以甲醛为交联剂,将胱氨酸修饰到啤酒酵母菌(SC)上,并采用海藻酸钠和明胶固定化,得到一种新型的生物吸附剂——修饰啤酒酵母菌(MSC)。通过红外光谱(IR)分别表征了两种吸附剂的结构,考察了其吸附铀的主要影响因素即溶液pH值、吸附时间等。结果表明:MSC细胞表面具有大量吸附铀的基团,MSC和SC吸附铀的最佳条件是:pH值为6.0,吸附时间分别为1.8、1.5h。对吸附动力学模型和吸附等温模型进行了分析,MSC和SC对铀的吸附动力学模型较好地符合了准二级动力学模型,MSC和SC的相关系数均大于0.99;吸附等温线均能符合Langmuir和Freundlich等温线模型,说明该吸附体系是一个单层覆盖与多层吸附相结合的吸附模式,且MSC的最大吸附量是SC的6.5倍。
Modified Saccharomyces cerevisiae (MSC) was prepared from Saccharomyces cerevisiae (SC) by cystine modification and formaldehyde as crosslinker, and was immobilized by alginate sodium and glut. FTIR was used to characterize MSC and SC, and the effects of pH value and time on uranium adsorption over MSC and SC were investigated. It was found that there were many functional groups on the cell wall of MSC for adsorbing uranium. The optimal conditions for uranium adsorption were as follows: pH of the solution 6.0; the adsorption time for MSC and SC was 1.8 h and 1.5 h, respectively. The adsorption kinetics and isotherm models were proposed for adsorption of uranium on MSC and SC by fitting experimental data. The pseudo-second-order mode was better for both MSC and SC, their correlation coefficient better than 0.99 (R2〉 0.99), and Langmuir and Freundlich models were better isotherm models, indicating that the adsorption mode of uranium adsorption on MSC and SC was a combination of monolayer cover and multilayer adsorption. The capability of adsorption for MSC was 6.5 times that for SC, and indicated that MSC had potential as bioadsorbent.