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51.
Fernando J. S. Oliveira Francisca P. de França 《Applied biochemistry and biotechnology》2005,122(1-3):581-591
Hexane is a toxic volatile organic compound that is quite abundant in gas emissions from chemical industries and printing
press and painting centers, and it is necessary to treat these airstreams before they discharge into the atmosphere. This
article presents a treatment for hexane-contaminated air in steady-state conditions using an internal-loop airlift bioreactor
inoculated with a Pseudomonas aeruginosa strain. Bioprocesses were conducted at 20-mL/min, a load of 1.26 g/m3 of C6H14, and a temperature of 28°C. The results of hexane removal efficiencies were presented as a function of the inoculum size
(approx 0.07 and 0.2 g/L) and cell reuse. Bioprocess monitoring comprises quantification of the biomass, the surface tension
of the medium, and the hexane concentration in the fermentation medium as well as in the inlet and outlet airstreams. The
steady-state results suggest that the variation in inoculum size from 0.07 to 0.2 g/L promotes hexane abatement from the influent
from 65 to 85%, respectively. Total hydrocarbon removal from the waste gas was achieved during experiments conducted using
reused cells at an initial microbial concentration of 0.2 g/L. 相似文献
52.
A. I. Bostan Yu. I. Pyatnitskii L. N. Raevskaya V. G. Pryanikova S. A. Nedil’ko A. G. Dzyaz’ko E. G. Zen’kovich 《Theoretical and Experimental Chemistry》2005,41(1):32-36
The oxidative coupling of methane (OCM) in a periodic regime over the SrMnO3 and its derivatives has been investigated. It has been established that partial replacement of the strontium ion by alkali metal ions leads to an increase in both catalytic activity and in selectivity with respect to higher hydrocarbons. Comparison of the results obtained in the present work with those obtained earlier for catalysts based on SrCoO3 led to the conclusion that the Co-containing catalysts were preferable to the Mn-containing catalysts for carrying out oxidative coupling of methane in a periodic regime.__________Translated from Teoreticheskaya i Éksperimentalnaya Khimiya, Vol. 41, No. 1, pp. 30–34, January–February, 2005. 相似文献
53.
The synthesis of model long-chain hydrocarbons (C13 and C19) carrying a vinyl group and a trichloro- or a triethoxysilyl group at each end is reported. These compounds are suitable for linkage to a hydroxylated silicon surface and at the other end with vinyl group for further functionalization and multilayer formation. 相似文献
54.
Results of using a field spectrophotometer and its appropriate protocols as a surrogate method for an oilfield produced water treatment process is presented. Methylene chloride extractions of the produced water before and after treatment maintained a yellow color pigment that was directly proportional to the hydrocarbon concentration. From this, an absorption spectrum and standard curve were developed. A resultant linear plot of the standard curve indicated that there is an excellent correlation (r2=0.9847) between the varying concentrations and the associated absorbance values at a wavelength of 400 nm. Total n-alkane concentration comparisons between the laboratory GC/MS analysis and the spectrophotometry analysis generated data of similar accuracy and precision at concentrations ranging from 1 to 137 mg/l (alpha=0.05). Linear comparisons between GC/MS and spectrophotometric coefficients were near unity, with the constant being near zero, with a correlation coefficient (r2) of 0.99. Based on this study, spectrophotometry is a complimentary method to GC/MS for determining total n-alkane concentrations in oilfield produced water samples. 相似文献
55.
H. G. Struppe F. Franke J. Hofmann B. Ondruschka 《Journal of chromatography. A》1996,750(1-2):239-244
In contrast to usability of Curie-point pyrolysis at 700°C directly attached to gas chromatography-mass spectrometry (GC-MS) for determination of organic wood preservatives in waste wood samples the investigation method reported here consists of thermal desorption at temperatures about 260°C in connection with GC-MS for peak identification or GC with flame ionization detection for quantitative analyses. So-called “modified closeable sampling columns” are used as batch-reactor in thermal desorption experiments. Desorbed vapours can be introduced on capillary columns without sample discrimination and without a disturbing lost of resolution. In this manner a lot of individual polycyclic aromatic hydrocarbons were determinated in waste wood samples, especially in railway sleepers. 相似文献
56.
The composition of hydrocarbons from the termites Reticulitermes lucifugus Rossi and Kalotermes flavicollis Fabr. belonging to different castes and populations was determined using GC and mass spectrometry. The role of cuticular hydrocarbons in olfactory recognition of termite caste and population status was demonstrated.__________Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–6, January–February, 2005. 相似文献
57.
The needle oil of the Algerian maritime pine (Pinus pinaster Ait.) growing in natural habitats in Sidi Feradj (Algiers region) was obtained by hydrodistillation in 0.3% yield and analyzed
by GC and GC/MS. More than 46 compounds amounting to 65.2% of the total oil were identified. The main components were β-caryophyllene
(26.6%), allo-aromadendrene (12.5%), and α-humulene (4.3%).
__________
Published in Kimiya Prirodnikh Soedinenii, No. 5, pp. 445–447, September–October, 2005. 相似文献
58.
Summary A computer interactive identification system is proposed which is based on the relationship between retention and molecular
properties such as the size and shape of polycyclic aromatic hydrocarbons (PAHs). This system offers an automatic analytical
process for liquid chromatography, providing a reliable identification of the separated components. The identification can
be further enhanced by the use of multiple detectors such as a multichannel UV detector. The system can be used for optimization
procedures, resulting in a highly automatic complex analytical system. 相似文献
59.
Chromatography has been an important tool in marine laboratories. Since the 1960s, marine laboratories have been involved in the analysis of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and brominated flame retardants (BFRs). Column chromatography and liquid chromatography (LC) techniques have been used, mainly in the clean-up phase, while gas chromatography (GC) has been used extensively in the final determination of these contaminants. Developments have been observed from the use of packed GC columns, via capillary columns to the use of heart-cut multi-dimensional GC and comprehensive multi-dimensional GC. The progress made in interlaboratory studies and the availability of certified reference materials are discussed. 相似文献
60.
By using the relationship equation of Partition coefficients with water solubilities for polycyclic aromatic hydrocarbons (PAHs), we have estimated the solubilities of PAHs. In addition the high-performance liquid chromatograph (HPLC) method has been used for the indirect determination of solubilities of PAHs. t3ased on the di-region theory, We have studied the relationship of the solubilities of PAHs with carcinogenicity and introduced the solubility parameter into the di-region theory equation. The calculated carcinogenicity of PAHs from the obtained equation shows little difference from that calculated from Dai Qianhuan's equation. 相似文献