The adsorption mechanism of coated activated carbon was analysed and the mathematical model of hemoperfusion process was established. The results of treating 20 groups of data of pig blood perfusion in vitro showed that the calculation values could fit the experimental data well

the adsorption equilibrium could be described as Langmuir equation

the adsorption rate controlling step of creatinine was the outside diffusion

but that of inulin was the inside diffusion or the coordination of both the outside and the inside diffusion. The influence of the ratio of height to diameter on hemoperfusion process was little.