Phenols-enriched biofuel and H2-rich gas from catalytic fast pyrolysis/gasification of agricultural biomass over a novel heavy metals-containing livestock manure biochar catalyst

Abstract

It is a thorny issue to properly handle heavy metals-contaminated livestock manure. The transformation of the heavy-metals-contaminated livestock manure into valuable carbonaceous material has motivated our curiosity. Herein, this study provided a new concept of valorizing the contaminated manure into heavy metals-containing biochar catalysts for catalytic fast pyrolysis/gasification of biomass to manufacture phenols-enriched biofuel and H2-rich gas. The versatile Cu, Pb, and Zn-containing cow manure biochar catalysts were newly prepared from Cu, Pb, and Zn-contaminated livestock manure through a single-step energy-efficient thermal process. Cu and Pb-containing biochar catalysts prepared at 500 °C were more favorable for the production of bio-oil and organic phase, and up to 41.20% of phenolics was found in the bio-oil by using the Pb-containing biochar catalyst. The highest gas yield (51.55 wt%), equaling to 550 NmL/gWS, was observed in the presence of Cu-containing biochar catalyst prepared at 500 °C. Meanwhile, the H2 concentration was elevated to 35.85 vol%, and the H2 yield was correspondingly promoted to 197 NmL/gWS. Additionally, a deep knowledge of the reaction mechanisms regarding the catalytic fast pyrolysis/gasification of biomass over heavy metals-containing biochar catalysts was elucidated. Overall, this study provided a novel way to valorize heavy metals-contaminated livestock manure into effective biochar catalysts for catalytic fast pyrolysis/gasification of biomass to produce phenols-enriched bio-fuel or H2-rich gas.