Investigation of the Effect of Waste Polystyrene Modified with AlCl3 and FeCl₃ on BPA Removal and Optimisation with CCD-RSM Model

In this study, waste polystyrene (PS) was chemically modified using aluminium chloride (AlCl₃) and ferric chloride (FeCl₃) to enhance its adsorption performance for the removal of Bisphenol A (BPA) from aqueous solutions. The modification significantly improved the surface characteristics and adsorption capacity of the polystyrene. The removal efficiency of BPA was systematically evaluated under varying experimental conditions, including initial BPA concentration, solution pH, adsorbent dosage, temperature, and contact time. In order to optimise these parameters, central composite design under response surface methodology (CCD-RSM) was applied to design the experiments: The optimised conditions for the AlCl₃-modified polystyrene (PS/AlCl₃) were determined to be; initial concentration 40 mg/L, pH 4, adsorbent amount 0.1 g/L, temperature 40°C and contact time 30 min, while for FeCl₃-modified polystyrene (PS/FeCl₃) were initial concentration 40 mg/L, pH 6.3, adsorbent amount 0.1 g/L, temperature 20°C and contact time 90 min. As a result of the adsorption experiments carried out using the developed materials, it was determined that BPA was effectively removed from the simulated wastewater. The maximum adsorption capacities were determined to be 52.17 mg/g for PS/AlCl₃ and 54.95 mg/g for PS/FeCl₃. The results demonstrate that metal chloride modification is an effective approach for valorising waste
PS in environmental remediation applications.