Preparation and adsorption performance of dopamine-modified crosslinked acylated polystyrene adsorbent

To address the dual environmental pressures of plastic pollution and textile dyeing wastewater, this study employed waste polystyrene foam as a substrate. Functional modification was achieved by introducing 3,3′,4,4’-biphenyltetracarboxylic dianhydride (BPDA) and dopamine (DA). A novel adsorbent, HPB-DA, was successfully prepared with the aim of realizing the synergistic enhancement of solid waste resource recovery and water purification. The physicochemical properties of the material were systematically characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area analysis, and X-ray photoelectron spectroscopy (XPS). Two representative cationic dyes, malachite green and safranine T, were used as target pollutants to evaluate the adsorption performance of HPB-DA. The results showed that the saturated adsorption capacity for malachite green reached 2065.27 ± 21.64 mg/g, and that for safranine T reached 1906.51 ± 26.99 mg/g. Isotherm and kinetic analyses revealed that the adsorption process exhibited heterogeneous multilayer chemisorption characteristics. After multiple regeneration cycles, the material still maintained high removal efficiency, demonstrating excellent regeneration performance. This study not only provided a new strategy for the high-value utilization of waste polystyrene foam, but also opened up a new pathway for material design for the efficient treatment of complex dye wastewater.