Characteristics of Zn^(2+) Biosorption by Saccharomyces cerevisiae

Objective To investigate the characteristics of Zn^2＋ biosorption and the release of cations during the process of Zn^2＋ biosorption by intact cells of Saccharomyces cerevisiae. Methods The batch adsorption test was used to study the biosorption equilibrium and isotherm. Zn^2＋ concentration was measured with atomic adsorption spectrophotometer （AAS） AAS 6.Vario. Results When the initial concentration of Zn^2＋ ranged between 0.08 and 0.8 retool/L, the initial pH was natural （about 5.65）, the sorbent concentration was about 1 g/L and the capacity ofZn〉 biosorption was from 74.8 to 654.8 μmol/g. The pH value increased by 0.55-1.28 and the intracellular cations （K^＋, Mg^2＋, Na^＋, Ca〉） of the cells were re/eased during the process of Zn〉 biosorption. Conclusion Ion exchange was one of the mechanisms for Zn^2＋ biosorption. The biomass of Saccharomyces cerevisiae is a potential biosorbent for the removal of Zn^2＋ from aqueous solution. More work needs to be done before putting it into practical application.

Removing cadmium from electroplating wastewater by waste saccharomyces cerevisiae

The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.

Biosorption of Cd2＋ and CU2＋ on immobilized Saccharomyces cerevisiae

The biosorption of Cd2＋ and CH2＋ onto the immobilized Saccharomyces cerevisiae （S. cerevisiae） was investigated in this study. Adsorption kinetics, isotherms and the effect ofpH were studied. The results indicated that the biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae was fast at initial stage and then became slow. The maximum biosorption of heavy metal ions on immobilized S. cerevisiae were observed at pH 4 for Cde＋ and Cu^2＋. by the pseudo-second-order model described the sorption kinetic data well according to the high correlation coefficient （R2） obtained. The biosorption isotherm was fitted well by the Langmuir model, indicating possible mono-layer biosorption of Cd^2＋ and Cu^2＋ on the immobilized S. cerevisiae. Moreover, the immobilized S. cerevisiae after the sorption of Cd^2＋ and Cu^2＋ could be regenerated and reused.

生物吸附-沉降法去除电镀废水中镉

以水洗废啤酒酵母为吸附剂,采用吸附-沉降法,研究水洗废啤酒酵母对电镀废水中镉的吸附规律及沉降效果。结果表明,在废水中镉含量为26mg/L、pH7、水洗废啤酒酵母用量40g/L(含水约72%)、室温(约18℃)、搅拌速度800r/min、吸附时间30min、沉降3.5h的条件下,废水中镉的吸附率及吸附-沉降后镉的去除率均达96%以上。并采用透射电子显微镜、电动电位及红外光谱分析手段,分析水洗废啤酒酵母对镉的吸附机理。水洗废啤酒酵母对镉的吸附不仅发生菌体表面,也发生在菌体内部。吸附过程存在化学络合、静电吸引、氢键等作用。

啤酒酵母吸附镉离子的试验研究

研究了啤酒酵母对镉的生物吸附过程 ,结果表明 ,啤酒酵母吸附镉的速度是非常快的 ;p H对镉的吸附影响较大 ,吸附较佳的 p H范围为 4～ 8,并且啤酒酵母有调节 p H的作用 ,p H为 4～ 8的溶液在吸附反应后 ,其 p H接近于 5 .8;温度、酵母用量、Cd2 +的初始浓度对吸附均有一定的影响。实际含镉废水处理结果表明 ,啤酒酵母处理含镉废水是有效的。

啤酒酵母对镉离子的吸附及镉离子的解吸

研究了啤酒酵母对镉的生物吸附过程及吸附后镉的解析过程。吸附试验表明:啤酒酵母吸附镉的速度非常快;初始pH值对镉的吸附影响较大,吸附过程最佳初始pH范围为4～8之间;啤酒酵母有调节pH值的作用,初始pH值为4～8的溶液在吸附反应后,最终pH值均为5.8左右;酵母用量对吸附有一定影响,但用量不宜过大;Cd2+的初始浓度对吸附影响较小,因而啤酒酵母可处理高浓度含镉废水。解吸试验表明:用稀盐酸可将吸附于啤酒酵母的镉快速解吸,盐酸浓度对解吸率影响不大。

酿酒酵母吸附Zn(Ⅱ)过程中阳离子(K^+,Mg^(2+),Na+,Ca^(2+))的变化分析

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38h内,酵母的Zn(Ⅱ)吸附量为74.8~654.8μmol.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.

灭活面包酵母菌对水溶液中镉离子的吸附特性

以灭活面包酵母菌(Saccharomyces cerevisiae)作为生物吸附剂,研究了初始液相pH值、吸附剂质量浓度ρa、Cd^(2+)初始质量浓度ρ0等因素对面包酵母菌吸附Cd^(2+)过程的影响,并进行吸附动力学、等温吸附和SEM/EDS分析.结果表明,较佳吸附条件:pH=4.5~7.0,ρa=4.0~6.0g/L,ρ0=112.4~224.8mg/L.吸附动力学分析表明面包酵母菌对Cd^(2+)的吸附是一个快速反应的过程,吸附过程可用准二级动力学模型来描述.等温吸附结果较好地符合Langmuir和Freundlich吸附模型.SEM/EDS分析发现,大量的Cd^(2+)被吸附在细胞表面,这说明灭活面包酵母菌对Cd^(2+)的吸附效果较好.

啤酒酵母对镉的吸附特性研究

以啤酒酵母为吸附剂,研究了吸附时间、pH、菌体用量和初始浓度对镉吸附效果的影响,采用Langmuir和Freundich方程对镉的等温吸附过程进行了拟合。结果表明,啤酒酵母对镉的吸附是一个先快后慢的过程,在pH 4.0时吸附量最大;提高菌体用量可增加啤酒酵母镉的总吸附量,但单位酵母的吸附量降低;提高初始浓度增加啤酒酵母对镉的吸附。啤酒酵母对镉的等温吸附可用Langmuir方程和Freundlich方程拟合,但Langmuir方程的拟合效果更好。Pb2+、Zn2+、Fe2+、Cu2+抑制啤酒酵母对Cd2+的吸附,抑制强弱为Pb2+<Zn2+<Fe2+<Cu2+。