2.2 Preparation and modification of magnetic diatomite
4.1 g of
FeCl3·6H2O
and 2.6 g of
FeCl2·4H2O
were dissolved in a quantity of deionized water and mixed
ultrasonically. After sufficient shaking, 6.0 g of diatomaceous earth
was added and stirred at 80 °C for 30 min using nitrogen protection. Add
ammonia, adjust pH to 10, and continue mixing for 1 h. Cooling slowly to
room temperature and crystallize for 2 h. The precipitate obtained after
magnetic field separation was sequentially washed with deionized water
and ethanol. After drying, magnetic diatomite (MD) was obtained.
1.0 g of MD was added to 50.0 mL of toluene, sonicated, and mixed for
0.5 h. After that, 0.8-2.4 g of
3-mercaptopropyltriethoxysilane
and 1.4-4.2 g of n-octadecyltriethoxysilane were added. Using nitrogen
protection, the reaction was heated to reflux for 12 hours. Then, the
diatomite was separated by a magnetic field, washed several times with
ethanol, and the product was dried under vacuum at 45°C to obtain
octadecyl and thiol co-bonded magnetic diatomite. The obtained octadecyl
and thiol co-bonded magnetic diatomite was added to a certain
concentration of
H2O2and stirred at 40°C for 24 h and then washed with water to remove the
excess H2O2. After drying under vacuum
at 60°C, octadecyl and sulfonyl co-bonded magnetic diatomite (OSMD) was
obtained.