The application belongs to the field of
water treatment, and discloses a
plant tannin grafted composite magnetic flocculant and a preparation method and application thereof. The composite magnetic flocculant comprises polymeric aluminum
ferric silicate, Chinese gallnut
tannic acid, a
grafting modifier, polyethyleneimine and
sodium acetate buffer. After the natural green substance Chinese gallnut
tannic acid is subjected to Michael addition by the
grafting modifier, graft copolymerization is realized, a large number of positive charge points are provided, a stable complex is formed through winding and
electrostatic interaction, more
flocculation bodies can be bridged, more compact and tough
alum flowers are formed, and magnetic medium material is put into the
flocculation bodies when the
flocculation bodies are formed, so that fine
magnetic powder particles are used as
precipitation nucleuses, a micro
magnetic field is formed to promote the growth of the flocculation bodies, the efficient removal of TP is accelerated, the input of reagents and
energy consumption is reduced, low-cost, high-efficiency and green TP removal of a
sewage treatment
plant is realized, the operation cost is reduced, and remarkable
economic benefits are achieved.