啤酒废酵母对镉离子的吸附研究

The biosorption of cadmium(II) by discarded brewers yeast

以啤酒酿造厂的啤酒废酵母为生物吸附剂,研究啤酒废酵母对Cd2+的生物吸附行为。利用原子吸收光谱法测定Cd2+含量。结果表明,啤酒废酵母吸附Cd2+受吸附时间、吸附温度、溶液pH值、酵母添加量和Cd2+起始浓度等因素的影响。实验确定了啤酒废酵母对Cd2+的最佳吸附条件。即:pH值6,Cd2+浓度为50mg/L,酵母添加量为1.0g/L,吸附温度25℃,吸附时间30min,此时啤酒废酵母对Cd2+的吸附量可达42.92mg/g干酵母。吸附Cd2+的啤酒废酵母用1.0mol/L的HCl解吸,解吸率达75.46%。对未吸附Cd2+的空白酵母和吸附Cd2+的酵母进行红外光谱分析,结果显示啤酒废酵母吸附Cd2+后羟基和羧基吸收峰发生明显变化,因此认为羟基和羧基在生物吸附中起着重要作用。

The discarded brewers yeast obtained from brewery was used as bio-adsorbent. The biosorption of cadmium ion by discarded brewers yeast was studied. The content of Cd^2＋ was determined by atomic absorption spectrometry （AAS） analysis. It showed that sorption time, temperature, pH, yeast recruitment, and Cd^2＋ initial concentration etc influenced on the biosorption of Cd^2＋. The optimal sorption condition for discarded brewers yeast were as follows： pH 6, Cd^2＋ concentration 50mg/L, yeast recruitment 1.0g/L, sorption temperature 25~C, sorption time 30 minutes. Under this condition, the biosorption capacity was 42. 92mg Cd^2＋/g dry cells. After sorption discarded brewers yeast was treated with 1.0 mol/L HCl, and 75.46% of uptaked Cd^2＋ was desorbed to the solution. The blank and cadmium-sorption yeast were studied by Fourier Transform Infrared （FFIR） spectroscopy. The hydroxyl and carboxyl absorption bands had obvious change after cadmium ion adsorbed. It indicated that hydroxyl and carboxyl were important for biosorption.