Abstract: In this study, the effects of superfine powdered Astragalus membranaceus radix-to-cholesterol solution ratio, adsorption time, particle size of superfine powdered Astragalus membranaceus radix, initial cholesterol concentration and temperature on the adsorption of cholesterol on superfine powdered Astragalus membranaceus radix. Meanwhile, the adsorption process was dynamically and thermodynamically analyzed. Good results were obtained after 60 min adsorption of 1.50 mg/mL cholesterol solution by superfine powdered Astragalus membranaceus radix at ratio of 1:30 (m/V) and 25 ℃. Under these conditions, the maximum adsorption quantity was 15.60 mg/g. Therefore, the adsorption process is a spontaneous process in which physical adsorption is dominant and easily occurs. Furthermore, surface absorption was dominant at low cholesterol concentrations, but both surface adsorption and intraparticle diffusion were dominant at high cholesterol concentrations.

Key words: superfine powdered Astragalus membranaceus radix, cholesterol, adsorption conditions, dynamics, thermodynamics