Influencing factors, such as the biomass concentration, pH value, temperature and time of adsorption on the removal of Cd^2＋ were investigated when Sphaerotilus natans was used as a biosorbent. The results show that ...Influencing factors, such as the biomass concentration, pH value, temperature and time of adsorption on the removal of Cd^2＋ were investigated when Sphaerotilus natans was used as a biosorbent. The results show that Sphaerotilus natans has a significant effect on the adsorption of Cd^2＋. The process of adsorption will reach the equilibrium in 20 min. Temperature has no significant effect on the adsorption. The removal rate of Cd^2＋. can approach to 90% under the conditions of pH 5.5, the biomass mass concentration O. 6 g/L and the initial mass concentration of cadmium ≤20 mg/L. The maximum specific uptake is 1.9 mmol/g dry biomass . The adsorption was fitted with the Freundlich isotherm adsorption equation when the concentration of Cd^2＋ is in a range of 0--100 mg/L. HCl and EDTA can desorb Cd^2＋ from biomass effectively.展开更多
Organically modified silica (ORMOSILS) thin films produced by sol-gel method were imprinted with two bacterial strains as whole cells in order to develop an easy, fast and specific probe to detect and specifically ide...Organically modified silica (ORMOSILS) thin films produced by sol-gel method were imprinted with two bacterial strains as whole cells in order to develop an easy, fast and specific probe to detect and specifically identify these micro-organisms when present in water samples. An important feature of the imprinting process was the molecular finger-prints left by these microorganisms alongside morphology, into imprinted film cavities. The films also showed high selectivity toward the imprinted template and were able to discriminate between two very close bacterial species (E. coli and S. typhimurium). In addition, several central physical parameters of the experimental water solution were examined (i.e., pH, ionic strength and the organic load exemplified by NaCl and TOC concentration, respectively). The method sensitivity to different bacterial concentrations was studied by confocal microscopy (CLSM) and quartz crystal microbalance (QCM) tools. Results showed that increased bacterial concentrations favor rapid adsorption onto imprinted sol-gel films with high affinity, while low pH, increased organic load and high ionic concentrations (i.e., seawater) interfere with bacteria re-adsorption, reducing detection capability. Under average drinking water chemical composition the method proved to be highly efficient.展开更多
文摘采用球衣菌(Sphaerotilus natans)为生物吸附剂,研究了初始离子浓度、吸附剂用量、菌龄、pH值、温度和吸附时间等因素对其吸附硝酸银溶液模拟废水中Ag+的影响及其吸附机理.结果表明,球衣菌在初始Ag+14 m.gL-1、吸附剂用量0.2.gL-1、菌龄32 h、pH 8、温度30℃、吸附时间60 m in的优化条件下,对Ag+的吸附率为71.75%,吸附量为50.23 m.gg-1;该吸附过程是一个快速的过程,在吸附5 m in时,吸附量已达总吸附量的91%,并且以被动吸附为主;吸附动力学符合准二级动力学方程.透射电镜观察和红外光谱分析显示,球衣菌细胞表面的活性基团与Ag+发生络合反应,同时还有少量Ag+通过主动吸收过程进入活细胞内.
文摘Influencing factors, such as the biomass concentration, pH value, temperature and time of adsorption on the removal of Cd^2＋ were investigated when Sphaerotilus natans was used as a biosorbent. The results show that Sphaerotilus natans has a significant effect on the adsorption of Cd^2＋. The process of adsorption will reach the equilibrium in 20 min. Temperature has no significant effect on the adsorption. The removal rate of Cd^2＋. can approach to 90% under the conditions of pH 5.5, the biomass mass concentration O. 6 g/L and the initial mass concentration of cadmium ≤20 mg/L. The maximum specific uptake is 1.9 mmol/g dry biomass . The adsorption was fitted with the Freundlich isotherm adsorption equation when the concentration of Cd^2＋ is in a range of 0--100 mg/L. HCl and EDTA can desorb Cd^2＋ from biomass effectively.
文摘Organically modified silica (ORMOSILS) thin films produced by sol-gel method were imprinted with two bacterial strains as whole cells in order to develop an easy, fast and specific probe to detect and specifically identify these micro-organisms when present in water samples. An important feature of the imprinting process was the molecular finger-prints left by these microorganisms alongside morphology, into imprinted film cavities. The films also showed high selectivity toward the imprinted template and were able to discriminate between two very close bacterial species (E. coli and S. typhimurium). In addition, several central physical parameters of the experimental water solution were examined (i.e., pH, ionic strength and the organic load exemplified by NaCl and TOC concentration, respectively). The method sensitivity to different bacterial concentrations was studied by confocal microscopy (CLSM) and quartz crystal microbalance (QCM) tools. Results showed that increased bacterial concentrations favor rapid adsorption onto imprinted sol-gel films with high affinity, while low pH, increased organic load and high ionic concentrations (i.e., seawater) interfere with bacteria re-adsorption, reducing detection capability. Under average drinking water chemical composition the method proved to be highly efficient.
