Highly efficient and rapid Pb(ii) removal from acidic wastewater using superhydrophilic polystyrene phosphate resin

Direct adsorption of heavy metal ions from acidic wastewater is a challenge in industrial wastewater treatment. The reported polystyrene-based adsorbents show poor hydrophilicity, long adsorption equilibrium time and poor adsorption effect under acidic conditions. The key to solve this problem is to construct hydrophilic adsorption materials which can be used for acidic wastewater. Herein, a novel polystyrene phosphate resin (PSP) was prepared by phosphorus pentoxide crosslinking reaction. Phosphate ester groups were used as both crosslinking site and chelating site to improve the hydrophilicity and adsorption performance of the adsorbent. The PSP could achieve the optimal adsorption of Pb(ii) at pH = 4 and reach equilibrium in 20 min. Compared with other polystyrene-based adsorbents, the PSP showed faster adsorption rates at lower pH value. The adsorption mechanism was elucidated via Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis combined with density functional theory (DFT) calculations. The PSP is expected to find industrial applications for acidic heavy metal sewage as sustainable and highly effective materials.

Automated summary

This study addresses the challenge of directly adsorbing heavy metal ions from acidic wastewater by constructing a novel polystyrene phosphate resin. The hydrophilic adsorption material showed improved adsorption performance, achieving optimal adsorption of Pb(ii) at pH=4 and reaching equilibrium in 20 minutes. Compared with other polystyrene-based adsorbents, the material exhibited faster adsorption rates at lower pH values. The adsorption mechanism was elucidated through FTIR, XPS analysis, and DFT calculations, providing insights for its industrial applications in acidic heavy metal sewage.