Activation of corn straw pith impregnated with bio-oil: Production of activated carbon with “painted” surface and highly developed pores

Bio-oil is a key outcome of biomass pyrolysis or activation, which can be used as a co-reactant in activation processes involving polymerization for further upgrading applications. Herein, the activation of corn straw pith (CSP) impregnated by bio-oil with ZnCl₂ was performed to understand impacts of bio-oil on yield and pore structures development of activated carbon (AC). The results indicated that derivatives of CSP and organics in bio-oil did cross-polymerize in activation, leading AC had higher yield and a “painted” outer-surface. More importantly, the S_BET of the AC from CSP/bio-oil activation (1046.2 m²·g⁻¹; mesopores: 25.2 %) was significantly higher than that from CSP (558.4 m²·g⁻¹; mesopores: 12.0 %) or bio-oil (673.6 m²·g⁻¹; mesopores: 38.0 %), improving tetracycline adsorption performance. The cross-reactions between CSP and the bio-oil, the enhanced proportion of aliphatic organics, and the supporting-structural skeleton of CSP together resulted in this. Additionally, cross-reactions also promoted deoxygenation, increased thermal stability and graphitization degree of AC.