复合柱净化法分析生物试样中残留的有机氯农药

用复合柱净化法分析生物试样中残留的有机氯农药,采用复合柱将少量硫酸含量较低的硅胶放在适量的硫酸含量较高的硅胶上,并将去活化硅胶复合在同一根柱子内,有效地避免了浓缩后的提取液与硫酸含量较高的硅胶直接接触时发生的板结现象。该方法对生物试样中8种有机氯农药六六六和滴滴涕的净化效果较好,当农药六六六和滴滴涕的标准加入量为200μg／kg和50μg／kg时,各目标物的平均回收率为63．9％～79．8％,相对标准偏差为5．6％-12．8％,检出限为0．001-0．040μg/kg。     

三氯乙酸与其他有机物在活性炭上的竞争吸附

通过等温吸附实验,考察了三氯乙酸(TCAA)与十二烷基苯磺酸钠(DBS)、腐殖酸(HA)在活性炭(GAC)上的竞争吸附现象。结果表明,GAC对TCAA的吸附符合Langmuir模型,对DBS和HA的吸附均符合Freudlich模型;在GAC上,DBS和HA对TCAA构成竞争吸附,大分子HA阻塞GAC的微孔,使得TCAA与DBS难以进入微孔;GAC对3种物质的吸附能力由大到小依次为DBS、TCAA和HA;离子型表面活性剂DBS憎水性一端与TCAA竞争吸附位,亲水性一端与TCAA形成吸附,使GAC总饱和吸附量有所加大。     

烧结纤维承载活性炭复合材料在苯蒸气脱除中的应用

以8μm的镍纤维和煤基活性炭为原材料,通过抄制和烧结工艺制备了烧结纤维承载活性炭粉末复合材料。为了减轻床层总重量,将这种材料和通常的颗粒状活性炭进行联合装填形成复合层,并进行了苯蒸气的吸附穿透实验。利用Wheeler方程对床层的饱和吸附容量和吸附速率常数进行了测定。结果表明,在相同的测试条件下,联合装填层比单独的颗粒炭装填层具有更好的苯蒸气脱除性能;对两种床层而言,其各自的饱和吸附容量是一个不随比速而变化的常数,而随着气流比速的增加,两种床层的吸附速度都呈增加的趋势。     

Biochemical study of retired pentachlorophenol workers with and without following dietary exposure to PCDD/Fs

Objectives

This is the first research study to compare among female, non-smoker workers: (a) the exposure to benzene, toluene and xylenes (BTXs) in urban air during work in the street (traffic policewomen, TP) vs. work in vehicles (police drivers, PD); (b) the exposure to BTXs in urban environments (in street and in car) vs. rural environments (roadwomen, RW); (c) the values of blood benzene, urinary trans, trans muconic acid (t,t-MA) and urinary S-phenylmercapturic acid (S-PMA) in urban areas (in street and in car) vs. rural areas.

Methods

Passive personal samplings and data acquired using fixed monitoring stations located in different areas of the city were used to measure environmental and occupational exposure to BTXs during the work shift in 48 TP, 21 PD and 22 RW. In the same study subjects, blood benzene, t,t-MA and S-PMA were measured at the end of each work shift.

Results

Personal exposure of urban workers to benzene seemed to be higher than the exposure measured by the fixed monitoring stations. Personal exposure to benzene and toluene was (a) similar among TP and PD and (b) higher among urban workers compared to rural workers. Personal exposure to xylenes was (a) higher in TP than in PD and (b) higher among urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA levels were similar among TP and PD, although the blood benzene level was significantly higher in urban workers compared to rural workers. In urban workers, airborne benzene and blood benzene levels were significantly correlated.

Conclusions

Benzene is a human carcinogen, and BTXs are potential reproductive toxins at low dose exposures. Biological and environmental monitoring to assess exposure to BTXs represents a preliminary and necessary tool for the implementation of preventive measures for female subjects working in outdoor environments.     

低温等离子体结合吸附处理含苯废气

以苯废气为降解对象,利用介质阻挡放电(DBD)产生等离子体进行处理,考察了放电频率、停留时间和气体湿度对苯去除效率的影响。研究发现,在一定浓度和电压下,等离子体对苯的去除率随放电频率的增加而升高,随着废气停留时间的增加而升高,随废气湿度的增大先升高后下降,当相对湿度为20%左右时效率最高。在利用介质阻挡放电结合MOF材料吸附处理含苯废气时,控制入口苯质量浓度小于500mg/m^3,可将出口苯质量浓度降解至4 mg/m^3以下,苯去除率保持在98%以上。     

改性聚丙烯纤维的制备及其对苯系物的吸附

分别采用熔融接枝法和共混法制备聚丙烯(PP)/苯乙烯(St)改性纤维(PP-g-St)和聚丙烯/聚苯乙烯(PS)改性纤维(PP/PS),研究了熔融接枝条件对St接枝率的影响,考察了PP纤维、PP/PS纤维和PP-g-St纤维对纯苯系物和水中乳化、溶解态苯系物的吸附性能,并探讨了再生后的重复吸附性能。实验结果表明:PP熔融接枝St的最优配比为w(St)=9%,w(过氧化二异丙苯)=0.5%,此时St接枝率为4.7%,且能顺利纺丝;相比于PP纤维,PP-g-St纤维和PP/PS纤维对纯苯系物和水中乳化、溶解态苯系物的吸附量显著提高;吸油饱和的PP-g-St纤维和PP/PS纤维通过离心法再生5次后吸附性能再生率仍能够分别达到82.0%和87.6%。     

环境风险评价中化学品苯泄漏的大气环境影响研究

以苯泄漏的大气影响为研究对象,模拟一起典型的突发性环境风险事故.依据<建设项目环境风险评价技术导则>,采用导则推荐的伯努利方程、质量蒸发量公式计算物质泄漏的源强,利用多烟团模式模拟计算其对环境的影响,预测出不同时间不同距离处的影响程度.根据这一预测结果,针对性地提出风险防范及应急措施,为环境风险事故的应急处置提供依据.     

地下车库空气中苯系物浓度的时间分布特征与污染评价

采用气相色谱法定量分析了地下车库空气中苯系物(苯、甲苯、二甲苯)的浓度并于不同时间段采集地下车库的空气样品,研究了地下车库内苯系物的浓度随时间的变化特征及污染状况。研究结果表明:①在实验色谱条件下,用外标法测定苯系物的准确度较高,回收率为90%~110%;②苯系物浓度随时间的变化呈现明显的周期性,苯系物单体浓度与总量浓度随时间的分布特征相似,表现为早晨的浓度大于中午及傍晚;③苯系物总量和单体浓度远远高于室外;④地下车库苯系物浓度低于中国室内空气质量标准限值,但检测结果表明地下车库存在苯系物的污染,长期累积对人体健康构成潜在威胁。     

便携式傅里叶红外分析仪测定水中挥发性有机污染物

发明了一种利用GASMET FTIR Dx4020便携式傅里叶红外分析仪测定水中挥发性有机物的实用方法,该方法可以定性定量25个水中挥发性有机物.该方法具有简便快捷、灵敏度高等特点,以苯系物中各单组分物质为例,方法检测限为11 ～45μg/L,相对标准偏差为3.4％ ～ 6.6％,加标回收率为98％ ～ 109％,在浓度范围内具有良好的线性.但对苯系物混合物定量准确性还需进一步研究提高.     

Modeling the spill in the Songhua River after the explosion in the petrochemical plant in Jilin

An explosion in a petrochemical plant in Jilin in the northeast of China on 13 November 2005 was responsible for the discharge of large quantities of benzene and nitrobenzene into Songhua River. This endangered the water supply of Harbin city and influenced the daily life for millions of people. The dispersion-advection equation was solved analytically and numerically and used to simulate the concentration of benzene and nitrobenzene in the Songhua River after the accident. Both solutions gave practically identical results. The main elimination process for both compounds was volatilization. The model results are quite close to the results obtained by measurements at monitoring stations. Arrival time of the pollutant wave, peak concentrations and end of the pollutant wave at Harbin and along the river were predicted successfully. The peak concentrations of nitrobenzene at Harbin were more than 30 times above the permissible limits for drinking water.