Application of positive matrix factorization to identify potential sources of PAHs in soil of Dalian, China

Soil derived sources of polycyclic aromatic hydrocarbons (PAHs) in the region of Dalian, China were investigated using positive matrix factorization (PMF). Three factors were separated based on PMF for the statistical investigation of the datasets both in summer and winter. These factors were dominated by the pattern of single sources or groups of similar sources, showing seasonal and regional variations. The main sources of PAHs in Dalian soil in summer were the emissions from coal combustion average (46%), diesel engine (30%), and gasoline engine (24%). In winter, the main sources were the emissions from coal-fired boiler (72%), traffic average (20%), and gasoline engine (8%). These factors with strong seasonality indicated that coal combustion in winter and traffic exhaust in summer dominated the sources of PAHs in soil. These results suggested that PMF model was a proper approach to identify the sources of PAHs in soil.     

损伤状态下变电构架可靠性分析的实用模型

按照结构形式对常见的变电构架进行分类,根据其中受损杆件的不同损伤类型,建立了截面面积损伤率和截面惯性矩损伤率之间的相关关系表达式,并以此来修改损伤杆件的单元刚度矩阵.在随后的结构可靠度分析中,采用响应面法和Monte Carlo法与有限元程序结合,使构件截面几何参数产生大量不同损伤水平的样本,从而得到不同损伤水平下各类变电构架结构的响应及其可靠度指标的变化规律,所得结论可供变电构架的安全监控参考.     

双循环多级水幕吸收塔烟气除尘脱硫性能研究

以改进后的双循环多级水幕塔对烟气进行除尘脱硫性能的研究,利用双循环不同pH值控制的优点和多级水幕的效果,增加气液接触面积和传质动力,提高SO₂吸收效果。在正交实验的最佳运行工况基础上,实验从烟气流量、上下两段pH、L/G和SO₂进气浓度等方面进行单因素研究。结果表明,除尘效率维持在98%以上,进气SO₂浓度在5 000 mg/m³以下时,脱硫率在93%以上。上段pH值为6、下段pH值为5、L/G在15左右的脱硫效率和运行工况最佳,无结垢现象发生。改进后的吸收塔具有良好的应用前景,实验结果对于现场脱硫设备的调试和运行有很好的参考价值。     

Emissions of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) in the Shing Mun Tunnel,Hong Kong

Real-world vehicle emission factors for seventeen gas and particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in the Shing Mun Tunnel, Hong Kong during summer and winter 2003. Naphthalene, acenaphthylene, and acenaphthene were the most abundant gas PAHs while fluoranthene and pyrene were the most abundant in the particle phase. Most (98%) of the gas PAHs consisted of two- and three-aromatic rings whereas most of the particle-phase PAHs were in four- (～60%) and five-ring (～17%) for fresh exhaust emissions. Average emission factors for the gas- and particle PAHs were 950–2564 μg veh^?1 km^?1 and 22–354 μg veh^?1 km^?1, respectively. Good correlations were found between diesel markers (fluoranthene and pyrene; 0.85) and gasoline markers (benzo[ghi]perylene and indeno[1,2,3-cd]pyrene; 0.96). Higher PAH emission factors were associated with a higher fraction of diesel-fueled vehicles (DV) passing through the tunnel. Separate emission factors were determined from diesel and non-diesel exhaust by the regression intercept method. The average PAH emission factor (i.e., sum of gas and particle phases) from DV (3085 ± 1058 μg veh^?1 km^?1) was ～5 times higher than that from non-diesel-fueled vehicles (NDV, 566 ± 428 μg veh^?1 km^?1). Ratios of DV to NDV emission factors were high for diesel markers (>24); and low for gasoline markers (<0.4).     

粉煤灰基混凝剂制备及处理印钞废水研究

将粉煤灰经过超细球磨后再采用微波处理,用于制备粉煤灰基混凝剂。结果表明,超细和微波处理能明显增加混凝剂的产率和性能。通过正交实验确定了去除印钞废水中浊度的粉煤灰基混凝剂的最佳制备工艺条件：粉煤灰/酸比为1∶4（w/v）,粉煤灰/碱比为1∶3（w/v）,熟化温度为40℃。当投加量为5 mL/100 mL时,粉煤灰基混凝剂对印钞废水处理的浊度去除率为98.37％。对粉煤灰基混凝剂的混凝机理进行了分析。     

有机磷降解酶的固定化及其工业化应用初探

采用一种新型的酶固定化方法,在大孔微球中对有机磷降解酶（OPHC2）固定化,制备固相载体化的交联酶聚集体固定化酶。对具有实际应用意义的参数：热稳定性、牢固度和连续反应批次进行了重点研究。结果表明,有机磷降解酶固定化酶的半衰期在70℃时比游离酶提高了2.1倍。固定化酶分别在37℃的摇床中经14 h高速振荡,以及在pH 8、37℃条件下循环反应49个批次降解甲基对硫磷后,均未发现固定化酶酶活力下降。在37℃,有机磷降解酶固定化酶柱以每小时3倍柱床体积的速率对甲基对硫磷农药乳油的稀释液（甲基对硫磷含量为216 mg/L）进行降解处理,系统连续工作156 h,甲基对硫磷的降解率保持在98.4%～99.9%。     

微波辅助白腐真菌煤炭脱硫试验研究

将微波技术与生物技术相结合用于煤炭脱硫,采用微波功率1 000 W、辐照时间80 s对煤样进行辐照处理后,考察了初始pH值、煤粉粒径和煤浆浓度对微波辅助白腐真菌脱硫效果的影响,以及脱硫过程中硫化物的转化规律。研究结果表明,微波辐照作用能够缩短脱硫周期,提高有机硫的脱除率。在初始pH值为4.5,煤粉粒径为80～120目,煤浆浓度为10%,浸出时间为3 d的条件下,煤中的全硫、无机硫和有机硫脱除率分别达到52.06%、51.61%和54.22%。     

用H_2O_2/Fe~(3+)处理高浓度含甲醛废水的研究

研究采用H2O2/Fe3+催化氧化处理高浓度含甲醛废水,探讨了双氧水和催化剂投加量、反应pH及反应温度等操作条件对处理效果的影响,并通过酸溶解回用失活催化剂.结果表明,较优的操作条件为:H2O2/COD(质量比)=2.2～2.6,Fe3+/H2O2(摩尔比)=0.048～0.058,反应pH 1.80～2.68,反应温度50℃,反应时间40 min;在上述操作条件下,甲醛去除率达到99%以上,COD去除率达到85%以上.失活的催化剂可通过稀酸溶解后循环使用,其效果与三价铁盐作催化剂的基本相同.采用H2O2/Fe3+处理含甲醛废水具有比采用H2O2/Fe2+较优的效果.     

漂浮植物塘协同处理农村分散生活污水研究

通过实验考察了漂浮植物塘对经模拟化粪池简易处理的农村分散生活污水的深度净化效果,结果表明：水葫芦、大薸、聚草塘对上述污水均具有良好的净化效果,水葫芦塘对TP的去除效果最好,大薸塘对TN和NH⁺₄-N的去除效果最好。当水力停留时间为20 d时,3种漂浮植物塘的出水污染物含量可低于GB/T 18921-2002观赏性景观环境用水河道类标准。在南方农村宅沟园河内种植漂浮植物是构建农村实用生活污水收集处理系统、控制农村生活污水对河道污染的一种有效措施。     

已二酸生产副产物——混合二元酸的综合利用

采用一水合硫酸氢钠作为催化剂,催化己二酸生产副产物——混合二元酸与甲醇反应合成混合二元酸二甲酯。优化工艺条件为：混合二元酸加入量0．1mol,无水甲醇加入量0．5mol,一水合硫酸氢钠加入量4．0g,环己烷加入量20mL,反应时间1．5h。合成混合二元酸二甲酯的酯化反应收率大于97％。经气相色谱检测,产物中酯的质量分数为98．91％。一水合硫酸氢钠可重复使用3次。