| This paper researched the composition, physicochemical property and the process of adsorption-desorption in orthophosphate of the landscape of Beijing Yuyuantan sediments, investigated the influence of solution conditions (pH, salinity, granularity and solid concentration effect) and other factors on the adsorption-desorption processes, and analyzed the fractal characteristics of the process of the adsorption kinetics and the law of the fractaql dimension on the surface of particles changing before and after adsorption.Canonical correlation analysis results demonstrated that linear correlations were observed between the metal contents of Al, Cu, Zn, Ni, Co and average particle size, Fe and Al contents, TOC and LOI, TOC and TN in these sediment particles, and the corresponding coefficients for above linear correlations were-0.842,0.857,0.878,0.94,0.961,0.931,0.832 and 0.875 respectively.The balance time of sediments adsorption phosphate determined by kinetics experiments sediments is 48h, and the whole process corresponds to the Pseudo-second-order kinetic plots. Initial concentration which is too high or too low will affect the adsorption rate.The adsorption process for all adsorption systems in the kinetic experiment of influence factors matched the Pseudo-second-order kinetic equation. The adsorption of sediment particles phosphate increased with the pH value and calculated equilibrium adsorption capacity and the rate of adsorption decreased first and then increased; in the 20-35℃temperature range, calculated equilibrium adsorption capacity increased first and then decreased; in the medium term of the adsorption, the rate of adsorption increased with the increase of speed.The kinetics experiment of influence factors found that salinity has a negative influence on the adsorption and particle diameter has a positive effect on the adsorption which increased as the particle diameter decreases. It's mean that as the particle diameter decreases, the adsorption capacity has a tendency to increase, in the same conditions of initial concentration of phosphorus, the effect on the adsorptionisotherm from the PH value is similar to the experiment of adsorptive dynamics.The adsorption capacity of sediment particles which had reached adsorption equilibrium on N2 has decreased under the different system of concentration of phosphorus. The sediment particle surface aperture has enlarge compare to the surface after the release of phosphate from sediment particle. After phosphate solution with original concentration of 2.00 mg.L-1 absorbed, the sediment particle surface aperture became slightly larger and other particles surface aperture with original concentration in the surface reduced in the aspect of surface and pore volume.Sediment particles in the initial phosphorus concentration 0,0.5,1.0,5.0 mg/L under the conditions of adsorption, the average pore size has been reduced, the pore size of sediments which dasorbed P in initial phosphorus concentration of 2.0,3.0,4.0 mg/L, increased,and the rate of increase decrease. The surface fractal dimensions Ds for Sediments in low P concentrations and high P concentrations absorbed are higher than that without P absorbed onto sediments, The desorption of P could raise the surface roughness of sediments in low P concentration,but in high P concentration, the interlayer expansion and pore opening could counteract the decrease in Ds through surface rugosity screening and pore blocking effect mechanisms. Then the surface roughness of sediments increased.
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