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Lilia Araujo Noreiva Villa Nuris Camargo Maikellys Bustos Theobaldo Garc��a Avismelsi de Jesus Prieto 《Environmental Chemistry Letters》2011,9(1):13-18
The occurrence of pharmaceuticals in natural waters is a potential threat to human nutrition and ecosystem quality. The persistence
of the acidic pharmaceuticals gemfibrozil, naproxen and mefenamic acid was studied in surface waters of Maracaibo Lake and
Tule reservoir (Venezuela) under laboratory conditions. A quick and easy analytical method was developed for the determination
of the acidic drugs at microgram per liter levels using aqueous derivatization, liquid–liquid extraction and gas chromatography–mass
spectrometry. Pharmaceuticals degradation followed a pseudo first-order kinetic and their half-lives were calculated for every
experimental condition. Under sunlight, naproxen and mefenamic acid were degraded at moderate rates with half-lives from 9.6 ± 0.5
to 27.0 ± 6.6 days, while gemfibrozil had a higher persistence (t
1/2 = 119.5 ± 15.6 − 288.8 ± 61.3 days). 相似文献
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Solid substrate fermentation of cassava fibrous residue for production of alpha-amylase, lactic acid and ethanol 总被引:1,自引:0,他引:1
Ray RC Mohapatra S Panda S Kar S 《Journal of environmental biology / Academy of Environmental Biology, India》2008,29(1):111-115
There is serious concern about the disposal of solid residues left after large scale extraction of starch from cassava. Owing to the high starch content (55-65% on dry weight basis) and organic matter of these wastes, an attempt has been made to utilize it for the production of three bioproducts, i.e. alpha-amylase, lactic acid and ethanol in solid substrate fermentation by incubating the solid residue at different moisture holding capacity (40-80%) and incubation period (12- 60 hr for alpha-amylase, 24-144 hr for ethanol and 2-10 days for lactic acid). The highest product yield was obtained at 60% moisture holding capacity of the residue and period of incubation varied from 36 hr (alpha-amylase), 120 hr (ethanol) to 6 days (lactic acid). This study showed that the solid residues from cassava starch factories could serve as a low-cost substrate for bioproducts production. 相似文献
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The fate of imazapyr (2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid), a broad-spectrum herbicide in the imidazolinone family, has been studied upon UV irradiation. Most of the photoproducts occurring during the photodegradation have been characterized by means of liquid chromatography and mass spectrometry coupled techniques (LC-MS). The use of high resolution mass spectrometry has allowed to maximize the chemical information obtained from a single LC-MS analysis. The degradation of a 10?ppm imazapyr solution leads to pyridine derivatives which remain in solution during 50–100?h while the imazapyr is completely degraded after 6?h. 相似文献
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Bhaskar AS Jayaraj R Dangi RS Prasad GK Singh B Rao PV 《Journal of environmental biology / Academy of Environmental Biology, India》2005,26(3):511-515
Most frequently encountered freshwater cyanobacterial toxin is Microcystin-LR (MC-LR). Microcystins released from cells into water have been responsible for the death of humans, domestic and wild animals. Removal of microcystin by active carbon has been one of the best methods available so far. This study evaluates three grades of active carbon namely 40, 60 and 80 CTC for their removal efficiency of MC-LR from contaminated water. Kinetics of toxin removal was studied in time course experiments. Protection in mouse model was studied for the samples after the adsorption. Toxin quantitation was done by HPLC method. The MC-LR concentration after 24 hr treatment with 40, 60 and 80 CTC carbons were 4.8, 3.3 and 1.3 microg/ml respectively from an initial concentration of 5.2 microg/ml. Protection in mouse bioassay was seen after 48, 24 and 2 hr of adsorption time respectively for 40, 60 and 80 CTC carbons. 80 CTC carbon was found to be most efficient in removing MC-LR from contaminated water. 相似文献
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部分水溶性偶氮染料的光催化降解研究 总被引:22,自引:2,他引:20
本研究以高压汞灯为光源,系统地研究了16种偶氮染料在水溶液中的TiO2光催化降解。结果表明,这些偶氮染料的光解为一级动力学反应,采用TiO2光催化降解方法处理所研究的偶氮染料是可行的,并初步探讨了染料的结构与光解反应表观速率常数之间的关系。 相似文献
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Thiobencarb, a thiocarbamate herbicide, is widely used to control weeds in rice paddies. Screening for highly efficient thiobencarb-degrading bacteria is important for the bioremediation of thiobencarb-contaminated environments. The aim of this study was to isolate and identify highly efficient thiobencarb-degrading bacteria and to identify the degradation pathway and the degrading properties. The thiobencarb-degrading strain was isolated using methods of microbiological acclimation and enrichment and was then identified using a 16S rRNA phylogenetic analysis. The degrading properties of the isolated bacterium were determined by single-factor experiments, and the degradation products were identified using gas chromatography-mass spectrometry (GC-MS). A thiobencarb-degrading strain T2, which can utilize thiobencarb as the sole source of carbon for energy and growth, was isolated from paddy soil. Strain T2 degraded more than 98.3% of 0.4 mmol/L of thiobencarb within 36 h. It was preliminarily identified as Bacillus sp. T2 according to the 16S rRNA gene analysis and from its morphological, physiological, and biochemical characteristics. The metabolic products of the thiobencarb degradation for strain T2 were identified as 4-chlorobenzyl mercaptan, 4-chlorobenzaldehyde, and 4-chlorobenzoic acid by the GC-MS. Based on metabolite identification, it was speculated that thiobencarb degradation in strain T2 was initiated by the hydrolysis of the thioester bond to produce 4-chlorobenzyl mercaptan, which was further oxidized to 4-chlorobenzaldehyde and 4-chlorobenzoic acid. The thiobencarb degradation that was initiated by the hydrolysis of the thioester bond by strain T2 is a new metabolic pathway, which provides valuable research material and reliable experimental data for revealing the metabolic process and mechanism of thiobencarb microbial degradation in soil. The strain Bacillus sp. T2 has a very high degradation efficiency, suggesting it is a good prospect for microbial remediation in thiobencarb-polluted environments. © 2018 Science Press. All rights reserved. 相似文献
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As a result of economic development and population explosion, global ecological environments have been severely disturbed and markedly changed. An ecological crisis involving desertification, soil erosion, degradation of land quality, loss of biodiversity and global climate change has been brought about all over the world. In order to manage ecosystems efficiently, it is necessary to assess ecological risk at multiple scales. Ecological risk is the probability that a region and/or site will experience defined ecological or environmental problems. In this paper, the ecological risks of soil erosion, desertification, and acid deposition have been assessed on a national scale according to natural and human factors, such as topography, soil, vegetation and climate. This assessment has provided very useful information for ecological environmental management in China. 相似文献