The invention provides a method for removing
heavy metals by acidizing bleaching earth. The
heavy metals in the bleaching earth are removed by using a heavy
metal adsorbent. Firstly,
acrylate reacts with diethanol amine to generate an esterification product, then the esterification product reacts with
trimethylolpropane to form a hydroxyl-terminated hyperbranched
polymer, and then the hydroxyl-terminated hyperbranched
polymer reacts with
isocyanate acrylate to introduce double bonds to obtain hyperbranched
acrylate. Meanwhile,
sodium alginate reacts with 4-chlorophenylboronic acid to obtain
boric acid modified
sodium alginate, then the
boric acid modified
sodium alginate reacts with
tannic acid to introduce a large amount of hydroxyl groups, and finally the
boric acid modified
sodium alginate reacts with 3-aminopropanol
vinyl ether to introduce double bonds, so that the
sodium alginate compound containing double bonds is prepared. And copolymerizing the two monomers with
acrylic acid, N-(2-aminoethyl)
acrylamide and 2-acrylamido-2-methylpropanesulfonic acid to obtain the adsorbent with a three-dimensional
network structure and multiple functional groups. Through the treatment, the heavy
metal content of the bleaching earth is obviously reduced, no foreign impurities exist, and the functions of high decolorization rate and strong adsorbability are reserved.