Sustainable water purification: Optimizing pectin hydrogels for copper and cobalt removal

Abstract A free radical polymerization method was utilized to produce the pectin‐based hydrogel (PIACHs). This hydrogel was synthesized using pectin as the main component, using acrylamide and acrylic acid as monomers, and itaconic acid as a crosslinking agent. Three distinct grades of pectin‐based hydrogel (PIACHs) were produced by varying the itaconic acid content. Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), scanning electron microscope (SEM), point of zero charge (ΔpHpzc) analysis, and x‐ray diffraction (XRD) analysis methods were used to characterize the hydrogels. The PIACHs hydrogel was used for the removal of Cu 2+ and Co 2+ from aqueous solutions. The hydrogels showed an excellent maximum removal efficiency of 99.10% for Cu 2+ ions and 97.13% for Co 2+ ions. The Langmuir isotherm model agreed well with the experimental data, indicating monolayer adsorption. For Cu 2+ and Co 2+ ions, the highest adsorption capacities were 333.57 and 321.54 mg/g. The pseudo‐second order model of the adsorption process was demonstrated by kinetic analysis, with rate constants of 0.9982 g/(mg min) for Cu 2+ and 0.9972 g/(mg min) for Co 2+ . The regeneration experiments revealed that the hydrogel's adsorption capability remained stable throughout several adsorption–desorption cycles, with just a small decrease in efficiency to 88.39% for Cu 2+ and 84.72% for Co 2+ .