pH、初始As（Ⅴ）浓度、共存离子等反应条件的影响.同时评价了吸附后材料的脱附性能及动态处理后材料的安全性.实验结果显示,初始浓度低于20 m.gL^-1时,5 h后As（Ⅴ）在GZI吸附剂上达到平衡,初始浓度为50 m.gL^-1时,...     

沿淮麦区大气无机态氮质量浓度的观测研究

2010年6月6日至6月16日,运用采样器TH-110B和TH-150C收集了地处沿淮麦区3个观测点的气体（NH3和NO2）和气溶胶样品,初步探讨了小麦收获期大气气态氮和颗粒态氮质量浓度的特征。结果表明：气态氮质量浓度以NO2最高,其时均质量浓度和日均质量浓度分别为0.57～0.64 mg.m-3和0.29～0.63 mg·m-3,且均超标（0.24和0.12 mg·m-3）;颗粒态氮质量浓度以NH4＋-N最高（4.12～78.28μg·m-3）,占总氮的47.00%～71.19%。此外,农业活动如收割,可增加大气气溶胶及无机态氮的质量浓度。     

Organic matter produced by algae and cyanobacteria: Quantitative and qualitative characterization

This work aims at characterizing organic matter produced by an alga Euglena gracilis and a cyanobacteria Microcystis aeruginosa and assessing the evolution of its characteristics during growth. A culture medium was optimized. The species growth phases were monitored using both visible spectrophotometry and flow cytometry cell counting. Organic matter fractionation according to hydrophobicity and specific UV absorbance (SUVA) index were used to specifically characterize the produced algal organic matter (AOM). The AOM characteristics were both growth phase and species dependent. However, a similar evolution was observed. The hydrophilic fraction (HPI) was the major fraction whatever the growth phases and was almost the only one produced during lag and exponential phases. It represented around 75% of AOM during exponential phase and then decreased when the stationary phase appeared. It represented 46% and 60% of the AOM during late decline phase for the cyanobacteria and the alga respectively. The hydrophobic (HPO) and transphilic (TPH) fractions started to appear from the beginning of the stationary phase with more hydrophobic compounds coming from intracellular organic material of dying cells. HPO and TPH percentages still increased during the decline phase probably because of two additional processes: photo-dissolution and leaching of particulate organic matter from cells fragments. A comparison of AOM during late decline phase and natural organic matter (NOM) from Glane River (France) underlined that AOM was more hydrophilic and presented a lower SUVA for each fractions than NOM. However, the difference between NOM and AOM hydrophobicity narrowed during decline phase.     

不同氮浓度冲击对颗粒污泥脱氮过程中N2 O产生量的影响

采用好氧-缺氧SBR污水生物处理系统,考察不同进水NH4+-N浓度冲击对同步硝化反硝化型颗粒污泥脱氮过中N2O的释放规律和脱氮效果的影响.结果表明,当进水NH4+-N浓度分别从稳定的30 mg·L-1突然提高到40、60和80 mg·L-1时,氨氮去除率从80.04%降至61.40%、39.65%和31.02%,但氨氮的去除量变化不大,都在25 mg·L-1左右;另外,N2O产生量受进水NH4+-N冲击较小,在4个不同的进水NH4+-N浓度下,典型周期N2O产生量分别为3.019、3.489、3.271和3.490 mg·m-3,而且N2O释放速率都在0.004 5 mg·(m3·min)-1左右.同步硝化反硝化型颗粒污泥系统的好氧阶段和缺氧阶段均有N2O产生.不同的NH4+-N浓度冲击下,同步硝化反硝化型颗粒污泥系统对NH4+-N的去除量没有变化,但由于进水NH4+-N浓度的提高引起系统脱氮率显著下降.     

Biological nutrient removal by internal circulation upflow sludge blanket reactor after landfill leachate pretreatment

The removal of biological nutrient from mature landfill leachate with a high nitrogen load by an internal circulation upflow sludge blanket （ICUSB） reactor was studied. The reactor is a set of anaerobic-anoxic-aerobic （A^2/O） bioreactors, developed on the basis of an expended granular sludge blanket （EGSB）, granular sequencing batch reactor （GSBR） and intermittent cycle extended aeration system （ICEAS）. Leachate was subjected to stripping by agitation process and poly ferric sulfate coagulation as a pretreatment process, in order to reduce both ammonia toxicity to microorganisms and the organic contents. The reactor was operated under three different operating systems, consisting of recycling sludge with air （A^2/O）, recycling sludge without air （low oxygen） and a combination of both （A^2/O and low oxygen）. The lowest effluent nutrient levels were realised by the combined system of A^2/O and low oxygen, which resulted in effluent of chemical oxygen demand （COD）, NH3-N and biological oxygen demand （BOD5） concentrations of 98.20, 13.50 and 22.50 mg/L. The optimal operating conditions for the efficient removal of biological nutrient using the ICUSB reactor were examined to evaluate the influence of the parameters on its performance. The results showed that average removal efflciencies of COD and NH3- N of 96.49% and 99.39%, respectively were achieved under the condition of a hydraulic retention time of 12 hr, including 4 hr of pumping air into the reactor, with dissolved oxygen at an rate of 4 mg/L and an upflow velocity 2 m/hr. These combined processes were successfully employed and effectively decreased pollutant loading.