An Evaluation of the Contribution of Cellulose, Hemicellulose and Lignin to Bio-Char Combustion and Adsorption Properties

The present work focuses on the contribution of cellulose, hemicellulose, and lignin for bio-char application in two aspects: fuels and adsorbent. The pyrolysis behaviors were studied at 300 to 700 °C, and the yields and characterization of bio-chars were compared. The results showed that in the three components, lignin was responsible for the formation of bio-char products, representing the main source of bio-char characterized by high heating value. Lignin was the strongest support for prepared bio-char as fuel decided by physico-chemical properties and combustion reactivity, while cellulose was the major contributor for bio-char products as ignition fuel. Scanning electron microscopy (SEM) and surface area analysis of bio-char showed that, in the three components, cellulose derived bio-chars exhibited a distinctive fibrous structure and the surface area was the largest at the same pyrolysis temperature. Compared with lignin, hemicellulose was a better precursor for adsorption, it is mainly determined by complex and abundant pore structure. Further adsorption tests of toxic substances in soil showed that, cellulose represented major adsorption donator for phenol, all bio-char samples had better adsorption capacity for Pb(II) than Cu(II), the rule on adsorption capacity of three different precursors for Cu(II) was as follows: cellulose>hemicellulose>lignin, for Pb(II): hemicellulose> cellulose> lignin.