Bio-oil as a filler for enhancing development of micropores in activation of chicken bone

Abstract

Animal bone, especially joint section, contains some carbonaceous organics, which, in theory, can be converted into activated carbon via activation. Nonetheless, the content of organics in animal bone is generally not high, which could lead to low yield of activated carbon and negatively impact development of pore structures. Hence, bio-oil was introduced to impregnate chicken bone joints (CB) herein for enhancing cracking/gasification reactions in activation for generation of pores with K2C2O4 or KOH as activator at 800 ºC. The results showed that addition of bio-oil to CB feedstock increased yield of activated carbon from 7.5% in activation of CB only with K2C2O4 to 19.5% as well as specific surface area of 851.6 m2g−1 (67.7% of micropores) to 1097.9 m2g−1 (73.9% of micropores). Activation of CB plus bio-oil with higher content of activator further increased specific surface area to 1565.4 m2g−1 with proportion of micropores reaching 94.0%. The carbonaceous deposit derived from bio-oil formed micropores through cracking/gasification of itself or filling macropores or mesopores derived from CB. In-situ IR characterization showed that aromatization proceeded to very limited extent in activation of CB only, limiting formation of aromatic carbon skeleton for generation of pore structures. In comparison, bio-oil addition promoted formation of much higher abundance of oxygen/carbon-containing intermediates, facilitating aromatization to form rigid aromatic ring structures for generation of micropores. Addition of bio-oil to CB followed by activation also resulted in deformation of biological tubulous structure of CB into spider web-like structures with abundant micropores, significantly enhancing capability for adsorption of phenol.