The invention provides a gel composite adsorbent with a foaming structure as well as a preparation method and application thereof, and the preparation method comprises the following steps: S1, dissolving
acrylamide powder in deionized water, and stirring to obtain a solution A; s2, dissolving
sodium alginate in the solution A for thickening to obtain a solution B; s3, transferring the solution B into an ice-water bath; s4, adding N, N-
methylene bisacrylamide into the solution B, stirring until the N, N-
methylene bisacrylamide is completely dissolved, then adding N, N, N ', N'-
tetramethylethylenediamine, and stirring until the N, N, N ', N'-
tetramethylethylenediamine is uniform to obtain a solution C; s5, adding
ammonium persulfate into the solution C, and stirring until the
ammonium persulfate is completely dissolved to obtain a solution D; s6, the solution D is poured into a mold and then vacuumized to form gel, and a hydrogel sample is obtained after
gel forming; s7,
drying the hydrogel sample, and then soaking the dried hydrogel sample in a
salt solution to obtain a soaked gel material; and S8,
drying the soaked gel material to obtain the finished product composite adsorbent.