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
The present study screens activity of different enzymes in Trapa natans under aerobic and anaerobic physiological conditions. Experimental analysis was carried out to assay the activities of ALDH and ADH in the seed e...The present study screens activity of different enzymes in Trapa natans under aerobic and anaerobic physiological conditions. Experimental analysis was carried out to assay the activities of ALDH and ADH in the seed extract of T. natans. These enzymes are associated with the alcohol metabolism of the T. natans. It was observed that a metabolic pathway shifts from aerobic respiration to anaerobic fermentation under anoxic conditions. Physiological stress related response in trapa seeds gives the leads to understand the other model for better fermentable products. During the experiment it was found that there is difference between the concenteration of enzymes in anaerobic and aerobic conditions. Concentration was check with the help of spectrophotometer at 340 nm.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
Objective:To evaluate the effect of some different water temperatures on growth of aquatic plants (Salvinia natans andCeratophyllum demersum). <br> Methods:The aquatic plants were brought from Shatt Al-Arab Rive...Objective:To evaluate the effect of some different water temperatures on growth of aquatic plants (Salvinia natans andCeratophyllum demersum). <br> Methods:The aquatic plants were brought from Shatt Al-Arab River in 2016. Equal weights of aquatic plants were aquacultured in aquaria, and were exposed to three different temperatures ( 12, 22 and 32°C). <br> Results: The results showed that the two plants did not show significant differences with respect to their effects on pH and electrical conductivity values. Time and temperature did not affect the values of pH and electrical conductivity. The values of dissolved oxygen was significantly influenced with variation of time and temperature, while the two plants did not have significant differences on dissolved oxygen values, nitrate ion concentration and was not significantly influenced with variation of plant species or temperature or time. Plant species and temperature significantly affected phosphate ion concentration, while the time did not significantly influence the concentration of phosphate ion. Chlorophyll a content and biomass were significantly influenced with the variation of plant species, and temperature . <br> Conclusions:Aquatic plants has a species specific respond to temperatures change in their environment. Water plant,Ceratophyllum demersum is more tolerant to temperatures change thanSalvinia natans.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The present study screens activity of different enzymes in Trapa natans under aerobic and anaerobic physiological conditions. Experimental analysis was carried out to assay the activities of ALDH and ADH in the seed extract of T. natans. These enzymes are associated with the alcohol metabolism of the T. natans. It was observed that a metabolic pathway shifts from aerobic respiration to anaerobic fermentation under anoxic conditions. Physiological stress related response in trapa seeds gives the leads to understand the other model for better fermentable products. During the experiment it was found that there is difference between the concenteration of enzymes in anaerobic and aerobic conditions. Concentration was check with the help of spectrophotometer at 340 nm.
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.
文摘Objective:To evaluate the effect of some different water temperatures on growth of aquatic plants (Salvinia natans andCeratophyllum demersum). <br> Methods:The aquatic plants were brought from Shatt Al-Arab River in 2016. Equal weights of aquatic plants were aquacultured in aquaria, and were exposed to three different temperatures ( 12, 22 and 32°C). <br> Results: The results showed that the two plants did not show significant differences with respect to their effects on pH and electrical conductivity values. Time and temperature did not affect the values of pH and electrical conductivity. The values of dissolved oxygen was significantly influenced with variation of time and temperature, while the two plants did not have significant differences on dissolved oxygen values, nitrate ion concentration and was not significantly influenced with variation of plant species or temperature or time. Plant species and temperature significantly affected phosphate ion concentration, while the time did not significantly influence the concentration of phosphate ion. Chlorophyll a content and biomass were significantly influenced with the variation of plant species, and temperature . <br> Conclusions:Aquatic plants has a species specific respond to temperatures change in their environment. Water plant,Ceratophyllum demersum is more tolerant to temperatures change thanSalvinia natans.
