The invention discloses a preparation method of
melamine-modified porous magnetic
dextran microspheres. The preparation method is characterized by comprising the following steps: by taking salad oil as an organic phase and
dextran as an aqueous phase, spraying the aqueous phase into the organic phase at
room temperature, stirring for carrying out a reaction for 1h, heating up to 80+ / -2 DEG C, continuously reacting for 3-4h, cooling to the
room temperature, carrying out
solid-liquid separation, rapidly freezing, and carrying out
freeze drying for 24h to obtain porous magnetic
dextran microspheres; after that, adding 60-68% of
methanol, 5-10% of
epoxy chloropropane and 8-14% of
melamine into a reactor according to composition
mass percent concentration, dissolving, and then adding 14-22% of the porous magnetic dextran microspheres, wherein the percentage sum of all the components is 100%; maintaining the constant temperature of 50+ / -2 DEG C, stirring, and carrying out a
reflux reaction for 2-3h; cooling, then washing a product respectively with deionized water and
methanol, carrying out
solid-liquid separation, and
drying to obtain the
melamine-modified porous magnetic dextran microspheres. The adsorbent has very high adsorption capacity for perfluoro
caprylic acid, and can be repeatedly used for a plurality of times, thus being low in cost and environment-friendly; furthermore, the melamine-modified porous magnetic dextran microspheres have
magnetism, thus being easy to separate.