摘要
以城市污水中3种典型多环芳烃(PAHs)——萘、菲、芘为对象,以无机颗粒(石英砂、高岭土、黄土)和活性污泥为吸附剂,研究了在污水处理过程中PAHs的吸附去除特性及其影响因素。结果表明,无机颗粒物对PAHs的作用以单分子层吸附为主,符合Langmuir吸附等温式,随着温度的升高吸附能力降低,具有放热反应的特征;活性污泥对PAHs的作用以多分子层吸附为主,符合Freundlich吸附等温式,随着温度升高吸附能力增强,具有吸热反应的特征。活性污泥对PAHs的吸附能力高于无机颗粒。PAHs的吸附去除性质与其辛醇/水分配系数密切相关,并存在相互间的竞争吸附。在pH=6.0～8.0的范围内,pH值对PAHs吸附效果的影响不明显。
Through a series of adsorption experiments, and by using quartz, kaolin, and natural clay as inorganic adsorbents and laborato- ry-cuhured activated sludge as organic adsorbent for adsorbing model polycyclic aromatic hydrocarbons （PAHs） of NAPT, PHEN and PYR, this paper is aimed to find the characteristics of PAHs adsorp- tion in the sewage treatment and analyze its main influential factors. Besides, we have also been trying to describe the inorganic suspend- ed solids in sewage treatment by using the inorganic adsorbents and the activated sludge as adsorbent and adding NaN3 to suppress the in- terference of biodegradation process. The results of our experiments show that the power of adsorption of PAHs with the above said three inorganic adsorbents, whose order of adsorption can be seen as fol- lows ： natural clay 〉 kaolin 〉 quartz. The adsorption isotherms of the above mentioned three inorganic adsorbents tends to well follow the Langmuir isotherm, indicating a single-layer adsorption nature. As for the activated sludge, its adsorption isotherm reveals a multi- molecular-level adsorption nature well following the Freundlich isotherm. Furthermore, we have also found that the adsorption capac- ity of the activated sludge for PAHs turns to be higher than that of the inorganic particles. Moreover, for all the absorbents with no excep- tion, the adsorption capabilities are all closely related to the octanol/ water partition coefficient of the PAHs, which was found to be ordered as ： PYR 〉 PHEN 〉 NAPT. In addition, we have also investi- gated the effects of temperature, pH, and the competitive adsorption properties between the different PAHs. The results of our investigation help us to conclude that the adsorption capacity of NAPT by kaolin turns to be falling with the temperature rising （ 10 ℃, 25 ℃, 30 ℃ ）, an exothermic reaction feature, as it were named. However, while the adsorption process of activated sludge turns to be at odds, it reveals an endothermic reaction feature. When the pH value turns up （6.0, 7.0, 8.0） and the adsorption capacity of kaolin and activated sludge for NAPT has slightly increased, no obvious influence is ob- served. Nevertheless, when NAPT and PHEN coexist in the adsorp- tion system, the adsorption capacity of a single PAH on kaolin and activated sludge proves lower than that of in-coexisting system, which indicates a competitive adsorption.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2011年第5期37-40,共4页
Journal of Safety and Environment
基金
国家自然科学基金重点项目(50838005)
教育部长江学者创新团队计划项目(IRT0853)
国家重大水专项课题(2008ZX07317-004)
关键词
环境工程学
多环芳烃
城市污水
吸附等温式
辛醇/水分配系数
environmental engineering
polycyclic aromatic hydro-carbons （ PAHs ）
wastewater treatment
adsorptionisotherm
octanol/water partition eoeffleient
