Catalytic pyrolysis of pine sawdust over activated carbon-supported Fe for phenol-rich bio-oil

In this study, catalytic pyrolysis was used to decompose pine sawdust into platform chemicals. A strategy to produce valuable alkylphenol compounds through catalytic pyrolysis was proposed by introducing surface active groups (metal iron species and oxygen-containing groups) to strengthen biochar-based catalyst. The results showed that the multiple active sites jointly promoted the further reaction of the pyrolytic intermediates absorbed on the Fe-activated carbon catalyst during the catalytic pyrolysis, and the furans and ketones, etc., were all converted into phenolic compounds under the action of fresh Fe-activated carbon catalyst (AC-Fe-1). After the fifth recycling of the catalyst (AC-Fe-5), the catalytic performance of deactivated catalyst could be well recovered by the simple regeneration treatment, showing a good selectivity for phenol production (AC-Fe-CO2, 87 %). Compared with non-catalytic pyrolysis, the relative content of phenolic substances generated by Fe-activated carbon in the catalytic pyrolysis increased from 15.42 % to more than 90 %, mainly methyl phenolics such as phenol, 2-methylphenol and 3-methylphenol. By contrast, the deactivation of Fe-activated carbon catalyst was not significant and the selectivity to phenol increased to 73.62 %80.01 %, while the original activated carbon (without adding iron species) was seriously deactivated and the selectivity to phenol decreased by 38.26 %.