The presence of heavy metals with high acute toxicity in wastewater poses a substantial risk to both the environment and human health. To address this issue, we developed a nanocomposite of alginate-encapsulated polypyrrole (PPy) decorated with α-Fe2O3 nanoparticles (Alg@Mag/PPy NCs), fabricated for the removal of mercury(II) from synthetic wastewater. In the adsorption experiments, various parameters were examined to identify the ideal conditions. These parameters included temperature (ranging from 298 to 323 K), initial pH levels (ranging from two to nine), interaction time, amount of adsorbent (from 8 to 80 mg/40 mL), and initial concentrations (from 10 to 200 mg/L). The results of these studies demonstrated that the removal efficiency of mercury(II) was obtained to be 95.58% at the optimum pH of 7 and a temperature of 303 K. The analysis of adsorption kinetics demonstrated that the removal of mercury(II) adhered closely to the pseudo-second-order model. Additionally, it displayed a three-stage intraparticle diffusion model throughout the entire adsorption process. The Langmuir model most accurately represented equilibrium data. The Alg@Mag/PPy NCs exhibited an estimated maximum adsorption capacity of 213.72 mg/g at 303 K, surpassing the capacities of most of the other polymer-based adsorbents previously reported. The thermodynamic analysis indicates that the removal of mercury(II) from the Alg@Mag/PPy NCs was endothermic and spontaneous in nature. In summary, this study suggests that Alg@Mag/PPy NCs could serve as a promising choice for confiscating toxic heavy metal ions from wastewater through adsorption.
Keywords: adsorption; mercury; nanocomposite; polypyrrole; water pollution.