RESUMO
A series of Ni1Mg2Al1Ox, Mn1Mg2Al1Ox, 0.5Pt/Ni1Mg2Al1Ox and 0.5Pt/Mn1Mg2Al1Ox catalysts were carefully prepared and their NOx storage and reduction (NSR) performance including NOx oxidation efficiency (NOE), NOx storage capacity (NSC), NOx conversion rate (XNO), N2 selectivity (SN2), N2O selectivity (SN2O) and NH3 selectivity (SNH3), was systematically investigated. A SO2 resistance test was also performed in the presence of 100 ppm SO2. The NOE and NSC experimental results revealed that the Ni1Mg2Al1Ox catalyst possesses a higher NSC, while the Mn1Mg2Al1Ox catalyst possesses a better NOE. With regard to XNO, 0.5Pt/Ni1Mg2Al1Ox presented higher results at 200 °C and 400 °C, while 0.5Pt/Mn1Mg2Al1Ox obtained the highest result at 300 °C, which was more than 60% for both. In addition, compared to 0.5Pt/Ni1Mg2Al1Ox, 0.5Pt/Mn1Mg2Al1Ox exhibited a relatively higher SN2 and lower SN2O and SNH3. The NOx-TPD and H2-TPSR results indicated that NOx adsorbed on Ni1Mg2Al1Ox and 0.5Pt/Ni1Mg2Al1Ox is more stable, and that NH3 can be formed in large amounts in a lower temperature range. Both Pt-containing catalysts presented a quite stable XNO in ten cycles in the presence of 100 ppm SO2, and their SN2 can be remarkably enhanced to more than 80%, which could be attributed to the reactions of NH3-SCR and SO2 + NH3. We believe this new insight can provide a new way of thinking for the development of NSR catalysts.
RESUMO
In this research, we investigated the hydrophobicity and dynamic adsorption-desorption behaviors of volatile organic compounds (VOCs) by applying different optimized coating dosage (25, 50, and 75%) on designed novel ZSM-5/MCM-41 and ZSM-5/Silicalite-1 hierarchical composites. The relatively large specific surface area and pore volume of adsorbents ZSM-5/MCM-41 and ZSM-5/Silicalite-1 composites with excellent stability were affirmed by ex-situ XRD, FTIR, BET, SEM, and water contact angle analyses. Regarding, toluene adsorption-desorption investigation, ZSM-5/MCM-41 composite lead a longer stable toluene breakthrough time no matter under dry or 50% humid conditions. However, under different loading dosage condition, the breakthrough time of 75% coating ratio was the longest, which was 1.6 times as long as that of pure ZSM-5 under wet adsorption. Meanwhile, the complete elimination of toluene for ZSM-5/MCM-41-75% was done by largest desorption peak area and the lowest desorption temperature of 101.9°C, while, the largest contact angle of ZSM-5/MCM-41-75% was 17.0° higher than pure ZSM-5 zeolite. Therefore, we believe that the present hydrophobic sorbent will provide new insight with great research potential for removing low concentration of VOCs at industrial scale.
RESUMO
CH4 as the paramount ingredient of natural gas plays an eminent role in C1 chemistry. CH4 catalytically converted to syngas is a significant route to transmute methane into high value-added chemicals. Moreover, the CO/CO2 methanation reaction is one of the potent technologies for CO2 valorization and the coal-derived natural gas production process. Due to the high thermal stability and high extent of dispersion of metallic particles, two-dimensional mixed metal oxides through calcined layered double hydroxides (LDHs) precursors are considered as the suitable supports or catalysts for both the reaction of methanation and methane reforming. The LDHs displayed compositional flexibility, small crystal sizes, high surface area and excellent basic properties. In this paper, we review previous works of LDHs applied in the reaction of both methanation and methane reforming, focus on the LDH-derived catalysts, which exhibit better catalytic performance and thermal stability than conventional catalysts prepared by impregnation method and also discuss the anti-coke ability and anti-sintering ability of LDH-derived catalysts. We believe that LDH-derived catalysts are promising materials in the heterogeneous catalytic field and provide new insight for the design of advance LDH-derived catalysts worthy of future research.
RESUMO
AIM: Ero proteins are central to oxidative protein folding in the endoplasmic reticulum (ER), but their expression varies in a tissue-specific manner. The aim of this work was to establish the expression of Ero1α in the digestive system and to examine the behavior of Ero1α in premalignant Barrett's esophagus, esophageal (OE) and gastric cancers and esophageal cancer cell lines. RESULTS: Ero1α is expressed in the columnar epithelium of Barrett's tissue, and in OE tumors and gastric tumors. Homocysteine, a precursor in the metabolism of cysteine and methionine, induces the active Ox1 form of Ero1α in the OE cancer cell line OE33. INNOVATION: These results demonstrate for the first time that Ero1α can sense the level of an amino acid precursor, identifying a potential link between diet, antioxidants, and oxidative protein folding in the ER. CONCLUSION: The high expression of Ero1α in cancers of the esophagus and stomach demonstrates the importance of ER redox regulation in the gastro-intestinal (GI) tract in health and disease. Proteins and metabolites involved in disulfide bond formation and redox regulation may be suitable targets for both biomarker and drug development in GI cancer.
