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PubMed2004

Pyrolysis of flame retardant brominated polyester composites.

A series of three flame retardant, thermoset polyester/styrene composite wastes were pyrolysed in a static-bed reactor. The wastes contained different proportions of brominated polyester resin. Higher char and gas yields were observed on the pyrolysis of the brominated samples than for a similar non-brominated sample. The pyrolysis gas composition showed a small, but significant influence of pyrolysis temperature and by the use of brominated resin. In all cases, over 95wt % of the bromine originally present in the composite ended up in the condensable products. Thermo-gravimetric analysis indicated that the presence of brominated polyester resins decreased the temperatures at which the main decomposition region started and the maximum rate of weight loss was observed. The global apparent activation energy of decomposition was between 83 and 97kJ mol(-1).

Bromine↗
PubMed2006

Pyrolysis and oxidation kinetics of medical wastes.

On account of the infectious properties of medical wastes, most are treated carefully by incineration to ensure proper destruction of pathogens. However, the behaviors of medical wastes are not well understood during the process of incineration. Thus, the aim of this work is to investigate pyrolysis and oxidation kinetics of the medical wastes, including cottons, gauzes, saline bottles, stomach medicines with the thermal gravimetric analysis (TGA) method. Experimentally, the degradation of cottons and saline bottles in pyrolysis and oxidation occurred at about 530 K and 510 K as well as 630 K and 530 K, respectively. Oxygen affects the degradation reaction of cottons and saline bottles at lower temperatures. The rate equations of the first stage of thermal treatment in different oxygen contents also showed that oxygen would decrease the activation energies of decomposition of cottons, gauzes and saline bottles. But the presence of oxygen did not influence the decomposition of stomach medicines at temperatures below 550 K, while only pyrolysis took place.

Hot Temperature↗
PubMedDate not supplied

Application of pyrolysis mass spectrometry to the classification and identification of mycobacteria.

Application of modern pyrolysis techniques offers the possibility for mass spectrometric analysis of complete bacterial cells. It was shown that pyrolysis mass spectra provide fingerprints of mycobacterial cells that are characteristic on the (sub)species level. Computer-aided comparisons of the spectra for mycobacteria were used for identification of unknown strains as members of either the "tuberculosis complex" (Mycobacterium tuberculosis, Mycobacterium bovis-BCG, M. bovis) or of the group referred to as "atypical mycobacteria." Pyrolysis mass spectrometry was performed with a completely automated instrument, and spectra were evaluated by two computerized numerical methods. The first method has general applicability to mass spectrometry data, while the second was devised for the routine identification of the "tuberculosis complex." With use of the latter method, 125 strains were identified. A positive correlation of 94.4% was found between the results of this method and the results of the usual bacteriologic procedures; 1.6% of all strains were given a falsely negative identification, and 4.0% were given a falsely positive identification.

Analysis of Variance↗
PubMed1978

Mass spectral studies of probe pyrolysis products of intact oligoribonucleotides.

Pyrolysis of underivatized homogeneous oligoribonucleotides in the source of a mass spectrometer leads to production of simple mass spectra which resemble the spectra of the bases themselves. It is proposed that pyrolysis occurs by hydrogen transfer to the base moiety followed by elimination of the neutral base. Ionization by electron impact gives rise to the observed spectra. Mixed oligoribonucleotides pyrolyze readily to give spectra of adenine and uracil, but evidence for the presence of guanine and cytosine in mixed polymers and native RNA's is difficult to obtain presumably because of their low vapor pressure. The method may be useful for detection of modified bases in tRNA and for studies of temperature effects on RNA pyrolysis.

Coliphages↗
PubMed1979

Differentiation of selected Enterobacteriaceae by pyrolysis-gas-liquid chromatography.

Pyrolysis-gas-liquid chromatography was used to differentiate selected species of Enterobacteriaceae. Individual cultures of Salmonella typhi, Hafnia alvei, and Proteus vulgaris, and 12 strains of Yersinia enterocolitica were grown in nutrient broth. After harvest and lyophilization, the bacterial samples were pyrolyzed at 900 degrees C, and their volatile fractions were separated on a 50-m capillary column coated with Carbowax 20M. The resulting pyrolysis elution patterns (pyrograms) of the four species were monitored on an integrating console, which was coupled with the chromatographic detector. The pyrograms were divided into 312 30-s time interval areas, and each interval area was normalized in relation to the area of the entire curve. The normalized areas were evaluated by stepwise linear discriminant analysis, and the discriminating component coordinates were used to generate a plot of the canonical variables. Distinct clustering patterns allowed discrimination among the four genera of Enterobacteriaceae studied. The tight clustering of the 12 Y. enterocolitica strains suggests the advantage of pyrolysis-gas-liquid chromatography over traditional approaches for species identification.

Bacteriological Techniques↗
PubMed1991

Characterization of exopolymers of aquatic bacteria by pyrolysis-mass spectrometry.

Exopolymers from a diverse collection of marine and freshwater bacteria were characterized by pyrolysis-mass spectrometry (Py-MS). Py-MS provides spectra of pyrolysis fragments that are characteristic of the original material. Analysis of the spectra by multivariate statistical techniques (principal component and canonical variate analysis) separated these exopolymers into distinct groups. Py-MS clearly distinguished characteristic fragments, which may be derived from components responsible for functional differences between polymers. The importance of these distinctions and the relevance of pyrolysis information to exopolysaccharide function in aquatic bacteria is discussed.

Carbohydrates↗
PubMed1992

Rapid differentiation of Mycobacterium xenopi from mycobacteria of the Mycobacterium avium-intracellulare complex by pyrolysis mass spectrometry.

Thirty four cultures of slow growing, Tween-80 negative mycobacteria were analysed by pyrolysis mass spectrometry. The results showed that pyrolysis mass spectrometry could positively distinguish strains of Mycobacterium xenopi from those of the Mycobacterium avium-intracellulare (MAI) complex. Pyrolysis mass spectrometry may be a useful technique for the rapid characterisation of non-tuberculous mycobacteria in such clinical settings as their isolation from immunocompromised patients-for example, those with AIDS.

Hot Temperature↗
PubMed1984

The destruction of halogenated organic chemicals by plasma pyrolysis.

Very high destruction efficiencies for halogenated chemicals have been achieved by plasma pyrolysis. Destruction efficiencies exceeded 99.9999999% for tests with polychlorinated biphenyls (PCBs). Preliminary tests with tetrachloromethane have obtained destruction efficiencies exceeding 99.99%. The plasma pyrolysis process involved the creation of a 250-kW plasma with a temperature in excess of 25 000 degrees C. The toxic material was injected into the plasma zone at a rate between 1 and 2 L/min. Thermochemical and photochemical dissociation of the toxic materials produced atoms and ions which recombined to form primarily H2, CO, HCl, and particulate carbon. The HCl was neutralized by NaOH. The flaring of the H2 and CO should destroy to a high degree any trace residuals. The application of plasma pyrolysis for the ultimate disposal of toxicological waste was also investigated. Rat carcasses containing mean lethal dosage of PCB were pyrolyzed.

Animals↗
PubMed2002

[Transformation of Na, K, Pb and Mn during pyrolysis of coal].

Transformation of Na, K, Pb and Mn in char for Shenhua and Yima coals at pyrolysis temperatures of 300 degrees C-700 degrees C was reported. Effects of atmosphere (N2, H2 and CO2) and pressure on release of the elements in Shenhua coal were also studied. The pyrolysis experiment was carried out in a closed stainless steal reactor. Results show that the bleeding ratio of Na, K, Pb and Mn varied with coal type but all increased with pyrolysis temperature. For example, the bleeding ratio of Na, K, Pb and Mn at 700 degrees C for Shenhua coal was 3, 4.2, 1.4, and 2.4 times larger than that of Yima coal. The effect of pressure was small. Among the N2, H2 and CO2 environments, H2 resulted in the highest bleeding ratio and CO2 the least bleeding ratio. Thermodynamic calculation shows that Pb was the most volatile element among the four inorganic harmful elements.

Coal↗
PubMed2000

[Structure determination of alkyd resins by simultaneous pyrolysis methylation gas chromatography-mass spectometry].

Several types of alkyd resins have been analyzed by simultaneous pyrolysis methylation gas chromatography mass spectrometry (SPM-GC-MS). The samples were mixed with tetramethylammonium hydroxide, and the process included simultaneous pyrolysis derivatization and mass spectrometry determination. SPM-GC-MS conditions: a vertical microfurnace-type pyrolyzer was directly attached to a gas chromatograph-mass spectrometer. About 20 ug of the mixed alkyd resin sample was introduced into the center of the pyrolyzer at 450 degrees C under the flow of helium carrier gas. The inlet mode was split with an injection interval of 10 s and the inlet pressure was 82.7 kPa. The gas chromatograph was fitted with a fused-silica capillary column ( SE-54 30 m x0.25 mm i.d. x 0.25 um). Temperature program settings were: initial temperature, 40 degrees C, hold 2 min; increase at 6 degrees C min 1 to 220 degrees C, hold 14 min; increase at 10 degrees C min 1 to 280 degrees C, hold 8 min. All pyrolysis products referred to were identified by mass spectrometry. The temperature of the ion source was 210 degrees C and that of the transfer line was 250 degrees C. The technique could give additional information about the composition of the dibasic acids, polyols, six types of drying oils, and modified alkyd resins. The method is sensitive, accurate, convenient, and involves minimal sample manipulation.

English Abstract↗
PubMed2003

[Transformation of sulfur forms during coal pyrolysis and partial gasification in a fixed bed reactor].

The development of various process to the pre-desulfurization of coal was drawn more attention. In present study, the transformation of sulfur forms of three different ranks high sulfur coals during coal pyrolysis and partial gasification were investigated in a fixed bed reactor. The sulfur and carbon content analysis of original coal and coal char produced were determined by LECO SC-444 and wet chemical analysis according to Sugawara's method. The results showed that half of inorganic sulfur and partial of organic sulfur were removed during coal pyrolysis. And the sulfur removal was much more than carbon during pyrolysis process; and the sulfur in the coal char, especially the sulfide sulfur was removed completely during partial gasification process for both Datong coal and Xishan coal, the degree of sulfide sulfur removal could be increased with increasing temperature. At the same time, the results of Yima coal showed that the effect of fixed-sulfur by alkaline metals increased when the temperature was higher than 700 degrees C, which attribute to the increase of the fixed sulfur reaction rate and the decrease of mass-transfer limitation.

Air Pollution↗
PubMed2004

[The effect of minerals on transformation of sulfur during pyrolysis and partial gasification].

In this study, the effect of acid treatment of Yima coal on predesulfurization during pyrolysis and partial gasification were investigated. The coal was treated with HCl, HCl-HF and HCl-HNO3 solution, in which different minerals were eliminated. The whole process could be divided into pyrolysis and partial gasification. In pyrolysis process, the evolution of H2S and COS show two peaks, which were 450 degrees C and 600 degrees C respectively. At high temperature, the amount of H2S evolution from acid treated coal was markedly increased compared to the raw coal through the elimination of minerals. In the case of HCl-HNO3 treated sample, the H2S evolution in the low temperature region, below 500 degrees C, was reduced and the COS evolution in higher temperature region, above 500 degrees C, was increased by the chemical oxidation. In the partial gasification process, the sulfide sulfur removal of acid treated coal char was increased, reached about 100% at 800 degrees C. The maximum of total and sulfide sulfur removal of parent coal char were 46.39% and 52.97% at 700 degrees C. Compared to acid treated coal char, the effect of alkaline minerals for fixing sulfur was strengthened with increasing the temperature. The organic sulfur of acid treated coal char was released with carbon gasification, and the value could be constant.

Air Pollutants↗
PubMed2005

[Investigation of inorganic sulfur decomposition in a coal-like environment during pyrolysis].

An activated charcoal (AC) was used to simulate coal-like environment, and the inorganic sulfur (pyrite or ferrous sulfate) was mixed with it in some ways. The dynamic characteristics and structure changes of FeS2 and FeSO4 with and without AC during pyrolysis, were investigated by temperature-programmed decomposition-flame photometric detector or mass spectrometer (TPD-FPD/ MS) and extended X-ray absorption fine Structure (EXAFS) spectroscopy. It is found that the decomposition of FeSO4 impregnated onto AC mainly happened between 200 degrees C and 500 degrees C , while the pure FeSO4 decomposed at around 450 degrees C - 600 degrees C. The comparison shows that the existence of AC lowered the decomposition temperature of FeSO4, and made the emission of sulfur more complex as well. However, the decomposition temperature of pyrite wasn't varied by the physical mixing with AC. Furthermore, the decomposition degree of pyrite depended on the existence of AC and the pyrolysis atmosphere used. Above 400 degrees C, the evolution of sulfur became remarkable. At around 550 degrees C the sulfur in the second sphere of Fe-S-S was lost, and the pyrolysis product FeS appeared simultaneously.

Air Pollutants↗
PubMedDate not supplied

[Consumption of water-insoluble phenolic products of lignin pyrolysis by the strain Penicillium tardum H-2].

Abstract-Physiological and biochemical properties of the strain Penicillium tardum H-2, a degrader of phenolic compounds formed during lignin pyrolysis, have been characterized. The micromycete P. tardum H-2 can consume phenol, pyrocatechol, p-cresol, vanillin, and guaiacum resin. When grown in a medium containing the water-soluble fraction of lignin pyrolysis waste at concentrations from 0.5 to 2%, it consumes 62-72% of the phenolic components of the waste. According to gas-liquid chromatography, cultivation of P. tardum H-2 in a medium with liquid pyrolysis products results in a complete consumption of the phenol-cresol fraction.

Benzaldehydes↗
PubMed1987

The effect of activity state upon the production of lethalities due to the inhalation of the toxic pyrolysis products of polyacrylonitrile.

Hydrogen cyanide is known to be produced upon the pyrolysis of the synthetic material polyacrylonitrile. Cyanide inhibits phosphorylation reactions, therefore, decreasing the amount of high energy bonds available for metabolic use. Since the energy requirements, as well as the respiratory minute volume, for an individual decrease with decreasing activity, it was of interest to investigate whether diminished physical activity would decrease the lethal potential of the pyrolysis products of polyacrylonitrile. In order to produce wide variations in physical activity, male ICR mice were pretreated with either 8.6 mg/kg dextroamphetamine sulfate ip 30 min prior to challenge, 75 mg/kg sodium pentobarbital ip 15 min prior to challenge, or 10 ml/kg of 70 proof ethyl alcohol ip 15 min prior to challenge. Control animals received injections of 10 ml/kg normal saline ip 15 min prior to challenge. Animals were subsequently challenged with the cooled/filtered smoke from the pyrolysis of polyacrylonitrile fibers at 660 C. Increased physical activity decreased the exposure time necessary to produce death. Animals pretreated with amphetamine appear to die more rapidly than control animals due to an increase in respiratory minute volume. Animals pretreated with sodium pentobarbital or ethanol appear to survive through long periods of exposure to the toxic gases due to both a decrease in minute volume and a decrease in energy utilization.

Acrylic Resins↗
PubMed1980

Differentiation of fetal and adult bloodstains by pyrolysis-gas-liquid chromatography.

A pyrolysis-gas-liquid chromatographic method has been developed for the differentiation of adult and fetal bloodstains. In a blind-coded study, five adult and three fetal bloodstains were correctly identified on the basis of the pyrograms of stain extracts. The differentiation between adult and fetal bloodstains is based on the peak height ratio of two long-retention-time peaks appearing in their pyrograms. The first of these peaks has been tentatively identified as indole derived from the pyrolysis of tryptophan, while the second peak is an as-yet unidentified molecular fragment produced by the pyrolysis of some component of the hemoglobin molecule other than the amino acids tryptophan, tyrosine, and phenylalanine.

Adult↗
PubMed1981

Control on the absence of DEAE-polysaccharides in DEAE-sephadex purified poliovirus suspensions by pyrolysis mass spectrometry.

Poliovirus suspensions produced in microcarrier culture of primary monkey kidney cells and purified by column chromatography on DEAE-sephadex have been tested for the presence of DEAE-polysaccharides (in essence DEAE-dextran) by pyrolysis mass spectrometry. Semi-quantitative evaluation of the pyrolysis mass spectra indicates that the concentration of DEAE-dextran in the purified poliovirus concentrates is below 20 ppm i.e. the lower detection level of the method. As the final vaccines contain a 1:50 to 1:100 dilution of the tested virus suspension, the DEAE-polysaccharide concentration in the vaccine will be below 1 ppm at least. Pyrolysis mass spectrometry appeared to be a vary suitable method for control on the absence of this component.

Animals↗
PubMed1996

Curie-point pyrolysis-gas chromatography/mass spectrometry in the art field. 2--The characterization of proteinaceous binders.

Curie point pyrolysis with gas chromatography/mass spectrometry has been employed to characterize some proteinaceous media used in the art field as painting binders: milk casein, egg yolk, egg albumin, bone glue, skin glue, rabbit glue and fish glue. A careful analysis of the gas chromatograms so obtained has led to the distinction of the different proteinaceous binders in terms of different chromatographic profiles. Some of the pyrolysis products have been identified by library search.

Adhesives↗