Remediation of paracetamol-contaminated water by novel burned hookah charcoal residues via persulfate activation under visible light: Optimization, mechanism, and real pharmaceutical wastewater application

This study presents the utilization of burned hookah charcoal (BHC) sourced from coffee shops waste without thermal treatment as a novel and sustainable activator of persulfate (PS) for the removal of paracetamol (PCM) The characterization revealed the porous structure, the abundance of functional groups, and the high carbon content of the BHC. The BHC exhibited significant activity with hydrogen peroxide, peroxymonosulfate, and persulfate oxidants, achieving the highest PCM removal efficiency (99.91 %) in the (BHC+Light)/PS degradation system within 60 min. The optimization using response surface methodology with central composite design identified the optimal initial concentrations of PCM (11 mg/L), PS (0.1 mM), and BHC (0.15 g/L) to attain a
complete PCM removal and a 75.82 % TOC mineralization efficiency. Under the optimal conditions, the system was checked for degrading other pollutants achieving 91.58, 73.96, 66.03, and 69.4 % removal ratios in the case of tetracycline, atrazine, chlorpyrifos, methylene blue, and bromothymol blue. The BHC demonstrated high stability across five succeeding cycles with a predominant contribution of sulfate and hydroxyl radicals to the degradation system. Further, the degradation system could achieve 83.9 % removal efficiency of PCM in real pharmaceutical wastewater. The suggested degradation system is promising due to the high degradation efficiency in the real and synthetic wastewater as well as the zero cost and sustainability of the BHC which supports
its practical application. Further, this study presents a sustainable approach to the management of BHC.