重金属镉对污水生物膜吸附菲的影响机制

为了探究重金属镉(Cd)对污水生物膜吸附菲(phenanthrene，PHE)的影响及机制，以新疆乌鲁木齐某含油污水库生物膜为研究对象，通过对比有Cd²⁺和无Cd²⁺条件下，污水生物膜对PHE的吸附性能，Cd²⁺的存在对污水生物膜吸附PHE有促进作用。有Cd²⁺和无Cd²⁺条件下，在pH=6、温度为35 ℃时污水生物膜对PHE的吸附效果最好；吸附动力学和吸附等温线方程均符合拟二级动力学和Langmuir模型，说明吸附以单分子层的化学吸附为主，并且有Cd²⁺时污水生物膜对PHE的最大吸附量比无Cd²⁺时高出21.8%。SEM、FTIR和XPS的表征分析结果表明，有Cd²⁺和无Cd²⁺条件下污水生物膜表面与PHE发生作用的基团基本相同，吸附过程中的主要官能团为有机质中的羟基、羧基和酰胺基团。

The influence mechanism of heavy metal cadmium on phenanthrene adsorption onto sewage biofilm

To explore the effect and mechanism of cadmium (Cd) on phenanthrene (PHE) adsorption onto sewage biofilm, Urumqi oil reservoir biofilm was taken as the research object, then the PHE adsorption performance onto the sewage biofilm was compared with and without Cd2+. The results showed that PHE adsorption onto the sewage biofilm was promoted in the presence of Cd2+. Whether with or without Cd2+, the best PHE adsorption effect onto the sewage biofilm occurred at pH 6 and 35 ℃. The simulated kinetics and isotherm equations were consistent with the pseudo-second-order kinetics and Langmuir model, indicating that the adsorption is dominated by the chemisorption of monolayers, and the maximum PHE adsorption amount with Cd2+ was 21.8% higher than that in the absence of Cd2+. The result of SEM, FTIR, and XPS characterization indicated that the groups on the sewage biofilm surface absorbing PHE with or without Cd2+ were basically same, and the main functional groups in organics were hydroxyl, carboxyl, and amide ones.