Experiments have been carried out to study the sorption of Benzo(a)pyrene(Bap)on sediment particles from the Yellow River using a batch equilibration technique.Effects of particle size on the adsorption and partition of Bap were investigated with the particle content of 3 g/L.Several significant results were obtained from the study.(1)Isotherms of Bap could be fitted with the dual adsorption-partition model under different particle sizes,and the measured value of the adsorption and partition was in agreement with the theoretical value of the dual adsorption-partition model.(2)When the particle diameter was d i 0.025 mm,the adsorp-tion was predominant in the sorption of Bap,which accounted for 68.7%-82.4%of the sorption.For the particles with the size of 0.007 mm≤d<0.025 mm,the adsorption was predominant when the equilibrium concentration of Bap was 0-8.87 mg/L in the water phase;and the partition was pre-dominant when the equilibrium concentration of Bap was higher than 8.87 mg/L in the water phase.When the particle diameter was d<0.007 mm,the partition was predominant.(3)On the point of particle size,the contribution of adsorption to sorption followed the order:“d≥0.025 mm”>“0.007 mm ≤d<0.025 mm”>“d<0.007 mm”.(4)The partition coeffi-cients of Bap in solids with different particle sizes were linearly correlated with the organic content,and the Koc of Bap was about 1.26 × 10^(5)(L/kg).
