Efficient adsorption of heavy metal ions chromium (III) by modified corn starch/GO composite aerogel

Starch is a natural polymer containing a large number of active hydroxyl groups, which make it an ideal material for preparation of adsorption functional aerogels. In this work, a modified carboxymethyl corn starch/organic glass composite aerogel (CMSHA-GO) was successfully prepared using starch as raw material and hexamethylenediamine as cross-linking agent. It showed significant adsorption properties for heavy metal ions. When the composite aerogel was introduced with 10 mg GO, the adsorption capacity of CMSHA-GO₁₀ aerogel for heavy metal ions was in the order of Cr³⁺ > Ni²⁺ > Cu²⁺ > Cr(VI) > Pb²⁺, while its adsorption performance for heavy metal ion Cr³⁺ was mainly discussed. The structures and morphologies of the composite aerogels were characterized by FTIR, XRD, and SEM techniques. The results showed that the CMSHA-GO composite aerogel has a stable three-dimensional mesh-like porous structure with good conditions for metal ion adsorption. In addition, the effects of different GO contents, pH values, and time conditions on the adsorption of metal ions by the CMSHA-GO composite aerogel were discussed. When the weight ratio of carboxymethyl starch: hexanediamine: GO was 10:0.1:0.1, the CMSHA-GO₁₀ composite aerogel showed the best adsorption performance for Cr³⁺ ions. The adsorption equilibrium was reached within 3 h at an initial Cr³⁺ concentration of 500 mg·L⁻¹, with a maximum equilibrium adsorption capacity (q_e^cale) of 212.7 mg/g.