排序方式: 共有35条查询结果,搜索用时 62 毫秒
31.
研究了1,2,4,5-四氯苯在C18膜/水相之间的分配规律。1,2,4,5-四氯苯在:25℃,80r/min条件下恒温震荡96h可达分配平衡,温度和盐度对1,2,4,5-四氯苯C18膜/水的分配过程影响很小,1,2,4,5-四氯苯C18膜/水分配平衡时间受溶液体积和容器容积的影响,但不受溶液中C18膜膜量的影响,推测脂溶性小于或接近1,2,4,5-四氯苯的有机污染物在恒温震荡条件下C18膜与水之间的分配96h可达到平衡。 相似文献
32.
Zunlong Zhou 《Environmental pollution (Barking, Essex : 1987)》2010,158(1):201-206
Chars were generated by pyrolyzing pine wood at temperatures between 300 °C and 700 °C for 6 h and at 500 °C for 10-300 min. Their organic content and surface acidity decreased, and BET surface area increased, with increasing pyrolytic temperature and time. The uptake of benzene and nitrobenzene increased with increasing pyrolytic temperature and time with isotherms characterized by a transition from less to more concave-downward. The isotherms with low-temperature and short-time chars were fitted to the dual Langmuir-partition model, whereas those with high-temperature chars to the dual-Langmuir model. Calculations suggest that the organic phases of chars functioned as partition media and the uptake of benzene and nitrobenzene on carbonized chars occurred first in micropores via pore-filling and later in larger pores through capillary condensation and adsorption. It is concluded that chars may be considered to consist of the partition domain, the high-energy micropores domain and the low-energy large pores domain. 相似文献
33.
农药分配系数及其在环境研究中的应用 总被引:3,自引:0,他引:3
简述了农药分配系数的直接摇瓶测定法和其它间接估算方法,讨论了分配系数与农药其他理化性质和环境行为之间的关系。分配系数是估测农药水溶性,生物富集性及底泥沉积物吸附系数等参数的较好方法。 相似文献
34.
Qiming Xian Jijie Kong Tao M Xiaoyu Cao Weidi Li Fengxiao Zhu Huan He Cheng Sun Shaogui Yang Shiyin Li 《环境科学学报(英文版)》2023,35(2):782-793
Nitrated polycyclic aromatic hydrocarbons (NPAHs) are widespread organic pollutants that possess carcinogenic and mutagenic properties, so they may pose a risk to the environment and human health. In this study, the concentrations of 15 NPAHs and 16 polycyclic aromatic hydrocarbons (PAHs) in 30 surface water samples and 26 sediment samples were measured in 2018 from the Taige Canal, one of the main rivers flowing into Taihu Lake, China. The total NPAH concentrations in water and sediment ranged from 14.7 to 235 ng/L and 22.9 to 96.5 ng/g dw, respectively. 9-nitrophenanthrene (nd–76.3 ng/L) was the dominant compound in surface water, while 2+3-nitrofluoranthene (1.73–18.1 ng/g dw) dominated in sediment. Among PAHs, concentration ranging from 1,097 to 2,981 ng/L and 1,089 to 4,489 ng/g dw in surface water and sediment, respectively. There was a strong positive correlation between the log octanol-water partition coefficient (Kow) and log sediment-water partition coefficient due to hydrophobic interaction. The fugacity fraction value increased with the decrease of log Kow, and chrysene was transferred from water into sediment. The residual NPAHs in surface water and sediment of the Taige Canal have partial correlation. Diesel engine and coal combustion emissions were probably the principal sources of NPAHs in surface water and sediment. The results of ecological risk assessment showed that some NPAHs in water (e.g, 1-nitropyrene and 6-nitrochrysene) and sediment (e.g., 2-nitrobiphenyl, 5-nitroacenaphthene, 9-nitrophenanthrene and 2+3-nitrofluoranthene) had moderate ecological risks, which should be of concern. 相似文献
35.
Photocatalysis has attracted worldwide attention due to its potential in solar energy conversion. As a “green” advanced oxidation technology, it has been extensively used for water disinfection and wastewater treatment. This article provides a review of the recent progress in solar energy-induced photocatalytic disinfection of bacteria, focusing on the development of highly efficient photocatalysts and their underlying mechanisms in bacterial inactivation. The photocatalysts are classified into TiO2-based and non-TiO2-based systems, as TiO2 is the most investigated photocatalyst. The synthesis methods, modification strategies, bacterial disinfection activities and mechanisms of different types of photocatalysts are reviewed in detail. Emphasis is given to the modified TiO2, including noble metal deposition, non-metal doping, dye sensitization and composite TiO2, along with typical non-TiO2-based photocatalysts for bacterial disinfection, including metal oxides, sulfides, bismuth metallates, graphene-based photocatalysts, carbon nitride-based photocatalysts and natural photocatalysts. A simple and versatile methodology by using a partition system combined with scavenging study is introduced to study the photocatalytic disinfection mechanisms in different photocatalytic systems. This review summarizes the current state of the work on photocatalytic disinfection of bacteria, and is expected to offer useful insights for the future development in the field. 相似文献