| 酿酒酵母吸附Zn(Ⅱ)过程中阳离子(K+，Mg2+，Na+，Ca2+)的变化分析 |
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| 中文关键词 酿酒酵母 生物吸附 锌离子 阳离子释放 K+ |
| 英文关键词 Saccharomyces cerevisiae biosorption zinc ions cation release Potassium ion |
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| 中文摘要 |
| 研究了酿酒酵母无缓冲溶液体系吸附Zn(Ⅱ)的过程中各种阳离子的变化情况。研究结果表明，当Zn(Ⅱ)的初始浓度是0.08 ～0.8 mmol?L-1，酵母浓度约1 g?L-1，初始pH为5.65，反应38 h内，酵母的Zn(Ⅱ)吸附量为74.8～654.8 μmol?g-1，去除率达到76.4%～92.8%，pH值升高0.55～1.28。吸附过程中酵母首先快速释放大量K+，其次是Mg2+和Na+，Ca2+的释放量较少，数量级一般可分别达到几百、几十和几个μmol?g-1。以离子交换为基础计算的各阳离子释放量总和一般超过Zn(Ⅱ)的吸附量，证明酵母吸附Zn(Ⅱ)的机理之一是离子交换，但不唯一。无缓冲溶液体系酵母吸附Zn(Ⅱ)的过程中溶液pH值升高，H+被吸收，K+等阳离子释放，是生物体细胞的本质属性，与Zn(Ⅱ)是否存在无关，但是Zn(Ⅱ)可以促进阳离子的释放以及降低酵母对H+的吸收，也反映出Zn(Ⅱ)与H+之间可以竞争细胞表面吸附位。死酵母的吸附量低于未处理酵母，与阳离子交换能力关系不大，可能与细胞表面变形导致Zn(Ⅱ)吸附困难有关。 |
| 英文摘要 |
| The biosorption of Zn(Ⅱ) by the intact yeast of Saccharomyces cerevisiae was investigated for different initial concentration of the metal ion (0.08～0.8 mmol?L-1) and for different time (0 ～38 h) at natural pH of 5.65 without buffer. The metal uptake was 74.84～654.76 μmol?g-1 when the sorbent concentration is about 1 g?L-1. The pH value increases and the release of physiological cations occured in the biosorption process. Potassium ion first released rapidly in the order of hundreds of μmol?g-1, then magnesium and sodium ions release slowly with several to less a hundred of μmol?g-1, and the release of cadmium ion were rare. The total quantity of release is often larger than that of Zn(Ⅱ) uptake. Increase in pH value and release of those cations reflected the intrinsic ability of the cell, however the presence of Zn(Ⅱ) would promote the release of those cations such as K+ and Mg2+, and decrease to absorb H+. Ion exchange was one of the mechanisms for Zn(Ⅱ) uptake by the biomass. |
