含有多孔载体的环流曝气塔处理污水的研究

利用环流塔式曝气装置并且在曝气体系中投入聚亚氨酯载体以固定微生物,可以用来同时去除污水中的COD、氨氮和硝酸氮.在气速为0.117～0.156 m³/(min·m³)之间,实验装置对氨氮具有较高的去除效率;而当气速大于0.039 m³/(min·m³)时,COD可以在1h之内得到较完全的降解.研究了载体在整个体系中的填充率对COD和氮的脱除效果的影响,当载体填充率达到15%时,可以得到较高的COD和氨氮去除水平.通过实验确定了处理过程合适的温度范围在25℃左右.     

长株潭城市群秋季大气颗粒物及其重金属元素污染特征

为研究长株潭城市群大气颗粒物及典型元素污染特征,于2011年11月在长沙、株洲、湘潭三地采集TSP和PM₁₀样品,同期在北京进行采样,以分析颗粒物及其中重金属元素(Cr、Cd、Hg、Pb和As)质量浓度的分布特征. 结果表明:秋季长沙、株洲、湘潭三地的ρ(TSP)均低于北京,背景点(长沙沙坪站)最低,为(110±48)μg/m3. 株洲ρ(PM₁₀)与北京相近,略高于湘潭和长沙,但背景点ρ(PM₁₀)仍为最低. ρ(PM₁₀)/ρ(TSP)在70.26%~95.80%之间,平均值为85.90%. 长株潭城市群的ρ(Cr)、ρ(Hg)、ρ(As)、ρ(Cd)和ρ(Pb)在TSP中分别为37.7~60.7、0.2~1.5、22.7~92.0、4.2~36.8和142.9~508.3ng/m3,在PM₁₀中相应分别为20.4~33.5、0.1~1.0、20.6~74.2、3.8~31.9和126.1~432.4ng/m3. 长株潭城市群各采样点Cd在TSP和PM₁₀中的富集因子均最大,分别为475.8~4690.7和840.5~7489.8;其次为Hg、Pb和As;Cr的富集因子在TSP和PM₁₀中分别为7.8~33.3和9.1~33.6,均为最小.      

北京市大气环境中硫酸盐、硝酸盐粒径分布及存在形式

为了解北京市大气颗粒物中,二次硫酸盐、硝酸盐的存在形式及其含量,于2008年5月～2009年4月,利用MOUDI对北京市大气颗粒物分10级进行采样,利用离子色谱技术对各粒径范围大气颗粒物中的无机水溶性组分进行分析,并利用偏相关分析的方法确定其存在形式和估算其含量.结果表明,北京市大气颗粒物中水溶性硫酸盐和硝酸盐表现为单...     

Photochemical properties and source of pollutants during continuous pollution episodes in Beijing, October, 2011

Beijing sufered from serious air pollution in October, 2011 with the occurrence of three continuous episodes. Here we analyze the pollution status of particulate matter, the relationship between the gaseous pollutants, physical and chemical properties of single particles, and the profile of watersoluble ions in PM2.5during the three episodes. Regional and photochemically aged air masses, which were characterized as having high values of O3and SO2, were hypothesized to have played a dominant role in the first episode. After mixing local air masses with freshly-emitted primary pollutants, the concentration of NOx continued to increase and the size of SO4 2, NO3 and NH4 +in the particle population continued to become smaller. The amount of elemental carbon-rich and organic carbonrich particles in the scaled single particles(0.2–2 μm) and water-soluble K+in PM2.5also increased in the episodes. All the available information suggests that the biomass or fuel burning sources in or around Beijing may have had a huge impact on the last two episodes.     

天津市PM10, PM2.5和PM1连续在线观测分析

利用2010年9月1日─11月30日在中国气象局天津大气边界层观测站采集的ρ(PM₁₀₎,ρ(PM_2.5)和ρ(PM₁)数据,分析了观测期间可吸入颗粒物的统计特征,结合同期气象观测资料,分析了典型天气条件下ρ(PM₁₀₎,ρ(PM_2.5)和ρ(PM₁)的日变化特征及与风速、风向的关系. 结果表明:观测期间,ρ(PM₁₀₎日均值有超过1/2的天数超过《国家环境空气质量标准》(GB 3095─1996)二级标准限值;ρ(PM_2.5)有63 d超过美国国家环境保护局(US EPA)1997标准限值,超标率高达76.8%;不同天气条件下,ρ(PM₁₀₎,ρ(PM_2.5)和ρ(PM₁)日变化特征明显,三者一般在大雾或扬沙/浮尘天气条件下出现高值,有降水过程时出现低值;可吸入颗粒物以粗粒子(PM_2.5～10)和PM₁为主,PM_2.5～10,PM_1～2.5和PM₁主要分布在风速小于3 m/s,风向为225°～280°和70°～110°范围内;风速大于3 m/s时,ρ(PM_2.5～10)和ρ(PM_1～2.5)有所增加. ρ(PM₁₀₎,ρ(PM_2.5)和ρ(PM₁)未出现周末效应,但存在明显的周内变化.      

“大气十条”实施期间南京市PM2.5化学组成与来源的演变特征

为深入认识“大气污染防治行动计划”(“大气十条”)对大气细颗粒物(PM_2.5)污染的影响,基于“大气十条”实施期间南京市主城区(草场门)PM_2.5的化学组分监测资料,研究了PM_2.5主要组分的浓度和占比、富集因子和酸度等变化特征,并采用正定矩阵因子分解法(PMF)进行了PM_2.5的来源解析.结果发现,“大气十条”实施期间,南京市PM_2.5中硫酸根(SO₄^2-)的占比总体下降,但硝酸根(NO^-₃)和铵根(NH⁺₄)的占比均明显上升,两者的占比从2014年的25.58%上升到2017年的37.15%;碳组分(OC和EC)的浓度在“大气十条”早期出现大幅下降,但后期的下降趋势明显变缓,其中,有机碳(OC),特别是二次有机碳(SOC)的占比不降反升;PM_2.5酸性显著减弱,阴阳离子的摩尔当量比值(CE/AE)从2014年的0.83上升...     

汽车排放超细微粒数浓度及粒径谱特征的实验研究

采用快速迁移率粒径谱仪(fast mobility particle sizer,FMPS)结合汽车尾气分析仪对3辆不同型号汽车排放超细颗粒数浓度进行测量,分析了空载情况不同转速下排气管附近超细颗粒数浓度及粒径谱特征.结果表明,在怠速800 r·min-1情况下,汽车排放的颗粒数浓度最低,随着空载转速的增加颗粒数浓度呈增高趋势.尾气颗粒以核模态和爱根核模态为主,峰值粒径集中在10 nm和50 nm.汽车加速过程排放颗粒数浓度有明显的急剧升高过程,在车速稳定后颗粒物浓度趋于稳定.在排气管尾部轴向距离0.4 m范围内颗粒稀释后数浓度衰减迅速,在0.4~1 m范围稀释不明显,均大于背景浓度.空载情况下随发动机转速增加,汽车排放尾气CO、HC和NO浓度呈减少趋势,与颗粒物数浓度排放趋势相反.     

固定源PM_(2.5)稀释采样器的研制

为研究固定源PM2.5的排放特征,研制开发了一套紧凑型稀释采样器,能模拟高温烟气排放到大气中的冷却、稀释、凝结等物理化学过程,采集固定源排放的一次PM2.5.稀释采样器主要的技术参数如下:稀释比在20∶1~50∶1范围内,在稀释器里的停留时间为10 s,稀释后的烟气温度和相对湿度分别小于42℃和50%,满足ISO 25597:2013的要求.稀释采样器的性能评价实验表明,稀释器气密性良好,稀释空气中颗粒物浓度低,气流混合均匀性良好,细颗粒在采样器内的损失小,表明稀释采样器可靠性高,适合于对固定源排放PM2.5的采集.     

Characteristics of air pollution by polychlorinated dibenzo-p-dioxins and dibenzofurans in the typical industrial areas of Tangshan City, China

The ambient air in vicinity of different industrial sources for PCDD/PCDFs was sampled by TSP/PM10 active samplers and passive PUF disk samplers in Tangshan City, a metropolis containing clusters of various industrial plants. The TEQ concentrations of PCDD/PCDFs ranged from 44.2 to 394.1 fg I-TEQ/m3 with an average of 169.9 fg I-TEQ/m3. 2,3,4,7,8-PeCDF was the dominant contributor to PTEQ, contributing 41% (12% to 55%), while 1,2,3,4,6,7,8-HpCDF, OCDD and OCDF were the major congeners for the total concentrations. The ratios of PPCDF/PPCDD reached 2.54 on average, suggesting that de novo synthesis in thermal processes played an important role to the airborne pollution of PCDD/PCDFs. The similarities congener profiles indicated that TSP and PM10 active sampling methods are comparable for the determination of the PCDD/PCDFs in ambient air, and the ratios of concentrations determined by the two methods suggested that the PCDD/PCDFs tended to stay in fine particles. It was found that 2,3,7,8-TCDF and OCDD were the dominating congeners in the passive PUF disks samples. Through principal components analysis, the coke industry was suggested to be a relatively high potential emission source for PCDD/PCDFs in the ambient air of Tangshan, which was possibly formed by de novo synthesis mechanism. In this study, the atmospheric impacts to the environment from di erent industrial sources could be ranked as follows (from high to low): coking, iron sintering, steel making, power generation and chlorinate alkali chemical production industries.     

老化前后轮胎磨损微粒与聚氯乙烯微粒对抗生素的吸附-解吸行为

近年来,微塑料（microplastics,MPs）作为一类新型污染物,广泛存在于水环境中而备受关注.与典型微塑料（PVC、PP、PE和PS）相比,轮胎磨损微粒（tire wear particles,TWP）在组成成分、添加剂种类和理化特性上存在显著差异.为深入比较TWP与典型MPs对有机污染物吸附-解吸行为的不同.以TWP和PVC微粒为目标MPs,土霉素（OTC）和磺胺甲唑（SMZ）为目标污染物,研究了TWP及PVC微粒老化前后对有机污染物的吸附-解吸特性,这对正确认识MPs潜在的水环境生态风险具有重要意义.结果表明,TWP及PVC在紫外线老化过程中,均表现为颗粒表面出现裂纹、凹坑和凸起,比表面积增大,含氧官能团强度增加,亲水性增强等现象.老化前后TWP及PVC的吸附模式均表现为表面吸附和液膜扩散两个阶段,其中TWP对Freundlich模型的拟合性较好,属于多层吸附;而PVC对Langmuir模型的拟合性较好,属于单层吸附.TWP对SMZ和OTC的载体能力均强于PVC,其中新制TWP与PVC对OTC的最大吸附量分别可达到5.14 mg·g^-1和1.38 mg·g^-1;而老化后TWP和PVC对OTC的最大吸附量分别增加至5.82 mg·g^-1和2.13 mg·g^-1,要大于老化前.解吸实验中,老化后TWP及PVC对抗生素的解吸量均高于老化前,而解吸率却随之降低.在同种解吸液中,老化前后TWP对抗生素的解吸量均高于PVC.而在模拟肠液环境下老化前后TWP及PVC对抗生素的解吸量均要高于在超纯水环境下.