Removal of Selected Pharmaceutical Compounds from Aqueous Media Using Granular Activated Carbon(Gac) Filter

Abstract

Pharmaceutical compounds, including the non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac and ibuprofen, are increasingly detected in water bodies globally, raising serious concerns about their ecological and public health impacts. Because conventional wastewater treatment systems are largely ineffective at removing these persistent micropollutants, low-cost decentralized alternatives are urgently required. This study designed and evaluated a simple, gravity-driven granular activated carbon (GAC) fixed-bed adsorption column for the removal of diclofenac and ibuprofen from synthetic aqueous solutions. The column was constructed from a plastic syringe packed with sequential layers of cotton, gravel and sand. Stock solutions of 1000 mg/L were prepared and diluted to working concentrations of 5 mg/L, 25 mg/L, and 50 mg/L. The effects of initial concentration, solution pH, contact time, and water matrix (distilled versus tap water) on removal efficiency were systematically investigated using UV-Visible spectrophotometry. The GAC column achieved a maximum removal efficiency of 97.1% for diclofenac at 50 mg/L in distilled water. For both target compounds, removal efficiency scaled positively with higher initial concentrations and extended contact times. Adsorption was highly pH-dependent; both compounds exhibited preferential removal under acidic conditions below their respective p�� values, where the molecules exist in an uncharged form that favors hydrophobic interaction with the carbon matrix. Conversely, tap water trials demonstrated a decline in performance due to competitive adsorption from co-existing dissolved matrix substances. Comparatively, diclofenac consistently outperformed ibuprofen across all experimental configurations due to its higher hydrophobicity and stronger interactions with the activated carbon surface. Ultimately, these findings contribute directly to SDG 3 and SDG 6 by demonstrating the technical feasibility of an electricity-free, low-cost approach to emerging contaminant remediation