Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH3.

Coal fly ash (CFA) is an ideal source for the preparation of heterogeneous catalysts due to its abundant silicon and aluminum oxides, but its activity needs to be improved. In this study, a green and moderate approach for CFA activation was proposed, and a series of CFA-based catalysts were prepared for NO selective catalytic reduction (SCR). The results indicated that CFA could be well activated via mechanochemical activation with 3 h of milling duration in 1 mol/L of acetic acid, and 90% of NO removal was achieved over the CFA-based catalyst in 250 to 375 °C. Two activating mechanisms, i.e., the enhanced CFA fragmentation and the motivated Al dissolution, were revealed during the mechanochemical activation. The former facilitated the formation of mesopores and the exposure of Fe components in CFA fragments, which enhanced the capacity of oxygen storage over the as-activated catalyst. The latter motivated the formation of Si-OH groups, which promoted the migration of electrons and the dispersion of V species, thereby increasing the capacity of NH3 adsorption over the as-obtained catalyst. Therefore, the performance of NO reduction was improved. The proposed activating approach could be a promising integration for CFA disposal and NO removal from inside coal-fired power plants.

Recovering high-quality glass fibers from end-of-life wind turbine blades through swelling-assisted low-temperature pyrolysis.

The recycling of end-of-life wind turbine blades has become a global environmental challenge driven by the rapid growth of wind power. Pyrolysis is a promising method for recovering glass fibers from these discarded blades, but traditional pyrolysis is often operated at high temperatures, which degrades the mechanical properties of recovered fibers. To address this issue, a swelling-assisted pyrolysis method was proposed to recover high-quality glass fibers from end-of-life wind turbine blades at low temperatures. The results confirmed that the decomposition of the resin matrix within the blade was significantly promoted at low temperatures in the swelling-assisted pyrolysis process, achieving a resin decomposition ratio of 76.8 % at 350 °C. This improvement was attributed to enhanced heat transfer and co-pyrolysis with acetic acid. Swelling could physically disrupt the cross-linked structure of the blade, creating a more porous and layered structure, thereby enhancing heat transfer during the pyrolysis process. Simultaneously, the co-pyrolysis with acetic acid could generate hydrogen radicals, which promoted the cracking of macromolecular oligomers into lighter products or gaseous alkanes. Consequently, the formation of pyrolysis char within the solid pyrolysis product was reduced, shortening the oxidation duration to 30 min. In comparison to traditional pyrolysis, the swelling-assisted pyrolysis process effectively suppressed the diffusion of surface defects over the recovered fibers, leading to promising improvements in their flexibility, elasticity, and mechanical properties, with tensile strength notably increased by 27.5 %. These findings provided valuable insights into recovering high-quality glass fibers from end-of-life wind turbine blades.

Effects of gaseous agents on the evolution of char physical and chemical structures during biomass gasification.

Bio-char samples were prepared from gasification of corn straw under N2, CO2 and H2O conditions, and systematically characterized to reveal the effects of gaseous agents on the evolution of char structural features during the gasification process. The results showed that the increase of reacting temperature had positive effects on the gasification of char in both H2O and CO2 atmospheres. The evolution of char pore structures under H2O and CO2 was quite different. The formation of micropores was facilitated by CO2, while mesopores and macropores were developed more in H2O condition. Besides, char structures obtained at 800 °C were more ordered than those obtained at 600 °C. Compared with the longitudinal merging, the aromatic layers preferred to grow laterally. Moreover, the mechanisms of gasification between char and gaseous agents were different. CO2 preferred to react with amorphous carbon, while the cross-linked carbon was more likely to be consumed during char gasification with H2O.

4α-Methylergosta-22(E),24(28)-dien-3ß-ol, a New Marine Sterol from the Octocoral Nephthea columnaris.

A new marine sterol, 4a-methylergosta-22(E),24(28)-dien-3 P-ol (1), was isolated from the octocoral Nephthea columnaris. The structure of I was elucidated on the basis of spectroscopic and mass spectrometric methods.