Ti(Ⅳ)催化臭氧化预处理酸性难降解制药废水

考察了酸性条件下Ti(Ⅳ)催化臭氧化预处理医药废水的效能,关联了废水氧化度与可生化性(BOD5/COD)的关系。结果表明,酸性条件下O3和O3/H2O2的氧化效率明显低于Ti(Ⅳ)/H2O2/O3。原始pH条件(3.5)下,Ti(Ⅳ)/H2O2/O3体系Ti(Ⅳ)离子和H2O2的最佳浓度分别为10 mg/L和200 mg/L。调节pH值至5.0处理120 min,制药废水的化学需氧量(COD)和总有机碳(TOC)的去除率分别为56.13%和31.49%。此时水样氧化度从原来的0.388提升到了0.608,BOD5/COD值从原来的0.019升至0.297,两者呈现较好的正相关性。以上结果表明,增大pH可以提高Ti(Ⅳ)/H2O2/O3的处理效果;此外,可以考虑利用氧化度的大小来快速判断水样的可生化性。     

不同树叶提取液绿色合成纳米铁的制备及应用

分别利用红背桂叶、菩提叶和龙眼叶的提取液,既作还原剂又作稳定剂,利用绿色方法制备纳米铁(E-Fe NPs、B-Fe NPs、L-Fe NPs)并用于亚甲基蓝的脱色。采用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)、热重分析(TG)、X射线光电子能谱(XPS)等表征手段对绿色合成的纳米铁进行表征。结果表明,E-Fe NPs、B-Fe NPs、L-Fe NPs均是呈球状和均匀分布的,其粒径分别为20~40、60~80 nm和80~120 nm。FT-IR和TG的分析结果表明,不同树叶的提取液所含生物分子不同,XPS结果显示,不同树叶提取液合成的纳米铁的组成不同(价态和成分)。E-Fe NPs、B-Fe NPs、L-Fe NPs对亚甲基蓝(MB)的脱色率分别为99.2%、54.2%和20.8%,造成MB脱色率不同的原因可能是,不同的纳米铁颗粒的组成成分比例及粒径有所不同。     

油田聚驱采出液乳化特性及其破乳-絮凝

为了解决国内某油田聚驱采出液油水分离的难题,对聚驱采出液的水质特性和乳化特性进行研究,考察了驱油剂聚丙烯酰胺(HPAM)对污水乳化程度的影响,针对该污水开发、筛选出最优的高效破乳剂,考察了投加量及温度对污水破乳效果的影响,并进行了破乳-絮凝复配实验研究。实验结果表明,该油田聚驱采油污水油含量、悬浮物、硫含量、Fe2+均较高,乳化程度严重且具有较强乳化稳定性,油水分离困难;HPAM的存在增强了污水的乳化程度;当破乳温度为65℃,停留时间为2 h时,投加6 mg/L的PAM4#时除油效率约为72%,在破乳后的水样中投加100 mg/L的PAS,含油量可降低至27.0 mg/L,悬浮物降低至9.0 mg/L,处理后水样达到该油田回注水的水质标准。     

不同油田油泥热裂解的特性分析及动力学研究

油泥是石油行业的产物,具有产量大、污染严重、处理困难等特点。运用热处理方法进行实验,通过对两个不同油田油泥的热裂解实验,发现不同来源的油泥,其组分与形态差异十分明显,从而导致热解结果也有一定的差异。经热解处理后,油泥质量减少50%~80%,减量化明显;通过释放气体的分析,对热解的反应历程以及反应机理做出了初步推测。最后通过动力学分析,得到了一定的动力学参数,为实际操作中的问题解决提供实践依据,从而提高该技术的适用性与实用性。     

The impact of land use and land cover changes on land surface temperature in a karst area of China

Satellite images have been used extensively to study temporal changes in land use and land cover (LULC) in China. However, few studies have been conducted in the karst areas despite the large area and population involved and the fragile ecosystem. In this study, LULC changes were examined in part of Guizhou Province of southern China from 1991 to 2001 based on Landsat Thematic Mapper (TM) images of November 7, 1991, December 5, 1994, and December 19, 2001. Land surface temperature (LST) and normalized difference vegetation index (NDVI) were computed based on LULC types. The results show that agricultural land decreased, while urban areas expanded dramatically, and forest land increased slightly. Barren land increased from 1991 to 1994, and then decreased from 1994 to 2001. These changes in LULC widened the temperature difference between the urban and the rural areas. The change in LST was mainly associated with changes in construction materials in the urban area and in vegetation abundance both in the urban and rural areas. Vegetation had a dual function in the temperatures of different LULC types. While it could ease the warming trend in the urban or built-up areas, it helped to keep other lands warmer in the cold weather. The study also reveals that due to the government's efforts on reforestation, rural ecosystems in some of the study area were being restored. The time required for the karst ecosystem to recover was shorter than previously thought.     

Effects of environment, vehicle and driver characteristics on risky driving behavior at work zones

This study aims to analyze the effects of environment, vehicle and driver characteristics on the risky driving behavior at work zones. A decision tree is developed using the classification and regression tree (CART) algorithm to graphically display the relationship between the risky driving behavior and its influencing factors. This approach could avoid the inherent problems occurred in the conventional logistic regression models and further improve the model prediction accuracy. Based on the Michigan M-94/I-94/I-94BL/I-94BR highway work zone driving behavior data, the decision tree comprising 33 leaf nodes is built. Bad weather, poor road and light conditions, partial/no access control, no traffic control devices, turning left/right and driving in an old vehicle are found to be associated with the risky driving behavior at work zones. The middle-aged drivers, who are going straight ahead in their vehicles with medium service time and equipped with an airbag system, are more likely to take risky behavior at lower work zone speed limits. Further, the middle-aged male drivers engage in risky driving behavior more frequently than the middle-aged female drivers. The number of lanes exhibits opposing effects on risky behavior under different traveling conditions. More specifically, the risky driving behavior is associated with the single-lane road under bad light or weather conditions while drivers are more likely to engage in risky behavior on the multi-lane road under good light conditions.     

氯化镉、灭多威和硝基苯对日本青鳉(Oryzias latipes) 行为抑制的生物应急监测

研究了氯化镉、灭多威和硝基苯对孵化以后7d左右日本青鳉(Oryzias latipes)行为毒性。结果表明,在不同污染物中,随暴露浓度的增加,第1尾日本青鳉产生行为抑制的时间逐渐缩短,并且半数行为抑制时间(time ofhalf behavior inhibition,THBI,Y)随暴露浓度(X)呈现幂指数关系Y=aXb,其中20相似文献   

Mechanical properties of incineration bottom ash: The influence of composite species

The mechanical properties, including strength, deformational behavior, and wetting softening phenomena of municipal solid waste incinerator (MSWI) bottom ash are one of the major concerns for reuse applications. However, owing to the complex constituents of municipal solid waste, the properties of MSWI bottom ash are often highly variable. A series of artificial specimens with controlled chemical components were tested in this study. The test results show that the artificial bottom ash possesses the following mechanical characteristics: (1) for the strength, the frictional angles of the bottom ash under dry and saturated conditions vary from 34.8° to 51.1° and 26.0° to 37.2°, respectively; (2) for the deformation, the shear stiffness increases with the normal stress arises and degrades upon increased shearing; (3) significant wetting degradation of the strength and stiffness were observed.The multi-variable regression analysis was conducted to evaluate the associated influence of the chemical components on the strength. Among the evaluated components, Fe₂O₃ and Al₂O₃ are key factors; an increase in either results in higher strength at both dry and saturated conditions. The results were used to propose empirical relationships for ?_dry and ?_sat, expressed in terms of Fe₂O₃ and Al₂O₃. Accordingly, a strength classification chart is proposed for engineering purposes.     

Forest value orientations and importance of forest recreation services

This study employs the notion of environmental value orientations as an approach to examine the relationships between forest value orientations and demand on services available in the National Forest Recreation Areas in Taiwan. Data for this investigation were collected from on-site, off-site, and online surveys (n = 1919). Statistical results suggest that the authorities should highlight the role of Taiwanese forest as public property with aesthetic, historic, and cultural values, and the use of more comprehensive dimensions of environmental value orientations is warranted when using value-related variables to address natural resource management issues. The correlation evidence of service demands of tourists with different forest value orientations indicates that the authorities should focus on maintaining and improving basic services available in the National Forest Recreation Areas.