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1.
Photodegradation of the novel fungicide fluopyram in aqueous solution: kinetics,transformation products,and toxicity evolvement 总被引:1,自引:0,他引:1
Bizhang Dong Jiye Hu 《Environmental science and pollution research international》2016,23(19):19096-19106
The aqueous photodegradation of fluopyram was investigated under UV light (λ?≥?200 nm) and simulated sunlight irradiation (λ?≥?290 nm). The effect of solution pH, fulvic acids (FA), nitrate (NO3 ?), Fe (III) ions, and titanium dioxide (TiO2) on direct photolysis of fluopyram was explored. The results showed that fluopyram photodegradation was faster in neutral solution than that in acidic and alkaline solutions. The presence of FA, NO3 ?, Fe (III), and TiO2 slightly affected the photodegradation of fluopyram under UV irradiation, whereas the photodegradation rates of fluopyram with 5 mg L?1 Fe (III) and 500 mg L?1 TiO2 were about 7-fold and 13-fold faster than that without Fe (III) and TiO2 under simulated sunlight irradiation, respectively. Three typical products for direct photolysis of fluopyram have been isolated and characterized by liquid chromatography tandem mass spectrometry. These products resulted from the intramolecular elimination of HCl, hydroxyl-substitution, and hydrogen extraction. Based on the identified transformation products and evolution profile, a plausible degradation pathway for the direct photolysis of fluopyram in aqueous solution was proposed. In addition, acute toxicity assays using the Vibrio fischeri bacteria test indicated that the transformation products were more toxic than the parent compound. 相似文献
2.
Zulin Hua Wenqiang Ma Xue Bai Ranran Feng Lu Yu Xiaoyuan Zhang Zhangyan Dai 《Environmental science and pollution research international》2014,21(12):7737-7745
A new method for the degradation of bisphenol A (BPA) in aqueous solution was developed. The oxidative degradation characteristics of BPA in a heterogeneous Fenton reaction catalyzed by Fe3O4/graphite oxide (GO) were studied. Transmission electron microscopic images showed that the Fe3O4 nanoparticles were evenly distributed and were ~6 nm in diameter. Experimental results suggested that BPA conversion was affected by several factors, such as the loading amount of Fe3O4/GO, pH, and initial H2O2 concentration. In the system with 1.0 g L?1 of Fe3O4/GO and 20 mmol L?1 of H2O2, almost 90 % of BPA (20 mg L?1) was degraded within 6 h at pH 6.0. Based on the degradation products identified by GC–MS, the degradation pathways of BPA were proposed. In addition, the reused catalyst Fe3O4/GO still retained its catalytic activity after three cycles, indicating that Fe3O4/GO had good stability and reusability. These results demonstrated that the heterogeneous Fenton reaction catalyzed by Fe3O4/GO is a promising advanced oxidation technology for the treatment of wastewater containing BPA. 相似文献
3.
Baharak Ayoubi-Feiz Soheil Aber Alireza Khataee Esmaeel Alipour 《Environmental science and pollution research international》2014,21(14):8555-8564
In the present study, an activated charcoal (AC) plate was prepared by physical activation method. Its surface was coated with TiO2 nanoparticles by electrophoretic deposition (EPD) method. The average crystallite size of TiO2 nanoparticles was determined approximately 28 nm. The nature of prepared electrode was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area measurement before and after immobilization. The electrosorption and photocatalytic one-stage combined process was investigated in degradation of Lanasol Red 5B (LR5B), and the effect of dye concentration, electrolyte concentration, pH, voltage, and contact time was optimized and modeled using response surface methodology (RSM) approach. The dye concentration of 30 mg L?1, Na2SO4 concentration of 4.38 g L?1, pH of 4, voltage of 250 mV, and contact time of 120 min were determined as optimum conditions. Decolorization efficiency increased in combined process to 85.65 % at optimum conditions compared to 66.03 % in TiO2/AC photocatalytic, 20.09 % in TiO2/AC electrosorption, and 1.91 % in AC photocatalytic processes. 相似文献
4.
João H. O. S. Pereira Ana C. Reis Olga C. Nunes Maria T. Borges Vítor J. P. Vilar Rui A. R. Boaventura 《Environmental science and pollution research international》2014,21(2):1292-1303
The objective of this work was to evaluate the efficiency of a solar TiO2-assisted photocatalytic process on amoxicillin (AMX) degradation, an antibiotic widely used in human and veterinary medicine. Firstly, solar photolysis of AMX was compared with solar photocatalysis in a compound parabolic collectors pilot scale photoreactor to assess the amount of accumulated UV energy in the system (Q UV) necessary to remove 20 mg L?1 AMX from aqueous solution and mineralize the intermediary by-products. Another experiment was also carried out to accurately follow the antibacterial activity against Escherichia coli DSM 1103 and Staphylococcus aureus DSM 1104 and mineralization of AMX by tracing the contents of dissolved organic carbon (DOC), low molecular weight carboxylate anions, and inorganic anions. Finally, the influence of individual inorganic ions on AMX photocatalytic degradation efficiency and the involvement of some reactive oxygen species were also assessed. Photolysis was shown to be completely ineffective, while only 3.1 kJUV?L?1 was sufficient to fully degrade 20 mg L?1 AMX and remove 61 % of initial DOC content in the presence of the photocatalyst and sunlight. In the experiment with an initial AMX concentration of 40 mg L?1, antibacterial activity of the solution was considerably reduced after elimination of AMX to levels below the respective detection limit. After 11.7 kJUV?L?1, DOC decreased by 71 %; 30 % of the AMX nitrogen was converted into ammonium and all sulfur compounds were converted into sulfate. A large percentage of the remaining DOC was in the form of low molecular weight carboxylic acids. Presence of phosphate ions promoted the removal of AMX from solution, while no sizeable effects on the kinetics were found for other inorganic ions. Although the AMX degradation was mainly attributed to hydroxyl radicals, singlet oxygen also plays an important role in AMX self-photosensitization under UV/visible solar light. 相似文献
5.
Akhil N. Kabra Min-Kyu Ji Jaewon Choi Jung Rae Kim Sanjay P. Govindwar Byong-Hun Jeon 《Environmental science and pollution research international》2014,21(21):12270-12278
This study evaluated the toxicity of herbicide atrazine, along with its bioaccumulation and biodegradation in the green microalga Chlamydomonas mexicana. At low concentration (10 μg L?1), atrazine had no profound effect on the microalga, while higher concentrations (25, 50, and 100 μg L?1) imposed toxicity, leading to inhibition of cell growth and chlorophyll a accumulation by 22 %, 33 %, and 36 %, and 13 %, 24 %, and 27 %, respectively. Atrazine 96-h EC50 for C. mexicana was estimated to be 33 μg L?1. Microalga showed a capability to accumulate atrazine in the cell and to biodegrade the cell-accumulated atrazine resulting in 14–36 % atrazine degradation at 10–100 μg L?1. Increasing atrazine concentration decreased the total fatty acids (from 102 to 75 mg g?1) and increased the unsaturated fatty acid content in the microalga. Carbohydrate content increased gradually with the increase in atrazine concentration up to 15 %. This study shows that C. mexicana has the capability to degrade atrazine and can be employed for the remediation of atrazine-contaminated streams. 相似文献
6.
M. A. Vishnuganth Neelancherry Remya N. Selvaraju 《Journal of environmental science and health. Part. B》2017,52(5):353-360
Carbofuran (CBF) removal in a continuous-flow photocatalytic reactor with granular activated carbon supported titanium dioxide (GAC-TiO2) catalyst was investigated. The effects of feed flow rate, TiO2 concentration and addition of supplementary oxidants on CBF removal were investigated. The central composite design (CCD) was used to design the experiments and to estimate the effects of feed flow rate and TiO2 concentration on CBF removal. The outcome of CCD experiments demonstrated that reactor performance was influenced mainly by feed flow rate compared to TiO2 concentration. A second-order polynomial model developed based on CCD experiments fitted the experimental data with good correlation (R2 ~ 0.964). The addition of 1 mL min?1 hydrogen peroxide has shown complete CBF degradation and 76% chemical oxygen demand removal under the following operating conditions of CBF ~50 mg L?1, TiO2 ~5 mg L?1 and feed flow rate ~82.5 mL min?1. Rate constant of the photodegradation process was also calculated by applying the kinetic data in pseudo-first-order kinetics. Four major degradation intermediates of CBF were identified using GC-MS analysis. As a whole, the reactor system and GAC-TiO2 catalyst used could be constructive in cost-effective CBF removal with no impact to receiving environment through getaway of photocatalyst. 相似文献
7.
Bikram Basak Biswanath Bhunia Subhasish Dutta Samayita Chakraborty Apurba Dey 《Environmental science and pollution research international》2014,21(2):1444-1454
A highly tolerant phenol-degrading yeast strain PHB5 was isolated from wastewater effluent of a coke oven plant and identified as Candida tropicalis based on phylogenetic analysis. Biodegradation experiments with C. tropicalis PHB5 showed that the strain was able to utilize 99.4 % of 2,400 mg l?1 phenol as sole source of carbon and energy within 48 h. Strain PHB5 was also observed to grow on 18 various aromatic hydrocarbons. Haldane model was used to fit the exponential growth data and the following kinetic parameters were obtained: μ max?=?0.3407 h?1, K S?=?15.81 mg l?1, K i?=?169.0 mg l?1 (R 2?=?0.9886). The true specific growth rate, calculated from μ max, was 0.2113. A volumetric phenol degradation rate (V max) was calculated by fitting the phenol consumption data with Gompertz model and specific degradation rate (q) was calculated from V max. The q values were fitted with Haldane model, yielding following parameters: q max?=?0.2766 g g?1 h?1, K S ′?=?2.819 mg l?1, K i ′?=?2,093 (R 2?=?0.8176). The yield factor (Y X/S ) varied between 0.185 to 0.96 g g?1 for different initial phenol concentrations. Phenol degradation by the strain proceeded through a pathway involving production of intermediates such as catechol and cis,cis-muconic acid which were identified by enzymatic assays and HPLC analysis. 相似文献
8.
R. R. Miranda A. L. R. Damaso da Silveira I. P. de Jesus S. R. Grötzner C. L. Voigt S. X. Campos J. R. E. Garcia M. A. F. Randi C. A. Oliveira Ribeiro F. Filipak Neto 《Environmental science and pollution research international》2016,23(6):5179-5188
The impact of nanoparticles on fish health is still a matter of debate, since nanotechnology is quite recent. In this study, freshwater benthonic juvenile fish Prochilodus lineatus were exposed through water to three concentrations of TiO2 (0.1, 1, and 10 μg l?1) and ZnO (7, 70, and 700 μg l?1) nanoparticles, as well as to a mixture of both (TiO2 1 μg l?1?+?ZnO 70 μg l?1) for 5 and 30 days. Nanoparticle characterization revealed an increase of aggregate size in the function of concentration, but suspensions were generally stable. Fish mortality was high at subchronic exposure to 70 and 700 μg l?1 of ZnO. Nanoparticle exposure led to decreased acetylcholinesterase activity either in the muscle or in the brain, depending on particle composition (muscle—TiO2 10 μg l?1; brain—ZnO 7 and 700 μg l?1), and protein oxidative damage increased in the brain (ZnO 70 μg l?1) and gills (ZnO 70 μg l?1 and mixture) but not in the liver. Exposed fish had more frequent alterations in the liver (necrosis, vascular congestion, leukocyte infiltration, and basophilic foci) and gills (hyperplasia and epithelial damages, e.g., epithelial disorganization and epithelial loss) than the control fish. Thus, predicted concentrations of TiO2 and ZnO nanoparticles caused detectable effects on P. lineatus that may have important consequences to fish health. But, these effects are much more subtle than those usually reported in the scientific literature for high concentrations or doses of metal nanoparticles. 相似文献
9.
Hai Sun Li Hong Wang Qing Zhou Xiao Hua Huang 《Environmental science and pollution research international》2013,20(12):8484-8490
Bisphenol A (BPA), which is ubiquitous in the environment, is an example of an endocrine-disrupting compound (EDC). Ammonium assimilation has an important function in plant growth and development. However, insufficient information on the potential effect of BPA on ammonium assimilation in plants is available. In this study, the effects of BPA on ammonium assimilation in roots of soybean seedlings were investigated. During the stress period, 1.5 mg L?1 of BPA improved glutamine synthetase (GS)/glutamate synthase (GOGAT) cycle and glutamate dehydrogenase (GDH) pathway in ammonium assimilation. The amino acid and the soluble protein contents increased in the soybeans. At 17.2 and 50.0 mg L?1 of BPA, the GS/GOGAT cycle was inhibited and the GDH pathway was promoted. The amino acid content increased and the soluble protein content decreased. During the recovery period, the GS/GOGAT cycle and the GDH pathway recovered at 1.5 and 17.2 mg L?1 of BPA but not at 50.0 mg L?1 of BPA. The amino acid content continuously increased and the soluble protein content decreased compared with those in the control treatment. In summary, BPA treatment could affect the contents of soluble protein and amino acid in the soybean roots by regulating ammonium assimilation. 相似文献
10.
Axelle Chiffre Christelle Clérandeau Charline Dwoinikoff Florane Le Bihanic Hélène Budzinski Florence Geret Jérôme Cachot 《Environmental science and pollution research international》2016,23(6):4964-4977
Psychiatric pharmaceuticals, such as anxiolytics, sedatives, hypnotics and antidepressors, are among the most prescribed active substances in the world. The occurrence of these compounds in the environment, as well as the adverse effects they can have on non-target organisms, justifies the growing concern about these emerging environmental pollutants. This study aims to analyse the effects of six psychotropic drugs, valproate, cyamemazine, citalopram, sertraline, fluoxetine and oxazepam, on the survival and locomotion of Japanese medaka Oryzias latipes larvae. Newly hatched Japanese medaka were exposed to individual compounds for 72 h, at concentrations ranging from 10 μg L?1 to 10 mg L?1. Lethal concentrations 50 % (LC50) were estimated at 840, 841 and 9,136 μg L?1 for fluoxetine, sertraline and citalopram, respectively, while other compounds did not induce any significant increase in mortality. Analysis of the swimming behaviour of larvae, including total distance moved, mobility and location, provided an estimated lowest observed effect concentration (LOEC) of 10 μg L?1 for citalopram and oxazepam, 12.2 μg L?1 for cyamemazine, 100 μg L?1 for fluoxetine, 1,000 μg L?1 for sertraline and >10,000 μg L?1 for valproate. Realistic environmental mixture of the six psychotropic compounds induced disruption of larval locomotor behaviour at concentrations about 10- to 100-fold greater than environmental concentrations. 相似文献
11.
Maria Maleva Galina Borisova Nadezda Chukina Galina Nekrasova M. N. V. Prasad 《Environmental science and pollution research international》2013,20(9):6172-6177
This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L?1) on photosynthetic pigments (measured spectrophotometrically), uptake of 14CO2 (using radioisotope), and urease activity (by measuring ammonia with Nessler’s reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L?1) stimulates the accumulation of photosynthetic pigments and intensifies photosynthesis in E. densa, whereas high concentration (1,000 mg L?1) suppresses these processes. Urease activity increased by approximately 2.7 and 8 fold when exogenous urea concentrations were 100 and 500 mg L?1, respectively. However, exogenous urea in high concentration (1,000 mg L?1) decreased urease activity by 1.5 fold compared to the control. The necessity of mitigating urea and other nitrogen-containing compounds (NH3 from urea) in water bodies has been discussed with emphasis on the potential for phytoremediation of urea using common water weed viz. E. densa. 相似文献
12.
Environmental effects of anticholinesterasic therapeutic drugs on a crustacean species,Daphnia magna
R. Rocha F. Gonçalves C. Marques B. Nunes 《Environmental science and pollution research international》2014,21(6):4418-4429
The presence of pharmaceutical drugs in the environment is an important field of toxicology, since such residues can cause deleterious effects on exposed biota. This study assessed the ecotoxicological acute and chronic effects of two anticholinesterasic drugs, neostigmine and pyridostigmine in Daphnia magna. Our study calculated 48 h-EC50 values for the immobilization assay of 167.7 μg L?1 for neostigmine and 91.3 μg L?1 for pyridostigmine. In terms of feeding behavior, we calculated a 5 h-EC50 for filtration rates of 7.1 and 0.2 μg L?1 for neostigmine and pyridostigmine, respectively; for the ingestion rates, the calculated EC50 values were, respectively, 7.5 and 0.2 μg L?1 for neostigmine and pyridostigmine. In the reproduction assay, the most affected parameter was the somatic growth rate (LOECs of 21.0 and 2.9 μg L?1 for neostigmine and pyridostigmine, respectively), followed by the fecundity (LOECs of 41.9 and 11.4 μg L?1 for neostigmine and pyridostigmine, respectively). We also determined a 48 h-IC50 for cholinesterase activity of 1.7 and 4.5 μg L?1 for neostigmine and pyridostigmine, respectively. These results demonstrated that both compounds are potentially toxic for D. magna at concentrations in the order of the μg L?1. 相似文献
13.
Shahid Umar Nidhi Gauba Naser A. Anjum Tariq O. Siddiqi 《Environmental science and pollution research international》2013,20(9):6039-6049
In a hydroponic culture, experiments were performed to study the influence of potassium (K) supplementation (0, 20, 40, 60, 80, and 100 mg L?1) on the arsenic (As; 0, 8, and 10 mg L?1)-accrued changes in growth traits (plant biomass, root–shoot length) and the contents of lepidine, As and K, in garden cress (Lepidium sativum Linn.) at 10 days after treatment. The changes in these traits were correlated with shoot proline content, protein profile, and the activities of antioxidant enzymes namely superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione reductase (GR, EC 1.8.1.7), and ascorbate peroxidase (APX, EC 1.11.1.11). In general, As-alone treatments significantly decreased the growth traits but lead to significant enhancements in shoot proline and enzyme activities. K-supplementation to As-treated L. sativum seedlings decreased shoot-As content, reduced As-induced decreases in growth traits but enhanced the content of shoot proline, and the activities of the studied enzymes maximally with K100 + As8 and As10 mg L?1. Both 8 and 10 mg L?1 of As drastically downregulated the shoot proteins ranging from 43–65 kDa. With As10 mg L?1, there was a total depletion of protein bands below 23 kDa; however, K80 mg L?1 maximally recovered and upregulated the protein bands. Additionally, protein bands were downregulated (at par with As-alone treatment) above K80 mg L?1 level. Interestingly, As-stress increased lepidine content in a dose-dependent manner which was further augmented with the K-supplementation. It is suggested that K protects L. sativum against As-toxicity by decreasing its accumulation and strengthening antioxidant defense system and protein stability. 相似文献
14.
Linlin Wang Litao Tang Ran Wang Xiaoya Wang Jinshao Ye Yan Long 《Environmental science and pollution research international》2016,23(6):5166-5178
There is global concern about the effects of decabromodiphenyl ether (BDE209) on environmental and public health. The molecular properties, biosorption, degradation, accumulation, and cellular metabolic effects of BDE209 were investigated in this study to identify the mechanisms involved in the aerobic biodegradation of BDE209. BDE209 is initially absorbed by wall teichoic acid and N-acetylglucosamine side chains in peptidoglycan, and then, BDE209 is transported and debrominated through three pathways, giving tri-, hepta-, octa-, and nona-bromodiphenyl ethers. The C–C bond energies decrease as the number of bromine atoms on the diphenyl decreases. Polybrominated diphenyl ethers (PBDEs) inhibit protein expression or accelerate protein degradation and increase membrane permeability and the release of Cl?, Na+, NH4 +, arabinose, proteins, acetic acid, and oxalic acid. However, PBDEs increase the amounts of K+, Mg2+, PO4 3?, SO4 2?, and NO3 ? assimilated. The biosorption, degradation, accumulation, and removal efficiencies when Brevibacillus brevis (1 g L?1) was exposed to BDE209 (0.5 mg L?1) for 7 days were 7.4, 69.5, 16.3, and 94.6 %, respectively. 相似文献
15.
Rania Nassar Samia Mokh Ahmad Rifai Fatmeh Chamas Maha Hoteit Mohamad Al Iskandarani 《Environmental science and pollution research international》2018,25(35):34863-34872
Sulfaquinoxaline (SQX) is an antimicrobial of the sulfonamide class, frequently detected at low levels in drinking and surface water as organic micropollutant. The main goal of the present study is the evaluation of SQX reactivity during chlorination and UV irradiations which are two processes mainly used in water treatment plants. The SQX transformation by chlorination and UV lights (254 nm) was investigated in purified water at common conditions used for water disinfection (pH =?7.2, temperature =?25 °C, [chlorine] =?3 mg L?1). The result shows a slow degradation of SQX during photolysis compared with chlorination process. Kinetic studies that fitted a fluence-based first-order kinetic model were used to determine the kinetic constants of SQX degradation; they were equal to 0.7?×?10?4 and 0.7?×?10?2 s?1corresponding to the half time lives of 162 and 1.64 min during photolysis and chlorination, respectively. In the second step, seven by-products were generated during a chlorination and photo-transformation of SQX and identified using liquid chromatography with electrospray ionization and tandem mass spectrometry (MS-MS). SO2 extrusion and direct decomposition were the common degradation pathway during photolysis and chlorination. Hydroxylation and isomerization were observed during photodegradation only while electrophilic substitution was observed during chlorination process. 相似文献
16.
Meizhen Wang Junjie Xu Juehua Wang Shuo Wang Huajun Feng Jiali Shentu Dongsheng Shen 《Environmental science and pollution research international》2013,20(9):6201-6209
To develop a bacterial bioaugmentation system for fluorine-containing industrial wastewater treatment, optimal conditions for 4-fluoroaniline (4-FA) degradation and autoinducer release in Acinetobacter sp. TW were determined. Quorum sensing in biofilms of strain TW was also investigated. Different optimal conditions exist for 4-FA degradation and autoinducer release, particularly with regard to pH. Quorum sensing modulates extracellular polymeric substance (EPS) secretion and biofilm formation in the strain but plays no role in 4-FA degradation. Under optimal conditions for 4-FA degradation, the release of N-3-oxo-hexanoyl-homoserine lactone (3-oxo-C6-HSL) and N-hexanoyl-homoserine lactone (C6-HSL) in strain TW was significantly lower than required for quorum sensing. Under optimal conditions for autoinducer release, on the other hand, 3-oxo-C6-HSL and C6-HSL levels exceeded the quorum sensing thresholds, thereby inducing EPS secretion and biofilm formation. We conclude that the optimal conditions for autoinducer release (25 °C, pH 5, 800 mg L?1 4-FA, and 0 % NaCl) are suitable for bacterial colonization in bioaugmentation, while those for 4-FA degradation (25–30 °C, pH 8 and 800 mg L?1 4-FA) maximize the system performance after colonization. 相似文献
17.
Lekha Siddamallaiah Soudamini Mohapatra Radhika Buddidathi Shibara Shankara Hebbar 《Environmental science and pollution research international》2017,24(30):23559-23570
Dissipation of spiromesifen and its metabolite, spiromesifen-enol, on tomato fruit, tomato leaf, and soil was studied in the open field and controlled environmental conditions. Sample preparation was carried out by QuEChERS method and analysis using LC-MS/MS. Method validation for analysis of the compounds was carried out as per “single laboratory method validation guidelines.” Method validation studies gave satisfactory recoveries for spiromesifen and spiromesifen-enol (71.59–105.3%) with relative standard deviation (RSD) < 20%. LOD and LOQ of the method were 0.0015 μg mL?1 and 0.005 mg kg?1, respectively. Spiromesifen residues on tomato fruits were 0.855 and 1.545 mg kg?1 in open field and 0.976 and 1.670 mg kg?1 under polyhouse condition, from treatments at the standard and double doses of 125 and 250 g a.i. ha?1, respectively. On tomato leaves, the residues were 5.64 and 8.226 mg kg?1 in open field and 6.874 and 10.187 mg kg?1 in the polyhouse. In soil, the residues were 0.532 and 1.032 mg kg?1 and 0.486 and 0.925 mg kg?1 under open field and polyhouse conditions, respectively. The half-life of degradation of spiromesifen on tomato fruit was 6–6.5 days in the open field and 8.1–9.3 days in the polyhouse. On tomato leaves, it was 7–7.6 and 17.6–18.4 days and in soil 5.6–7.4 and 8.4–9.5 days, respectively. Metabolite, spiromesifen-enol, was not detected in any of the sample throughout the study period. Photodegradation could be the major route for dissipation of spiromesifen in the tomato leaves, whereas in the fruits, it may be the combination of photodegradation and dilution due to fruit growth. The results of the study can be utilized for application of spiromesifen in plant protection of tomato crop under protected environmental conditions. 相似文献
18.
K. Jaworek M. Czaplicka Ł. Bratek 《Environmental science and pollution research international》2014,21(20):11917-11923
The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm?3 phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H2O2, UV/O3, H2O2, and O3 systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45?×?10?3 and 20.12?×?10?3) and degradation efficiencies at pH 2 and 7 were obtained at UV/O3 processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified. 相似文献
19.
Michael Moustakas Paraskevi Malea Katerina Haritonidou Ilektra Sperdouli 《Environmental science and pollution research international》2017,24(19):16007-16018
Photosynthetic activity, oxidative stress, and Cu bioaccumulation in the seagrass Cymodocea nodosa were assessed 4, 12, 24, 48, and 72 h after exposure to two copper oxide nanoparticle (CuO NP) concentrations (5 and 10 mg L?1). CuO NPs were characterized by scanning electron microscopy (SEM) and dynamic light scattering measurements (DLS). Chlorophyll fluorescence analysis was applied to detect photosystem II (PSII) functionality, while the Cu accumulation kinetics into the leaf blades was fitted to the Michaelis-Menten equation. The uptake kinetics was rapid during the first 4 h of exposure and reached an equilibrium state after 10 h exposure to 10 mg L?1 and after 27 h to 5 mg L?1 CuO NPs. As a result, 4-h treatment with 5 mg L?1 CuO NPs, decreased the quantum yield of PS II photochemistry (Φ PSΙΙ ) with a parallel increase in the regulated non-photochemical energy loss in PSII (Φ NPQ ). However, the photoprotective dissipation of excess absorbed light energy as heat, through the process of non-photochemical quenching (NPQ), did not maintain the same fraction of open reaction centers (q p ) as in control plants. This reduced number of open reaction centers resulted in a significant increase of H2O2 production in the leaf veins serving possibly as an antioxidant defense signal. Twenty-four-hour treatment had no significant effect on Φ PSΙΙ and q p compared to controls. However, 24 h exposure to 5 mg L?1 CuO NPs increased the quantum yield of non-regulated energy loss in PSII (Φ NO ), and thus the formation of singlet oxygen (1O2) via the triplet state of chlorophyll, possible because the uptake kinetics had not yet reached the equilibrium state as did 10 mg L?1. Longer-duration treatment (48 and 72 h) had less effect on the allocation of absorbed light energy at PSII and the fraction of open reaction centers, compared to 4-h treatment, suggesting the function of a stress defense mechanism. The response of C. nodosa leaves to CuO NPs fits the “Threshold for Tolerance Model” with a threshold time (more than 4 h) required for induction of a stress defense mechanism, through H2O2 production. 相似文献
20.
Carmen M. Domínguez Macarena Munoz Asunción Quintanilla Zahara M. de Pedro Jose A. Casas 《Environmental science and pollution research international》2018,25(35):34811-34817
In the last few years, several works dealing with Fenton oxidation of ionic liquids (ILs) have proved the capability of this technology for their degradation, achieving complete ILs removal and non-toxic effluents. Nevertheless, very little is known about the kinetics of this process, crucial for its potential application. In this work, the effect of several operating conditions, including reaction temperature (50–90 °C), catalyst load (10–50 mg L?1 Fe3+), initial IL concentration (100–2000 mg L?1), and hydrogen peroxide dose (10–200% of the stoichiometric amount for the complete IL mineralization) on 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) oxidation has been investigated. Under the optimum operating conditions (T = 90 °C; [Fe3+]0 = 50 mg L?1; [H2O2]0 = 100% of the stoichiometric amount), the complete removal of [C4mim]Cl (1000 mg L?1) was achieved at 1.5-min reaction time. From the experimental results, a potential kinetic model capable to describe the removal of imidazolium-based ILs by Fenton oxidation has been developed. By fitting the proposed model to the experimental data, the orders of the reaction with respect to IL initial concentration, Fe3+ amount and H2O2 dose were found to be close to 1, with an apparent activation energy of 43.3 kJ mol?1. The model resulted in a reasonable fit within the wide range of operating conditions tested in this work. 相似文献