This invention discloses an iron-containing diatomaceous earth shell material, its preparation method, applications, and a method for preparing a
tannic acid-diatomaceous earth shell
composite material containing this material. The iron-containing diatomaceous earth shell material contains at least 0.4% iron by weight and at least 88%
silicon, retaining the highly ordered nanoscale porous structure of natural diatomaceous earth shells. The preparation method involves culturing diatoms in G11 medium supplemented with
sodium silicate nonahydrate and
ferrous sulfate heptahydrate, followed by extraction via
hydrogen peroxide oxidation,
acid washing, and high-temperature
calcination. This invention further utilizes the reaction of this iron-containing diatomaceous earth shell with
tannic acid in a buffer
system at pH 7.0-8.0, achieving efficient loading of
tannic acid through the coordination of iron ions with tannic acid and physical adsorption. This invention features a simple process, low cost, and environmental friendliness. The prepared
composite material significantly improves the
chemical stability and
bioavailability of tannic acid, showing broad application prospects in biomaterials fields such as
drug delivery, antibacterial applications, and
tissue engineering.