Mahmoud Mohamed E, Yakout Amr A, Osman Maher M
Medical Chemistry Department, Faculty of Medicine, King Abdullaziz University, Jeddah, Saudi Arabia.
J Hazard Mater. 2009 May 30;164(2-3):1036-44. doi: 10.1016/j.jhazmat.2008.09.017. Epub 2008 Sep 12.
Dowex anion exchanger-immobilized-baker's yeast [Dae-yeast] were synthesized and potentially applied as environmental friendly biosorbents to evaluate the up-take process of anionic and cationic mercury(II) species as well as other metal ions. Optimization of mass ratio of Dowex anion exchanger versus yeast (1:1-1:10) in presence of various interacting buffer solutions (pH 4.0-9.0) was performed and evaluated. Surface modification of [Dae-yeast] was characterized by scanning electron microscopy (SEM) and infrared spectroscopy. The maximum metal biosorption capacity values of [Dae-yeast] towards mercury(II) were found in the range of 0.800-0.960, 0.840-0.950 and 0.730-0.900 mmol g(-1) in presence of buffer solutions pH 2.0, 4.0 and 7.0, respectively. Three possible and different mechanisms are proposed to account for the biosorption of mercury and mercuric species under these three buffering conditions based on ion exchange, ion pair and chelation interaction processes. Factors affecting biosorption of mercury from aqueous medium including the pH effect of aqueous solutions (1.0-7.0), shaking time (1-30 min) and interfering ions were se arched. The potential applications of modified biosorbents for selective biosorption and extraction of mercury from different real matrices including dental filling waste materials, industrial waste water samples and mercury lamp waste materials were also explored. The results denote to excellent percentage extraction values, from nitric acid as the dissolution solvent with a pH 2.0, as determined in the range of 90.77-97.91+/-3.00-5.00%, 90.00-93.40+/-4.00-5.00% and 92.31-100.00+/-3.00-4.00% for the three tested samples, respectively.
合成了强碱性阴离子交换树脂固定化面包酵母[Dae-酵母]，并将其作为环境友好型生物吸附剂用于评估阴离子和阳离子汞（II）物种以及其他金属离子的吸收过程。在各种相互作用的缓冲溶液（pH 4.0 - 9.0）存在的情况下，对强碱性阴离子交换树脂与酵母的质量比（1:1 - 1:10）进行了优化和评估。通过扫描电子显微镜（SEM）和红外光谱对[Dae-酵母]的表面改性进行了表征。在pH 2.0、4.0和7.0的缓冲溶液存在下，[Dae-酵母]对汞（II）的最大金属生物吸附容量值分别在0.800 - 0.960、0.840 - 0.950和0.730 - 0.900 mmol g⁻¹范围内。基于离子交换、离子对和螯合相互作用过程，提出了三种可能且不同的机制来解释在这三种缓冲条件下汞和汞物种的生物吸附。研究了影响从水介质中生物吸附汞的因素，包括水溶液的pH值（1.0 - 7.0）、振荡时间（1 - 30分钟）和干扰离子。还探索了改性生物吸附剂在从不同实际基质（包括牙科填充废料、工业废水样品和汞灯废料）中选择性生物吸附和提取汞方面的潜在应用。结果表明，以pH 2.0的硝酸作为溶解溶剂时，三种测试样品的提取率分别在90.77 - 97.91±³.⁰⁰ - ⁵.⁰⁰%、90.00 - 93.40±⁴.⁰⁰ - ⁵.⁰⁰%和92.31 - 100.00±³.⁰⁰ - ⁴.⁰⁰%范围内，提取率极高。
