黄河水体颗粒物对3种多环芳烃光化学降解的影响

研究了、苯并(a)芘、苯并(ghi)3种多环芳烃在黄河水体中的光化学降解规律,探讨了黄河泥沙和黄土2种颗粒物对多环芳烃光化学降解的影响.结果表明:①当水体不含任何颗粒物时,多环芳烃的光降解符合一级反应动力学规律,且反应动力学常数随污染物初始浓度的降低而增加;3种多环芳烃的光降解速率与分子的吸收光谱相关.②黄土通过对光强的阻碍作用和其中所含腐殖质的光敏化作用影响多环芳烃的光化学降解,这2方面的共同作用导致不同浓度黄土所产生的影响不同.黄土浓度为0.1g/L或5g/L时促进了和苯并(a)芘的光降解;黄土浓度为5g/L时促进了苯并(ghi)的降解.当水体含有黄土时,多环芳烃的光降解符合二级动力学规律.③对多环芳烃光化学降解起主要作用的是黄土中存在的溶解性腐殖质,非溶解性腐殖质的作用不大.④由于黄河泥沙在河水中长期存在,泥沙中的溶解性腐殖质都已溶于水中,泥沙主要通过对光强的阻碍作用影响水体中多环芳烃的光降解,使光降解速率随泥沙浓度的增加呈幂指数降低.     

西安夏季大气亚微米颗粒物化学组成与来源的在线观测研究

西安作为汾渭平原地区最大的城市,大气颗粒物污染形势严峻.2017年夏季期间,在西安市浐灞生态园区运用气溶胶化学组分监测仪,对大气亚微米颗粒物中的非难挥发性组分(NR-PM1)进行了在线监测.观测期间NR-PM1的平均质量浓度为(30.1?±?15.4)μg???m?3.其中有机物含量最高,占NR-PM1总质量浓度的63...     

苯胺在水体悬浮颗粒物上吸附特征

通过批量平衡法实验,比较了作为有机碱离子化有机污染物之一的苯胺在酸性、天然水和碱性水体中悬浮颗粒物上的吸附特征,并观察了水体颗粒物中腐殖酸含量对苯胺吸附行为的影响。结果表明,苯胺在水体悬浮颗粒物上的吸附遵守Ｆｒｅ－ｕｎｄｌｉｃｈ方程：在ｐＨ５—１０范围内苯胺被吸附的能力随介质ｐＨ值和颗粒物中有机质含量的升高而增大．     

氧化·热化学脱硫研究

热化学脱硫法因铵盐回收率低、产物不稳定,无法解决实用化问题。氧化热化学法应用超强脉冲电场产生高浓度、高能量的活性粒子,使SO₂在氧化过程中生成H₂SO₄,与NH3进行热化学反应,生成稳定的固体微粒（NH₄）₂SO₄,用电收尘器加以回收。脱除率、回收率可达90％左右,脱除1m³烟气中SO₂耗能为4Wh,实现了干法高效脱硫。一次投资大幅度减少,回收铵盐基本上抵消了药品费和电费。     

应用模式生物检测饮用水源颗粒物的毒性效应

悬浮颗粒物在自然水体中广泛存在,大量小颗粒物(粒径<1μm)可吸附、聚集水中多种污染物,从而形成新的复合污染,影响水生生态系统。已有研究表明,颗粒物粒径越小,传统饮用水处理工艺越难以去除,因此,其表面吸附的污染物也会随之残留在水体中,对饮用水安全产生影响。本研究对南京某自来水厂进水和出水中的颗粒物进行了测定和对比,并选用3种不同种类的模式生物包括发光菌(Photobacterium phosphoreum)、纤细裸藻(Euglena gracilis)和蚕豆(Vicia faba L.),对饮用水源水中不同粒径颗粒物的毒性效应进行了测试。结果表明,传统水处理工艺对小颗粒物(粒径<1μm)的去除效果并不理想;经传统水处理工艺处理后,出水仍显著抑制发光菌发光强度以及纤细裸藻生长,对蚕豆的污染指数较高,可能存在一定健康隐患;进水中颗粒物粒径<1μm组对发光菌发光强度和纤细裸藻生长的抑制效应显著大于粒径≥1μm颗粒物组,蚕豆根尖的污染指数也更高,毒性更强。本研究结果可为饮用水的生物毒性检测和水处理工艺改良提供参考。     

旋流场超细颗粒聚集实验研究

不同粒径分布和浓度的催化裂化(FCC)三旋回收超细催化剂颗粒在旋流场中经过50 h循环回流,颗粒中值粒径变化明显。物料中分散相越多、颗粒粒径越小时,颗粒碰撞越频繁,其聚集趋势越明显。颗粒聚集体在旋流场内不够稳定,通过对比不同进料速率下的旋流场聚集效果,得到最适合颗粒聚集的旋流场雷诺数为20 000。颗粒聚集体存在聚集极限粒径,其最佳聚集时间约为40 h,颗粒聚集后的旋流分离效率提高近5%。     

Effects of suspended common-scale and nanoscale particles on the survival,growth and reproduction of Daphnia magna

Suspended particles are a natural component of aquatic ecosystems. This study provides a report on the survival, growth and reproduction of common-scale and nanoscale particles of Daphnia magna Straus exposed to five types of particles (i.e. KN (kaolinite), MN (montmorillonite), MNn (nanoscale MN), NP (natural particles), and NPn (nanoscale NP)). The results of the study show that the suspended particles elicited a dose-dependent toxicity in KN, MN and MNn, with the following toxicity pattern: MN > KN > MNn. On the contrary, NP and NPn did not show any harmful effects on the animals. Instead, NP and NPn, especially NPn, contributed to the survivorship of the animals. The animals were able to survive throughout the 21-day period of bioassays, and when the particle concentration reached 600 mg L⁻¹, they produced many neonates without any addition of food. This experimental results also indicated that the nanoscale particles were less toxic than the common-scale ones, both for MN and NP. Moreover, the results of the 21-day period of bioassays indicated that when the organisms were exposed to particles of different size scales, they showed different selection patterns for allocating resources. This may be due to the generation of different assimilation and digestion patterns.     

Temporal variations of airborne particles concentration in the Brussels environment

We report and analyze data on the PM10 fraction of airborne particles measured at five recording stations in the Brussels region from October 2002 till September 2003. These stations are representative of the various activity sectors of the Brussels urban area. The objective was the determination of the origin of the PM10 particles (particles up to 10 μm) that are recorded in that region in order to follow the EU directives concerning tolerance level of airborne particles concentration. In order to evaluate the impacts of local and external factors that inject solid particles in the atmosphere of Brussels we compared concentration data from working and not working (holidays) periods. Moreover, we also compared concentrations from periods of agricultural activity and rest in the Brabant provinces surrounding the Brussels region for various crop types. The results lead to the conclusion that the impact or urban traffic is rather limited while that of the agricultural activities is important. Moreover, there appears a clear-cut distinction between different types of crops.     

北京西北城区春季PM10单颗粒形貌类型及成分特征

主要对北京西北城区2010年度春季大气可吸入颗粒物的理化特征进行分析研究,通过利用高分辨率场发射扫描电镜和图像分析技术研究了区内可吸入颗粒物的微观形貌类型及百分含量特征,利用扫描电镜及能谱分析研究矿物颗粒的元素组成及富集类型。结果表明,在西北城区春季大气PM₁₀中可识别出烟尘集合体、球形颗粒、矿物和其他未知颗粒等4种单颗粒类型,沙尘暴天气对矿物颗粒的数量比例影响较大,同时影响颗粒物粒度分布。矿物颗粒按成分可分为"富Si"、"富Ca"、"富Fe"、"富S"、"富Na"、"富Ti"、"富Al"、"富Cl"和"富Mg"颗粒九大类,沙尘天气与非沙尘天气的矿物颗粒均以"富Si"颗粒、"富Ca"颗粒、"富Fe"颗粒、"富S"颗粒等为主。     

天津市PM2.5中水溶性离子组分特征

2006年8—12月连续采集PM_2.5样品,分析其中水溶性无机离子浓度特征。结果表明,采样期间,天津市PM_2.5日均浓度均不同程度超过美国EPA日均浓度标准(35 μg/m³);SO₄^2-、NO₃^-、NH₄⁺和Cl^-为无机离子的主要成分,占全部无机离子的88.6%;各离子均表现出不同季节变化特征。对NH₄⁺和NO₃^-、SO₄^2-进行相关性分析发现,NH₄⁺和NO₃^-相关性最好,相关系数为0.795。SOR和NOR的平均值分别为0.16和0.23,均为8月最高,表明前体物二次转化夏季最明显。