Papers by Keyword: Pyrene

Abstract: The aims of the present work were simulating actual environmental pollution to select and compare the bacterial communities under different environmental stresses such as phenanthrene and pyrene. Two bacterial consortia named as Phe consortium and Pyr consortium were enriched from activated sludge obtained from a wastewater treatment plant. The PCR-DGGE analysis showed that the original active sludge harbored abundantly diverse PAH-degrading bacteria at first, then under different environmental pressures the consortium species tended to be concentrated and had species structure differences. In addition, the abilities of the two bacterial consortia to remediate a mixture of 4 PAHs (50 mg Kg^-1 each) in soil were studied. Of the 4 PAHs, greater than 80% of the fluorene and phenanthrene in soil were removed by the Phe consortium in just 7-days respectively; whereas the Pyr-consortium could degrade over 60% of anthracene and pyrene.

Abstract: The potentials of three plant species, rape, alfalfa and white clover, separately or jointly on the degradation of polycyclic aromatic hydrocarbons (PAHs) in soils were estimated by pots experiments. Results showed that the presence of vegetation apparently enhanced the dissipation of PAHs at initial concentrations ranging from 20.05 to 322.06 mg·kg^-1, but the efficacy enhanced varied greatly among plant species and cropping patterns. Within 70-day experiment, alfalfa and white clover showed higher efficiencies for the removal of PAHs than those of rape, and mixed cropping greatly enhanced the dissipation of PAHs as compared to single cropping. On average 74.87% of phenanthrene or 62.81% of pyrene were removed from soils with mixed cropping of rape and alfalfa, and 72.01% of phenanthren or 68.44% of pyrene removed by mixed cropping of rape and white clover. Under similar pollution level, PAHs accumulated in plant, irrespective of root and shoot, was much lower in mutli-planted treatments than in mono-planted ones. Results suggested a feasibility of the establishment of multispecies remediation for enforcing the dissipation of PAHs, which may also decrease the accumulations of PAHs in plant and thus reduce their risks to humans.

Abstract: Pyrene was adsorbed to a TiO2 surface from water-alcohol mixture solutions at 25°C and pyrene-TiO2 particles were recovered by filtration. We found that the surface of TiO2 thus recovered is relatively hydrophobic and pyrene is not decomposed but keep its fluorescence characteristics on the spectral measurement under ultraviolet excitation.

Abstract: A novel one-pot catalytic synthesis of 1-benzoylpyrene through acylation of pyrene with benzoyl chloride catalyzed by various Keggin type heteropoly acids (salts) was investigated. Pure 1-benzoylpyrene was obtained and the structure of 1-benzoylpyrene was identified by GC/MS, FT-IR and 1H NMR spectra. H3PW12O40 (PW) was found to be the most active catalyst in the acylation. The yield and the selectivity of 1-benzoylpyrene were up to 97.6 % and 100 %, respectively. The effects of experimental parameters on the catalytic acylation reaction and the recycling performance of PW catalyst were studied. PW catalyst shows well catalytic activity after running for 5 times. The facile product separation and the recycling performance of PW catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 1-benzoylpyrene.

Abstract: The pyrene/pyrrole copolymer (Pn/Py copolymer) has been sucessfully synthesized by the facile chemically oxidative copolymerization. UV-vis and FT-IR spectra are used to investigate the molecular structure of the copolymer. The results show that pyrene and pyrrole units in the copolymer chain are interconnected via α, α-coupling to form a linear structure. At the same concentration, the copolymer solution exhibits the strongest green fluorescence with a maximum emission at 503 nm and a large stokes shift of about 113 nm by fluorescence spectrometer. The excellent fluorescence of Pn/Py copolymer may be due to its better planar molecular structure and higher large π-conjugation, that is confirmed by UV-vis spectra and molecular simulation.

Abstract: A novel stem-loop structured fluorescent oligoDNA probe (molecular beacon probe) bearing a silylated pyrene derivative at C-5 position of deoxyuridine has been synthesized. The fluorescently labeled modified nucleoside has been incorporated into two consecutive positions in the stem segment of the DNA using an automated DNA synthesizer. The resulting modified DNA exhibited an excimer fluorescent signal upon binding to the fully matched complementary DNA strand. The excimer emission was, however, effectively quenched while it stays alone or it hybridizes to a single base mismatched complementary target.

Abstract: With electron assisted chemical vapour deposition technology, some nanocrystalline diamond films have been deposited, which precipitate polycyclic aromatic clusters in the film matrix. Optical properties of the films have been characterized. The results of characteristics show that Raman and photoluminescence spectrum of the films conform to identity of pyrene except for diamond peaks; photoluminescence emission spectrum of the films show stronger emission peaks at 385nm and 470nm. Our results show that purer polycyclic aromatic clusters of four fused sixfold ring, which are the same as pyrene in structure, can form in the nanocrystalline diamond film matrix by bombarding the films with electrons.

Abstract: This paper used the pressure sensitive paints(PSP) as the experimental object, the organic silicon type of the 9801 is selected as one of the best binder. Fluorescence characteristics and oxygen quenching coefficient were studied on PSP with different pyrene contents. The result shows that the fluorescence intensity in Monomer Emission is gradually reduced with the increase of the content of pyrene in paint, but the fluorescence intensity in Excimer Emission is gradually increased. With the increase of the content of pyrene in PSP, oxygen quenching coefficient shows a normal distribution, it can be up to 21%.