Catalytic Fast Pyrolysis of Kraft Lignin With Conventional, Mesoporous and Nanosized ZSM-5 Zeolite for the Production of Alkyl-Phenols and Aromatics

The valorization of lignin that derives as by product in various biomass conversion processes has become a major research and technological objective. The potential of the production of valuable mono-aromatics (BTX and others) and (alkyl)phenols by catalytic fast pyrolysis of lignin is investigated in this work by the use of ZSM-5 zeolites with different acidic and porosity characteristics. More specifically, conventional microporous ZSM-5 (Si/Al = 11.5, 25, 40), nano-sized (≤20 nm, by direct synthesis) and mesoporous (9 nm, by mild alkaline treatment) ZSM-5 zeolites were tested in the fast pyrolysis of a softwood kraft lignin at 400–600°C on a Py/GC-MS system and a fixed-bed reactor unit. The composition of lignin (FT-IR, 2D HSQC NMR) was correlated with the composition of the thermal (non-catalytic) pyrolysis oil, while the effect of pyrolysis temperature and catalyst-to-lignin (C/L) ratio, as well as of the Si/Al ratio, acidity, micro/mesoporosity and nano-size of ZSM-5, on bio-oil composition was thoroughly investigated. It was shown that the conventional microporous ZSM-5 zeolites are more selective toward mono-aromatics while the nano-sized and mesoporous ZSM-5 exhibited also high selectivity for (alkyl)phenols. However, the nano-sized ZSM-5 zeolite exhibited the lowest yield of organic bio-oil and highest production of water, coke and non-condensable gases compared to the conventional microporous and mesoporous ZSM-5 zeolites

Data_Sheet_1_Catalytic Fast Pyrolysis of Kraft Lignin With Conventional, Mesoporous and Nanosized ZSM-5 Zeolite for the Production of Alkyl-Phenols and Aromatics.PDF

<p>The valorization of lignin that derives as by product in various biomass conversion processes has become a major research and technological objective. The potential of the production of valuable mono-aromatics (BTX and others) and (alkyl)phenols by catalytic fast pyrolysis of lignin is investigated in this work by the use of ZSM-5 zeolites with different acidic and porosity characteristics. More specifically, conventional microporous ZSM-5 (Si/Al = 11.5, 25, 40), nano-sized (≤20 nm, by direct synthesis) and mesoporous (9 nm, by mild alkaline treatment) ZSM-5 zeolites were tested in the fast pyrolysis of a softwood kraft lignin at 400–600°C on a Py/GC-MS system and a fixed-bed reactor unit. The composition of lignin (FT-IR, 2D HSQC NMR) was correlated with the composition of the thermal (non-catalytic) pyrolysis oil, while the effect of pyrolysis temperature and catalyst-to-lignin (C/L) ratio, as well as of the Si/Al ratio, acidity, micro/mesoporosity and nano-size of ZSM-5, on bio-oil composition was thoroughly investigated. It was shown that the conventional microporous ZSM-5 zeolites are more selective toward mono-aromatics while the nano-sized and mesoporous ZSM-5 exhibited also high selectivity for (alkyl)phenols. However, the nano-sized ZSM-5 zeolite exhibited the lowest yield of organic bio-oil and highest production of water, coke and non-condensable gases compared to the conventional microporous and mesoporous ZSM-5 zeolites.</p

Support-induced modifications on the CO2 hydrogenation performance of Ni/CeO2: the effect of ZnO doping on CeO2 nanorods

This research has been co-financed by the European Union and Greek national funds through the Greece 2.0 National Recovery and Resilience Fund, under the call RESEARCH - CREATE - INNOVATE (project code: T2EDK-01378).Summarization: The production of either CO or CH4 via the hydrogenation of CO2 is amongst the most promising routes for CO2 utilization. However, kinetic barriers necessitate the use of a catalyst, with Ni/CeO2 being one of the most investigated systems. Nevertheless, surface chemistry fine-tuning via appropriate promotional routes can induce significant modifications on the solid-state properties of catalysts and in turn on their activity/selectivity. In the present work, we originally report on the outstanding selectivity alteration of Ni/CeO2 by ZnO doping. Specifically, Ni-based catalysts supported on ZnO, CeO2 nanorods or a mixed ZnO-CeO2 oxide were synthesized by a modified hydrothermal method and characterized by various physicochemical methods. Notable changes in the reaction pathway were demonstrated, as the presence of ZnO largely favored CO production at T < 450 oC for both Ni/ZnO and Ni/ZnO-CeO2, whereas Ni/CeO2 was completely selective to CH4. These findings were interpreted on the basis of ZnO-induced inhibitory effects on key activity/selectivity descriptors like the redox and basic properties, as well as on the adsorption affinity of CO species, which are considered as intermediate species for CO2 methanation.Presented on: Journal of Co2 Utilizatio