Poly(acrylamide/styrenesulfonic acid) hydrogels for effective removal of Cr(III) ions

Techniques for chromium ion removal have been researched more and more because of the significant harm to human health posed by this hazardous contamination in water. The present work represents the preparation of poly[acrylamide(Acr)/styrenesulfonicacid sodium salt (Sty)] hydrogels by free radical cross-linking polymerization applying various Acr and Sty monomer molar ratios. To produce Cr-poly(Acr/Sty) chelates, the produced hydrogels were examined for adsorption and desorption tests towards Cr(III) ions. The resulting hydrogels displayed a significant capacity for Cr(III) ion adsorption. Notably, the amount of Sty monomer in the hydrogel has a substantial effect on the Cr(III) ion capturing capacity. Cr-poly(Acr/Sty) and poly(Acr/Sty) hydrogels were characterized by modern analytical techniques such as X-ray diffraction (XRD), Energy Dispersive X-ray (EDX), scanning electron microscopy (SEM), Furrier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA). Research on the impacts of time and starting concentration of Cr(III) ions showed that hydrogels had the highest adsorption capacity for Cr(III) ions, at 346.48 mg g-1 dry gel. Hydrogels exhibited an exceptionally high swelling ratio, with a maximum value of 10490.46%. According to their adsorption kinetics, the findings are aligned with the pseudo second-order approach, and their adsorption performance coincides with the Freundlich isotherm. Their potential for reuse in environmental applications is demonstrated by the high desorption recovery percentage (almost 100 weight%), which could be used for the treatment of wastewater. Adsorption using Cr(III) from tanning industrial wastewater was conducted on the prepared hydrogels with efficient capturing capacity.