活性污泥对直接耐晒黑G的吸附动力学及热力学研究

Kinetic and Thermodynamic Characteristics of Direct Black G Adsorption on Activated Sludge

以污水厂的活性污泥为吸附剂,对水溶液中的直接耐晒黑G(Direct Black G,DB G)进行吸附性能研究.考察了污泥pH、吸附时间、污泥量、离子浓度和温度等对吸附的影响,对吸附热力学和吸附动力学进行了探讨.结果表明,污泥可以快速吸附水中的DB G,污泥吸附DB G时最佳污泥pH为1;离子浓度和温度变化对污泥吸附DB G的影响很小;Freundlich方程可以较好的描述DB G在污泥上的吸附等温过程;污泥对DB G的吸附行为可以用假二级动力学来描述,其吸附过程受膜扩散和颗粒扩散的共同影响,DB G质量浓度越高,前者影响作用越大.热力学分析表明污泥对DB G的吸附为自发、吸热过程,温度升高自发进行的趋势增大.

Adsorption of direct black G（DB G） with excess activated sludge（AS） was studied in simulated wastewater. The effects of EAS p H, adsorption time, sludge dosage, ion concentration and temperature on DB G removal efficiency were investigated. The adsorption kinetics and thermodynamics were also analyzed. The results showed that the EAS adsorbed DB G in a short time and the best p H value of EAS was p H1. The variations of ion concentration and temperature had a little impact on the adsorption process. Mathematical model simulation showed that the adsorption process by EAS better followed the Freundlich adsorption isotherm. The kinetic experimental results were best adjusted to the pseudo second order model. The adsorption process was controlled by both membrane diffusion and internal diffusion, and the influence of the former became more obvious with the increase of the DB G concentration. The study on thermodynamics showed that the adsorption process was endothermic and spontaneous. High temperatures favored the sorption process.