Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunli...Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.展开更多
The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic ...The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;C atrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min -1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.展开更多
文章将鸽粪作为发酵原料,在30℃±0.2℃恒温槽水浴条件下,以全混合批量式发酵的方法产沼气。实验结果表明,鸽粪是较为良好的发酵原料,其TS产气率和VS产气率分别为486 m L·g-1和631 m L·g-1。与其他原料相比,分别是鸡粪的1...文章将鸽粪作为发酵原料,在30℃±0.2℃恒温槽水浴条件下,以全混合批量式发酵的方法产沼气。实验结果表明,鸽粪是较为良好的发酵原料,其TS产气率和VS产气率分别为486 m L·g-1和631 m L·g-1。与其他原料相比,分别是鸡粪的1.56倍,兔粪的1.08倍,猪粪的1.15倍。运用一级动力学的相关原理和修正后的Gompertz方程进行计算机拟合,分析了整个鸽粪厌氧消化周期中的产沼气规律。展开更多
The application of organic amendments in upland soils may influence soil carbon (C) and nitrogen (N) mineralization, which are very important for understanding plant nutrition. However, the kinetics of C and N mineral...The application of organic amendments in upland soils may influence soil carbon (C) and nitrogen (N) mineralization, which are very important for understanding plant nutrition. However, the kinetics of C and N mineralization from organically amended upland purplish soils has been poorly studied. Therefore, this study investigates C and N mineralization kinetics in organically amended upland purplish soils. Incubation experiments were conducted using soil samples collected from experimental plots that have been under long-term organic amendment fertilization, which includes: Organic manure (OM), crop residues (CR), combined organic manure with inorganic fertilizers (OMNPK), combined crop residue with inorganic fertilizers (CRNPK), conventional inorganic fertilizer (NPK), and no fertilizer (CK). The results showed that organically amended treatments increased C and N mineralization rates by 8 - 24% and 17 - 33%, respectively, compared with NPK. Likewise, the amount of potentially mineralizable carbon (Co) and nitrogen (No) increased by 4 - 9% and 15 - 20%, respectively, compared to the conventional NPK treatment. The rate constants for labile C (kC) and N (kN) were 6 - 29% and 3 - 27% higher than the NPK treatment, respectively. In addition, the initial potential rate of C (Co × kC) and N (No × kN) in organically amended soils were 10 - 37% and 18 - 52% higher compared to NPK. This study tried to show that the mechanisms of N supply was direct application of mineral N fertilizer and mineralization of organic N, while the N retention was reducing soil active N loss and storing more active N in cropland of purplish soil. These results suggest that the long-term application of organic amendments to upland soils may increase nutrient bioavailability.展开更多
The interaction of salinity stress and plant residue quality on C mineralization kinetics in soil is not well understood. A laboratory experiment was conducted to study the effects of salinity stress on C mineralizati...The interaction of salinity stress and plant residue quality on C mineralization kinetics in soil is not well understood. A laboratory experiment was conducted to study the effects of salinity stress on C mineralization kinetics in a soil amended with alfalfa, wheat and corn residues. A factorial combination of two salinity levels （0.97 and 18.2 dS/m） and four levels of plant residues （control, alfalfa, wheat and corn） with three replications was performed. A first order kinetic model was used to describe the C mineralization and to calculate the potentially mineralizable C. The CO2-C evolved under non-saline condition, ranged from 814.6 to 4842.4 mg CO2-C/kg in control and alfalfa residue-amended soils, respectively. Salinization reduced the rates of CO2 evolution by 18.7%, 6.2% and 5.2% in alfalfa, wheat and corn residue-amended soils, respectively. Potentially mineralizable C （Co） was reduced significantly in salinized alfalfa residue-treated soils whereas, no significant difference was observed for control treatments as well as wheat and corn residue-treated soils. We concluded that the response pattern of C mineralization to salinity stress depended on the plant residue quality and duration of incubation.展开更多
文摘Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.
文摘The utility of nickel/iron in the remediation of atrazine-contaminated water was investigated. The experimental results showed that nickel/iron had effective catalytic activity in dechlorinating atrazine under acidic conditions. The dechlorination reaction approximately followed the first-order kinetics under the experimental conditions(nickel/iron:1.0 g/250 ml;C atrazine=20.0 mg/L), the reaction rate increased with decreasing pH value of the reaction solution and increasing the proportion of Ni:Fe within 2.95%. For condition with 2.95% nickel/iron, the reaction rate constants were 0.07518(R=0.9927), 0.06212(R=0.9846) and 0.00131 min -1(R=0.9565) at pH=2.0, 3.0 and 4.0, respectively. HPLC analysis was used to monitor the decline of atrazine concentration.
文摘文章将鸽粪作为发酵原料,在30℃±0.2℃恒温槽水浴条件下,以全混合批量式发酵的方法产沼气。实验结果表明,鸽粪是较为良好的发酵原料,其TS产气率和VS产气率分别为486 m L·g-1和631 m L·g-1。与其他原料相比,分别是鸡粪的1.56倍,兔粪的1.08倍,猪粪的1.15倍。运用一级动力学的相关原理和修正后的Gompertz方程进行计算机拟合,分析了整个鸽粪厌氧消化周期中的产沼气规律。
文摘The application of organic amendments in upland soils may influence soil carbon (C) and nitrogen (N) mineralization, which are very important for understanding plant nutrition. However, the kinetics of C and N mineralization from organically amended upland purplish soils has been poorly studied. Therefore, this study investigates C and N mineralization kinetics in organically amended upland purplish soils. Incubation experiments were conducted using soil samples collected from experimental plots that have been under long-term organic amendment fertilization, which includes: Organic manure (OM), crop residues (CR), combined organic manure with inorganic fertilizers (OMNPK), combined crop residue with inorganic fertilizers (CRNPK), conventional inorganic fertilizer (NPK), and no fertilizer (CK). The results showed that organically amended treatments increased C and N mineralization rates by 8 - 24% and 17 - 33%, respectively, compared with NPK. Likewise, the amount of potentially mineralizable carbon (Co) and nitrogen (No) increased by 4 - 9% and 15 - 20%, respectively, compared to the conventional NPK treatment. The rate constants for labile C (kC) and N (kN) were 6 - 29% and 3 - 27% higher than the NPK treatment, respectively. In addition, the initial potential rate of C (Co × kC) and N (No × kN) in organically amended soils were 10 - 37% and 18 - 52% higher compared to NPK. This study tried to show that the mechanisms of N supply was direct application of mineral N fertilizer and mineralization of organic N, while the N retention was reducing soil active N loss and storing more active N in cropland of purplish soil. These results suggest that the long-term application of organic amendments to upland soils may increase nutrient bioavailability.
基金Project (No. 1AGH811) supported by Isfahan University of Tech-nology, Iran
文摘The interaction of salinity stress and plant residue quality on C mineralization kinetics in soil is not well understood. A laboratory experiment was conducted to study the effects of salinity stress on C mineralization kinetics in a soil amended with alfalfa, wheat and corn residues. A factorial combination of two salinity levels （0.97 and 18.2 dS/m） and four levels of plant residues （control, alfalfa, wheat and corn） with three replications was performed. A first order kinetic model was used to describe the C mineralization and to calculate the potentially mineralizable C. The CO2-C evolved under non-saline condition, ranged from 814.6 to 4842.4 mg CO2-C/kg in control and alfalfa residue-amended soils, respectively. Salinization reduced the rates of CO2 evolution by 18.7%, 6.2% and 5.2% in alfalfa, wheat and corn residue-amended soils, respectively. Potentially mineralizable C （Co） was reduced significantly in salinized alfalfa residue-treated soils whereas, no significant difference was observed for control treatments as well as wheat and corn residue-treated soils. We concluded that the response pattern of C mineralization to salinity stress depended on the plant residue quality and duration of incubation.
