Preparation method of sewage treatment adsorbent

The invention relates to the technical field of water treatment, and discloses a preparation method of a sewage treatment adsorbent, mesoporous nano-silica reacts with 3-aminopropyltriethoxysilane and 4-vinylbenzaldehyde to obtain styryl modified mesoporous silica; a cysteine amide butyric acid monomer and triethanolamine are subjected to an esterification condensation reaction to prepare novel sulfydryl hyperbranched polyester, part of sulfydryl and a styrene functional group modified on the surface of mesoporous nano-silica are subjected to a light click reaction, so that the sulfydryl hyperbranched polyester is grafted to the surface of silica, and the sewage treatment adsorbent is obtained. The grafted sulfydryl hyperbranched polyester contains functional functional groups such as sulfydryl, an amide group and carboxyl, has very strong coordination chelation and adsorption performance on metal ions such as lead, copper and cadmium, and has wide application prospects in wastewater treatment and marine poll