Removal of pyrene from domestic water supply using styrene-based imprinted polymer

Pyrene removal from domestic water supply (DWS) is important due to its mutagenicity, toxicity, and carcinogenicity. Use of molecularly imprinted polymer for pyrene removal is scarce, therefore the study developed polystyrene to complement conventional water treatment methods for pyrene removal. Bulk polymerisation was used to synthesise Pyrene imprinted polystyrene (PIP) and its non-imprinted analogue (NIP). Monoliths were characterised using SEM–EDX, FT-IR, and XRD. Extraction and concentration of pyrene were determined using GC–MS. Adsorption experiments on simulated solutions of pyrene with different concentrations, pH, adsorbent dosage, time, and temperature using PIP and NIP with equilibrium studies were done. Recovery was performed, while pyrene was adsorbed using simulated experiment best conditions. Used PIP and NIP were characterised. Pre-adsorption characterisation confirmed PIP and NIP while post-adsorption showed a clogged surface for NIP, but PIP was pyrene-selective. Pyrene concentration (0.05 mg/L) in DWS was > WHO standard (0.0002 mg/L) with 100% recovery. Adsorption efficiencies ranged from 25–100% and 15–100% with varied parameters for PIP and NIP respectively. However, best adsorption conditions are pH-9, time-1 h, adsorbent dosage-0.8 g, concentration-0.001 mgL−1, and temperature-27 °C with ΔG° (KJmol−1)13.48, 13.70, 13.94 for NIP and 21.24, 21.60, 21.95 for PIP. NIP ΔH° -0.3233 KJmol−1 and ΔS, 0.046 KJmol−1 k−1, while PIP ΔH° -0.0717KJmol−1 and ΔS, 0.071 KJmol−1 k−1. Adsorption fits Langmuir isotherm compared to others with R2 of 0.9140 and 0.9540 for PIP and NIP respectively. The study showed that both PIP and NIP removed pyrene from DWS with excellent efficiencies. However, PIP showed greater selectivity for pyrene removal.