###### Abstract
In addition to these advantages, graphene has a huge specific surface area (\(\sim\)2600 m\({}^{2}\cdot\)g\({}^{-1}\)) and a rich pore structure that is of wide interest for the adsorption of pollutants [15]. Graphene oxide, a derivative of graphene, is not only electrically conductive, but also has a series of oxygen-containing functional groups, such as hydroxyl, carboxyl, and epoxy groups, attached to the lamellar structure of graphene that can effectively combine with other ions [16]. The use of graphene powder enables the preparation of graphene with a large number of carboxyl groups. Graphene oxide powders with a large number of carboxyl groups can be prepared using graphite powder [17]. Moreover, graphene oxide can also be combined with other materials, such as gold nanomaterials, to form complexes, and has been used to adsorb dyes from wastewater, showing that graphene oxide-gold nanomaterials can adsorb two dyes, methylene blue and methyl orange, within a short period [18]. Graphene oxide, Fe\({}_{3}\)O\({}_{4}\), and chitosan have been prepared as ternary composites in which the epoxy, carboxyl, aromatic ring, and trivalent irons interacted with each other; these ternary composites were shown to have some adsorption effect on the Ni(II), Cu(II), and Pb(II) cations [19]. Acrylic acid can be polymerized alone or together with other materials under certain conditions to form polyacrylic acid hydrogels, which are cross-linked polymers with a three-dimensional network structure containing a large number of hydrophilic groups inside the network structure, with water absorption and high water retention properties, and can be modified by other materials due to the ease of cross-linking with other materials. Polyacrylic acid can be polymerized together with saprolite to form a hydrogel, which can adsorb silver nanoparticles, allowing them to be uniformly dispersed on the surface of the hydrogel [20]. The reaction of acrylic acid with acrylamide is a free radical reaction. The free radical polymerization of acrylic acid with acrylamide leads to the formation of polyacrylic acid-polyacrylamideamide hydrogels, which can also adsorb silver nanoparticles, allowing them to be uniformly dispersed [21]. This hydrogel also adsorbs nano-silver ions, which allows for their uniform dispersion. Hydrogels with hydrogen bonding, amide groups, and electrostatic interaction were prepared from a high-performance montmorillonite with acrylic acid and acrylamide and used for the adsorption of dyes, which were shown to be very effective for the adsorption of methylene blue at 200 mg\(\cdot\)L\({}^{-1}\) due to the presence of electronegative particles and reaction sites on the surface of the hydrogel [22]. Hydrogels are simple to make and do not consume a lot of resources and energy. Hydrogels formed using graphene oxide and ascorbic acid have good adsorption properties for Pd and Cd, and the adsorption performance can still reach 80% after six reuses. Therefore, hydrogels are often used as an adsorbent material and have the advantage of being reusable [23]. In this paper, graphene oxide-modified acrylic hydrogels were used to increase the specific surface area of the hydrogels and the number of oxygen-containing functional groups on the surface of the hydrogels, which improved the adsorption capacity for heavy metals. The crystal structure, functional groups, and adsorption properties of the synthesized products were studied using various characterization methods. The adsorption capacity of graphene oxide hydrogels for Cu(II), Pb(II), Zn(II), and Cd(II) metal ions was compared. The effects of pH, temperature, initial metal concentration, contact time, competitive adsorption between various ions, and interfering ions on the adsorption of heavy metals by GO/P(AA-co-AM) were investigated. The [PERSON] monolayer adsorption model and the quasi-secondary reaction kinetic model were used to fit the correlation study results.