Divalent metal ion removal from simulated water using sustainable starch aerogels: Effect of crosslinking agent concentration and sorption conditions

This paper evaluates corn starch aerogels, studying different crosslinking agent (trisodium citrate) concentrations (1:1, 1:1.5, and 1:2) and sorption conditions (contact time, adsorbent weight, and initial concentration) regarding the potentially toxic elements (PTEs) [Cd(II) or Zn(II)] adsorption of the aqueous systems. Besides, other properties of aerogels, such as structural properties, specific surface area, and mechanical performance, were evaluated. For adsorption results, better values were observed in adsorption capacity and efficiency for the initial concentration of 100 ppm. In addition, an adsorption time of 12 h and an adsorbent weight of 3.0 g obtained better results due to the possible balance in this time and the high specific surface area available for Cd (II) adsorption. As for the type of adsorbent, the Aero 1:1.5 sample (intermediate crosslinking agent concentration) obtained better results, possibly due to the high porosity, smaller pore sizes, high pore density, and high specific surface area (198 m2 center dot g(-1)). In addition, hydroxyl groups in the starch aerogel removed Cd(II) ions with 30 % adsorption efficiency. Lastly, Aero 1:1.5 obtained a high mechanical strength at compression and a satisfactory compressive modulus. In contrast, starch aerogels did not absorb the Zn(II) ion.

Automated summary

This study evaluates corn starch aerogels for the adsorption of potentially toxic elements (PTEs) [Cd(II) or Zn(II)] in aqueous systems. Different crosslinking agent concentrations and sorption conditions were studied, and the properties of the aerogels were evaluated. The results showed that higher adsorption capacity and efficiency were achieved at an initial concentration of 100 ppm, with an adsorption time of 12 hours and an adsorbent weight of 3.0 g. The Aero 1:1.5 sample showed better results due to its high porosity, smaller pore sizes, high pore density, and high specific surface area. Hydroxyl groups in the starch aerogel exhibited 30% adsorption efficiency for Cd(II) ions, while Zn(II) ions were not absorbed.