Acid-activated vermiculites as catalysts of the DeNOx process

Preparation and characterization of capric-myristic-stearic acid eutectic mixture/modified expanded vermiculite composite as a form-stable phase change material

“…From the patterns of the EVC and aEVC, the d 001 -values of phlogopite are close to that of EV, suggesting that the CTAB in the layer was carbonated in situ [19]. Moreover, the intensity of phlogopite diffraction peak weaken evidently by acid treatment, which could be related to the less ordered layered structure [29]. …”

Thermal insulation with 2D materials: liquid phase exfoliated vermiculite functional nanosheets

“…64 On the other hand, increasing the acidic strength (0.75 -1 M, pH = 0.12 and 0, respectively) results in, first, dissolving ions from the octahedral sheets and then tetrahedral aluminum ions. 64,65 Further increase of concentration of HCl (> 2M) leads to total transformation of vermiculite structure to amorphous silica. 41,64 Combination of both, ultrasounds and acid solution, gives the opportunity to use low quantity of acid, which only influences the interlayer ions and supports ultrasonication.…”

Cu and Fe modified derivatives of 2D MWW-type zeolites (MCM-22, ITQ-2 and MCM-36) as new catalysts for DeNO x process

“…For these catalysts, the NO conversion starts at about 398 K and reaches 100% at about 573 K. A decrease in NO conversion at higher temperatures [33,34] is associated with a side process of direct ammonia oxidation by oxygen present in the reaction mixture. It is also worth to mention that the MWW family samples show high selectivity to N 2 (above 90%).…”

“…The Fe-MCM-22 sample, containing part of deposited iron in the aggregated form, was more active than Fe-ITQ-2, containing nearly exclusively iron in the form monocular iron ions. Therefore, these differences in the low-temperature activity can be explained by higher activity of more aggregated iron oxide species comparing to mononuclear Fe 3+ ions in the low-temperature DeNO x process [37]. However, in this case also a significant influence of surface acidity and porous structure of the catalysts on their catalytic performance cannot be excluded.…”