Hydrotalcite loading boosts the potentially toxic element's retention in hydrogel nanocomposites for environmental treatment

The improper disposal of potentially dangerous metal-containing wastes is detrimental to the environment and human health, requiring the development of easy methods for removing these cations, particularly in water bodies. The influence of different surface-charged lamellar materials on the sorption and desorption of Cr6+, Cu2+, and Mn2+ in aqueous solutions was investigated by modifying polyacrylamide/methylcellulose (PAc-MC) hydrogels with bentonite or hydrotalcite. In disk or powder form, the adsorption and desorption capabilities were examined. Regardless of their shape, the bentonite-hydrogel and unmodified hydrogel revealed lower contaminant retention capacities on polymeric structures. In contrast, the hydrotalcite-hydrogel demonstrated a stronger affinity for holding ions in the nanocomposite polymeric structure. The nanocomposite produced by calcining hydrotalcite at 550 °C displayed the best retention properties. Shapes of disks or powders did not affect sorption capacity, but disks were considerably more practical for recovering processed materials. These findings contribute to comprehending the retention capacity of modified hydrogels (or modified nanocomposites).