Different mathematical methods, including linearization, differential, integration and nonlinear least squares approximation (Newton-Marquardt method), were used to fit different kinetic equations, such as zero-order,...Different mathematical methods, including linearization, differential, integration and nonlinear least squares approximation (Newton-Marquardt method), were used to fit different kinetic equations, such as zero-order, first-order (i. e, membrane diffusion), second-order, parabolic-diffusion, Elovich, two-constant equations, to the experimental data of Pb2+ and Cu2+ adsorption on variable charge soils and kaolinite. Assuming each M2+ occupied two adsorption sites, two more equations, the so-called surface second-order equation and third-order equation were derived and compared with the above equations according to the fitting results, which showed that the second-order equation and surface second-order equation, being one equation in different expressions under some conditions, were better than the other equations in describing the Pb2+ and Cu2+ adsorption kinetics, and the latter was the best.展开更多
The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to t...The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the ahove two heavy metal ions, The resubs showed that low concentration of Cu^2＋ and Cd^2＋ could promote the growth and could enhance the POD activity of tomato seedlings, while high concentratiun Cu^2＋ and Cd^2＋ could inhibit seedling growth and POD activity of tomato seedlings. Cd^2＋ functioned more obviously than that of Cu^2＋ , two tomato cultivars also presented difference in response to heavy metal stress.展开更多
In order to realize resource utilization of industrial tungsten residue and treatment of heavy metal wastewater in mining and metallurgical area of south China,a novel ceramsite was prepared with the main raw material...In order to realize resource utilization of industrial tungsten residue and treatment of heavy metal wastewater in mining and metallurgical area of south China,a novel ceramsite was prepared with the main raw materials of diatomite and tungsten residue.The adsorption behavior of copper ions in solution on the ceramsite was investigated.Results indicated that the surface of the newly-developed ceramsite was rough and porous.There were lots of pores across the ceramsite from inner to outside.MnFe2O4 was one of the main components of the ceramsite.The Cu^2＋adsorption capacity by the ceramsite reached 9.421 mg/g with copper removal efficiency of 94.21%at 303 K,initial Cu^2＋concentration of 100 mg/L and dosage of 0.5 g after 300 min adsorption.With increase of ceramsite dosage,the total adsorption amount of Cu^2＋increased,but the adsorption capacity decreased.The adsorption capacity increased with the increase of solution p H.The isothermal adsorption of Cu^2＋by the ceramsite fitted the Freundlich model better.The adsorption mainly occurred on a heterogeneous surface,and was a favorable process.The adsorption process closely followed the pseudo-second kinetic equation.In initial stage of wastewater treatment,the adsorption process should be controlled mainly by diffusion,and the removal of Cu^2＋can be improved by enhancing agitation.展开更多
基金Project supported by the N ational Natural Science Foundation of China.
文摘Different mathematical methods, including linearization, differential, integration and nonlinear least squares approximation (Newton-Marquardt method), were used to fit different kinetic equations, such as zero-order, first-order (i. e, membrane diffusion), second-order, parabolic-diffusion, Elovich, two-constant equations, to the experimental data of Pb2+ and Cu2+ adsorption on variable charge soils and kaolinite. Assuming each M2+ occupied two adsorption sites, two more equations, the so-called surface second-order equation and third-order equation were derived and compared with the above equations according to the fitting results, which showed that the second-order equation and surface second-order equation, being one equation in different expressions under some conditions, were better than the other equations in describing the Pb2+ and Cu2+ adsorption kinetics, and the latter was the best.
文摘The growth situation and peroxidase （POD） of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu^2＋ and Cd^2＋ . The toxicity differences of Cu^2＋ and Cd^2＋ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the ahove two heavy metal ions, The resubs showed that low concentration of Cu^2＋ and Cd^2＋ could promote the growth and could enhance the POD activity of tomato seedlings, while high concentratiun Cu^2＋ and Cd^2＋ could inhibit seedling growth and POD activity of tomato seedlings. Cd^2＋ functioned more obviously than that of Cu^2＋ , two tomato cultivars also presented difference in response to heavy metal stress.
基金Project(51674305)supported by the National Natural Science Foundation of ChinaKey Project(1602FKDC007)supported by Science and Technology Program of Gansu Province,China+1 种基金Projects(2016YT03N101,2017A090905024)supported by Science and Technology Program of Guangdong Province,ChinaProject(NSFJ2015-K06)supported by Jiangxi University of Science and Technology,China
文摘In order to realize resource utilization of industrial tungsten residue and treatment of heavy metal wastewater in mining and metallurgical area of south China,a novel ceramsite was prepared with the main raw materials of diatomite and tungsten residue.The adsorption behavior of copper ions in solution on the ceramsite was investigated.Results indicated that the surface of the newly-developed ceramsite was rough and porous.There were lots of pores across the ceramsite from inner to outside.MnFe2O4 was one of the main components of the ceramsite.The Cu^2＋adsorption capacity by the ceramsite reached 9.421 mg/g with copper removal efficiency of 94.21%at 303 K,initial Cu^2＋concentration of 100 mg/L and dosage of 0.5 g after 300 min adsorption.With increase of ceramsite dosage,the total adsorption amount of Cu^2＋increased,but the adsorption capacity decreased.The adsorption capacity increased with the increase of solution p H.The isothermal adsorption of Cu^2＋by the ceramsite fitted the Freundlich model better.The adsorption mainly occurred on a heterogeneous surface,and was a favorable process.The adsorption process closely followed the pseudo-second kinetic equation.In initial stage of wastewater treatment,the adsorption process should be controlled mainly by diffusion,and the removal of Cu^2＋can be improved by enhancing agitation.
