A comparison of biochars from lignin, cellulose and wood as the sorbent to an aromatic pollutant

Biochars' performance as the sorbent to pollutants is dependent on their compositions and surface characteristics, which are then related to the feedstock used for biochar preparation. The objective of this work is to probe the feedstock's influence on biochar's sorption property through a comparative study on biochars from lignin, cellulose and wood prepared at 400 °C and 600 °C, respectively. Elemental and spectral analyses demonstrated that the wood biochar had a composition and carbonization degree close to the cellulose biochar but much different from the lignin biochar prepared at the same temperature, suggesting that lignin is not dominant to properties of plant-derived biochars. The lignin biochar showed a sorption capacity comparable to both cellulose and wood biochars as the sorbent to nitrobenzene, with a higher partition contribution to the total sorption due to the lower carbonization of lignin. In general, the lignin biochar is a good candidate of sorbent to aromatic pollutants, and is advantageous over the other two species with its efficient carbon utilization.