Hypercrosslinked polystyrene-based adsorbents for the removal of lead ions from aqueous effluents: experimental and RSM modeling

This study covers the synthesis of hypercrosslinked polystyrene adsorbents based on polystyrene (P-HCP) and expanded polystyrene (EPS-HCP) with a simple one-step Friedel-Crafts reaction to remove lead. The surface areas for P-HCP and EPS-HCP were obtained as 370.79 and 689.38 m(2)/g, respectively. The FESEM analysis for P-HCP and EPS-HCP adsorbents displays a porous morphology and a rough building with many spherical pores. The polymers were hyper-crosslinked using formaldehyde dimethylacetal. The synthesized polymers were used for removal of lead ions at different operating conditions. The experiments were designed using a response surface methodology (RSM) based on a central composite design. The designed tests were performed in the temperature range of 20-60 degrees C, using lead concentration range of 20-100 mg/L and the adsorption time of 10-50 min. The results showed that the synthesized hypercrosslinked adsorbent can remove more than 95.3% of lead ions from the effluent solution. The optimal conditions of the adsorption were obtained at temperature of 30 degrees C, contact time of 40 min, and lead concentration of 80 mg/L. To assess the behavior of the adsorbent, the experimental data were fitted using the adsorption isotherm and kinetic models. The results illustrated that the adsorption isotherm data were well fitted by Freundlich model for EPS-HCP and Temkin isotherm for P-HCP, whereas the adsorption kinetics pursued the pseudo-second-order kinetic model for both absorbents. The experimental results showed that the synthesized polymeric adsorbents have an excellent potential for removing metal contaminants from the effluent.

Automated summary

This study synthesized hypercrosslinked polystyrene adsorbents based on polystyrene (P-HCP) and expanded polystyrene (EPS-HCP) using a simple one-step Friedel-Crafts reaction for lead removal. The synthesized adsorbents showed high surface areas and porous morphologies. The experiments demonstrated that the hypercrosslinked adsorbent can effectively remove lead ions from the effluent solution, with optimal conditions of 30°C temperature, 40 minutes contact time, and 80 mg/L lead concentration.