Removal of Cd2+ and Pb2+ heavy metal ions from aqueous water using starch acrylate and octa-armed (3-thiolpropyl) cubic silsesquioxane hydrogel

Abstract

One of the most serious problems concerning the environment of our planet is water pollution caused by toxic metal ions. Adsorption is the leading method of treatment. Environmentally friendly hydrogels were formed from starch acrylate and octa-armed (3-thiolpropyl) cubic silsesquioxane as a cross-linker, containing a thiol functional group. The properties of starch acrylate and octa-armed (3-thiolpropyl) cubic silsesquioxane ((StA)x-OTCSS) hydrogel were characterized by FTIR, FESEM, EDX, and TGA techniques. All effective factors on the adsorption capacity of StA-OTCSS hydrogel at Pb2+ and Cd2+ absorption were considered. The maximum adsorption capacities for these ions were 381.30 and 366.80 mg/g, respectively, at an initial concentration of 200 ppm. Moreover, experiments showed that under optimal conditions, StA-OTCSS hydrogel absorbed lead and cadmium within 60 min. The Langmuir isotherm for the adsorption of each metal by hydrogel was observed, and the pseudo-first-order (PFO) of the kinetic model best fitted the experimental data. Thermodynamic studies indicate that metal adsorptions are in an endothermic and spontaneous mode. Further, the performance of the prepared hydrogel was unaltered by the presence of other ions. Therefore, the prepared hydrogel can extract toxic metals from the aqueous media. © 2025 The Institution of Chemical Engineers