面包酵母菌对锶离子的吸附行为及其机理研究

Biosorption Behavior of Strontium Ions and Mechanism Analysis on Baker’s Yeast

  • 摘要: 采用面包酵母菌为生物吸附剂,进行了模拟含锶废液中Sr2+的批量吸附实验研究。分析了液相pH、Sr2+初始浓度、菌体加入量、温度等因素对吸附效果的影响,进行了吸附热力学相关分析,并通过红外光谱、扫描电镜等探讨了其吸附机理。结果表明:实验室环境下的最佳吸附条件为pH=4.5,t=30 ℃c0=1.0 mmol/L,ρm4.0 g/L。不同温度下对Sr2+的等温吸附结果均很好地符合了Langmuir和Freunlich两个吸附模型,R2均在0.988以上。不同温度条件下酵母菌对Sr2+的吸附反应均能够自发进行,且在一定温度范围(10~30 ℃)内提高温度有利于酵母菌对Sr2+吸附反应的自发进行。FTIR与SEM分析结果认为,酵母菌吸附Sr2+的过程的确存在化学吸附过程,酵母菌细胞上的多糖、蛋白质酰胺成分更多地参与了对Sr2+的吸附过程,且主要以菌体表面活性点位吸附为主。

     

    Abstract: The baker’s yeast was utilized as biosorption material to remove Sr2+ from simulant aquous solution. The effect factors on biosorption were analyzed, which included pH values, initial concentration (c0), adsorbent concentration (ρm), and temperature (t). Meanwhile, the correlation biosorption thermodynamics was analyzed and the mechanism of biosorption was researched. The results show that the optimum condition for biosorption is as follows: pH=4.5, t=30 ℃, c0=1.0 mmol/L,ρm4.0 g/L. The isotherm adsorption curve of Sr2+ under different temperatures accords well with the Langmuir and Freunlich absorption models, and both R2 are above 0.988. The biosorption of Sr2+ by yeast can proceed spontaneously under different temperatures. And the higher temperature is in favour of the spontaneous process of Sr2+ biosorption at the range of 10-30 ℃. The analysis indicates that there is chemisorption in the course of Sr2+ biosorption by yeast. The components of yeast cell, including polysaccharide and amide protein, are involved in the Sr2+ biosorption. And the principal absorption sites are the active sites on the cell wall surface.

     

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