nitrophenol

Microbial and kinetic characterization of pure and mixed cultures aerobically degrading 4-nitrophenol [An article from: Chemosphere]
$4.95
This digital document is a journal article from Chemosphere, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The molecular and kinetic characterization of a microorganism able to aerobically degrade 4-nitrophenol (4NP) is presented. The microorganism was isolated from a mixed culture operating in a laboratory-scale sequencing batch reactor with an aerobic anoxic cycle. It was identified as a member of Ralstonia genus within Betaproteobacteria. It is a gram negative coccobacillum (cell length of 2-3@mm) able to aerobically store lipid inclusions when grown aerobically on nitrophenol as the sole carbon source in the range of tested concentrations (80-320mgl^-^1). Batch kinetic tests were performed with the pure culture, while the kinetics of the mixed biomass was directly investigated in the reactor. For pure cultures exponential growth was observed, with growth rate values in the range of 2-6d^-^1; in experiments with the mixed cultures 4NP concentrations were correlated with growth using the Haldane equation (k"m"a"x=0.30mg 4NPmg^-^1VSSh^-^1; K"s=55mg 4NPl^-^1 and K"I=15mg 4NPl^-^1). Observed pure culture growth rates were higher than those of mixed cultures. This result can be explained by considering that in mixed culture the biomass is evaluated as volatile suspended solids, including both specialized biomass for 4NP removal and denitrifying bacteria.

Influence of metal ion on sorption of p-nitrophenol onto sediment in the presence of cetylpyridinium chloride [An article from: Chemosphere]
$10.95
This digital document is a journal article from Chemosphere, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Heavy metals and surfactants have a significant effect on the sorption of organic contaminants. In this study, batch equilibrium experiments were carried out to investigate the influence of Pb(NO"3)"2 on the sorption of p-nitrophenol (PNP) onto sediments in the presence of cationic surfactant cetylpyridinium chloride (CPC). Results indicated that in the complex system containing PNP, Pb(NO"3)"2 and CPC, the sorption of PNP decreased with increasing concentration of Pb(NO"3)"2 due primarily to competing for adsorption sites. Likewise, partitioning of PNP in adsorbed surfactant layers and micelles decreased with increasing level of Pb(NO"3)"2. Moreover, the influence of different metal ions (Pb^2^+, Cd^2^+, Zn^2^+) was examined and results indicated that the presence of heavy metals inhibited the sorption of PNP in the order: Pb^2^+>Cd^2^+>Zn^2^+. The competitive effect of the heavy metals was in agreement with the hydration energy and hydrated radius. The results are believed to provide a useful insight into describing the transport and fate of PNP in natural environments.

Disposition of 2,6-di-tert-butyl-4-nitrophenol (DBNP), a submarine atmosphere contaminant, in male Sprague-Dawley rats [An article from: Environmental Research]
$10.95
This digital document is a journal article from Environmental Research, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The phenol 2,6-di-tert-butyl-4-nitrophenol (DBNP) is a contaminant found onboard submarines and is formed by the nitration of an antioxidant present in turbine lubricating oil TEP 2190. DBNP has been found on submarine interior surfaces, on eating utensils and dishes, and on the skin of submariners. DBNP exposure is a potential health concern because it is an uncoupler of mitochondrial oxidative phosphorylation. Adult male rats were dosed once by oral gavage with 15 or 40mg/kg DBNP mixed with ^1^4C-DBNP in kanola oil and 0.8% v/v DMSO (n=16/group). The distribution of ^1^4C in major tissues was measured over time for up to 240h post-dose. Unexpectedly, 6/16 (40%) of the rats gavaged with 40mg/kg DBNP died within 24h of dosing. Prostration, no auditory startle response, reduced locomotor activity, and muscular rigidity persisted in survivors for up to 8 days after dosing. For animals dosed with 15mg/kg DBNP, radioactivity levels were significantly elevated in the following tissues 24h after dosing: fat@?liver>kidneys>heart>lungs>brain>striated muscle>spleen. Radioactivity levels were elevated for fat, liver, kidney, heart, and lungs of animals euthanized 144h post-dosing and in the liver of animals euthanized 240h post-dosing. These findings suggest that DBNP may accumulate in the body as a result of continuous or repeat exposures of short interval to DBNP.

Chitosan-supported palladium catalyst. IV. Influence of temperature on nitrophenol degradation and thermodynamic parameters [An article from: Journal of Environmental Management]
$8.95
This digital document is a journal article from Journal of Environmental Management, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Glutaraldehyde cross-linked chitosan was loaded with palladium and then reduced using an in situ hydrogen generation procedure (Zn in sulfuric acid solution) to prepare a chitosan-supported palladium catalyst. This catalyst was successfully used to degrade nitrophenol in dilute solutions in the presence of sodium formate as the hydrogen donor. The influence of the initial concentration of nitrophenol and sodium formate was studied in order to determine the minimum molar ratio between these compounds required to achieve complete conversion of the nitrogenous product at two temperatures. Increasing the temperature decreased the excess of hydrogen donor required for complete conversion of nitrophenol. The temperature was also varied between 10 and 60 ^oC in order to determine the activation energy. The pseudo first-order equation was shown to fit degradation kinetics in most cases; however, for some cases it was necessary to use a variable-order equation to model the kinetics.