MHC synthesis
MHC was synthesized by combining co-precipitation and
slow alkalinity titration method into
one step. First, 150 mL deionized water was added to a three-necked
flask and deoxygenated by bubbling N2 gas for 5 min.
Under a nitrogen atmosphere, 32.5 g
FeCl3·6H2O and 4.8 g
FeCl2·4H2O were added, and the mixture
was stirred at room temperature for 5 min until dissolved. Then the
mixture was gradually heated to 80 ℃, and TPODAC was added at the Si/Fe
molar ratio of 1/6. The mixture was titrated by 1 mol/L NaOH (270 mL)
for 3 h under rapid stirring. After cooling to room temperature, the
product aged for 12 h to obtain MHC.