Aromatics Production With Cobalt-Modified Ultra-Stable Y Zeolites As Catalysts In Catalytic Pyrolysis of Ginkgo Biloba Residue

The current research studied the performance of novel and cheap catalysts, ultra-stable Y zeolites (USY) and cobalt-modified USY for the efficient production of aromatics from the ginkgo Biloba residue (GBR) using a pyrolysis reactor. Cobalt-modified USY improved the quality of the pyrolysis products e.g. removed unwanted impurities from bio-oil, increased the yield of gases, and overall boosted the GBR conversion. Under the action of USY modified with cobalt, the yield of CO, CH4, and CO2 in the gas production increased significantly, while the yield of H2 was dropped. The selectivity of naphthalene and 1-methylnaphthalene gradually decreased. The composition of aromatic hydrocarbons was reduced, while the content and selectivity ratios of toluene and xylene were increased. This study describes a high-value method using GBR, which could be used as a sustainable resource for the production of hydrocarbons, especially for the preparation of high-quality toluene and phenols.

Adsorption of Toluene and Water over Cationic-Exchanged Y Zeolites: A DFT Exploration

In this study, density functional theory (DFT) calculations have been performed to investigate the adsorption mechanisms of toluene and water onto various cationic forms of Y zeolite (LiY, NaY, KY, CsY, CuY and AgY). Our computational investigation revealed that toluene is mainly adsorbed via π–interactions on alkalis exchanged Y zeolites, where the adsorbed toluene moiety interacts with a single cation for all cases with the exception of CsY, where two cations can simultaneously contribute to the adsorption of the toluene, hence leading to the highest interaction observed among the series. Furthermore, we find that the interaction energies of toluene increase while moving down in the alkaline series where interaction energies are 87.8, 105.5, 97.8, and 114.4 kJ/mol for LiY, NaY, KY and CsY, respectively. For zeolites based on transition metals (CuY and AgY), our calculations reveal a different adsorption mode where only one cation interacts with toluene through two carbon atoms of the aromatic ring with interaction energies of 147.0 and 131.5 kJ/mol for CuY and AgY, respectively. More importantly, we show that water presents no inhibitory effect on the adsorption of toluene, where interaction energies of this latter were 10 kJ/mol (LiY) to 47 kJ/mol (CsY) higher than those of water. Our results point out that LiY would be less efficient for the toluene/water separation while CuY, AgY and CsY would be the ideal candidates for this application.