Comparison of the performance of a hydrogel and hybrid graphene oxide with hydrogel to remove iron (III) and phenol from wastewater

In this study, two different polymers have been synthesized and introduced as adsorbents to study their performances in the removal of Fe(III) ions and phenol from wastewater. The polymers have been synthesized by mixing acrylic acid, acryl amide, and N,N-dimethylacrylamide. This is both used as a primary polymer and grafted with graphene oxide as modified polymer to compare their performances in Fe(III) ions and phenol removal. The structure and morphology of the polymer and the grafting polymer with GO were characterized by FT-IR, SEM, and TEM. The effects of pH, time, contact temperature, and dosage of adsorbent were evaluated. From the obtained results, the optimum condition of the adsorption process was concluded to be a concentration of graphene oxide/polymer (1 g L−1) and polymer (3 g L−1) at an ion concentration of 75 ppm, pH 8 for 2 h. The highest removal rates for Fe3+ and phenol were 92–98% and 86–89%, respectively. The Freundlich and Langmuir adsorption isotherm model was studied. The removal of Fe3+ and phenol is consistent with a pseudo-second-order model, meaning physical adsorption occurs on the surface of both polymers. Other isotherm models, like Temkin and intra-particle, were used; the error function was calculated to test the fitness of all the models’ results. Adsorption was not consistent with the last two models and the result from the error function proved that the pseudo-second-order model is favorable for the removal of Fe(III) and phenol.