CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH_3(NH_3-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH_3-SCR p...CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH_3(NH_3-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH_3-SCR performance, Fe was loaded into one-pot synthesized Cu-SSZ-13 catalysts through solid-state ion-exchange(SSIE), homogeneous deposition precipitation(HDP) and liquid ion-exchange(IE), respectively. Three CuFe-SSZ-13 catalysts showed similar SO_2 resistance, which was better than that of Cu-SSZ-13. The improvement was attributed to the protection of Fe species. Hydrothermal stability of three CuFe-SSZ-13 catalysts was significantly different, which was attributed to the state of active species caused by different preparation methods. Compared with the other two catalysts, more active species existed inside the zeolite pores of CuFe-SSZ-13 SSIE. During hydrothermal aging, the aggregation of these active species in the pores caused the collapse of catalyst structure, ultimately leading to the deactivation of CuFe-SSZ-13 SSIE. In contrast, Fe species was dispersed better on the surface over CuFe-SSZ-13 IE, enhancing the hydrothermal stability of catalysts. Consequently, Fe loading effectively improved the resistance of SO_2 and H_2O over Cu-SSZ-13. For CuFe-SSZ-13, large amounts of active species located inside the zeolite pores are not beneficial for the hydrothermal stability.展开更多
Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmissi...Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope(TEM) and Fourier transform infrared(FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% A d and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H 2 O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer(GC/MS).The results show that extract is more reactive with H 2 O 2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.展开更多
Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcrib...Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.展开更多
基金supported by the National Natural Science Foundation of China(No.51508231)
文摘CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH_3(NH_3-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH_3-SCR performance, Fe was loaded into one-pot synthesized Cu-SSZ-13 catalysts through solid-state ion-exchange(SSIE), homogeneous deposition precipitation(HDP) and liquid ion-exchange(IE), respectively. Three CuFe-SSZ-13 catalysts showed similar SO_2 resistance, which was better than that of Cu-SSZ-13. The improvement was attributed to the protection of Fe species. Hydrothermal stability of three CuFe-SSZ-13 catalysts was significantly different, which was attributed to the state of active species caused by different preparation methods. Compared with the other two catalysts, more active species existed inside the zeolite pores of CuFe-SSZ-13 SSIE. During hydrothermal aging, the aggregation of these active species in the pores caused the collapse of catalyst structure, ultimately leading to the deactivation of CuFe-SSZ-13 SSIE. In contrast, Fe species was dispersed better on the surface over CuFe-SSZ-13 IE, enhancing the hydrothermal stability of catalysts. Consequently, Fe loading effectively improved the resistance of SO_2 and H_2O over Cu-SSZ-13. For CuFe-SSZ-13, large amounts of active species located inside the zeolite pores are not beneficial for the hydrothermal stability.
基金subsidized by the National Natural Science Foundation of China (Nos.50474066,50874108 and 50921002)the Fundamental Research Funds for the Central Universities(No.2010LKHX01)the National Basic Research Program of China (No.2012CB214900)
文摘Tongting coal(TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone(CS 2 /NMP) mixed solvents to afford brown particles of extract,which was characterized with proximate analyzer,transmission electron microscope(TEM) and Fourier transform infrared(FTIR) spectrometer.The results show that the nanometer particles of extract,which were free of ash,are superfine and superclean with tract content of 0.02% A d and particles size of about 100-150 nm.TTC and extract were then subject to oxidation with H 2 O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer(GC/MS).The results show that extract is more reactive with H 2 O 2 in comparison to TTC and richer in oxygen-containing species including phenols,alcohols,ethers,esters,carboxylic acids and anhydrides.
基金supported by the National Natural Science Foundation of China (21073235,21173270,21177160)the National High Technology Research and Development Program of China (863 Program,2013AA065302F)China University of Petroleum Fund (LLYJ-2011-39 and KYJJ2012-06-31)~~
基金The work was supported by the National Natural Science Foundation of China (Grant No. 39730070).
文摘Phylogenetic relationships among six species of Epistylis (i. e. E. plicatilis, E. urceolata, E. chrysemydis, E. hentscheli, E. wenrichi, and E. galea) were investigated using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA). Amplified rDNA fragment sequences consisted of 215 or 217 bases of the flanking 18S and 5.8S regions, and the entire ITS-1 region (from 145 to 155 bases). There were more than 33 variable bases between E. galea and the other five species in both the 18S region and the ITS-1 region. The affiliation of them was assessed using Neighbor-joining (NJ), maximum parsimony (MP) and maximum likelihood (ML) analyses. In all the NJ, MP and ML analyses E. galea, whose macronucleic position and shape are distinctly different from those of the other five species, was probably diverged from the ancestor of Epistylis earlier than the other five species. The topology in which E. plicatilis and E. hentscheli formed a strongly supported sister clade to E. urceolata, E. chrysemydis, and E. wenrichi was consistent with variations in the thickness of the peristomial lip. We concluded that the macronucleus and peristomial lip might be the important phylogenetic characteristics within the genus Epistylis.