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目的以自然水体培育生物膜,研究了该生物膜对铜铁的吸附特性。方法采集自然水体培育的生物膜,对模拟配制的含铜铁的实验用废水进行吸附实验。在吸附过程中分别改变p H、反应时间、温度等因素,得到最佳的吸附条件,并在此基础上进行吸附等温线和动力学研究。结果生物膜对铜铁的吸附量分别随p H、温度的升高表现出先增加后降低。随着吸附时间的延长,在早期生物膜与金属离子的反应速率较快,之后趋于平稳。吸附实验开始前30 min内,p H=5~6,温度25℃~45℃,为吸附的最佳条件。Langmuir和Freundlich两种吸附等温式均能准确表达生物膜对Fe2+和Cu2+的吸附过程,但Langmuir模型表现出更好的拟合度。吸附动力学符合准二级动力学方程,相关系数分别为R2Fe=0.9996、R2Cu=0.9953。结论在最适反应条件下,生物膜对铜铁有较高的去除率,并且对铁的吸附量高于铜。
Objective To cultivate biofilm from natural water and study the adsorption characteristics of the biofilm to copper and iron. Methods The biofilm cultivated in natural water was collected and the experimental wastewater containing copper and iron was simulated. In the adsorption process were changed p H, reaction time, temperature and other factors, the best adsorption conditions, and on the basis of adsorption isotherms and kinetics. Results The adsorption capacity of biofilm to copper and iron increased first and then decreased with the increase of p H and temperature, respectively. With the extension of adsorption time, the reaction rate of biofilm with metal ions in the early stage was faster and then stabilized. Within 30 min before the adsorption experiment, p H = 5 ~ 6 and temperature 25 ℃ ~ 45 ℃ were the best adsorption conditions. Both Langmuir and Freundlich adsorption isotherms could express biofilms’ adsorption of Fe2 + and Cu2 + accurately, but the Langmuir model showed a better fit. The adsorption kinetics was in accordance with the quasi-second-order kinetic equation with correlation coefficients of R2Fe = 0.9996 and R2Cu = 0.9953, respectively. Conclusion Under optimal reaction conditions, the biofilm has a higher removal rate of copper and iron, and the adsorption capacity of iron is higher than that of copper.