自然水体生物膜对铜(Ⅱ)、镉(Ⅱ)的吸附研究

以董铺水库为水源、天然纯棉绳为人工基质培养生物膜,研究了附着在棉绳表面上的自然水体生物膜吸附Cu和Cd的热力学和动力学特征及pH对吸附性能的影响.通过对实验数据进行非线型拟合,发现生物膜对2种重金属的吸附均符合Freundlich(F)和Langmuir(L)吸附等温式,对2种金属的吸附能力顺序是:Cu＞Cd.生物膜对Cu和Cd的吸附在数小时内可达到平衡,吸附过程符合二级动力学特征.通过调节吸附液的pH值,研究了不同pH对吸附效果的影响.结果表明,随着pH的升高,2种金属的吸附量明显增加.

Sorption of Cu( Ⅱ ) and Cd( Ⅱ ) by natural biofilms

With high adsorption capability and adsorption surface area, biofilms are actively researched, especially in the area of adsorption of heavy metals. Heavy metal adsorption is greatly affected by the method of developing the biofilm. A biofilm was developed in Dongpu reservoir on the surface of a cotton thread. The characteristics and thermodynamics of Cu and Cd adsorption on the biofilm were studies. Statistical analysis of the adsorption data showed that the thermodynamic data for each metal fit the Freundlich(F) and Langmuir(L) isotherms. The capacity of adsorption of Cu was greater than that for Cd. The adsorption of both Cu and Cd reached equilibrium in less than one hour and fit a second-order kinetics equation. The adsorption of Cu and Cd increased with pH up to pH 7.