Exploring the Potential of Multiple Brazilian Clays as Adsorbents in Corn Starch Hydrogels for the Removal of Potentially Toxic Metal

Abstract Modern industrialization has led to heavy metal contamination of vital natural resources for animals and humans. This study explores eco‐friendly strategies to address this issue, focusing on synthesizing a starch hydrogel (SH) composite reinforced with six clays: brasgel (B), chocobofe (Cb), cloisite 20A (C20A), chocolate (Ch), palygorskite (P), and treated palygorskite (Tp). Physical–chemical, morphological, and thermal properties of the hydrogels were evaluated, along with their capacity to remove metallic ions (Cr(VI), Cd(II), Ni(II), Mn(II), Zn(II), and Cu(II)) via ion chromatography. FTIR confirmed successful clay incorporation into the hydrogel structure, with Van der Waals interactions most prominent with Ch clay. The clays enhanced three‐dimensional (3D) porous structures with accessible functional groups, improving ion removal. All hydrogels showed increased d‐spacing of clays (except Cb), indicating intercalated/exfoliated composites, which improved water absorption and thermal resistance. Sorption data revealed significant metal ion absorption, particularly Cr(VI) oxyanions. For divalent ions, the affinity order was Mn(II) > Zn(II) > Cu(II) > Cd(II) > Ni(II). Notably, SH‐Cb and SH‐Ch hydrogels excelled in metal ion adsorption, proving their effectiveness. Overall, clay‐reinforced hydrogels effectively treated contaminated effluents, offering a promising solution to heavy metal pollution.