The characteristics of Pb^2＋ adsorption on the surface of birnessites with different average oxidation states （AOS） of Mn, synthesized under acidic and alkali conditions, were investigated. The results indicated th...The characteristics of Pb^2＋ adsorption on the surface of birnessites with different average oxidation states （AOS） of Mn, synthesized under acidic and alkali conditions, were investigated. The results indicated that the amount of adsorbed Pb^2＋ increased with the increase of Mn AOS in birnessites. The amount of Pb〉 adsorbed positively correlated with the amount of released Mn^2＋, H^＋, and K^＋ （r = 0.9962 〉 0.6614, n = 14, ct = 0.01）. The released Mn^2＋, H^＋, and K^＋ were derived mostly from the corresponding cations adsorbed on the vacant sites. The maximum amount of adsorbed Pb^2＋ increased with the increasing vacant cation sites, leading to an increase of the total amount of released Mn^2＋, H^＋, and K^＋, and the increased likelihood for two Pb^2＋ adsorbed in the region of one side of a vacant site.展开更多
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...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.展开更多
基金supported by the National Natural Science Foundation of China (No. 40471070)the National Excellent Doctoral Dissertation of China(No. 200767)
文摘The characteristics of Pb^2＋ adsorption on the surface of birnessites with different average oxidation states （AOS） of Mn, synthesized under acidic and alkali conditions, were investigated. The results indicated that the amount of adsorbed Pb^2＋ increased with the increase of Mn AOS in birnessites. The amount of Pb〉 adsorbed positively correlated with the amount of released Mn^2＋, H^＋, and K^＋ （r = 0.9962 〉 0.6614, n = 14, ct = 0.01）. The released Mn^2＋, H^＋, and K^＋ were derived mostly from the corresponding cations adsorbed on the vacant sites. The maximum amount of adsorbed Pb^2＋ increased with the increasing vacant cation sites, leading to an increase of the total amount of released Mn^2＋, H^＋, and K^＋, and the increased likelihood for two Pb^2＋ adsorbed in the region of one side of a vacant site.
基金supported by the National Natural Science Foundation of China (No. 50278045)the Basic Research Fund of Tsinghua University (No. JC2002054).
文摘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.
