Abstract: Characteristics of the adsorption of ortho-substituted non-planar 2-chlorobiphenyl (2-CB) and non-ortho-substituted co-planar 4-chlorobiphenyl (4-CB) on three major simulated sorptive soil components:K⁺ saturated montmorillonite(K⁺-Mont), humic acid-clay mineral complexes(HA-Mont) and biochar(BC) were studied through batch equilibration experiments. Results show that the linear eqatio could be used to fit the adsorption isotherms of PCBs on all the three absorbents with the adsorption coefficient K_w being in the order of BC> HA-Mont> K⁺-Mont. Thermodynamic analysis of the adsorption isotherms as a function of temperature indicated that both surface adsorption and hydrophobic effect were the driving forces of the PCBs sorption on K⁺-Mont, while partition was the major one of the PCBs sorption on HA-Mont, for the interlayer spaces of montmorillonite are the major adsorption area, and the aromatic nanoporous surface of BC and the π-π effect between PCB molecules were the major driving forces, for the surface was the major adsorption area of BC. The sorption of 4-CB was higher than that of 2-CB on all the three absorbents despite that 2-CB and 4-CB are similar in hydrophobicity, which suggests that steric effect of the non-planar structure prevents 2-CB from accessing nano sized interlayer spaces of montmorillonite or nanopores on the surface of BC. All the findings in this study indicate that the three dimensional structures of organic pollutant molecules play an important role in their sorption and translocation in the soil.