Contributions of different biomass components to the sorption of 1,2,4-trichlorobenzene under a series of pyrolytic temperatures

• Cellulose biochar developed the highest surface area and micropore volume.
• Cellulose and hemicellulose biochar showed higher ability in adsorbing 1,2,4-TCB.
• The sorption capacity of biochar may be depressed in the presence of lignin.
• Lignocellulose biochar depended on the ability and content of each component.
• Different components differed in the sorption mechanisms.

In order to investigate contributions of cellulose (CEL), hemicellulose (HEM), lignin (LIG) to the sorption capacity of biochar derived from lignocellulose, the individual component and their artificially modeled biomass mixture (C-H-L) were pyrolyzed under oxygen-limited condition at various pyrolytic temperatures (i.e. 250, 350, 500, 700 °C). The characterization analysis of biochars and sorption batch experiments were carried out. Variations in physiochemical property of different component biochars resulted in discrepancies in their ability to function as sorbents to 1,2,4-trichlorobenzene (1,2,4-TCB). The maximum mass sorption capacity (Qfm) of 1,2,4-TCB was the greatest on CEL biochars ranging from 58.31 to 601.20 mg g−1, and can be best explained by their huge surface area and micropore volume. Hydrophobic partitioning-sorption into ‘soft’ amorphous alkyl carbon may account for the second greatest Qfm (45.09–56.57 mg g−1) on HEM biochars under low pyrolytic temperatures (250–350 °C) with the lowest surface area. LIG biochars with more compact and smooth aromatic structure surface may undergo a surface monolayer specific adsorption. The Qfm (87.86–196.53 mg g−1) on C-H-L biochars were largely dependent on CEL and HEM components for their outstanding sorption capacity and higher content in biomass. Therefore, the results highlighted the importance of CEL and HEM components for 1,2,4-TCB sorption to biochar.

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