The molecule of berberine was selected as a model molecule. The effects of operation time
operation pressure
solution concentration
ionic strength
and other factors on the rejection efficiency were investigated. The results indicated that the rejection rates of berberine by polyamide nanofiltration membrane were approximately equivalent after 80 min. The flux and rejection rate of berberine increased with the increase of operation pressure. The flux decreased with the increase of berberine concentration
and the rejection rate of berberine first rose up then decreased with the increase of berberine concentration. Both flux and rejection rate of berberine decreased with the increase of ionic strength. At the condition of the content of alkaloids 0.025g/L and operation pressure 0.4MPa
alkaloids in the extract of ahizoma coptidis were concentrated 6.27 times.