Monolith or Powder: Improper Sample Pretreatment May Mislead the Understanding of Industrial V2O5-WO3/TiO2 Catalysts Operated in Stationary Resources.

Although various characterizations are widely applied to commercial V2O5-WO3/TiO2 catalysts, the influence of the catalyst physical structure, i.e., monolith or powder, on the characterization results has not been investigated. Several important catalytic behaviors and phenomena were observed in this study using V2O5-WO3/TiO2 monolithic catalysts employed for over 5000 h in various stationary flue gases, and many of the results were only observable on monolithic catalysts, such as depth-dependent distribution of external elements, penetration of As2O3, and the formation of Tl2O-TiO2 p-n junctions. If the monolith is ground into powder states, it will alter or destroy the catalyst surface and remove important clues closely related to catalytic performance under working conditions. The redox and acidity properties of V2O5-WO3/TiO2 obtained from powder samples may be significantly different from their true state under working conditions, resulting in a misperception of catalyst performance. Therefore, a cautious pretreatment should be taken into careful consideration when analyzing commercial honeycomb V2O5-WO3/TiO2 catalysts.

Penetration of Arsenic and Deactivation of a Honeycomb V2O5-WO3/TiO2 Catalyst in a Glass Furnace.

Deactivation of honeycomb V2O5-WO3/TiO2 catalysts by arsenic has been studied widely in coal-fired power plants but rarely in glass furnaces. In this paper, deactivated catalysts that had been used for more than 4000 h were analyzed. We maintained the catalysts in their original monolith shape to retain their adhered substance and used appropriate methods to strip the substance layer by layer. With various characterization techniques, it was determined that the adhered substance was composed almost entirely of Na2SO4 and CaSO4. We also quantified the penetration depth of arsenic visually, which was more than 370 µm. A three-stage penetration and deactivation process induced by arsenic was proposed. It was pointed out that molten and volatile As2O3 played a key role in the deactivation process, while substances in the solid state had little impact on the deep bulk of the catalyst. In this study, we proposed an integrated deactivation process consisting of adhesion, penetration, and deactivation in a honeycomb V2O5-WO3/TiO2 catalyst by arsenic in a glass furnace. Finally, we also provided guidance on alleviating the deactivation caused by arsenic. The key is to convert molten and volatile As2O3 to solid-state substances before it contacts the catalyst.

FIB-SEM analysis on three-dimensional structures of growing organelles in wild Chlorella pyrenoidosa cells.

To clarify dynamic changes of organelle microstructures in Chlorella pyrenoidosa cells during photosynthetic growth with CO2 fixation, three-dimensional (3D) organelle microstructures in three growth periods of meristem, elongation, and maturity were quantitatively determined and comprehensively reconstructed with focused ion beam scanning electron microscopy (FIB-SEM). The single round-pancake mitochondria in each cell split into a dumbbell and then into a circular ring, while the barycenter distance of mitochondria to chloroplast and nucleus was reduced to 45.5% and 88.3% to strengthen energy transfer, respectively. The single pyrenoid consisting of a large part and another small part in each chloroplast gradually developed to a mature state in which the two parts were nearly equal in size. The nucleolus progressively became larger with euchromatin replication. The number of starch grains gradually increased, but the mean grain volume remained nearly unchanged.

Partitioning characteristic of chlorine ion in gas and solid phases in process of desulfurization wastewater evaporation: model development and calculation.

Since the promulgation of "Water Pollution Control Action Plan " in China, zero liquid discharge of desulfurization wastewater has become a new trend of power plant water pollution control. Aiming at the application of desulfurization wastewater evaporation technology using high-temperature flue gas, simulation and experimental research on quantifying and predicting gas-solid partitioning of chlorine ion under different operation conditions are carried out in this paper. The gas-liquid equilibrium theory is applied to the complex mixed salt system; based on state equation, the semi-empirical model of gas-solid phase partitioning coefficient of chlorine ion is calculated, with high degree of fitting range from 180 to 380 °C. The essential effects of pH, Cl- concentration, and total dissolved solids (TDS) on the gas-solid phase partitioning coefficient of chlorine ion are investigated. The study provides key data for the application of evaporation technology using high-temperature flue gas, obtaining the quantification and prediction of chlorine ion volatilization during desulfurization wastewater evaporation.

Effect of intravenous infusion of dexmedetomidine combined with inhalation of isoflurane on arterial oxygenation and intrapulmonary shunt during single-lung ventilation.

To investigate the changes in arterial oxygenation and intrapulmonary shunt during one-lung ventilation (OLV) with intravenous infusion of dexmedetomidine combined with isoflurane inhalation. ASA I-II 60 patients aged 18-70 year, undergoing OLV during elective thoracic surgery were randomly allocated to two groups: (1) isoflurane + saline (group NISO, n = 30) and (2) isoflurane + dexmedetomidine (group DISO, n = 30). After induction, anesthesia was maintained with intravenous infusion of remifentanil 0.1-0.2 µg kg(-1) min(-1) and inhalation isoflurane (1.0-2.0%). In addition, anesthesia was maintained with intravenous infusion of dexmedetomidine 0.7 µg kg(-1) h(-1) in DISO group and saline 0.25 ml kg(-1) h(-1) in NISO group. Bispectral Index values were maintained within 40-60 by changing the concentration of isoflurane in all groups. Arterial blood gas samples and central venous blood gas samples were taken as follows: during two-lung ventilation before OLV and during the first 40 min of OLV. 45 Patients completed the study, with 23 patients in DISO group and 22 patients in NISO group. The two groups were comparable in terms of demographic variables, hemodynamic, PaO2, Qs/QT, end expiration isoflurane and BIS levels during the operation. Compared with patients in the group NISO, there were significant increases with PaO2, significant decrease with Qs/QT, significant decrease with end expiration isoflurane, and significant decrease with HR in the group DISO during the first 40 min of OLV (P < 0.05). Dexmedetomidine infusions decrease the requirement for isoflurane, decrease intrapulmonary shunt, and moderate the change in PaO2 and may be useful in managing OLV.