Rapid removal of polycyclic aromatic hydrocarbons from water using sulfonated mesoporous polymeric adsorbents

Polycyclic aromatic hydrocarbons (PAHs) are potential hazards and are often found in aquatic environments through industrial effluents. Herein, we report sulfonated modified mesoporous thermoplastic polymers to remove potentially carcinogenic PAHs from water rapidly. Mesoporous structures of the thermoplastics (polystyrene, polysulfone, and polycarbonate) were attained using nano-crystallization induced phase separation by flash-freezing route. Sulfonation reactions carried out hydrophilic surface modifications of the polymers. Their ion exchange capacity (IEC) values determined the degree of sulfonation. The sulfonated mesoporous polymers were characterized using Fourier-Transform Infra-Red spectroscopy (FT-IR) for functional groups, Field-Emission Scanning Electron Microscopy (FE-SEM) for mesoporous structures, Brunauer-Emmet-Teller method for specific surface area, and Barrett-Joyner-Halenda method for pore size distributions. The IEC values for the sulfonated mesoporous polymers range from 1.13 – 1.15 × 10^-2 meq. g⁻¹. The sulfonated mesoporous polymers showed high specific surface areas (176–185 m²/g) with pore sizes ranging from 5 nm to 9 nm. The sulfonated mesoporous polymers rapidly adsorb PAHs from nearly saturated water solutions within 60 min with % removal of over 98 %. The adsorbents can also be easily regenerated by simple washing with methanol and are found to be recycled up to 10 cycles with only a marginal reduction in adsorption capacities.